THz-Near-Field Micro-Spectroscopy with Backward-Wave Oscillators and a Photo-Induced Aperture

We have developed a near-field spectrometer operating in the THz-range between 30 GHz and 1.4 THz, where we use backward-wave oscillators (BWO) as continues wave sources and a photo-induced aperture as near-field probe. This instrument allows performing THz-imaging and spectroscopy with sub-wavelength resolution without a complicated probe-sample distance control and with a continuously adjustable aperture.