Terahertz-bandwidth pulses for coherent time-domain spectroscopy

Book · Sat Dec 31 00:00:00 EST 1994

OSTI ID:94444

Whitaker, J F; Gao, F; Liu, Y ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States). Center for Ultrafast Optical Science

Ultrashort pulses of electromagnetic radiation propagating through free space are used to perform coherent time-domain spectroscopy by probing the complex index of refraction of various materials, in particular thin films of high-critical-temperature superconductors and the microwave substrates the support them. The terahertz beam system utilizes Hertz ion-dipole-like antennas consisting of a dc-biased photoconductive gap in a coplanar stripline as a transmitter, and an identical receiver with a photoconductive gap biased by the THz radiation. The transmitter is driven to produce the short radiation bursts by a 100-fs optical pulse from a Ti:sapphire self-mode-locked laser, while the receiver is synchronously gated by laser pulses split from the original beam. By performing measurements in the time domain and transforming data to the frequency domain, both the real and imaginary parts of the index of refraction of dielectrics and the conductivity of superconductors are determined over the entire range from {approximately}200 GHz to several terahertz. This technique allows the direct broadband determination of these quantities in the millimeter-wave and submillimeter-wave regimes from the measurement of only a few time-domain waveforms and without the need for Kramers-Kroenig analysis or complicated processing.

• OSTI ID: 94444
• Report Number(s): CONF-940142-; ISBN 0-8194-1440-9; TRN: 95:018791
• Resource Relation: Conference: OE/LASE `94: conference on optics, electro-optics, and laser applications in science and engineering, Los Angeles, CA (United States), 22-29 Jan 1994; Other Information: PBD: 1994; Related Information: Is Part Of Nonlinear optics for high-speed electronics and optical frequency conversion. Proceedings, SPIE Volume 2145; Peygambarian, N.; Everitt, H.; Eckardt, R.C.; Lowenthal, D.D. [eds.]; PB: 366 p.
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
HIGH-TC SUPERCONDUCTORS
PHYSICAL PROPERTIES
SPECTROSCOPY
LANTHANUM OXIDES
ALUMINIUM OXIDES
BARIUM OXIDES
BISMUTH OXIDES
POTASSIUM OXIDES
ZIRCONIUM OXIDES
FOURIER TRANSFORM SPECTROMETERS
FAR INFRARED RADIATION
MICROWAVE RADIATION
EXPERIMENTAL DATA
SUBSTRATES
PENETRATION DEPTH
ELECTRIC CONDUCTIVITY