Sensitive detection of infrared photons using a high-Q microcantilever

A new approach based on microcantilevers is presented to detect infrared photons with high sensitivity. Infrared photons are measured by monitoring the amplitude change of a vibrating microcantilever under light pressure force. The irradiating light is modulated into sinusoidal and pulsed waves, and to be in-phase and anti-phase with the cantilever driving signal. A linear relationship between the amplitude change of the cantilever and the light power distributing on the cantilever was observed. Under a vacuum of10-4 Pa, an infrared light power of7.4 nW was detected with the cantilever. The in-phase and anti-phase modulation to the cantilever vibration using a pulsed light results in an enhanced response of the cantilever.?2011 Chinese Institute of Electronics