Event Details
Towards Terahertz system-on-chip devices
Presenter: Levi Smith
Supervisor:
Date: Wed, April 17, 2019
Time: 12:00:00 - 13:00:00
Place: EOW 430
ABSTRACT
Abstract:
Distortion-free transmission of THz-bandwidth pulses over centimeter-scale distances is desirable for THz system-on-chip applications. This property is difficult to achieve due to geometrical and material constraints. In this seminar two techniques are discussed which overcome these difficulties by using metallic-slit and coplanar strip (CPS) waveguide systems. The metallic-slit waveguide (MSWG) system uses photoconductive near-field edge-coupling for excitation and detection. To reduce the overall attenuation after excitation the MSWG tapers to a low-loss geometrical configuration. A broadband pulse with 1.5 THz bandwidth was detected after propagating for 25 mm.
The lithographically-defined CPS system also uses photoconductive switching for THz generation and detection. THz sources and receivers were fabricated from small (20 um x 40 um x 0.4 um) discrete epilayers of low-temperature grown gallium arsenide (LTG-GaAs). The LTG-GaAs devices were removed from their host substrate by wet etching then connected to a CPS waveguide on a lattice mismatched substrate (thin silicon nitride
membrane) via Van der Waals bonding. This technique is used to overcome leaky-wave losses. We demonstrate detection of pulses containing frequencies up to 1.5 THz after propagating for 10 mm.