Absolute frequency synthesis of pulsed coherent light waves through phase-modulation active optical feedback

Area of Science:

• Photonics
• Laser Physics
• Optical Engineering

Background:

• Absolute frequency synthesis is crucial for various scientific applications.
• Existing methods for pulsed coherent lightwaves have limitations in broadband synthesis.
• Precise control over laser frequencies is essential for high-resolution spectroscopy and metrology.

Purpose of the Study:

• To demonstrate a novel method for broadband absolute frequency synthesis of pulsed coherent lightwaves.
• To achieve precise frequency control over a wide spectral range.
• To overcome limitations of current frequency synthesis techniques for pulsed lasers.

Main Methods:

• A novel method employing pulse recirculation within an active optical feedback ring.
• Integration of a delay-line fiber, phase modulator, acousto-optic frequency shifter (AOFS), and a high-finesse Fabry-Perot étalon.
• Strategic design of modulation frequency (F(M)) and AOFS frequency shift (F(AO)) relative to the étalon's free-spectral range and resonant peak width.

Main Results:

• Successful demonstration of broadband absolute frequency synthesis for pulsed coherent lightwaves.
• Achieved frequency synthesis over a 700 GHz span around the master laser's stabilized frequency.
• Observed frequency jumping of recirculating pulses to adjacent étalon peaks with each round trip.

Conclusions:

• The demonstrated method offers a robust approach for broadband absolute frequency synthesis.
• This technique enables precise control and extension of pulsed laser frequencies.
• The findings have implications for advanced optical metrology and spectroscopy.