What is a high-precision in asphere?

 asphere production case study pict4a

 

 

 

 

 

 

 Thorlabs defines their high-precision line of aspheres as being diffraction limited at discrete wavelengths

  • A Strehl ratio >0.8 is generally accepted as diffraction limited
  • What is the Strehl ratio?
  • Ratio of the peak intensity of the measured PSF divided by the maximum intensity of the perfect diffraction limited PSF
  • S=  (I(x=0))/(P(x=0))

K. Strehl Zeitschrift für Instrumentenkunde 22, p. 213, 1901.