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Control of optically induced currents in semiconductor crystals

Abstract

The generation and control of optically induced currents has the potential to become an important building block for optical computers. Here, shift and rectification currents are investigated that emerge from a divergence of the optical susceptibility. It is known that these currents react to the shape of the impinging laser pulse, and especially to the shape of the pulse envelope. The main goal is the systematic manipulation of the pulse envelope with an optical pulse shaper that is integrated into a standard THz emission setup. The initial approach, the chirping of the laser pulse only has a weak influence on the envelope and the currents. Instead, a second approach is suggested that uses the combined envelope of a phase-stable pulse-pair as a parameter. In a laser pulse, the position of the maxima of the electrical field and the pulse envelope are shifted relative to each other. This shift is known as the Carrier-Envelope Phase (CEP). It is a new degree of freedom that is usually only accessible in specially stabilized systems. It is shown, that in a phase-stable pulse-pair, at least the relative CEP is usable as a new degree of freedom. It has a great influence on the shape  More>>
Publication Date:
Jun 01, 2010
Product Type:
Thesis/Dissertation
Report Number:
ETDE-DE-2394
Resource Relation:
Other Information: TH: Diss. (Dr.rer.nat.)
Subject:
36 MATERIALS SCIENCE; ALGORITHMS; CONTROL; CRYSTALS; CURRENT DENSITY; ELECTROMAGNETIC PULSES; ITERATIVE METHODS; LASER RADIATION; PHOTOCURRENTS; SEMICONDUCTOR MATERIALS
OSTI ID:
21403555
Research Organizations:
Marburg Univ. (Germany). Fachbereich 13 - Physik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE11G2393
Availability:
Commercial reproduction prohibited; OSTI as DE21403555
Submitting Site:
DE
Size:
154 pages
Announcement Date:
Mar 19, 2011

Citation Formats

Kohli, Kapil Kumar. Control of optically induced currents in semiconductor crystals. Germany: N. p., 2010. Web.
Kohli, Kapil Kumar. Control of optically induced currents in semiconductor crystals. Germany.
Kohli, Kapil Kumar. 2010. "Control of optically induced currents in semiconductor crystals." Germany.
@misc{etde_21403555,
title = {Control of optically induced currents in semiconductor crystals}
author = {Kohli, Kapil Kumar}
abstractNote = {The generation and control of optically induced currents has the potential to become an important building block for optical computers. Here, shift and rectification currents are investigated that emerge from a divergence of the optical susceptibility. It is known that these currents react to the shape of the impinging laser pulse, and especially to the shape of the pulse envelope. The main goal is the systematic manipulation of the pulse envelope with an optical pulse shaper that is integrated into a standard THz emission setup. The initial approach, the chirping of the laser pulse only has a weak influence on the envelope and the currents. Instead, a second approach is suggested that uses the combined envelope of a phase-stable pulse-pair as a parameter. In a laser pulse, the position of the maxima of the electrical field and the pulse envelope are shifted relative to each other. This shift is known as the Carrier-Envelope Phase (CEP). It is a new degree of freedom that is usually only accessible in specially stabilized systems. It is shown, that in a phase-stable pulse-pair, at least the relative CEP is usable as a new degree of freedom. It has a great influence on the shape of the pulse envelope and thus on the current density. It is shown that this approach enables the coherent control of the current density. The experiments are corroborated by a theoretical model of the system. The potential of this approach is demonstrated in an application. A framework is presented that uses an iterative genetic algorithm to create arbitrarily shaped THz traces. The algorithm controls the optical pulse shaper, and varies the phase of the impinging laser pulses until the desired target trace is found. (orig.)}
place = {Germany}
year = {2010}
month = {Jun}
}