The grating - prism array - grating optic demonstrates some of the similarities and differences between diffraction (from the gratings) and refraction (from the prism array). The prism array refracts light perpendicularly incident on the back of the ruler by ~1°, more or less independently of wavelength, and refracts all the light into one spot. By contrast, each wavelength-specific grating diffracts most of the light at the design wavelength perpendicularly incident on the back of the ruler into the first diffraction order at 1°, but does not work in quite the same way with a different wavelength. The grooves of the prism array are much wider and much deeper than those of the blazed gratings.
532nm grating period: 37.2μm; Prism array period: 1.0mm; 650nm grating period: 30.5μm;
Blaze angle and apex angle: 2°
This light-shaping lens requires sharp corners to shape an incident collimated beam into a precise square or rectangular output.
18 mm diameter and focal length
18 mm diameter and focal length
Use a flashlight or other large-ish partially collimated beam to investigate the different behavior of cylindrical vs round Fresnel lenses. Note the linear output of the Cylindrical Fresnel lens and the spot resultant from use of a round Fresnel lens.
Fresnel Technologies, Inc. specializes in the design and manufacturing of molded plastic Fresnel lenses, molded polymer optics in general, and infrared-transmitting optical materials. We offer design assistance, diamond machining, prototyping, tooling, and production. Stock or custom, we’re your optics partner.
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Phone: (817) 926-7474
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