| Abstract: |
Commercially available neon indicator lamps, known as glow discharge detectors [GDD], have been shown to exhibit sensitivities and speed comparable to those of Schottky diodes at frequencies on the order of 10-380 GHz [1]. These room temperature operation plasma devices cost on the order of half a dollar each, are not damaged by high EM wave intensities, and can be used in both direct [2] and heterodyne detection [3]. Detection is manifested as changes in current [4] and in emitted light intensity [5]. The first is limited in speed by parasitic electrode impedance effects on current to microsecond risetime [4]. However, the second can approach speed of light. The reason is that GDD output is optical, ie, changes in light intensity deriving from incident MMW/THz radiation. Indeed, we have measured detected bandwidths above 3 GHz for 100 GHz radiation [5] in measurements limited by speed of the photodiode measuring GDD light intensity. This optical upconversion approach is probably more promising. More recently we have found that, using the Particle in Cell/Monte Carlo Collision (PIC/MCC) method based on kinetic approach, the behavior of the glow can be analyzed as a function of varying frequency and power of the interacting MMW/THz radiation [6]. These simulations have also shown that the higher the modulation frequency, the stronger the GDD response. We believe the plasma attempts to return to its stable state (where signal = 0) at time intervals when the incident radiation is off. Since electrons lose a smaller amount of energy for shorter periods, an overall larger net increase in current can be seen at the end of the period for higher modulation frequencies. In preliminary experiments GDDs were studied to understand dynamics of optical emission and compare it with simulation results. GDD light output was monitored as a function of the modulation frequency of MMW radiation. By simulating the same lamp discharge geometry in 1D using the developed PIC/MCC model, good agreement was observed between the simulated glow response and the observed experimental response of the GDD in time period limited to the first 20 microseconds after discharge.
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[2] A. Abramovich, N.S. Kopeika, D. Rozban, and E. Farber, “Inexpensive detector for terahertz imaging,” Appl. Opt. 46(29), 7207-7211, 2007.
[3] H. Joseph, N.S. Kopeika, A. Abramovich, A. Akram, A. Levanon, and D. Rozban, “Heterodyne detection by miniature neon indicator lamp glow discharge detectors," IEEE Sensors J. 11(9),1879-1884, 2011.
[4] N.S. Kopeika,"Glow discharge detection of long wavelength electromagnetic radiation: cascade ionization process internal signal gain and temporal and spectral response properties," IEEE Trans. Plasma Sci. 6, 139-157, June 1978.
[5] A. Aharon, D. Rozban, M. Ben-Laish, A. Abramovich, Y. Yitzhaky, and N.S. Kopeika, “Ultra - wideband and inexpensive glow discharge detector for millimeter wave wireless communication based on upconversion to visible light”, Applied Opt. 58(22), F26-F31;10.1364/AO.58.000F26 Aug 1, 2019.
[6] Kusoglu Sarikaya, C., Altan, H., Akbar, D., and Ribeiro, M. A. "Understanding the detection mechanism of mm wave radiation in glow discharge detectors", in Millimetre Wave and Terahertz Sensors and Technology XI (eds. Salmon, N. A. & Gumbmann, F.) SPIE, 10.1117/12.2324440, 2018. |