Abstract-Learning-Based Shadow Mitigation for Terahertz Multi-Layer Imaging

P, Wang, T. Koike-Akino,  A. Bose, R. Ma,  P.V. Orlik,  W.Tsujita,  K. Sadamoto,  H. Tsutada,
M. Soltanalian

http://www.merl.com/publications/docs/TR2019-090.pdf

This paper proposes a learning-based approach to mitigate the shadow effect in the pixel domain for Terahertz Time-Domain Spectroscopy (THz-TDS) multi-layer imaging. Compared with model-based approaches, this learning-based approach requires no prior knowledge of material properties of the sample. Preliminary simulations confirm the effectiveness of the proposed method.

 International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

Abstract-Gain measurement of terahertz quantum cascade laser via a master-oscillator power-amplifier configuration

Chenren Yu, Huan Zhu, Fangfang, Wang, Gaolei Chang, Haiqing Zhu, Jianxin Chen, Gangyi Xu, Li He,



https://www.sciencedirect.com/science/article/pii/S0022024819301551

We report a method to measure the net loss and gain of a terahertz quantum cascade laser (THz-QCL), which is based on a master-oscillator power-amplifier (MOPA) configuration. In the measurement, the master-oscillator (MO) section and power-amplifier (PA) section are separately biased. With the fixed seed power from the MO section, the output power of the device is measured at various bias voltage applied on the PA section, from which the net loss and gain is deduced as a function of bias. We demonstrate that gain clamping and gain saturation can be avoided in our measurement, which allow a complete evolution of the loss and gain characteristics. For a THz-QCL with the bound-to-continuum active region and the metal-metal waveguide, the measured maximal net gain is about 13.0-16.5 cm-1 at 2.58 THz at a 20 K, which is in qualitative agreement with the theoretical analysis.