Sensitive Terahertz Imaging Using Quantum Dot sensor

S Pellinga), E Ottob), S Spasova), S Kubatkinb), A. Tzalenchukc), R Shaikhaidarov a),

S Komiyamad) and V.N. Antonova)

a) Physics Department, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK

b) Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, S-41296, Göteborg, Sweden

c) National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom

d) Department of Basic Science, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan

 

We study operation of cryogenic quantum dot (QD) sensor for purpose of spectral sensitive imaging of materials held at room temperature. The QD sensor consists of the quantum dot formed in 2DEG of GaAs/AlGsAs hetero-structure, which absorbs THz radiation, and the read out element, point contact (PC) or single electron transistor (SET), which probe the excitation of the QD, see Fig.1a. Advantage of the QD sensor lies in a high spectral sensitivity: a plasma waves are excited in the QD upon THz photon absorption, which lately decay to the single electron excitations probed by the PC or SET. A single photon sensitivity has been achieved with this device [1].The THz radiation is fed form the material held at room temperature to the QD sensor by the optical system. Design of the optical system enables to cut unwanted high frequency radiation, keeping the THz band untouched, and to form an image of the material at the sensor plane. An image of the ivy leaf hidden in envelope taken at 0.17 THz is shown in Fig. 1b. In a context of our experiments we discuss a passive spectral sensitive imaging of different materials.

 

References

[1] H Hashiba, V Antonov, L Kulik, A Tzalenchuk and S Komiyama, Sensing

individual terahertz photons, Nanotechnology 21, 165203 (2010)