Thorlabs offers a selection of ruled diffraction gratings optimized with blaze wavelengths from 300 nm to 1.6 µm. Ruled gratings are ideal for applications centered at the grating's blaze angle. The grating will have a relatively sharp efficiency peak about the blaze wavelength. Ruled gratings typically offer higher efficiencies than holographic gratings, while holographic gratings do not produce ghosting effects. For information regarding the differences between grating types, please click on the Selection Guide tab above.
A form of the grating equation is:
nλ = d(sinΘ - sinΘ')
where n is the order of diffraction, λ is the diffracted wavelength, d is the grating constant (distance between grooves), Θ is the angle of incidence measured from the grating normal, and Θ' is the angle of diffraction measured from the grating normal. Different wavelengths of light are thus diffracted at different angles. The efficiency of these gratings is affected by various parameters such as wavelength, polarization of light, and angle of incidence. The efficiency curves below were obtained by using the gratings in Littrow configuration.
Warning:
Optical gratings can be easily damaged by moisture, fingerprints, aerosols, or the slightest contact with any abrasive material. Gratings should only be handled when necessary and always held by the sides. Latex gloves or a similar protective covering should be worn to prevent oil from fingers from reaching the grating surface. Any attempt to clean a grating with a solvent voids the warranty. No attempt should be made to clean a grating other than blowing off dust with clean, dry air or nitrogen. Scratches or other minor cosmetic imperfections on the surface of a grating do not usually affect performance and are not considered defects.
Thorlabs uses a clean room facility for assembly of gratings into mechanical setups. If your application requires integrating the grating into a sub-assembly or a setup please contact us to learn more about our assembly capabilities.