题目: Air-plasma-based ultra-broadband THz spectroscopy and its applications on different material systems
报告人：Associate Prof. Binbin Zhou
Technical University of Denmark, Denmark
摘要：
The Terahertz (THz) region of the electromagnetic spectrum is rich in intricate light-matter interactions in physical, chemical, and biological systems. THz time-domain spectroscopy (THz-TDS) explores these interactions to provide essential insights into material properties and has emerged as a transformative tool across various scientific disciplines. Among ultrafast THz platforms, THz sources based on femtosecond (fs) laser-induced two-color air plasma stand out due to their extremely short pulse duration (tens of fs) and smooth spectrum across the entire THz regime (1 – 30 THz).
This presentation will explore our recent advances in the fs laser-induced air-plasma-based THz platform. Initially, we will discuss efficient THz generation using either long-wavelength driving lasers or third harmonic mixing. The second part will focus on ultra-broadband coherent detection. High dynamic range (DR) and signal-to-noise ratio (SNR), crucial for spectroscopy applications, can be achieved with this ultra-broadband THz spectrometer. Innovative detection schemes, such as solid-state biased coherent detection (SSBCD), single-shot detection, and a novel balanced air-biased detection method for ultra-broadband THz waveforms, will be discussed.
In the third part, we will delve into key spectroscopy applications, including accurate characterization of graphene electrical properties, analysis of morphology shifts in polymer films, and detection of hidden trap states in photovoltaic materials. These applications illustrate the unique advantages and potential of the ultra-broadband THz platform in various scientific fields, offering 10 times sharper temporal resolution and 10 times broader spectral bandwidth compared to traditional THz platforms, significantly facilitating material property exploration.
简介：
Binbin Zhou is an Associate Professor at the Department of Electrical and Photonics Engineering, Technical University of Denmark (DTU).
He obtained his Ph.D. in optical physics from the Institute of Physics, Chinese Academy of Sciences, in 2009. After completing his Ph.D., Dr. Zhou joined DTU as a postdoctoral researcher in 2009 and was promoted to Associate Professor in 2021. His current research focuses on ultra-broadband THz generation and detection techniques, with a particular emphasis on exploring novel material properties under both equilibrium and non-equilibrium conditions using advanced THz spectroscopy platforms.
时间：2024年7月10日（星期三）上午10:00
地点：中科院物理研究所M249会议室
邀请人：李玉同 研究员（Tel：82648014）
主办单位：中国科学院光物理重点实验室
