Simple method for mid-infrared optical frequency comb generation with dynamic offset frequency tuning

Abstract

We present a simple method for mid-infrared optical frequency comb generation based on singlepass femtosecond optical parametric generation that is seeded by a continuous-wave laser. We have implemented the method in a periodically poled lithium niobate crystal that produces a frequency comb tunable across 3325 -4000 nm (2380 -3030 cm -1 ). The method generates a midinfrared (idler) comb with known and stabilized Carrier-Envelope Offset (CEO) frequency without the need to directly detect it. The idler CEO is continuously tunable for almost half of the repetition rate and can be modulated, while maintaining its central frequency. Together with the high output power (up to 700 mW) and low intensity noise (0.018% integrated in 10 Hz -2 MHz bandwidth) this makes the demonstrated mid-infrared frequency comb promising for applications that require precise CEO control, such as dual-comb spectroscopy, cavity enhanced spectroscopy and high harmonic generation.

Efficient carrier-envelope phase tunable mid-infrared frequency combs based on CW-seeded optical parametric generation

“…We would like to note that the bulk and waveguide implementations have excellent versatility in terms of offset frequency adjustments. The offset can be freely tuned, scanned or modulated with metrological precision [4,5]. Our scheme does not have any cavities meaning that the signal/idler comb repetition rate can be freely adjusted by simply changing the pump laser repetition rate.…”

“…In this work we show that the CW seed laser can be phase-locked to a supercontinuum generated by the pump MLL, which guarantees full stabilization of the MIR comb [4,5]. When the signal comb of the OPG is seeded by a such phase-locked CW seed laser (see Fig.…”

“…The bulk system is realized using fanout crystal structure making the idler comb easily tunable across 3325 -4000 nm (2380 -3030 cm -1 ). For more details on the bulk system as well as on waveguide see [4] and [5], respectively.…”

Supplementary document for Mid-infrared frequency comb with 25 pJ threshold via CW-seeded optical parametric generation in nonlinear waveguide - 5346785.pdf

“…In addition to applying a waveguide crystal instead of a bulk crystal for OPG, we have improved the experimental setup compared to our previous reports [1] by eliminating optical fibers in the CW seed laser phase-locking procedure. In Fig.…”