N-slit diffraction grating intensity pattern (Ronchi)

Setup of spatial filter (2 double convex lenses and a 50 micron aperture)

Unfiltered light/ Airy pattern through aperture/ Pattern after light exits second lens

Principal maximum of Airy pattern (used iris to get rid of outer rings)/The same beam about 2 meters away, still collimated

N-Slit grating in front of beam/ The image created of the grating using a third lens (simple optics)

I straightened out my setup: everything is parallel

Optimized Airy Disk pattern (50 micron aperture)

Main 4f Setup

Object for high-pass filtering/ Mask for high-pass filtering

Unfiltered image of the object/ Filtered images of the object (high-pass)

Unfiltered image of an edge/ Filtered (edge highlighted) image (high-pass)

Unfiltered image of the crossing of 2 gratings/ Filtered image with one slit in Fourier plane/ Filtered image with a grating in Fourier plane
Orientation filtering-- slit in Fourier plane oriented perpendicular to the pattern to be filtered (in this case the horizontal pattern in the object)

Unfiltered image/Image with iris in Fourier plane half-way closed (low-pass filtering)/ Image with iris blocking almost all of the frequencies higher than the 0th order

Setup and Apparatus for Data Collection

Full setup for low-pass spatial filtering (with CCD camera)/Iris used for low-pass filter/Ronchi used in setup

High-pass filter/ Object used for high-pass filtering

Lidiya Mishchenko
June 2004
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