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Our foundational technology allows us to create replicated gratings that offer affordable performance and our products cover the spectrum from the vacuum ultraviolet (VUV) to long-wave infrared (LWIR).

Secondorder diffraction

A transmission grating offers a basic simplicity for optical designs that can be beneficial in fixed grating applications such as spectrographs (aka optical spectrometer). The incident light is dispersed on the opposite side of the grating at a fixed angle. Transmission gratings are very forgiving for certain types of grating alignment errors.

A diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams traveling in different directions. The directions of the beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as the dispersive element.

Omega Optical has a patent-pending deep ultraviolet transmission grating. Formerly the domain of expensive etched fused silica gratings, these economical yet high performance gratings are available for your instrumentation today.

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Our patented filtered diffraction gratings are a custom solution for OEM applications requiring isolation of the desired spectral band prior to diffraction, and are design limited in doing so prior to the diffraction grating component. Filtering the undesired spectral band prior to diffraction minimizes second order and ray scattering effects, maximizing spectral dynamic range.

We manufacture custom gratings to meet specialty needs including: Multi-zone gratings, cylindrical gratings, and concave gratings.

Original gratings are first-run diffraction gratings where a substrate, likely glass or copper, is polished to a finish better than one-tenth of a wavelength (λ/10) with a high degree of flatness. For ruled diffraction gratings, the surface is then coated with aluminum using vacuum deposition. Photosensitive (photoresist) coating is used for holographic diffraction gratings. The master grating is completed by grooving the surface with either a ruling engine or holographic system.

Typical holographic diffraction gratings are produced on soda lime and fused silica glass substrates from high quality holographic master gratings and are intended for use in spectrometers and monochromators where cost and low stray light are of primary concern. They exhibit a flatter response due to their sinusoidal groove profile.

Diffractiongrating formula

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Ruled diffraction gratings have a higher peak efficiency than holographic diffraction gratings and a sharper spectral response around their blaze wavelength, due to their “sawtooth” groove profile. Applications like fluorescence excitation, analytical chemistry, life sciences, telecom, physics, education and space sciences – centered around a narrow wavelength range – benefit from a ruled diffraction grating blazed at that wavelength.

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Omega Optical designs and manufactures exceptional volumes of highly accurate ruled and holographic gratings, wire-grid polarizers and beamsplitters for OEM and reseller markets with our proven design approach and vast library of masters.

We provide several coating options to tailor reflectivity and efficiency. Protected Aluminum (Al) – Aluminum coat with a thin overcoat of magnesium flouride (MgF2) which prevents the formation of aluminum oxide which is absorbing in deep UV. It provides no benefit over bare aluminum for gratings used in VIS and IR. Gold (Au) – Superior performance over aluminum in the NIR region. Below 600nm the reflectance of gold falls off significantly and is a poor choice. Above 1200nm, gold offers very little advantage for a single pass application.

Dispersion required and efficiency at peak wavelength are often trade-offs. Coarse gratings, for example, generally have higher peak efficiency but lower dispersion.

Echelle replica gratings are special low period gratings designed for use in high orders only. The maximum possible resolution is obtained but, in general, it is necessary to use a second grating or prism to separate out the overlapping diffracted orders. Echelle replica gratings are an ideal solution for high-resolution spectroscopy due to their high dispersion in high orders.