Photothermal transducer based on ultrathin bimetal Si resonator

In this paper, we present a photothermal transducer consisted of an ultrathin Au/Si bimetal cantilever as a resonator with a total thickness of 45 nm and quality factor of -12000. Due to the high quality factor and small size, this transducer is sensitive to photothermal effect and its thermal response frequency can be up to 140 kHz. It is demonstrated that the irradiation of weak laser can enhance the response of the transducer due to the nonlinear photothermal effect. The mechanical FM detection of modulated light is demonstrated using this bimetal transducer.