二氧化钒材料相变的太赫兹光谱与阵列成像

二氧化钒是一种具有绝缘态到金属态可逆相变特性的材料，在光器件及信息技术中有非常广泛的应用。分别采用太赫兹频段的光谱测量技术和阵列成像技术研究分析了硅基二氧化钒材料的相变过程。采用傅里叶变换光谱测量系统，获得了整个样品在2.5~20.0 THz频段透射谱和反射谱随温度的变化，分析得到了硅基二氧化钒材料相变的温度范围为334~341 K，对应温差为7 K；得到了相变前后样品对4.3 THz辐射的透过率变化达40%以上，反射率变化接近30%。随后采用一套4.3 THz的阵列成像系统，测量了整个样品在相变前后的太赫兹图像，获得了该材料由金属态转变为绝缘态时，其对4.3 THz激光信号的透过率由6.7%升至50.7%，透过率变化达44%，与傅里叶变换光谱在4.3 THz处的测量结果相当。上述研究结果为硅基二氧化钒材料用于2.5 THz以上电磁辐射的透射调制和反射调制提供了很好的实验数据支撑。

Terahertz spectroscopy and array imaging of phase transition of vanadium dioxide

Vanadium dioxide is a kind of material with reversible phase transition from insulating state to metallic state. It is widely used in optical devices and information technology. In this paper, the phase transition process of silicon-based vanadium dioxide is studied and analyzed by terahertz spectroscopy and array imaging technology. Firstly, the transmission spectra and reflection spectra of the whole sample in the 2.5~20.0 THz region are obtained by using the Fourier transform spectrometer. The analysis shows that the temperature range of phase transition of silicon-based vanadium dioxide is from 334 K to 341 K, and the corresponding temperature difference is 7 K. It is obtained that the transmittance of the sample to 4.3 THz radiation changes more than 40% and the reflectivity changes close to 30% after phase transition; then, a set of 4.3 THz array imaging system is utilized to measure the THz images of the whole sample before and after phase transition. When the material changes from metal state to insulating state, the transmittance of 4.3 THz light increases from 6.7% to 50.7%, and the transmittance change is 44%, which is near to the results of Fourier transform spectra at 4.3 THz. The above research results provide good experimental data support for the transmission modulation and reflection modulation of silicon-based vanadium dioxide for electromagnetic radiation above 2.5 THz.