In
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...
, diffraction efficiency is the performance of
diffractive optical elements – especially
diffraction grating
In optics, a diffraction grating is an optical grating with a periodic structure that diffraction, diffracts light, or another type of electromagnetic radiation, into several beams traveling in different directions (i.e., different diffractio ...
s – in terms of
power throughput. It's a measure of how much
optical power
In optics, optical power (also referred to as dioptric power, refractive power, focal power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the ...
is diffracted into a designated direction compared to the power incident onto the diffractive element of grating.
If the diffracted power is designated with and the incident power with , the efficiency reads
Grating efficiency
In the most common case – the diffraction efficiency of optical gratings (therefore also called ''grating efficiency'') – there are two possibilities to specify efficiency:
*The ''absolute efficiency'' is defined as above and relates the power diffracted into a particular order to the incident power.
*The ''relative efficiency'' relates the power diffracted into a particular order to the power that would be reflected by a mirror of the same coating as the grating, therefore attributing to inevitable reflection losses at the grating but not caused by inefficient diffraction itself.
References
External links
*{{cite web , url=https://www.gratinglab.com/Information/Handbook/Handbook.aspx , title=Efficiency Characteristics of Diffraction Gratings , author=Christopher Palmer , year=2020 , work=Diffraction Grating Handbook (8th edition) , publisher=MKS Newport , accessdate=13 March 2020
Diffraction