Study on the MWIR imaging ability of optical readout bimaterial microcantilever FPA uncooled infrared imaging system

In this paper, we analyze and experimentally demonstrate the medium-wave infrared (MWIR) imaging ability based on optical readout bimaterial microcantilever focal plane array (FPA) uncooled infrared imaging system. Multiband infrared imaging technology has been a hotspot in the field of infrared imaging. In the infrared band, medium-wave infrared (3∼5 μm) has minimal attenuation of atmospheric infrared window, and it also covers many atomic and molecular absorption peak. Imaging study on MWIR radiation source also appears particularly important. First of all, we introduce the bimaterial microcantilever IR sensing principle and the fabrication of the bimaterial microcantilever FPA. Secondly, the paper introduces the theory of the optical-thermal-mechnical reading based on FPA. Finally, the experimental platform was constructed to conduct the MWIR imaging experiment. The medium-wave infrared radiation source consists of a continuous-wave optical parametric oscillator (OPO) that is pumped by a polarization-maintained, single-mode fiber amplifier. The length of the 50mm periodically polarized LiNbO₃ crystal (5%MgO) is used as the nonlinear crystal. The stable cavity of the ring is designed, and the output of the 3∼4 μm band is realized by the design of the nonlinear crystal polarization period. And the FPA employed in our experiment contains 256×256 pixels fabricated on a glass substrate, whose working bandwidth is covering the three IR atmospheric windows. The experimental results show that the bimaterial microcantilever FPA has a good imaging ability to the MWIR sources.