Specific detectivity

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For a photodetector, a figure of merit used to characterize performance, equal to the reciprocal of noise equivalent power (NEP), normalized to unit area and unit bandwidth.

Specific detectivity, $D *$ (synonym D-Star), is given by $D^*=\frac{\sqrt{A \cdot \Delta f}}{NEP}$ , where $A$ is the area of the photosensitive region of the detector and $Δ f$ is the effective noise bandwidth. Its common units are $cm \cdot Hz^{1/2} / W$ , also called the Jones in honour to R. Clark Jones who defined this magnitude. ^[1] ^[2]

Given noise equivalent power can be expressed as a function of responsivity, noise spectral density ( $A / H z 1 / 2$ ) and noise bandwidth as $NEP=\frac{S_n\cdot\sqrt{\Delta f}}{\mathfrak{R}}$ , it's common to see Specific detectivity expressed as $D^*=\frac{\mathfrak{R}\cdot\sqrt{A}}{S_n}$ .

[edit] References and footnotes

^ R. Clark Jones, Proc. IRIS 2, No. 1, 9-12 (1957)
^ R. C. Jones, "Proposal of the detectivity D** for detectors limited by radiation noise," J. Opt. Soc. Am. 50, 1058- (1960) (LINK)

This article contains material from the Federal Standard 1037C, which, as a work of the United States Government, is in the public domain.