PCF-Based Cavity Enhanced Spectroscopic Sensors for Simultaneous Multicomponent Trace Gas Analysis

A multiwavelength, multicomponent CRDS gas sensor operating on the basis of a compact photonic crystal fibre supercontinuum light source has been constructed. It features a simple design encompassing one radiation source, one cavity and one detection unit (a spectrograph with a fitted ICCD camera) that are common for all wavelengths. Multicomponent detection capability of the device is demonstrated by simultaneous measurements of the absorption spectra of molecular oxygen (spin-forbidden b-X branch) and water vapor (polyads 4v, 4v + δ) in ambient atmospheric air. Issues related to multimodal cavity excitation, as well as to obtaining the best signal-to-noise ratio are discussed together with methods for their practical resolution based on operating the cavity in a “quasi continuum” mode and setting long camera gate widths, respectively. A comprehensive review of multiwavelength CRDS techniques is also given

620 nm source by second harmonic generation of a phosphosilicate raman fiber amplifier

We demonstrate a nanosecond-pulsed 620 nm source through frequency doubling a 1240 nm phosphosilicate Raman fiber amplifier. The source emits up to 213 mW of average power, and is repetition rate and pulse duration tunable