Terahertz generation mechanism in nano-grating electrode photomixers on Fe-doped InGaAsP.
Opt Express
; 25(9): 10177-10188, 2017 May 01.
Article
em En
| MEDLINE
| ID: mdl-28468392
ABSTRACT
We report the generation mechanism associated with nano-grating electrode photomixers fabricated on Fe-doped InGaAsP substrates. Two different emitter designs incorporating nano-gratings coupled to the same broadband antenna were characterized in a continuous-wave terahertz (THz) frequency system employing telecommunications wavelength lasers for generation and coherent detection. The current-voltage characteristics and THz emission bandwidth of the emitters is compared for different bias polarities and optical polarisations. The THz output from the emitters is also mapped as a function of the position of the laser excitation spot for both continuous-wave and pulsed excitation. This mapping, together with full-wave simulations of the structures, confirms the generation mechanism to be due to an enhanced optical electric field at the grating tips resulting in increased optical absorption, coinciding with a concentration of the electrostatic field.
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01-internacional
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MEDLINE
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En
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Opt Express
Ano de publicação:
2017
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Article