Author : Yue Shen
Publisher :
ISBN 13 :
Total Pages : 67 pages
Book Rating : 4.:/5 (113 download)
Book Synopsis Terahertz Time-domain Characterization of Amplifying Quantum Cascade Metasurface by : Yue Shen
Download or read book Terahertz Time-domain Characterization of Amplifying Quantum Cascade Metasurface written by Yue Shen and published by . This book was released on 2019 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: The THz quantum-cascade vertical-external-cavity surface-emitting-laser (QC-VECSEL) is a recently developed approach for designing high-power, electrically pumped THz lasers with excellent beam quality and broadband tunability. The key component of the QC-VECSEL is an amplifying reflectarray metasurface, based on a subwavelength array of surface radiating metal-metal waveguide antenna elements loaded with QC-laser gain material. Despite its importance, the gain properties of the QC-metasurface are designed by simulation and have only been verified indirectly through observation of the QC-VECSEL lasing characteristics, or by passive FTIR reflectance measurements at room-temperature. THz time-domain spectroscopy (TDS) has been widely used to investigate gain spectra and laser dynamics of THz QC-lasers based on various ridge waveguide geometries. In this thesis, I describe my construction of a THz TDS system and present the first direct spectral measurement using reflection-mode THz TDS of an amplifying QC-metasurface resonant at 2.6 THz under different conditions. The large surface-radiating aperture of the metasurface (1.5 1.5 mm2 in this case) eases free-space TDS measurements compared to ridge waveguide QC-devices with sub-wavelength sized facets.