Reconfigurable terahertz grating with enhanced transmission of TE polarized light
J. W. He,
X. K. Wang,
Z. W. Xie,
Y. Z. Xue,
S. Wang,
Y. Zhang
Affiliations
J. W. He
Beijing Key Laboratory of Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Beijing Advanced Innovation Center for Imaging Technology, and Department of Physics, Capital Normal University, Beijing 100048, People’s Republic of China
X. K. Wang
Beijing Key Laboratory of Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Beijing Advanced Innovation Center for Imaging Technology, and Department of Physics, Capital Normal University, Beijing 100048, People’s Republic of China
Z. W. Xie
Nanophotonics Research Centre, Shenzhen University & Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People’s Republic of China
Y. Z. Xue
Beijing Key Laboratory of Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Beijing Advanced Innovation Center for Imaging Technology, and Department of Physics, Capital Normal University, Beijing 100048, People’s Republic of China
S. Wang
School of Physics and Electronics, Shandong Normal University, Jinan 250014, People’s Republic of China
Y. Zhang
Beijing Key Laboratory of Metamaterials and Devices, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Beijing Advanced Innovation Center for Imaging Technology, and Department of Physics, Capital Normal University, Beijing 100048, People’s Republic of China
We demonstrate an optically reconfigurable grating with enhanced transmission of TE-polarized waves in the terahertz (THz) waveband. This kind of grating is realized by projecting a grating image onto a thin Si wafer with a digital micromirror device (DMD). The enhanced transmission is caused by a resonance of the electromagnetic fields between the photoexcited strips. The position of the transmission peak shifts with the variation of the period and duty cycle of the photoinduced grating, which can be readily controlled by the DMD. Furthermore, a flattened Gaussian model was applied to describe the distribution of the photoexcited free carriers in the Si wafer, and the simulated transmittance spectra are shown to be in good agreement with the experimental results. In future, the photoexcited carriers could also be used to produce THz diffractive elements with reconfigurable functionality.
