Samenvatting
We demonstrate a novel method for measuring terahertz (THz) photoconductivity of semiconductors on length scales smaller than the diffraction limit at THz frequencies. This method is based on a near-field microscope that measures the transmission of a THz pulse through the semiconductor following photoexcitation by an ultrafast laser pulse. Combining back-excitation of the sample using a Dove prism, and a dual lock-in detection scheme, our microscope design offers a flexible platform for near-field time-resolved THz time-domain spectroscopy, using fluences available to typical laser oscillators. Experimental results on a thin film of gallium arsenide grown by metal organic chemical vapor deposition are presented as a proof-of-concept, demonstrating the ability to map the complex conductivity as well as sub-ps dynamics of photoexcited carriers with a resolution of λ/10 at 0.5 THz.
Originele taal-2 | Engels |
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Pagina's (van-tot) | 32118-32129 |
Aantal pagina's | 12 |
Tijdschrift | Optics Express |
Volume | 26 |
Nummer van het tijdschrift | 24 |
DOI's | |
Status | Gepubliceerd - 26 nov. 2018 |