• OT: Atomic nucleus excited with laser: a breakthrough after decades

    From Jan Panteltje@21:1/5 to All on Tue May 7 05:06:12 2024
    Atomic nucleus excited with laser: a breakthrough after decades
    https://www.sciencedaily.com/releases/2024/04/240429103045.htm
    The 'thorium transition', which has been sought after for decades,
    has now been excited for the first time with lasers.
    This paves the way for revolutionary high precision technologies, including nuclear clocks

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Martin Brown@21:1/5 to Jan Panteltje on Tue May 7 14:35:12 2024
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
    https://www.sciencedaily.com/releases/2024/04/240429103045.htm
    The 'thorium transition', which has been sought after for decades,
    has now been excited for the first time with lasers.
    This paves the way for revolutionary high precision technologies, including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?

    --
    Martin Brown

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Martin Brown on Tue May 7 16:26:27 2024
    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
      https://www.sciencedaily.com/releases/2024/04/240429103045.htm
       The 'thorium transition', which has been sought after for decades,
       has now been excited for the first time with lasers.
       This paves the way for revolutionary high precision technologies,
    including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to '''newspam'''@nonad.co.uk on Tue May 7 07:41:54 2024
    On Tue, 7 May 2024 14:35:12 +0100, Martin Brown
    <'''newspam'''@nonad.co.uk> wrote:

    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
    https://www.sciencedaily.com/releases/2024/04/240429103045.htm
    The 'thorium transition', which has been sought after for decades,
    has now been excited for the first time with lasers.
    This paves the way for revolutionary high precision technologies, including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?

    "the correct energy of the thorium transition was hit exactly, the
    thorium nuclei delivered a clear signal for the first time. "

    I wonder what that signal was.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to John Larkin on Tue May 7 17:48:23 2024
    On 5/7/24 16:41, John Larkin wrote:
    On Tue, 7 May 2024 14:35:12 +0100, Martin Brown
    <'''newspam'''@nonad.co.uk> wrote:

    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
    https://www.sciencedaily.com/releases/2024/04/240429103045.htm
    The 'thorium transition', which has been sought after for decades,
    has now been excited for the first time with lasers.
    This paves the way for revolutionary high precision technologies, including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?

    "the correct energy of the thorium transition was hit exactly, the
    thorium nuclei delivered a clear signal for the first time. "

    I wonder what that signal was.


    It says so in the paper: Fluorescent UV light.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to John Larkin on Wed May 8 01:44:10 2024
    On 8/05/2024 12:41 am, John Larkin wrote:
    On Tue, 7 May 2024 14:35:12 +0100, Martin Brown
    <'''newspam'''@nonad.co.uk> wrote:

    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
    https://www.sciencedaily.com/releases/2024/04/240429103045.htm
    The 'thorium transition', which has been sought after for decades,
    has now been excited for the first time with lasers.
    This paves the way for revolutionary high precision technologies, including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?

    "the correct energy of the thorium transition was hit exactly, the
    thorium nuclei delivered a clear signal for the first time. "

    I wonder what that signal was.

    Presumably the thorium nucleus absorbs the photon, then remits it when
    it decays back to the ground state, presumably not in the original
    direction.

    The life-time of the excited state is 630sec when the thorium atoms are presented in a CaF2 crystal. It you hit the crystal briefly with
    precisely the right frequency, then observed a slowly decaying
    fluorescent signal at the same wavelength, you'd have a clear enough
    signal (though not all that much of it).

    In fact they gradually stepped up the exciting beam wavelength from
    148.2 to 150.3 nm.,and observed a fluorescence peak at around 148.38 nm.

    The observed central wavelength of the nuclear transition amounted to 148.3821(5) nm, equivalent to a transition energy of 8.35574(3) eV,
    which was consistent with the 1 σ-uncertainty of the value reported in radiative-decay experiments but with 800-fold improved precision.

    The implication is that their excitation wavelength wasn't all that
    precise either and will need to be made even more precise for nuclear
    clock work.

    I wonder if they could use it to get Doppler shifts from continental drift?

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to jeroen@nospam.please on Tue May 7 12:17:24 2024
    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
      <https://www.sciencedaily.com/releases/2024/04/240429103045.htm>
       The 'thorium transition', which has been sought after for decades,
       has now been excited for the first time with lasers.
       This paves the way for revolutionary high precision technologies,
    including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to electromagnetic radiation. This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to All on Tue May 7 16:36:04 2024
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
      <https://www.sciencedaily.com/releases/2024/04/240429103045.htm>
       The 'thorium transition', which has been sought after for decades,
       has now been excited for the first time with lasers.
       This paves the way for revolutionary high precision technologies,
    including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to >electromagnetic radiation. This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to John Larkin on Wed May 8 15:36:32 2024
    On 8/05/2024 9:36 am, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net> wrote:
    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman <jeroen@nospam.please> wrote:
    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
      <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>    The 'thorium transition', which has been sought after for decades, >>>>>    has now been excited for the first time with lasers.
       This paves the way for revolutionary high precision technologies, >>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to
    electromagnetic radiation. This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Probably not. The technique to used to generate very precise laser
    wavelengths does seem to be difficult and demanding to work with.

    The few people who can do it will have a field day, but they will only
    generate a few papers - it takes time to do the work and more time to
    write it up.
    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    Nuclear energy levels aren't "resonances" but quantum states, and the transition between them isn't a "resonance" either, though one can talk
    about the kind of resonance that would behave in a similar way.

    --
    Bill Sloman, Sydney

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to John Larkin on Wed May 8 10:44:05 2024
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
      <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>    The 'thorium transition', which has been sought after for decades, >>>>>    has now been excited for the first time with lasers.
       This paves the way for revolutionary high precision technologies, >>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to
    electromagnetic radiation. This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.


    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Martin Brown@21:1/5 to Jeroen Belleman on Wed May 8 12:52:27 2024
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
       <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>     The 'thorium transition', which has been sought after for
    decades,
        has now been excited for the first time with lasers.
        This paves the way for revolutionary high precision technologies, >>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to
    electromagnetic radiation.  This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to
    double optical frequencies but how do you halve or quarter them?

    --
    Martin Brown

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to Martin Brown on Wed May 8 15:12:43 2024
    On 5/8/24 13:52, Martin Brown wrote:
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
       <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>>     The 'thorium transition', which has been sought after for >>>>>>> decades,
        has now been excited for the first time with lasers.
        This paves the way for revolutionary high precision
    technologies,
    including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to
    electromagnetic radiation.  This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to double optical frequencies but how do you halve or quarter them?


    Something involving optical frequency combs might work.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to '''newspam'''@nonad.co.uk on Wed May 8 07:27:42 2024
    On Wed, 8 May 2024 12:52:27 +0100, Martin Brown
    <'''newspam'''@nonad.co.uk> wrote:

    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
       <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>>     The 'thorium transition', which has been sought after for
    decades,
        has now been excited for the first time with lasers.
        This paves the way for revolutionary high precision technologies, >>>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to
    electromagnetic radiation.  This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the >continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to >double optical frequencies but how do you halve or quarter them?

    I don't know if there is a way to divide a lightwave-sorts of
    frequency down into the electronic domain. Much less gamma ray
    frequencies.

    Even the small differences cited here are still optical.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Martin Brown on Wed May 8 14:45:42 2024
    Martin Brown <'''newspam'''@nonad.co.uk> wrote:
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades
    ÿÿ <https://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>> ÿÿÿ The 'thorium transition', which has been sought after for
    decades,
    ÿÿÿ has now been excited for the first time with lasers.
    ÿÿÿ This paves the way for revolutionary high precision technologies, >>>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to
    electromagnetic radiation.ÿ This will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to double optical frequencies but how do you halve or quarter them?


    You mix with an optical frequency comb, possibly with an intermediate
    locking step.

    The cleverest part of the Hall-Haensch comb generator is that you can lock
    the blue end of the comb to the second harmonic of the red end, one tooth
    off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    That 0.002 Hz line width is going to make the locker design entertaining.

    Cheers

    Phil Hobbs
    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed May 8 11:22:25 2024
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Martin Brown <'''newspam'''@nonad.co.uk> wrote:
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades >>>>>>>> ?tps://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>>> ?e 'thorium transition', which has been sought after for
    decades,
    ?s now been excited for the first time with lasers.
    ?is paves the way for revolutionary high precision technologies, >>>>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to >>>>> electromagnetic radiation.? will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the
    continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to
    double optical frequencies but how do you halve or quarter them?


    You mix with an optical frequency comb, possibly with an intermediate
    locking step.

    The cleverest part of the Hall-Haensch comb generator is that you can lock >the blue end of the comb to the second harmonic of the red end, one tooth >off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    That 0.002 Hz line width is going to make the locker design entertaining.

    Yes, it will be combs and etalons.

    I'm waiting for a flood on the Time Nuts reflector.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Gerhard Hoffmann@21:1/5 to All on Wed May 8 18:48:29 2024
    Am 08.05.24 um 17:22 schrieb Joe Gwinn:

    That 0.002 Hz line width is going to make the locker design entertaining.

    Yes, it will be combs and etalons.

    I'm waiting for a flood on the Time Nuts reflector.

    Joe Gwinn

    I have posted already a pointer to this thread here on time nuts.

    :-) Gerhard dk4xp

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From John Larkin@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed May 8 10:11:14 2024
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Martin Brown <'''newspam'''@nonad.co.uk> wrote:
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades >>>>>>>> ?tps://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>>> ?e 'thorium transition', which has been sought after for
    decades,
    ?s now been excited for the first time with lasers.
    ?is paves the way for revolutionary high precision technologies, >>>>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious.
    No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to >>>>> electromagnetic radiation.? will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two
    close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the
    continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to
    double optical frequencies but how do you halve or quarter them?


    You mix with an optical frequency comb, possibly with an intermediate
    locking step.

    The cleverest part of the Hall-Haensch comb generator is that you can lock >the blue end of the comb to the second harmonic of the red end, one tooth >off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    That 0.002 Hz line width is going to make the locker design entertaining.

    Cheers

    Phil Hobbs

    Is there any way to divide a lightwave down into the electronic
    frequency domain?

    Rubidium clocks use an indirect way that doesn't actually divide.

    --- SoupGate-Win32 v1.05
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  • From Jeroen Belleman@21:1/5 to John Larkin on Wed May 8 23:08:35 2024
    On 5/8/24 19:11, John Larkin wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Martin Brown <'''newspam'''@nonad.co.uk> wrote:
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net> >>>>> wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades >>>>>>>>> ?tps://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>>>> ?e 'thorium transition', which has been sought after for
    decades,
    ?s now been excited for the first time with lasers.
    ?is paves the way for revolutionary high precision technologies, >>>>>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious. >>>>>>> No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to >>>>>> electromagnetic radiation.? will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two >>>>> close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the
    continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to >>> double optical frequencies but how do you halve or quarter them?


    You mix with an optical frequency comb, possibly with an intermediate
    locking step.

    The cleverest part of the Hall-Haensch comb generator is that you can lock >> the blue end of the comb to the second harmonic of the red end, one tooth
    off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    That 0.002 Hz line width is going to make the locker design entertaining.

    Cheers

    Phil Hobbs

    Is there any way to divide a lightwave down into the electronic
    frequency domain?

    Not to my knowledge. The usual way is down-mixing. The optical
    frequency comb provides a way to generate an accurately known
    optical local oscillator, so to speak.

    Jeroen Belleman

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  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Wed May 8 17:57:05 2024
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you can lock >the blue end of the comb to the second harmonic of the red end, one tooth >off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to John Larkin on Wed May 8 23:25:55 2024
    John Larkin <jjSNIPlarkin@highNONOlandtechnology.com> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Martin Brown <'''newspam'''@nonad.co.uk> wrote:
    On 08/05/2024 09:44, Jeroen Belleman wrote:
    On 5/8/24 01:36, John Larkin wrote:
    On Tue, 07 May 2024 12:17:24 -0400, Joe Gwinn <joegwinn@comcast.net> >>>>> wrote:

    On Tue, 7 May 2024 16:26:27 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 5/7/24 15:35, Martin Brown wrote:
    On 07/05/2024 06:06, Jan Panteltje wrote:
    Atomic nucleus excited with laser: a breakthrough after decades >>>>>>>>> ?tps://www.sciencedaily.com/releases/2024/04/240429103045.htm> >>>>>>>>> ?e 'thorium transition', which has been sought after for
    decades,
    ?s now been excited for the first time with lasers.
    ?is paves the way for revolutionary high precision technologies, >>>>>>>>> including nuclear clocks

    I wonder what the Q value for stimulated nuclear emission is?


    They state a centre frequency of roughly 2 PHz and a decay time
    of 630s, which would put the Q in the 1e19 ballpark. Prodigious. >>>>>>> No wonder it was hard to find.

    The Time guys have been looking for this forever, so to speak.

    It's the only atomic kernel transition with any degree of coupling to >>>>>> electromagnetic radiation.? will be orders of magnitude better
    than such as lattice clocks.

    There will be a flood of papers.

    Joe Gwinn

    They aren't tuning to a resonance, but to the difference between two >>>>> close resonances.

    The current definition of the second uses something similar: Some
    hyperfine resonance of cesium. Normal resonances are in the optical
    domain, but hyperfine ones are RF.

    Which puts them in the RF frequency domain where counting cycles of the
    continuous sine reference waveform is relatively easy.

    Likewise for H-maser another favourite local time reference signal.

    In nuclei, normal transitions are in the gamma domain, and
    hyperfine ones are in the domain of optics. It's just a change
    of scale, if you will.

    Although there will be some big practical difficulties counting cycles
    of a waveform at 8eV which is up into the UV. What is the current
    highest frequency that a semiconductor divider is capable of accepting?

    I know that there are some optical logic circuits about but how capable
    are they at near UV light?

    You can't mix this thing down without losing its fidelity. I know how to >>> double optical frequencies but how do you halve or quarter them?


    You mix with an optical frequency comb, possibly with an intermediate
    locking step.

    The cleverest part of the Hall-Haensch comb generator is that you can lock >> the blue end of the comb to the second harmonic of the red end, one tooth
    off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    That 0.002 Hz line width is going to make the locker design entertaining.

    Cheers

    Phil Hobbs

    Is there any way to divide a lightwave down into the electronic
    frequency domain?

    Rubidium clocks use an indirect way that doesn't actually divide.



    Not really. There are optical parametric oscillators, but their phase noise
    is horrible by comparison. A 1-cm-long crystal produces a nice tunable
    output, but its line width will be c/1cm wide.

    Degenerate OPOs exist, whose signal and idler are at the same frequency,
    but I believe their phase noise is not that different—there’s an additional degree of freedom in the signal/idler relationship that would have to be constrained somehow.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

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  • From Phil Hobbs@21:1/5 to Joe Gwinn on Wed May 8 23:35:19 2024
    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you can lock >> the blue end of the comb to the second harmonic of the red end, one tooth
    off, and lock the difference to a good reference. Then all the teeth have
    the same phase noise as the reference oscillator, rather than 20 log(600
    THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn


    Don’t have the reference handy, but the basic idea is to use a modelocked system Ti:sapphire laser at 750 nm to generate ~100-fs pulses, then use fiber/grating pulse compression to bring that down to a few femtoseconds, followed by a holey fiber to broaden the spectrum to more than an octave.

    Jan Hall is one of the best instruments guys ever.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

    --- SoupGate-Win32 v1.05
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  • From Joe Gwinn@21:1/5 to pcdhSpamMeSenseless@electrooptical. on Thu May 9 14:26:12 2024
    On Wed, 8 May 2024 23:35:19 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you can lock >>> the blue end of the comb to the second harmonic of the red end, one tooth >>> off, and lock the difference to a good reference. Then all the teeth have >>> the same phase noise as the reference oscillator, rather than 20 log(600 >>> THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn


    Don’t have the reference handy, but the basic idea is to use a modelocked >system Ti:sapphire laser at 750 nm to generate ~100-fs pulses, then use >fiber/grating pulse compression to bring that down to a few femtoseconds, >followed by a holey fiber to broaden the spectrum to more than an octave.

    Jan Hall is one of the best instruments guys ever.

    I'll poke around his publications. He's bound to have left tracks.

    Thanks,

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to All on Thu May 9 17:56:06 2024
    On Thu, 09 May 2024 14:26:12 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Wed, 8 May 2024 23:35:19 -0000 (UTC), Phil Hobbs ><pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you can lock >>>> the blue end of the comb to the second harmonic of the red end, one tooth >>>> off, and lock the difference to a good reference. Then all the teeth have >>>> the same phase noise as the reference oscillator, rather than 20 log(600 >>>> THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn


    Don’t have the reference handy, but the basic idea is to use a modelocked >>system Ti:sapphire laser at 750 nm to generate ~100-fs pulses, then use >>fiber/grating pulse compression to bring that down to a few femtoseconds, >>followed by a holey fiber to broaden the spectrum to more than an octave.

    Jan Hall is one of the best instruments guys ever.

    I'll poke around his publications. He's bound to have left tracks.

    The best source I've found so far is:

    Optical and microwave metrology with frequency combs
    Tara Fortier
    NIST Time and Frequency Division
    Oct 10, 2023

    And

    COMMUNICATIONS PHYSICS | (2019)2:153 | https://doi.org/10.1038/s42005-019-0249-y | www.nature.com/commsphys

    These are open access.

    Joe Gwinn

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  • From Phil Hobbs@21:1/5 to Joe Gwinn on Thu May 9 21:35:36 2024
    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 23:35:19 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you can lock >>>> the blue end of the comb to the second harmonic of the red end, one tooth >>>> off, and lock the difference to a good reference. Then all the teeth have >>>> the same phase noise as the reference oscillator, rather than 20 log(600 >>>> THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn


    DonÂ’t have the reference handy, but the basic idea is to use a modelocked >> system Ti:sapphire laser at 750 nm to generate ~100-fs pulses, then use
    fiber/grating pulse compression to bring that down to a few femtoseconds,
    followed by a holey fiber to broaden the spectrum to more than an octave.

    Jan Hall is one of the best instruments guys ever.

    I'll poke around his publications. He's bound to have left tracks.

    Thanks,

    Joe Gwinn


    His given name is John L.

    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

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  • From Glen Walpert@21:1/5 to Phil Hobbs on Thu May 9 22:56:19 2024
    On Thu, 9 May 2024 21:35:36 -0000 (UTC), Phil Hobbs wrote:

    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 23:35:19 -0000 (UTC), Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you
    can lock the blue end of the comb to the second harmonic of the red
    end, one tooth off, and lock the difference to a good reference.
    Then all the teeth have the same phase noise as the reference
    oscillator, rather than 20 log(600 THz / 100 MHz) ~ 138 dB worse,
    as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn


    DonÂ’t have the reference handy, but the basic idea is to use a
    modelocked system Ti:sapphire laser at 750 nm to generate ~100-fs
    pulses, then use fiber/grating pulse compression to bring that down to
    a few femtoseconds, followed by a holey fiber to broaden the spectrum
    to more than an octave.

    Jan Hall is one of the best instruments guys ever.

    I'll poke around his publications. He's bound to have left tracks.

    Thanks,

    Joe Gwinn


    His given name is John L.

    His Nobel Prize lecture is an interesting read:

    https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.78.1279

    PDF Free to Read:

    https://journals.aps.org/rmp/pdf/10.1103/RevModPhys.78.1279

    Nobel Lecture: Defining and measuring optical frequencies*
    John L. Hall
    Rev. Mod. Phys. 78, 1279 – Published 17 November 2006

    *The 2005 Nobel Prize for Physics was shared by Roy J. Glauber, John L.
    Hall, and Theodor W. Hänsch. This lecture is the text of Dr. Hall’s
    address on the occasion of the award.

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  • From Joe Gwinn@21:1/5 to All on Thu Jul 4 19:06:34 2024
    On Thu, 09 May 2024 17:56:06 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Thu, 09 May 2024 14:26:12 -0400, Joe Gwinn <joegwinn@comcast.net>
    wrote:

    On Wed, 8 May 2024 23:35:19 -0000 (UTC), Phil Hobbs >><pcdhSpamMeSenseless@electrooptical.net> wrote:

    Joe Gwinn <joegwinn@comcast.net> wrote:
    On Wed, 8 May 2024 14:45:42 -0000 (UTC), Phil Hobbs
    <pcdhSpamMeSenseless@electrooptical.net> wrote:

    [snip]

    The cleverest part of the Hall-Haensch comb generator is that you can lock
    the blue end of the comb to the second harmonic of the red end, one tooth >>>>> off, and lock the difference to a good reference. Then all the teeth have >>>>> the same phase noise as the reference oscillator, rather than 20 log(600 >>>>> THz / 100 MHz) ~ 138 dB worse, as it would be in a multiplier.

    Hmm. It had to be true, but I never connected the dots there. What
    is mechanism by which this is achieved? References?

    Thanks,

    Joe Gwinn


    Don’t have the reference handy, but the basic idea is to use a modelocked >>>system Ti:sapphire laser at 750 nm to generate ~100-fs pulses, then use >>>fiber/grating pulse compression to bring that down to a few femtoseconds, >>>followed by a holey fiber to broaden the spectrum to more than an octave. >>>
    Jan Hall is one of the best instruments guys ever.

    I'll poke around his publications. He's bound to have left tracks.

    The best source I've found so far is:

    Optical and microwave metrology with frequency combs
    Tara Fortier
    NIST Time and Frequency Division
    Oct 10, 2023

    And

    COMMUNICATIONS PHYSICS | (2019)2:153 | >https://doi.org/10.1038/s42005-019-0249-y | www.nature.com/commsphys

    These are open access.

    Joe Gwinn

    The gory details are in:
    "Optical frequency synthesis based on mode-locked lasers",
    Rev. Sci. Instrum., Vol. 72, No. 10, October 2001
    Cundiff, Ye, and Hall
    DOI: 10.1063/1.1400144

    ResearchGate has it.

    Joe Gwinn

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