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Proceedings Paper

Room-temperature semiconductor modulators for free-space signal transmission with THz waves
Author(s): Thomas Kleine-Ostmann; Klaus Pierz; Günter Hein; Philip Dawson; Martin Koch
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Paper Abstract

We have used device structures based on the well-established technology for producing high electron mobility transistors to modulate the amplitude and the phase of broadband terahertz pulses. The application of an external gate voltage allowed us to deplete the two-dimensional electron gas, which in turn increased the transmission of the device to THz radiation. In differential transmission experiments at room-temperature we achieved a typical amplitude change of 2-3 % for THz pulses passing through the device. In this paper we present the results of a detailed investigation of the device behavior including I-V characteristics and capacitance measurements that reflect the depletion of the two-dimensional electron gas. In a first demonstration experiment we were also able to use the modulator for audio signal transmission over a THz communication channel. To do this we modified a standard THz time-domain spectrometer to transmit signals up to 25 kHz imprinted onto a 75 MHz train of broadband THz pulses with frequencies between 100 GHz and 3 THz.

Paper Details

Date Published: 29 December 2004
PDF: 12 pages
Proc. SPIE 5593, Nanosensing: Materials and Devices, (29 December 2004); doi: 10.1117/12.569576
Show Author Affiliations
Thomas Kleine-Ostmann, Institut fur Hochfrequenztechnik, TV Braunschweig (Germany)
Klaus Pierz, Physikalisch-Technische Bundesanstalt (Germany)
Günter Hein, Physikalisch-Technische Bundesanstalt (Germany)
Philip Dawson, Univ. of Manchester Institute of Science and Technology (United Kingdom)
Martin Koch, Institut fur Hochfrequenztechnik, TV Braunschweig (Germany)

Published in SPIE Proceedings Vol. 5593:
Nanosensing: Materials and Devices
M. Saif Islam; Achyut K. Dutta, Editor(s)

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