No abstract

We present a new method for detecting near-infrared, mid-infrared, and far-infrared photons with an ultrahigh sensitivity. The infrared photon detection was carried out by monitoring the displacement change of a vibrating microcantilever under light pressure using a laser Doppler vibrometer. Ultrathin silicon cantilevers with high sensitivity were produced using micro/nano-fabrication technology. The photon detection system was set up. The response of the microcantilever to the photon illumination is theoretically estimated, and a nanowatt resolution for the infrared photon detection is expected at room temperature with this method.

The stability of mechanical properties of submicrometer-thick cantilevers was systematically investigated under different conditions: driving force, vacuum, humidity, and temperature. For the submicrometer-thick cantilever, the cyclic test did not lead to failure but resulted in distinguish resonantfrequency shift. The frequency shift is caused by fatigue stress, adsorption/desorption, and temperature-induced lever softening effect. At a vacuum of 10 −3 Pa, the stress change makes a dominant contribution to the frequency shift, and the desorptioninduced lever softening is a secondary factor. The resonant frequency continuously goes down with the cycles, and this frequency shift increases with the driving force of the lever. At a vacuum of 1 Pa, the resonant frequency is nearly unchanged until 10 9 cycles. Humid air accelerates water adsorption and dramatically enhances the lever stiffness, resulting in frequency increase. At room temperature, the Q factors of the lever change a little with the cycles in spite of the frequency decrease. At elevated temperature (100 • C and 200 • C), the frequency and Q factors increase with the cycles due to the dominant desorption.[2010-0233]