Opco - Stock Diffraction Gratings

Replicated Diffraction Gratings From Existing Grating Masters

In the 1940s, new technology allowed manufacturers to replicate master gratings onto other substrates, resulting in high-efficiency, cost-effective optical solutions.  Master gratings are first-run diffraction gratings refined to a final product.

Before the development of efficient replication techniques, all diffraction gratings were simply master gratings. This practice was difficult and time-consuming due to variations in groove size, spacing, and other flaws that could result in out-of-spec gratings. Thanks to replication technology, replicas are nearly identical to the master, exhibiting the same size, shape, and topography without the labor-intensive process.

Replication Process for Diffraction Gratings

Compared to producing a new grating master every time, it is much easier to replicate diffraction gratings from a master grating. The process begins with the fabrication and verification of a master grating, followed by applying a releasing agent to its surface. On top of this goes the epoxy and the replica substrate. The epoxy is cured and the replica is released. Unless it is a transmission grating, a reflective coating should be added to the surface of the replica.  Replicating from an existing grating master is ideal for lowering costs incurred by custom tooling.

Using high-quality epoxies, substrates, and coatings, this technique yields excellent diffraction gratings that have minimal deviation from the existing master grating.

Groove Density and Blaze Wavelength

Groove density is the measurement of the internal angles between the zero-order and first-order diffraction gratings for two distinct wavelengths with the same incidence angles.

Blaze wavelength is the wavelength at which the diffraction efficiency curve achieves its maximum for a specific order. It is determined by the shape of the grating and reveals its overall effectiveness.

Our Stock Grating Efficiency Curves

This list is a representative sample of our grating efficiency curves at various groove densities and blaze wavelengths. Scroll down the list or re-sort it by column, click on the graph icon to see the efficiency curve.

Even though stock diffraction grating masters are based on decades-old designs, many are still in operation today. For instance, replicated diffraction gratings can be found in modern monochromators, spectrometers, and other optical devices that use standard parts. Grating masters also help produce stock diffraction gratings that provide high efficiency at lower costs. Replicating grating masters eliminates expenses associated with custom tooling, a requirement for creating custom diffraction grating masters.

Stock diffraction gratings offer a variety of benefits, including:

• Linear wavelength dispersion
• No absorption issues
• Increased efficiency
• Cost-effectiveness

Our engineers and technicians have helped customers overcome spectrometer design obstacles by providing them with affordable components like replicated diffraction gratings.

• Aluminum, Enhanced Al (Al+MgF₂, Al+oxide overcoat), Protected Al (SiO, SiO₂, and others)
• Enhanced Silver (Ag+oxide overcoat), Protected Silver (Ag+SiO₂ and other oxides)
• Bare Gold, Protected Au (Au+SiO, SiO₂, oxide overcoats)
• Bare Platinum
• Bare Chromium, Coatings
• Nickel alloys (NiCr, Inconel™)
• Bare Copper