Broadband phase-coherent optical frequency synthesis with actively linked Ti:sapphire and Cr:forsterite femtosecond lasers

Abstract

We link the output spectra of a Ti.sapphire and a Cr .forst erite femtosecond laser phase coher ently to form a continuous frequ ency comb with a wavelength coverage of O.57-1.45 μm a t power levels of 1 nW to 40 /LWper frequ ency mode. To achieve this, the la ser repetition rates and the carri er- envelope offset frequ encies are phase locked to ea ch other . The coher ence tim e between the individual components of the two combs is 40 μS. The timing jitter between the laser s is 20 fs. The combined frequ ency comb is self-refere nced for access to it s over all offset frequency. We report the first demonstration to our knowledge of an extremely broadband and continuous, high-power ed and phase-coherent frequ ency comb from two femtosecond la ser s with different gain media.