Diffraction Grating

Standard Ruled and Holographic Replicated Gratings

Standard replicated gratings are produced from ruled and holographic originals and are intended for use in moderate resolution spectrophotometers, spectrometers and monochromators where low cost, high efficiency, and low stray light are of primary concern. Since standard gratings are cut from larger replicas, they are ruled over their entire surface. Incident radiation should, however, be restricted to 90 % of the ruled area. Replicated gratings meet or exceed the performance characteristics of the originals.

Replicating on Pyrex produces gratings with a surface flatness of l/4 or better, good thermal stability, and a resolution equal to 80 to 90 % of the master. High resolution gratings are available in groove spacings from 120 to 1800 g/mm, blazed from 250 nm to 12.0 µm. For even better thermal stability, ask for an estimate on quotation for gratings replicated on Zerodur.

Replica gratings are available with damage thresholds as high as 250 watt/cm² for CW sources. They are produced by a proprietary process to withstand high incident energies.

Special low period gratings were designed for use in high diffracted orders. They are generally used with a second grating or prism to separate overlapping diffracted orders. Supplied on precision glass substrates, echelles have a theoretical resolution of 80 - 90 %.

Using a single beam holographic technique produces a grating with a sawtooth profile that is blazed at approx. 250 nm for each angle of incidence and each groove spacing. The result is a well-compensated system response from 190 to 800 nm.

A new 600 line/mm reflection grating, specifically designed for use in telecommunications applications, this grating is engineered to offer both high efficiency and low polarization dependence between 1500 and 1600 nm. It is available on float glass, Pyrex or Zerodur.

Molecular Laser (ML) gratings are used primarily to tune the output wavelength of high powered lasers. High peak efficiencies, typically from 92 % - 96 %, are achieved by orientating the polarization of the "E" vector perpendicular to the grooves rather than the unpolarized average. Original MLs consist of an aluminium coating on a cooper substrate, resulting in an inherently high damage threshold. Standard MLs are available in a number of blazes (2.8 µ to 16.0 µ) and groove spacings (75 g/mm to 450 g/mm).

Transmission gratings offer a basic simplicity for optical designs that can be beneficial in fixed grating applications such as spectrographs. The incident light is dispersed on the opposite side of the grating at a fixed angle. Transmission gratings are also very forgiving when it comes to some types of grating alignment errors.

Used for laser beam divison and multiple laser line separation in visible wavelengths, the transmitted beam is diffracted into multiple orders.