THz imaging and microscopy, a multiplexed near-field TeraHertz microscope

Abstract

None of the THz imaging techniques developed to date, permits high spatial resolution spectroscopic imaging at fast acquisition rates. In the classical THz sub-wavelength imaging with a single aperture, the image is composed by mechanically scanning the sample against a single sub-wavelength aperture. Only one pixel of the final image is acquired for every integration time of a THz photodetector which leads to long acquisition times. A solution to this problem is a multiple sub-wavelength aperture array – an imaging spatial modulator with each of its sub-wavelength apertures acting as a separate pixel. The device function is to provide a multiple pixel imaging capability for a single source/single photodetector THz setup. The increase in image acquisition speed results from the fact that the signals of all apertures are acquired within one integration time of the THz photodetector. This spatial modulator can also be employed for Far-Infrared spectroscopy, resulting in a functional THz imaging-spectroscopy system. The THz modulators optoelectronic performance was thoroughly examined in medium-, long-wave infrared, and THz regimes. This project results in a first ever fully functional, multiple pixel THz imaging microscope. The microscope was used to acquire THz trans-mission images at λ≈118μm with λ/4 resolution.

More information

Identifiers

Catalogue record

Export record