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Incoming links: Optical frequency comb
Comb self-referencing 2026-10-18
Comb self-referencing compares two parts of one optical frequency comb. Coherent broadening supplies an octave, a factor of two in frequency. Second-harmonic generation doubles a red tooth; a photodiode detects its beat with an original blue tooth.[ref]
Introduction to Self-reference Comb Laser by Comblaser Laboratory, Department of Physics, National Central University. Introduction to Self-reference Comb Laser, Fig.1 explanation
Applying the tooth formula givesThe doubled branch carries , while the original high-frequency branch carries : their difference retains exactly one offset.
Read the tooth spacing and offset through separate electronic signals
. Original functional comb self-referencing scheme. Solid optical paths bring doubled red light and original blue light to one detector. Dashed electronic paths connect both readouts to a common reference and feedback controls. Actuators can affect both parameters. Details.
The displayed difference uses the order doubled tooth minus original tooth. An ordinary electronic frequency counter returns a nonnegative beat magnitude; spectral selection and known electronic shifts must identify whether it represents , , or a shifted version. Coherent broadening, overlapping photon polarization, spatial alignment and temporal overlap are required. Merely producing a broad patch of colored light does not establish a usable offset signal.
David J. Jones 2026-10-18
A physicist working on optical frequency combs.[ref]
Professional profile of David J. Jones. Independent professional identity
Nobel Prize in Physics in 2005 2026-10-18
One half went to Roy J. Glauber for contributions to the quantum theory of optical coherence. One quarter each went to John L. Hall and Theodor W. Hänsch for developing precision laser spectroscopy, including the optical frequency comb technique.[ref]
The Nobel Prize in Physics 2005 by Nobel Prize Outreach. Individual official 2005 summary: Glauber one half for quantum optical coherence; Hall and Hänsch one quarter each for laser-based precision spectroscopy including frequency combs.
Optical frequency comb 2026-10-18
An optical frequency comb has evenly spaced optical spectral lines, or teeth. A mode-locked laser supplies short optical pulses at repetition frequency , the tooth spacing. The carrier-envelope offset frequency positions the whole ruler:Only teeth within the emitted optical spectrum are present; the extrapolated intercept need not be an emitted tooth.[ref]
Passion for Precision by Theodor W. Hänsch. Passion for Precision, p.157: tooth relation
The achievement associated with John L. Hall and Theodor W. Hänsch is a practical bridge between optical frequencies and countable electronic frequencies. Instead of constructing a separate chain of lasers for each optical measurement, a broad comb supplies many linked reference teeth. Stable lasers, short optical pulses and strong nonlinear optics in optical fibers came together around 1999–2000.[ref]
Nobel Lecture: Defining and measuring optical frequencies by John L. Hall. Nobel Lecture: Defining and measuring optical frequencies, pp.1288–1291: chains and comb development
Scott A. Diddams 2026-10-18
A physicist working on optical frequency combs.[ref]
Professional profile of Scott A. Diddams. Independent professional identity