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e) To see the result, remove the 100 mm lens in the outgoing beam path. We use a blankslide immediately after the spatial filter slide to be able to go back and forth betweenfiltered and unfiltered image in PowerPoint.f) A few notes: at 633 nm (red He‐Ne), the SLM can only delay the phase by 0.8 ,resulting in an imperfect amplitude aperture. Shifting to green (543 nm He‐Ne or 532nm DPSS) allows the phase delay to be increased to closer to (0.95 at 532 nm). Thismay help improve the aperture filtering. Other fun filters include a low‐pass filter(simply a small white circle on a black background – this removes the high‐frequencyinformation, resulting in a blurred image; a high‐pass filter (small black circle on a whitebackground), which removes the DC component (that is, the mean intensity), whichtends to make dark regions bright and vice versa; and a “razor‐blade” filter, with twolarge black rectangles surrounding a narrow white slit – using this and a square‐gridobject allows either the horizontal or vertical lines of the grid to be removed (in fact, afilter with actual razor blades in the transform plane, no SLM, works fantastically for thisspatial filter).Doug Martindouglas.s.martin@lawrence.eduShannon O’Learysoleary@lclark.edu