THz pulsed solid immersion microscopy with subwavelength resolution

Abstract

In order to combine the high resolution of solid immersion terahertz (THz) imaging with the ability to obtain time- and frequency-domain data using pulsed THz spectroscopy, we have developed a terahertz pulsed solid immersion (SI) microscope operating in reflection mode. We have assembled an experimental setup using a SI objective and a pair of photoconductive antennas (PCAs – i.e., a source and detector of broadband terahertz pulses) to perform spectral imaging in the terahertz range with ultra-high resolution. Three-dimensional images are produced using raster scanning and can be represented in both the time and frequency domains, with a variety of terahertz signal analysis capabilities. The microscope resolution δ depends on the THz data presentation. When analyzed in the time domain, the resolution is 0.136λc–0.20λc (the wavelength λc ≈ 360 μm corresponds to the carrier frequency νc ≈ 0.83 THz). In the spectral domain (the 0.5–1.7 THz frequency range), it is 0.147λ–0.304λ and 0.047λ–0.156λ in the amplitude and phase detection modes, respectively. The capability to record subwavelength elements of objects and collect their local spectral data makes THz pulsed SI microscope extremely promising for various applications where it is necessary to obtain spectral images on a scale of ~10-100 µm.

Speaker

Vladislav Zhelnov
Prokhorov General Physics Institute of the Russian Academy of Sciences
Russia

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