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High-frequency driven semiconductor superlattice oscillators for generation of subterahertz and terahertz radiation

URN to cite this document: urn:nbn:de:bvb:355-opus-10242

Rogl, Andreas (2009) High-frequency driven semiconductor superlattice oscillators for generation of subterahertz and terahertz radiation. Dissertationsreihe der Fakultät für Physik der Universität Regensburg 1, PhD, Universität Regensburg

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Other URL: http://www.universitaetsverlag-regensburg.de/artikel_6524.ahtml

Abstract (English)

In this work we report on two novel types of high-frequency driven semiconductor superlattice oscillators, suitable for generation of subterahertz and terahertz (THz) radiation. The oscillators are based on high-frequency driven miniband transport. For the first of the two oscillators, we present experimental and theoretical results and for the second oscillator a theoretical treatment; this oscillator has not yet been realised experimentally.
The second oscillator we present, the double resonance superlattice parametric oscillator, is for up conversion of radiation. It oscillates simultaneously at the third and fifth harmonic of a pump frequency. We could demonstrate experimentally double resonance oscillations in a GaAs/AlAs superlattice pumped at 100 GHz. The superlattice was mounted in a waveguide structure that served as resonator for both harmonics. Double resonance oscillations were indicated by a threshold behaviour of the third and fifth harmonic. We found that oscillations at the fifth harmonic did occur only together with oscillations at the third harmonic. On the basis of the double resonance oscillator we built a sub-THz source delivering tunable (~ 10%), monochromatic radiation around 500 GHz (output power ~ 10µW). Used as a frequency multiplier, the superlattice generated radiation at the eleventh harmonic with a frequency of about 1.1 THz.
A theoretical treatment of the double-resonance oscillator, based on a semiclassical theory of the miniband transport, showed that two coupled parametric processes occur and that double-resonance oscillations are in principle possible up to a fifth harmonic frequency of the order of 10 THz.
The second oscillator we propose, the THz-field driven Bloch oscillator, is for down conversion of THz-radiation. It is driven by a THz-field of fixed frequency and can generate radiation in a wide frequency range. Our theoretical treatment shows that the THz-field driven Bloch oscillator can generate radiation within the whole frequency range from almost zero frequency to the pump frequency with a high conversion efficiency (~5-15%). The oscillator is based on a synchronised motion of the miniband electrons under the influence of a THz-pump field. We present superlattice material which is suitable as active element of a THz-field driven Bloch oscillator.

Translation of the abstract (German)

In dieser Arbeit werden zwei neue Typen von hochfrequenzgepumpten Übergitter oszillatoren präsentiert. In einem wird über zwei gekoppelte parametrische Prozesse Strahlung bei einem vielfachen der Pumpfrequenz erzeugt. (Dieser Oszillator wurde theoretisch untersucht und in einem Experiment wurde Strahlung bei 0.5 THz erzeugt). Im anderen kann mittels hochfrequenzgetrieben Blochoszillationen breitbandig THz-Strahlung erzeugt werden.

Item Type:

Thesis of the University of Regensburg (PhD)

Referee:

Prof. Dr. Karl Friedrich Renk

Date of exam:

11 April 2008

Institutions:

Physics > Institute of Experimental and Applied Physics > Retired Professors > Group Karl F. Renk

Classification:

Notation	Type
68.65.Cd	PACS
42.70.Nq	PACS
42.65.Yj	PACS
87.50.U	PACS

Keywords:

Übergitter , Parametrischer Oszillator , Anharmonischer Oszillator , Oszillator , Multiplikationsoperator , THz , Subterahertz , Teraherz , subterahertz , terahertz , parametric oscillator , superlattice

Subjects:

500 Science > 530 Physics

Status:

Published

Refereed:

Yes, this version has been refereed

Created at the University of Regensburg:

Yes

Owner:

Universitätsbibliothek Regensburg

Deposited On:

14 Jan 2010 16:26