Development and characterization of PILOT: a transportable instrument for laser-induced grating spectroscopy

Laser-induced grating spectroscopy (LIGS) is an optical diagnostic technique for gas-phase thermometry in challenging environments where physical probes are undesirable. The Portable In-line LIGS for Optical Thermometry (PILOT) instrument is a novel self-contained, compact device capable of tracer-free LIGS measurements at 400 Hz. It can be mounted in any orientation and includes internal alignment capability, adjustable path length matching for the pump beams, and an energy/power attenuation mechanism for the pump/probe beams. Characterization of the instrument demonstrated that it can produce accurate (<0.37% in ambient air) and precise (±0.7% in ambient air) spatially- and temporally-resolved temperature measurements, and is now ready to be deployed in research facilities.