High dynamic range, hyper-terahertz coherent detection with silicon photoconductors

A. C. Muir, A. Hussain, S. R. Andrews

OAI: oai:purehost.bath.ac.uk:publications/f195edee-01e5-42f5-af49-a44b12a0a983 • DOI: https://doi.org/10.1063/1.4954029

The frequency response of ion implanted silicon photoconductors for detection in time domain terahertz spectroscopy has been studied between 0.2 and 30 THz. Unlike devices using polar photoconductors or ones having polar substrates, which have a complicated response spectrum in the region of their restrahlen bands, the response of silicon detectors fabricated on silicon substrates is relatively featureless. When used with amplified laser systems the dynamic range of Si detectors is shown to be very similar to GaAs devices with the same geometry over a 20 THz range, superior to air biased coherent detection (ABCD) at frequencies below ~7 THz and comparable with both ABCD and electro-optic sampling in thin ZnTe crystals between 7 and 20 THz. Together with their ease of use and linear response to terahertz fields approaching 1 MV/cm, this suggests that Si photoconductors could be a competitive choice for sensitive detection in nonlinear hyper-terahertz spectroscopy.