Robust, frequency-stable and accurate mid-IR laser spectrometer based on frequency comb metrology of quantum cascade lasers up-converted in orientation-patterned GaAs

Summary form only given. The mid-infrared (MIR) spectral range (λ > 4.5 μm) is of interest in both applied and fundamental spectroscopy, for diverse applications such as trace gas detection and molecular frequency metrology. Approaches currently pursued for enabling MIR spectroscopy with accurate frequency control are based on generating the desired radiation by down-conversion, either of frequency combs or of cw near-infrared (NIR) sources. Such downconverted sources, however, typically have low power per frequency interval.Upconversion of the MIR radiation to the NIR range in principle provides a way to take advantage of the frequency measurement capabilities of the standard Erbium-fiber frequency comb. In previous work, the spectral range λ