Using a spatially structured, optical pump pulse with a THz probe pulse, we are able to determine spatial variations of the ultrafast THz photoconductivity with sub-wavelength resolution (75 μm≈λ/5 at 0.8 THz) in a planar graphene sample. We compare our results to Raman spectroscopy and correlate the existence of the spatial inhomogeneities between the two measurements. We find a strong correlation with inhomogeneity in electron density. This demonstrates the importance of eliminating inhomogeneities in doping density during CVD growth and fabrication for photoconductive devices.
@article{arxiv.1610.06742,
title = {Subwavelength THz imaging of graphene photoconductivity},
author = {Samuel M. Hornett and Rayko I. Stantchev and Martha Z. Vardaki and Chris Beckerleg and Euan Hendry},
journal= {arXiv preprint arXiv:1610.06742},
year = {2016}
}