Institutional research of nanoelectromagnetics

Gintaras VALUSIS

Center for Physical Sciences and Technology, Lithuania
Solid state based room temperature terahertz imaging systems

Conventional way to realize room temperature terahertz (THz) imaging is based on usage optoelectronic approach when femtosecond lasers are used to generate-detect radiation via coherent scheme [1]. Such set-ups are rather bulky, hence, for practical aims, one need to have compact room temperature operating THz imaging systems which is free of optical laboratory environment and precise alignment issues. In a given lecture, we discuss several principles can be applied to realise such THz imaging systems based on solid-state devices. Our focus will be given to electronic multiplier sources [2], quantum-cascade lasers [3] and plasmonic nanometric field effect transistors [4]. We consider room temperature THz sensors – plasmonic nanometric field effect transistors, too, and bow-tie diodes [5] with special emphasis on spectroscopic THz imaging applications [6]. Particular attention will be given to illustrate bow-tie diodes’ heterodyne detection scheme and its advantages in the context of operation frequency range, sensitivity and noise-equivalent power. [1] B. B. Hu and M. C. Nuss, Opt. Lett. 20, 1716 (1995). [2] A. Maestrini, J. S. Ward, J. J. Gill, Ch. Lee, B. Thomas, R. H. Lin, G. Chattopadhyay, and I. Mehdi, IEEE Trans. Microwave Theory and Techniques 58, 1925 (2010). [3] Q. Y. Lu, et al., Appl. Phys. Lett. 99, 131106 (2011). [4] W. Knap, et al., J. Infrared Milli. & Terahertz Waves 30, 1319 (2009). [5] L. Minkevičius, et al., Appl. Phys. Lett. 99, 131101 (2011). [6] I. Kašalynas, R. Venckevičius, D. Seliuta, I. Grigelionis, and G. Valušis, J. Appl. Phys. 110, 114505 (2011).