Improved coherent terahertz emission by modification of the dielectric environment

Zedler, M.; Janke, C.; Bolivar, P. Haring; Kurz, H.; Künzel, H.
November 2003
Applied Physics Letters;11/17/2003, Vol. 83 Issue 20, p4196
Academic Journal
We present a generally applicable approach to enhance the conversion efficiency from optical input to usable coherent output power for THz emitters based on optically excited charge carriers. Guided by numerical simulations, the dielectric environment of the emitter is modified to improve radiation rate and spatial emission characteristics. The modifications comprise a sapphire layer applied on the semiconductor surface and a gold backside metallization. Comparison between a standard InGaAs semiconductor surface field emitter and an optimized version yields an increase of one order of magnitude in coherently emitted THz power. This result is in close agreement with the numerical simulations. © 2003 American Institute of Physics.


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