Compensator which experiences thermal expansion to compensate for changes in optical distance through a transparent material

摘要

An apparatus which includes a transparent material and a compensator. Light travels through the transparent material for an optical distance. The compensator is attached to the transparent material and experiences thermal expansion which deforms the transparent material to reduce changes in the optical distance caused by changes in temperature of the transparent material. The optical distance is defined as a product of the refractive index of the transparent material and the physical length of an optical path travelled by the light through the transparent material. Preferably, the compensator reduces changes in the optical distance so that the optical distance is maintained to be approximately constant.