Golay cell

A Golay cell is a pneumatic radiation detector (hence referred to as Golay detector ), which was first developed around 1947 by Marcel JE Golay. It is operable at room temperature, and typically covers a wavelength range from 1 micron up to few millimeters. This makes it ideal for use as a detector for terahertz radiation.

Operation

The incident radiation passes through a window (such as diamond or PE-HD ) in the cell, where it is absorbed by a partially transparent thin film. The cell is filled with a gas, to which the film releases the absorbed energy, whereby it generates heat. Characterized the gas expands a little, and the pressure in the cell increases. On the back of the cell is closed by an elastic membrane which is deformed due to the pressure increase. This deformation is at Golay cells detected optically, e.g., with the light of a light diode reflected from the membrane. This is accomplished with a specially tailored optics, which focuses the first beam on the diaphragm and directs it after reflection on a photodiode. Registered by the photodiode intensity depends functionally on the stretching of the membrane.

Golay cells ( such as pyroelectric detectors ) detecting terahertz radiation, but they have, for example, while compared with bolometers the advantage that they can be therefore operated at room temperature without cooling. The measurable wavelength range is determined only by the absorption behavior of the film in the measuring cell. The sensitivity of a Golay cell can be, for example, increased by the fact that it uses a laser as a light source in the optical part and the membrane movement proves interferometrically.