Abstract
We theoretically investigate the feasibility of terahertz
detection via electro-optic (EO) sampling using 6H-SiC single crystal. The
frequency response is simulated based on the principle of phase-matching
condition. The optical dispersion of 6H-SiC was calculated by Sellmeier
equation. In collinear incidence approach, the THz detectable bandwidths are
simulated by a frequency response function at different excitation wavelengths.
The cut-off frequency as a function of crystal thickness is revealed. In non-collinear
incidence approach, the phase-matching condition can be achieved by using a
silicon prism to couple the THz radiation into 6H-SiC single crystal. The
crossing angle between THz radiation and incident optical beam is subject to
the THz dispersion of Si prism and group index of 6H-SiC. The relation between
THz coherence length and crossing angle is discussed. Both approaches display
that 6H-SiC performs a broadband THz response for EO sampling at 515 nm. The
sensitivity of EO sampling of 6H-SiC is triple times higher than GaP. In
combination of the high critical breakdown field, 6H-SiC is consider to be a
promising candidate for detecting high field THz radiation.
Keywords:6H-SiC;electro-optic (EO);THz radiation;
Source: iopscience
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