玻璃衬底二氧化钒薄膜的宽频带太赫兹波调制特性

针对二氧化钒（VO2）薄膜在可调谐太赫兹功能器件中的应用, 采用磁控溅射法在K9玻璃衬底上制备了VO2薄膜, 并用X射线衍射（XRD）对薄膜的晶相进行表征。利用配备加热装置的太赫兹时域光谱系统（THz-TDS）研究了薄膜样品在变温过程中的THz反射、透射光谱特性及其变化规律。实验结果表明, 随着加热温度的升高, VO2薄膜发生半导体-金属相变并对宽频段THz波产生显著的调制作用。调制深度明显依赖于THz频率, 薄膜样品对THz波反射功率、透射率的幅度调制深度在0.3~0.5 THz范围波动较大；对THz波的透射率在低频处较大, 高频处较小, 调制深度在35%~65%之间变化。该薄膜制备简单, 质量高, 可应用于太赫兹开关和调制器等功能器件。

Broadband THz modulation characteristics of vanadium dioxide thin film prepared on glass substrate

For the applications of vanadium dioxide (VO2) thin film in terahertz tunable functional devices, the vanadium dioxide VO2 thin film was prepared by magnetron sputtering technique on K9 glass substrate, and the crystal structure was characterized by X-ray diffraction (XRD). Spectral characteristics and their variations of terahertz (THz) reflection and transmission signal passing through the sample at different temperatures were studied by the THz time domain spectroscopy system (THz-TDS) equipped with heating device. The experimental results indicated that the semiconductor-metal transition of VO2 thin film occurred with the increase of the heating temperature and showed excellent modulation to the broadband THz wave. The modulation depth was dependent on the THz frequency. The THz wave amplitude modulation depth of reflection power and transmission showed remarkable fluctuation in the band of 0.3-0.5 THz. The transmittance of THz wave was larger in the low frequency band than that in the high frequency band, and the modulation depth varied in the range of 35%-65%. The thin film was prepared simply and had high quality, which can be applied to THz modulator functions such as devices and switches.