METHOD OF COMPENSATING FOR THERMAL BIAS OF INTERFERENTIAL-POLARISATION FILTER BAND Russian patent published in 2015 - IPC G02B5/28 G02F1/21 G01J7/00 

FIELD: physics, optics.

SUBSTANCE: invention relates to optical instrument-making and a method of compensating for thermal bias of the transmission band of an interferential-polarisation filter. The filter comprises a stack of adjustable elements with half-wave plates, rotation of which adjusts the transmission band of the adjustable filter elements to the measured spectral line of the object. To compensate for thermal bias of the transmission band, a light beam from a reference source is directed through each adjustable element simultaneously with light of the measured spectral line of the object. The beam of the reference source transmitted by the element is split into two beams, an usual and an unusual beam, and the change in the difference of intensities of said beams, caused by change in temperature of the element, is used as a feedback signal for turning the half-wave plate which compensates for thermal bias of the transmission band of the element.

EFFECT: more accurate and simpler method.

2 dwg