Abstract-Fluence and polarisation dependence of GaAs based Lateral Photo-Dember terahertz emitters

D. McBryde, M. E. Barnes, S. A. Berry, P. Gow, H. E. Beere, D. A. Ritchie, and V. Apostolopoulos  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-3-3234

Optics Express, Vol. 22, Issue 3, pp. 3234-3243 (2014)
http://dx.doi.org/10.1364/OE.22.003234

We characterise THz output of lateral photo-Dember (LPD) emitters based on semi-insulating (SI), unannealed and annealed low temperature grown (LTG) GaAs. Saturation of THz pulse power with optical fluence is observed, with unannealed LTG GaAs showing highest saturation fluence at 1.1 ± 0.1 mJ cm⁻². SI-GaAs LPD emitters show a flip in signal polarity with optical fluence that is attributed to THz emission from the metal-semiconductor contact. Variation in optical polarisation affects THz pulse power that is attributed to a local optical excitation near the metal contact.

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