Giordano, MC;
Viti, L;
Mitrofanov, O;
Scamarcio, G;
Mastel, S;
Hillenbrand, R;
Ercolani, D;
... Vitiello, MS; + view all
(2018)
Sub-wavelength near field imaging techniques at terahertz frequencies.
In: Razeghi, M and Brown, GJ and Lewis, JS and Leo, G, (eds.)
Proceedings of the Quantum Sensing and Nano Electronics and Photonics XV.
SPIE: Bellingham (WA), USA.
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Abstract
Near-field imaging techniques at terahertz (THz) frequencies are severely restricted by diffraction. To date, different detection schemes have been developed, based either on sub-wavelength metallic apertures or on sharp metallic tips. However high-resolution THz imaging, so far, has been relying predominantly on detection techniques that require either an ultrafast laser or a cryogenically-cooled THz detector, at the expenses of a lack of sensitivity when high resolution levels are needed. Here, we demonstrate two novel near-field THz imaging techniques able to combine strongly sub-wavelength spatial resolution with highly sensitive amplitude and phase detection capability. The first technique exploits an interferometric optical setup based on a THz quantum cascade laser (QCL) and on a near-field probe nanodetector, operating at room temperature. By performing phase-sensitive imaging of THz intensity patterns we demonstrate the potential of our novel architecture for coherent imaging with sub-wavelength spatial resolution improved up to 17 μm. The second technique is a detector-less s-SNOM system, exploiting a THz QCL as source and detector simultaneously. This approach enables amplitude- and phase-sensitive imaging by self-mixing interferometry with spatial resolution of 60-70 nm.
| Type: | Proceedings paper |
|---|---|
| Title: | Sub-wavelength near field imaging techniques at terahertz frequencies |
| Event: | Quantum Sensing and Nano Electronics and Photonics XV |
| Location: | San Francisco (CA), USA |
| Dates: | 27th January - 1st February 2018 |
| ISBN-13: | 9781510615663 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1117/12.2291518 |
| Publisher version: | https://doi.org/10.1117/12.2291518 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Terahertz radiation, Near field, Near field optics, Quantum cascade lasers, Signal detection, Sensors, Spatial resolution |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10060151 |
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