DEVICE FOR CORRELATION-OPTICAL MEASUREMENT OF GAS CONCENTRATION Russian patent published in 2000 - IPC

FIELD: optical instruments, in particular, selective monitoring of gases. SUBSTANCE: device has collimator, band-pass filter, interference polarization filter, which has polarization unit, analysis unit, forming double-refracting plate and photo elastic modulator. Goal of invention is achieved by correcting double-refracting plate, which is introduced into interference polarization filter. Its height is greater than height of forming plate by factor of four. Optical axis of correcting plate is rotated by 45 degrees with respect to optical axis of forming plate. Analysis unit is designed as polarization splitter, which one polarization provides reference signal. This results in possibility to decrease zero signal drift without drop in sensitivity caused by additional light losses. EFFECT: increased selectivity and sensitivity of device. 2 cl, 2 dwg