Diffraction efficiency explained

Diffraction efficiency is the performance of diffractive optical elements  - especially diffraction gratings  - in terms of power throughput. It's a measure of how much optical power is diffracted into a designated direction compared to the power incident onto the diffractive element of grating.

If the diffracted power is designated with

P and the incident power with P _{0} the efficiency η readsη = (P)/(P _{0}) .

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:^{[1] [2]}

• 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

1. Web site: Diffraction Efficiency & Relationship between Diffraction Efficiency and Polarization . 2012 . Shimadzu Corporation . 1 November 2012.
2. Web site: Technical Note 10  - Guidelines for specifying diffraction gratings . Newport Corporation . 1 November 2012.

External links

• Web site: Efficiency Characteristics of Diffraction Gratings . Christopher Palmer . 2020 . Diffraction Grating Handbook (8th edition) . MKS Newport . 13 March 2020.