Editing Neon lamp (section)

=== Detector ===
Neon lamps have been historically used as microwave and millimeter-wave detectors ("plasma diodes" or glow discharge detectors (GDDs)) up to about 100&nbsp;GHz or so and in such service were said to exhibit comparable sensitivity (of the order of a few 10s to perhaps 100 microvolts) to the familiar 1N23-type catwhisker-contacted silicon diodes{{citation needed|date=October 2017}} once ubiquitous in microwave equipment. More recently it has been found that these lamps work well as detectors even at sub-millimeter ("terahertz") frequencies and they have been successfully used as pixels in several experimental imaging arrays at these wavelengths.

In these applications the lamps are operated either in "starvation" mode (to reduce lamp-current noise) or in normal glow discharge mode; some literature references their use as detectors of radiation up into the optical regime when operated in abnormal glow mode. Coupling of microwaves into the plasma may be in free space, in waveguide, by means of a parabolic concentrator (e.g., [[Winston cone]]), or via capacitive means via a loop or dipole antenna mounted directly to the lamp.

Although most of these applications use ordinary off-the-shelf dual-electrode lamps, in one case it was found that special three (or more) electrode lamps, with the extra electrode acting as the coupling antenna, provided even better results (lower noise and higher sensitivity). This discovery received a US patent.<ref>{{cite web |last1=Farhat|first1=N|last2=Kopeika|first2=N|title=Glow discharge millimeter wave detector and method of biasing same|publisher=US patent 3790895 A|date=19 Oct 1972|url=http://www.google.co.uk/patents/US3790895|url-status=live|archive-url=https://web.archive.org/web/20180114235506/http://www.google.co.uk/patents/US3790895|archive-date=2018-01-14}}</ref>