Optical Sensors

Differential Absorption Lidar (DIAL) has the ability to measure in near real-time multiple atmospheric trace gases over a large area using high-intensity, well-focused laser beam. The innovation of the DIAL instrument is the implementation of a compact solid-state laser and a quasi-phase matched (QPM) optical parametric oscillator (OPO) of a periodically poled (PP) nonlinear crystal to produce radiation tunable over the spectral range from 3μm to 5μm.

Miniature Laser Doppler Velocimeter (LDV) is a 2-dimensional LDV system with all optical components located inside a probe head no bigger than 2.54cm in diameter, 7cm in length and a focal distance of 15cm. It has two laser diodes and photodiodes sensitive to wavelengths in the visible range (780-880nm).

Aerodynamic Particle Sizer (APS) is an instrument consisted of a small wind-tunnel, a pair of miniature LDV systems and a pressure sensor. As particles are drawn into the vena contracta of the wind-tunnel, velocity gradient of each particle is measured by a pair of LDVs. The measured velocity gradients are then used to calculate the aerodynamic diameter of each particle.

Mid-Infrared Spectrometer is a unique spectrometer operating over the range from 3μm to 5μm. It comprises of a solid-state laser and a QPM OPO of a PP nonlinear crystal. Balanced ratiometric detection modulation technique is employed to obtain highly sensitive measurements.