In this study, we investigated the effect of the resonator beam shape on the thermal stress and the resonance frequency change when providing heat to the resonator beam by nearinfrared laser irradiation. This investigation provides crucial data for optical and heat sensing application using microresonators. The microresonator beam with an optical absorber for near-infrared region was fabricated, varying the numbers of beams and corners. When irradiating the optical absorber with a laser, the resonant frequency decreased. It is because the photothermal effect provides compressive stress in the beam, resulting in resonant frequency decrease. The resonant frequency change rate increased with decreasing the number of beams. According to the analytical results, we confirmed that the analytical thermal stress determined the resonant frequency change rate in the same beam length. The corner remarkably decreased the resonant frequency change rate. The straight beams bend to the orthogonal direction by the thermal expansion of another straight part of the beam, resulting in deformation of the beam in the axial direction. Therefore, the reaction force and compressive stress in the axial direction reduces.

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As a plasmonic absorber for short-wavelength infrared hyperspectral imaging, a silicon-coated gold nanodiffraction grating structure is proposed. This plasmonic absorber leads to absorption peaks in short-wavelength infrared region by the high refractive index of silicon coating on gold grating. It is relatively easy to fabricate with smaller size than those of already known absorbers. By performing fabrication, simulation, and measurement, we demonstrate the sharp absorption peaks of short-wavelength infrared light using only 400–1000 nm grating interval. We believe this miniaturized absorber will be able to be applied to hyperspectral imaging without a spectroscope owing to its sharp absorption peak at a specific wavelength.