Colloquium: Jim Schwiegerling

    Thursday, March 13, 2014 - 3:30pm - 5:00pm
    Meinel 307

    Relating Wavefront Error, Apodization and the Optical Transfer Function


    The Pupil Function is defined by the amplitude transmission of the pupil and the wavefront errors introduced by the optical system.  The incoherent Optical Transfer Function (OTF) describes the contrast degradation and potential phase shift of sinusoidal objects of all spatial frequencies and orientations. The OTF is normally calculated either as an autocorrelation of the pupil function or by first calculating the Point Spread Function (PSF) by taking the squared modulus of the Fourier transform of the Pupil Function and then Fourier transforming the PSF.  Even with Fast Fourier Transform algorithms, these calculations can be slow for a densely sampled pupil.  In this talk, a linear expansion of the OTF is developed in which the expansion coefficients are directly related to the wavefront error coefficients and the apodization coefficients.  The advantage of such a representation is that the OTF can be quickly generated from parameters of the optical system.  The technique has applications to OTF optimization, as well as the design of multifocal and extended depth of focus systems.