Amir Khodabakhsh

Surpassing the path-limited resolution of Fourier-transform spectrometry with frequency combs

We overcome the resolution limit of Fourier-transform spectrometry and measure instrumental line-shape-free broadband molecular spectra with lines narrower than the optical path-limited resolution. ...

Fourier transform and Vernier spectroscopy using an optical frequency comb at 3–5.4 μm

We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH4 at 3.3 μm and NO at 5.25 μm, the latter for the first time with comb spectroscopy, and we detect atmospheric species (CH4, CO, CO2, and H2O) in air in the signal and idler ranges. Multiline fitting yields minimum detectable concentrations of 10-20  ppb Hz-1/2 for CH4, NO, and CO. For the first time in the mid-infrared, we perform CF-VS using an enhancement cavity, a grating, and a single detector, and we measure the absorption spectrum of CH4 and H2O in ambient air at ∼3.3  μm, reaching a 40 ppb concentration detection limit for CH4 in 2 ms.We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 {\mu}m range and two detection methods, a Fourier transform spectrometer (FTS) and a Vernier spectrometer. Using the FTS with a multipass cell we measure high-precision broadband absorption spectra of CH

Noise-immune cavity-enhanced optical frequency comb spectroscopy.

_4

Cavity-enhanced optical frequency comb spectroscopy of high-temperature H2O in a flame

and NO at ~3.3 {\mu}m and ~5.2 {\mu}m, respectively, and of atmospheric species (CH

Optical frequency comb Fourier transform spectroscopy with sub-nominal resolution and precision beyond the Voigt profile

_4

An experimental water line list at 1950 K in the 6250–6670 cm−1 region

, CO, CO

Sensitive and broadband measurement of dispersion in a cavity using a Fourier transform spectrometer with kHz resolution

_2

Sensitive Spectroscopy of Acetone Using a Widely Tunable External-Cavity Quantum Cascade Laser

and H

Laser spectroscopy for breath analysis : towards clinical implementation

_2

Faraday rotation spectroscopy using an optical frequency comb

O) in air in the signal and idler wavelength range. The figure of merit of the system is on the order of 10