Combination of a continuous-wave optical parametric oscillator and a femtosecond frequency comb for optical frequency metrology

Abstract

We combine a tunable continuous-wave optical parametric oscillator and a femtosecond Ti:Sapphire laser frequency comb to provide a phase-coherent bridge between the visible and mid-infrared spectral ranges. As a first demonstration of this new technique we perform a direct frequency comparison between an iodine stabilized Nd:YAG laser at 1064 nm and an infrared methane optical frequency standard at 3.39 µm. Accepted for publication in Optics Letters c 2005 Optical Society of AmericaContinuous-wave optical parametric oscillators (cwOPOs) are one of the most promising infrared (IR) laser sources for high-resolution molecular spectroscopy.

High performance iodine frequency reference for tests of the LISA laser system

“…This has to be improved for better performance of the long term stability of the iodine reference. A short term stability of 8·10 -15 at 1 s averaging time has been determined from a data record of 10 s. The long term stability shows a flicker floor around 1·10 -14 at averaging times from 1 s to 500 s with a minimum of 8·10 -15 at 100 s. It is worth to mention, that the implementation of the intensity noise canceling detection scheme and the three-fold pass through the iodine cell have led to an improvement of the short term stability of the present iodine standard of about two orders of magnitude with respect to the precursor setup investigated previously [13].…”

Frequency-comb-referenced molecular spectroscopy in the mid-infrared region

“…The basic idea is similar to that previously reported by Kovalchuk et al for frequency comparison between a 3:39 μm CH 4 -stabilized HeNe laser and a 532 nm I 2 =Nd:YAG laser [9]. Kovalchuk et al used non-phase-matched components of a pumpresonant, singly resonant OPO [10] to bridge the two wavelength regions [9]. Our solution relies on the use of a cw optical parametric oscillator that is truly singly resonant (SRO).…”

“…The basic idea common to all such techniques is to use nonlinear optics to link a cw mid-IR beam to a visible/near-IR OFC and hence further to a microwave frequency standard. This can be done by difference frequency generation [6,7], sum-frequency mixing [8], or by using a cw optical parametric oscillator that is pumped with a near-IR laser [9]. These techniques have been used to measure absolute frequencies of some molecular transitions between 3 and 5 μm [6][7][8].…”

Referencing femtosecond laser frequency combs to a He-Ne/CH<inf>4</inf> optical frequency standard

“…The first methane optical clock developed in our group is set up on a fs Ti:Sapphire comb referenced to the frequency of a He-Ne/CH 4 standard. This clock was involved in a direct frequency comparison with an iodine stabilized frequency doubled Nd:YAG laser at 532 nm, which was reported previously [3], [4].…”