A tunable optical cavity can be tuned by relative movement between two reflection surfaces, such as by deforming elastomer spacers connected between mirrors or other light-reflective components that include the reflection surfaces. The optical cavity structure includes an analyte region in its light-transmissive...http://www.google.com/patents/US20080186508?utm_source=gb-gplus-sharePatent US20080186508 - Tuning optical cavities
