Seminar: Fundamentals and Recent Advances in Terahertz Time-Domain Spectroscopy by Prof. Tani, Fukui Univ

Title: Fundamentals and Recent Advances in Terahertz Time-Domain Spectroscopy

Speaker: Prof. Masahiko Tani, Research Center for Development of Far-Infrared Region, University of Fukui

Abstract:

Terahertz (THz) time-domain spectroscopy (TDS) is the most popular and powerful spectroscopic method in THz frequency region (0.1 - 10 THz). THz-TDS is based on sub-picosecond electromagnetic pulse generation and its sampling detection by femtosecond (fs) laser pulses [1-2]. In this lecture, the author illustrates the basic elements and recent advances in THz-TDS.  For a realization of a cost effective THz-TDS, it is essential to develop efficient THz wave emitters and detectors, which can be used with the communication wavelength (1550 -1560 nm) fs fiber-lasers. Following topics are picked up with a special attention for realization THz-TDS system based on fs fiber laser at the communication wavelength.

(i)       Sub-bandgap excitation of photoconductive antennas with low-temperature-grown GaAs (LT-GaAs substrate) [3-5]

(ii)          LiNbO₃ (LN) waveguide THz emitter with Cherenkov phase matching [6-7]

(iii)         Electro-optic (EO) sampling based on non-collinear Cherenkov phase matching [8-11]

(iv)         Spintronic THz emitter [12]

The principle and performance of each device or technique are discussed.

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11. R. delos Santos, et al, Opt. Express, 24 (2016), 24980.
12. E. Th. Papaioannou, et al, IEEE Transactions on Magnetics, 54 (2018), 9100205.