CircFresnel

MATLAB

[alphaL,c] = CircFresnel(R0,Dp,R,Dt,lambda,Ngrid,[OutForm])

Description

Computes the complex field resulting from the Fresnel diffraction of a circular aperture illuminated by an on-axis point source R0 meters from the aperture at an observation plane R meters from the aperture.

Parameters

Parameters	Description
R0 [scalar]	Phase curvature of illuminating field (m)
Dp [scalar]	Aperture diameter (m)
R [scalar]	Range from aperture to observation plane (m)
Dt [scalar]	Diameter of interest in the observation plane (m)
lambda [scalar]	Wavelength (m)
Ngrid [scalar]	Number of grid points in the observation plane.
OutForm [string]	(Optional) Output format. 'S' for slice, 'Q' for quadrant, 'F' for full image, and 'T' for full image in a structure format (.x, .y, .g). If quadrant is specified, the grid dimension is Ngrid x Ngrid, for full pattern, the grid is 2(Ngrid-1)x2(Ngrid-1). If Ngrid is $2^n + 1$ and the full pattern is returned, it will be properly centered for use with FFT2.

Return Values

Return Values	Description
alphaL [vector/matrix]	Normalized complex field (${W}^{1/2}$)
c [vector]	Evaluation points along one axis (m)

References

K. D. Mielenz, "Algorithms for Fresnel Diffraction at Rectangular and Circular Apertures," J. Res. Natl. Inst. Stand. Technol., vol. 103, pp. 497-509, 1998.