| abstract |
A thermal sensor for low level radiation with built-in photo-thermal gain utilizing a thin film of pyro-optical material to modulate the reflectivity and/or transmission of a photonic carrier beam. The photonic carrier beam is modulated by the temperature of the pyro-optical film and detected by typically a silicon detector. A slight temperature increase of the pyro-optical film due to absorption of low level radiation increases the coefficient of absorption of the photonic carrier beam which in turn causes a further increase in temperature of the pyro-optical film. The photonic carrier beam provides power to increase the temperature of the pyro-optical film beyond the heating caused by the absorption of low level radiation alone. This thermal amplification effect provides a radiation sensor with photo-thermal gain. |