Fast, accurate measurement of the methane mixing ratio in natural air samples using a compact solid-state 3.4-μm difference-frequency spectrometer is reported. The spectrometer employed bulk periodically poled lithium niobate (PPLN) pumped by a solitary diode laser at 808 nm and a diode-pumped monolithic ring Nd:YAG laser at 1064 nm, and a 300 cm3 volume multi-pass absorption cell with an 18m p...

Dual-wavelength mode-locked lasers can be widely used in optical communication, pump-probe experiment, nonlinear frequency conversion, etc. In this paper, a dual-wavelength self-mode-locked semiconductor disk laser is reported for the first time, to best of our knowledge. A simple linear resonator formed by using high reflectivity distributed Bragg reflector at bottom gain chip, and an external...

We demonstrate selective detection of hydrocarbons using a widely-tunable, rapidlyswept, high-resolution spectrometer based on a mid-infrared laser source using differencefrequency generation in periodically poled lithium niobate waveguides. ©2006 Optical Society of America OCIS codes: (120.6200) Spectrometers and spectroscopic instrumentation General; (190.2620) Frequency conversion Rapid, non...

A difference-frequency generation based spectrometer system for simultaneous ultra-sensitive measurements of formaldehyde (CH2O) and Methane (CH4) is presented. A new multiplexing approach using collinear quasi-phase-matching in a single grating period of periodically poled lithium niobate (PPLN) is discussed and demonstrated for two pairs of pump and signal lasers to generate mid-infrared freq...

We present results on high-average power difference frequency generation of pulsed Yb/Er fiber systems to the mid-IR (6.2 W at 3.35 μm), and use focused Gaussian beam theory to validate our experimental results. OCIS codes: (190.4970) Parametric oscillators and amplifiers; (140.3070) Infrared and far-infrared lasers; (140.3510) Lasers, fiber

A metallic slot waveguide, with a dielectric strip embedded within, is investigated for the purpose of enhancing the optics-to-THz conversion efficiency using the difference-frequency generation (DFG) process. To describe the frequency conversion process in such lossy waveguides, a fully-vectorial coupled-mode theory is developed. Using the coupled-mode theory, we outline the basic theoretical ...

We extend earlier work on nonlinear tube wave propagation in permeable formations to study, analytically and numerically, the generation and propagation of a difference frequency, ∆ω = ω1 − ω2, due to an initial pulse consisting of carrier frequencies ω1 and ω2. Tube waves in permeable formations have very significant linear dispersion/attenuation, which is specifically addressed here. We find ...

Terahertz (THz) waves present attractive possibilities in advanced applications including biomedical analysis and stand-off detection for hazardous materials. The development of monochromatic and tunable coherent THz-wave sources is of great interest for use in these applications. Recently, a parametric process based on second-order nonlinearities was used to generate tunable monochromatic cohe...