Abstract-New Ultra-Fast Sub-Terahertz Linear Scanner for Postal Security Screening

A. V. Shchepetilnikov, P. A. Gusikhin, V. M. Muravev, G. E. Tsydynzhapov, Yu. A. Nefyodov, A. A. Dremin.  I. V. Kukushkin

https://link.springer.com/article/10.1007/s10762-020-00692-4

To meet increasingly demanding technological needs in modern security and industrial applications involving rapid close-range screening, we have developed a 100-GHz linear scanner. Having incorporated a novel approach in terahertz sensing and an advanced IMPATT-diode signal generating technique, the proposed system offers an efficient non-destructive testing (NDT) solution that is absolutely safe, fast, highly portable, and cost-effective. The test results demonstrate outstanding capability of the scanner to provide continuous, high-throughput security screening of mail. The system can perform real-time imaging with effective resolution approaching 5 mm at conveyor speeds of up to 15 m/s.

Abstract-High-frequency breakdown of the integer QHE in GaAs/AlGaAs heterojunctions

V. Dziom, A. Shuvaev, A. V. Shchepetilnikov, D. MacFarland, G. Strasser, A. Pimenov

https://arxiv.org/abs/1811.08777

The integer quantum Hall effect is a well-studied phenomenon at frequencies below about 100 Hz. The plateaus in high-frequency Hall conductivity were experimentally proven to retain up to 33 GHz, but the behavior at higher frequencies has remained largely unexplored. Using continuous wave THz spectroscopy, the complex Hall conductivity of GaAs/AlGaAs heterojunctions was studied in the range of 69-1100 GHz. Above 100 GHz, the quantum plateaus are strongly smeared out and replaced by weak quantum oscillations in the real part of the conductivity. The amplitude of the oscillations decreases with increasing frequency. Near 1 THz, the Hall conductivity does not reveal any features related to the filling of Landau levels. Similar oscillations are observed in the imaginary part as well, this effect has no analogy at zero frequency. This experimental picture is in disagreement with existing theoretical considerations of the high-frequency quantum Hall effect.