Yuwei Jin

Two-crystal mid-infrared optical parametric oscillator for absorption and dispersion dual-comb spectroscopy

We present a femtosecond optical parametric oscillator (OPO) containing two magnesium-doped periodically poled lithium niobate crystals in a singly resonant ring cavity, pumped by two mode-locked Yb-fiber lasers. As such, the OPO generates two idler combs (up to 220 mW), covering a wavelength range from 2.7 to 4.2 μm, from which a mid-infrared dual-comb Fourier transform spectrometer is constructed. By detecting the heterodyning signal between the two idler beams a full broadband spectrum of a molecular gas can be observed over 250  cm(-1) within 70 μs with a spectral resolution of 15 GHz. The absorption and dispersion spectra of acetylene and methane have been measured around 3000  cm(-1), indicating that this OPO represents an ideal broadband mid-infrared source for fast chemical sensing.

Broadly, independent-tunable, dual-wavelength mid-infrared ultrafast optical parametric oscillator

We demonstrate a two-crystal mid-infrared dual-wavelength optical parametric oscillator, synchronously pumped by a high power femtosecond Yb:fiber laser. The singly-resonant ring cavity, containing two periodically poled lithium niobate crystals, is capable of generating two synchronized idler wavelengths, independently tunable over 30 THz in the 2.9 - 4.2 μm wavelength region, due to the cascaded quadratic nonlinear effect. The independent tunability of the two idlers makes the optical parametric oscillator a promising source for ultrafast pulse generation towards the THz wavelength region, based on different frequency generation. In addition, the observed frequency doubled idler within the crystal indicates the possibility to realize a broadband optical self-phase locking between pump, signal, idler and higher order generated parametric lights.

Dual-frequency comb spectroscopy: A digital solution for coherent averaging

We present a dual-comb spectrometer in which a new digital solution allows long-time coherent averaging of molecular spectra without spectral distortion even when the combs are free-running and subject to frequency drifting and jittering.

Measurement of H 2 O and OH in a flame by optical frequency comb spectroscopy

We measure broadband H2O and OH spectra in a flame using near-infrared cavity-enhanced Fourier transform optical frequency comb spectroscopy, we retrieve temperature and OH concentration, and compare water spectra to an improved line list.

Tunable High Repetition Rates Femtosecond Pulses from an Optical Parametric Oscillator

A tunable high repetition rates source is achieved from a femtosecond synchronously pump OPO cavity. Pulses from several MHz to 1 THz are generated in the C- and L-bands of the telecom wavelength region.

Mid-infrared two-color optical parametric oscillator across a 30 THz spectral range

We present a broadband tunable two-color optical parametric oscillator. The single cavity is capable of generating two idlers that are separated up to 30 THz. Fourier transform spectroscopy with this source has been demonstrated for multi-gas detection.

An Optical Parametric Oscillator Based On Two PPNL Crystals for Mid-Infrared Dual-Comb Spectroscopy

We present a mid-infrared optical-parametric-oscillator (OPO) based on two PPNL crystals for dual-comb spectroscopy. The OPO cavity offers several advantages to generate two mid-infrared beams for high resolution spectra between 2.5 and 4.5 µm.

Dual frequency combs fourier transform spectrometer in mid-infrared region based on femtosecond optical parametric oscillators

To avoid disadvantages of the traditional Fourier transform spectrometer and achieve fast acquisition time for on-line measurement, dual frequency combs spectroscopy was demonstrated. Dual frequency combs cavity-enhanced spectroscopy has been achieved in the near-infrared, and nowadays, this technique has been implemented in the spectral region of 2.4 μm, offering a 70 nm spectral coverage at full width at half maximum.

Optical parametric oscillator based detection of hydrogen cyanide for bio-medical applications

There is an increasing interest in the development of sensitive and selective methods to detect hydrogen cyanide (HCN) from biological samples [1,2]. Several studies have been conducted with different types of matrices, such as water, soil, air, exhaled breath and food. Different methods have been used to monitor HCN; however, most of them are complex and involve a large amount of manipulations of samples or the use of solvents. Additionally, they feature slow response time (in the order of minutes) and therefore hardly any continuous gas monitoring over days or weeks can be performed. In most cases the reported detection limit is in the part-per-million volume (ppmv) mixing range, which is not sufficient to perform trace emission experiments on small amounts of biological samples. Thus, the development of more sensitive methods able of measuring ppbv (parts-per-billion volume) level of HCN, becomes very motivated.

Mid-infrared frequency comb based-on low threshold optical parametric oscillator

Summary form only given. Over the last decade, Frequency combs (FCs) have triggered new attractive methods for absorption spectroscopy and have been successfully implemented in the visible and near-infrared spectral region. When combined with Fourier transform spectrometers, it shows remarkable advantages of large spectral bandwidth, high spectral resolution and high sensitivity. For trace gas detection, extending the wavelength of FCs in the mid-infrared region is beneficial, as many molecules exhibit here their strongest absorption lines. Several methods have been proposed to extend FCs in the mid-infrared region [1]. Among those methods, Optical Parametric Oscillators (OPOs) are used as efficient light converters [2].Here we report on a FC-based single resonant OPO for the 3.5 μm region with low threshold power. The designed OPO consists of a 1 mm-long periodically polled MgO-doped PPLN crystal pumped by an Yb-fiber laser. A schematic of the setup is depicted in Fig. 1a. The pump laser is a femtosecond laser delivering up to 2 W, 80 fs optical pulses at 1.04 μm. The repetition rate of the laser is stabilized by a frequency generator at 90 MHz. The OPO cavity is designed with a 6-mirrors linear cavity. To compensate the light dispersion of the cavity introduced by the crystal and the curved mirrors, the 1.7 m long linear cavity is folded with chirped mirrors. One of the chirped mirrors is mounted on a piezo actuator to stabilize the cavity length.