Study Of Shortwave Photothermal Effect Based On Surface Plasmon Resonance And Its Application

The localized surface plasmon resonance?LSPR?excited by conductive nanostructures has local field enhancement and photothermal effect,which have been extensively applied in the field of cell detection and photothermal therapy.Vanadium oxide is a thermistor material with a high temperature coefficient of resistance,and its TCR can reach to-2%/K.In this paper,a combination of the LSPR nanostructure and Vanadium oxide is used for radiation detection.The nanostructures of different metals and conductive compounds are used to excite LSPR in the wide wavelength range from the ultraviolet to the infrared,then effects of the combination of conductive nanostructures and vanadium oxide are investigated.To lay the technical foundation for the future development of high-performance spectral imaging and wide-band imaging detectors,the following are mainly completed:1.Use COMSOL Multiphysics simulation to explore the photothermal dynamics of LSPR and calculate the steady-state temperature distribution of nanoparticles.Theoretical simulations studied the influence of shape,size of nanostructures and environmental media on the LSPR response band and response bandwidth.2.Proposes an ultra-wideband polarization near-perfect absorber at visible-near-infrared frequencies based on metal-dielectric-metal structures using vanadium dioxide phase-change material as dielectric layer.For TM and TE Polarization,it is found that peak light absorption can reach to 99%at a wide angle of incidence up to 60°.The physical mechanism of the proposed ultra-wideband absorption is analyzed.At the same time,the heating process of the structure under nanosecond pulse light is studied.The VO₂ layer rises from room temperature to VO₂ phase transition temperature 340K within 0.35 ns under low light intensity of 1.43x 10 ⁵ W/m².3.Design and fabricate a new type of detector unit structure based on the photothermal effect of localized surface plasmon resonance.The experiment explores the detection effect of element devices combined with aluminum oxide nanoparticles and vanadium oxide heat-sensitive wires.Its spectral responsivity was measured by established test system.When the aluminum squares have 120 nanometers of length of side and their period is 500 nanometers,the absorption peak is near 500 nanometers,which is basically consistent with the simulation and achieves preliminary verification.