Continuously-variable apodising filters

Edmund Optics has introduced a new line of continuously-variable apodising filters, which are used to eliminate undesirable intensity variations and create an even illumination profile in an optical system. Each filter's density can either increase or decrease radially from light to dark or dark to light. The company offers both bull's eye and reverse bull's eye type filters in two standard diameters that are in-stock and available for immediate delivery, thereby saving time and prototyping costs.

The company's bull's eye filters feature a high optical density in the centre, decreasing continuously to an uncoated edge. These filters are commonly used to flatten the intensity profile of Gaussian beams. Edmund Optics' reverse bull's eye type filter features a high optical density coating on the edge of the filter, which decreases continuously to an uncoated centre. Reverse bull's eye type filters are used to improve dynamic range in imaging systems.

Edmund Optics' standard bull's eye type filters are available in 25mm and 50mm diameters, with end densities of 1.0 and 2.0. They are manufactured using a B270 substrate to a dimensional tolerance of +0.00/-0.20, a surface quality of 60-40 and a thickness of 1.50 +0.10. The filters are suited for a design wavelength range of 400-700nm. A wide variety of custom substrates, sizes or intensity profiles are also available.