• Photonics Research
  • Vol. 10, Issue 6, 06001374 (2022)
Qinggang Lin1、2, Xinming Yuan1, Xuanke Zeng1、3, Yatao Yang2, Yi Cai1, Xiaowei Lu1, Maijie Zheng1, Congying Wang1, Wenhua Cao2, and Shixiang Xu1、*
Author Affiliations
  • 1Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
  • 2College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China
  • 3e-mail: xuankezeng@szu.edu.cn
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    DOI: 10.1364/PRJ.449196 Cite this Article
    Qinggang Lin, Xinming Yuan, Xuanke Zeng, Yatao Yang, Yi Cai, Xiaowei Lu, Maijie Zheng, Congying Wang, Wenhua Cao, Shixiang Xu. Single-shot terahertz polarization detection based on terahertz time-domain spectroscopy[J]. Photonics Research, 2022, 10(6): 06001374 Copy Citation Text show less

    Abstract

    This paper presents a novel design for single-shot terahertz polarization detection based on terahertz time-domain spectroscopy (THz-TDS). Its validity has been confirmed by comparing its detection results with those of the THz common-path spectral interferometer through two separate measurements for the orthogonal components. Our results also show that its detection signal-to-noise ratios (SNRs) are obviously superior to those of the 45° optical bias THz-TDS by electro-optical sampling due to its operation on common-path spectral interference rather than the polarization-sensitive intensity modulation. The setup works without need of any optical scan, which does not only save time, but also efficiently avoids the disturbances from the fluctuations of the system and environment. Its single-shot mode allows it to work well for the applications with poor or no repeatability.

    1. INTRODUCTION

    Terahertz (THz) time-domain spectroscopy (THz-TDS) has been widely applied due to its unique ability to simultaneously measure the refractive indices and absorption coefficients of various materials in the THz region [13]. However, traditional THz-TDS fails to detect directly polarization information, so it cannot be used to sample directly the polarization-related properties, such as magneto-optical effect [4,5], birefringence and complex permittivity [1,6], chiral molecular identification [7], and polarization imaging [8,9]. Despite this, through traditional THz-TDS, THz polarization information can still be characterized by multiple measurements with different orientations of the THz polarizer or electro-optical (EO) crystal used [13,8]. By inducing time delays to cascade the THz-TDS of the THz orthogonal components [10,11], THz-TDS by electro-optical sampling (EOS) with birefringent crystals can carry out the THz polarization detection with a single scan. Some other developments have also been made to detect the THz orthogonal components, simultaneously, e.g., setting two arms for orthogonal detection in THz-TDS by EOS [12,13], adding periodic modulation of the probes through rotating the EO crystals or the polarizers continuously [1418], as well as adopting special photoconductive antenna detectors with three contacts or four contacts [1921]. However, all above need pump-probe scans for one or more times, so excellent repetition is required for their targets, and the detections are vulnerable to the disturbances from the fluctuations of the detection systems and environments. In recent years, some methods have been made to realize single-shot THz-TDS [2224], which can avoid the detections from the time-consuming pump-probe scans and the requirement of repeatability. Unfortunately, all the single-shot setups are not able to work directly well for THz polarization characterization. Consequently, we focus on the design to realize effectively single-shot THz polarization detection (SS-THz-PD) based on THz-TDS by EOS. It can simultaneously detect the horizontal and vertical components of THz-TDS based on THz phase modulations without the need for an optical scan; thus, it can work with high effectivity and high quality.

    Copy Citation Text
    Qinggang Lin, Xinming Yuan, Xuanke Zeng, Yatao Yang, Yi Cai, Xiaowei Lu, Maijie Zheng, Congying Wang, Wenhua Cao, Shixiang Xu. Single-shot terahertz polarization detection based on terahertz time-domain spectroscopy[J]. Photonics Research, 2022, 10(6): 06001374
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