THz Polarization Effects on Detection Responsivity of Glow Discharge Detectors (GDDs)

Abstract

The detection mechanism of glow discharge plasma in neon indicator lamps has been investigated in the terahertz and microwave spectral regions. The influence of the THz radiation polarization on the responsivity of glow discharge detectors (GDD) is considered here. There are two detection mechanisms in the GDD that exist simultaneously, each at the expense of the other. Experiments with GDD neon indicator lamps in the THz regime prove that the dominant detection mechanism of the GDD is enhanced cascade ionization rather than enhanced diffusion current. Our polarization experiments in the THz regime show that when the electric field of the THz radiation is in the same direction as the DC bias electric field of the lamp, the responsivity is about 50% higher than when the THz electric field is orthogonal to the DC field. This supports the concept that the dominant detection mechanism of the GDD in the THz regime is enhanced cascade ionization.

Characterization of a Glow Discharge Detector With Terahertz Time Domain Spectroscopy

“…These preliminary studies have shown that for the wavelength range Manuscript of a few millimeters, far infrared radiation with relatively high field amplitudes can be detected by GDDs [5]- [7]. The detection of the far-infrared wave was attributed to the wave giving energy to the plasma itself thereby changing the current through the plasma [4], [5], [7]. It was also shown that the responsivity of a GDD can be changed by changing the polarization of the far-infrared radiation [5].…”

“…Here, researchers used low cost neon indicators otherwise known as glow discharge detectors (GDDs) for microwave/submillimeter wave detection [3], [4]. These preliminary studies have shown that for the wavelength range Manuscript of a few millimeters, far infrared radiation with relatively high field amplitudes can be detected by GDDs [5]- [7]. The detection of the far-infrared wave was attributed to the wave giving energy to the plasma itself thereby changing the current through the plasma [4], [5], [7].…”

“…The detection of the far-infrared wave was attributed to the wave giving energy to the plasma itself thereby changing the current through the plasma [4], [5], [7]. It was also shown that the responsivity of a GDD can be changed by changing the polarization of the far-infrared radiation [5]. Because of the detection capability of GDDs and their lower manufacturing price compared to other room temperature detectors such as pyroelectric devices [6], there continues to be a great interest in developing system architectures around them, as was done by using them in THz imaging applications [6].…”

“…These studies have ascribed the detection mechanism in the GDD to variation in electron space charge and enhanced diffusion of the charge carriers in the plasma [3]- [5], [7]. For dc discharges, electron energy becomes minimum around the Faraday dark space as well as the negative glow region and the electric field also diminishes [2].…”

Measurements and simulations of the optical parameters of the Glow Discharge Detector (GDD) Focal Plane Array (FPA) millimeter wavelength imaging system

“…Its NEP is on the order of 10 -9 W/Hz 1/2 , and rise time is on the order of a microsecond and less. The detection mechanism of the GDD involves both enhanced cascade ionization [3][4][5][6][7][8] which was found to be dominant and enhanced diffusion current [3,4,7,[9][10][11] caused by the incident terahertz wave. The former increases lamp current, while the latter decreases it.…”