Definitions for "Strehl ratio"
A measurement of optical precision that expresses the fraction of light that the mirror concentrates into the airy disk. A perfect mirror, therefore, has a Strehl ratio of 1--it reflects all of the light into the airy disk. Back to top of glossary
A figure of merit for beam propagation. For tilt corrected images it is the ratio of uncorrected on-axis intensity to corrected on-axis intensity. For non-tilt corrected images it is the same ratio in the axis normal to the plane of the tilt, rather than parallel to the z-axis.
The ratio of the peak intensity in the diffraction pattern of a point image with aberration to the peak intensity in the diffraction pattern of the same point image, but without aberration.