How does a holographic plane grating work to disperse light spectrally?

Holographic plane gratings rely on interference between the incident wave and the periodic index or surface modulation to generate diffracted orders according to the grating equation mλ = d (sin θi + sin θm). The sinusoidal groove pattern behaves like a spatial frequency filter, separating wavelengths at different diffraction angles; the line density (1/d) and incidence geometry determine dispersion, angular separation, and usable spectral range.

What are the main types of holographic plane gratings and their typical applications?

Key variants include surface-relief holographic gratings (grooves etched or replicated on the surface) and volume phase holographic (VPH) gratings, where the refractive index is modulated in the bulk of a photosensitive medium. Surface-relief holographic plane gratings are common in compact spectrometers and monochromators, while VPH plane gratings offer higher diffraction efficiency and are widely used in astronomical spectrographs, Raman systems, and high-throughput analytical instrumentation.

Which technical specifications are most important when selecting a holographic plane grating?

Critical parameters include groove density (lines/mm), blaze or peak efficiency wavelength (for VPH this is set by fringe spacing and index modulation), spectral range, and diffraction efficiency in the required polarization state. You should also consider substrate material and coatings for your wavelength band, grating size and clear aperture, wavefront flatness, and the specified stray light level or scattered light performance for sensitive spectroscopy applications.

How do groove density and incidence geometry affect resolution and throughput in a holographic plane grating system?

Higher groove density increases angular dispersion and can improve spectral resolution for a given optical layout, but it narrows the usable spectral range and can increase polarization sensitivity. Incidence angle and configuration (Littrow vs off-Littrow) influence efficiency at the target wavelength and the mechanical packaging of the spectrometer; selecting these together with the grating size and f-number of your optics allows you to balance resolution, throughput, and footprint.

What are typical lead times, customization options, and main cost drivers for holographic plane gratings?

Standard catalog holographic plane gratings are often available from stock or with lead times of 2–6 weeks, while custom groove densities, sizes, substrates, or VPH designs can extend lead times to 8–16 weeks due to new mastering and metrology. Cost is mainly driven by grating area, custom line density or fringe design, substrate material, surface quality and flatness tolerances, AR or protective coatings, and any environmental or packaging requirements (e.g., hermetic sealing for VPH gratings).

How can I find, compare, and request quotes for holographic plane gratings on FindLight without creating an account?

On FindLight, navigate to Optics > Diffractive Optics and Gratings > Holographic Plane Gratings, then use filters for wavelength range, groove density, grating size, and substrate to narrow the results. You can open multiple product pages in separate tabs to compare specifications side-by-side, then use the built-in contact or “Request Quote” forms on each listing to send your requirements directly to suppliers without registration; responses will be sent to the email you provide.

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Holographic Plane Gratings

Holographic Plane Gratings for Precision Optics

Holographic Reflective Diffraction Gratings

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Sold by: Albrighter Technology Co.,Ltd. Ships from: China

Specifications
Groove Density:	600 l/mm
Spectral Range:	250 – 500 nm
Blaze:	Not Blazed
Dimension (Length):	12 mm
Dimension (Height):	12 mm

Did You Know?

Holographic diffraction gratings are produced using a photolithographic approach. Unlike ruled gratings, which contain a reflective layer, holographic diffraction gratings use substrates coated with a photosensitive material (photoresist). The photoresist is specially positioned so that the coated blank lies between intersecting, monochromatic, coherent laser beams, usually from a 488nm Argon laser. The intersecting laser beams generate a sinusoidal intensity pattern of parallel, equally spaced interference fringes in the photoresist material. Since the solubility of the photoresist is dependent on its exposure to light, the gratings can be formed after the material is immersed into a specific solvent and etched accordingly. Holographic diffraction gratings are produced optically; hence, the groove spacing is extremely uniform. Most importantly, holographic gratings do not exhibit the ghosting effects seen in ruled gratings. They are designed to minimize aberrations and can enhance efficiency in a single plane of polarization.

Related Resources

Frequently Asked Questions

A holographic plane grating is a flat diffractive optic whose groove structure is recorded interferometrically in a photosensitive layer and then transferred into a substrate, rather than being mechanically ruled. This process produces a near-sinusoidal groove profile with very low periodic errors and reduced stray light compared to ruled gratings, which typically have a sawtooth (blazed) profile and higher ghosting from ruling artifacts.

Overview of Holographic Plane Gratings

Holographic Plane Gratings are diffraction gratings fabricated by recording an interference pattern in a photosensitive layer and transferring it to a planar substrate. Unlike ruled gratings, holographic structures exhibit low scatter and ghosting, which is crucial for high dynamic range spectroscopy and precision light transport applications.

These Holographic Plane Gratings are utilized to disperse or split light by wavelength while maintaining planar geometry, making them suitable for compact spectrometers, monochromators, beam conditioning modules, and tunable light sources.

Typical Specifications

When evaluating Holographic Plane Gratings on FindLight, procurement engineers typically compare:

Groove density: Common ranges from ~150 to >3600 lines/mm, determining dispersion and spectral resolution.
Wavelength range: Designs optimized for UV, visible, NIR, or broad-band operation; groove profiles tailored to the target band.
Substrate material: Fused silica, BK7, and other optical glasses chosen for thermal and spectral performance.
Diffraction efficiency: Peak and average efficiency in the specified orders and wavelength bands.
Coatings: Bare, Al, enhanced Al, or dielectric AR coatings to match the operational spectrum and environmental constraints.
Clear aperture and dimensions: Grating area and overall size compatible with your optical bench and mounts.
Surface quality and flatness: Scratch-dig and λ/ flatness impacting stray light and imaging quality.

Use Cases in Light Transport Systems

Holographic Plane Gratings are commonly integrated into fiber-coupled and free-space spectrometers, hyperspectral imaging systems, tunable filters, and beam sampling modules. In light transport setups, they enable wavelength multiplexing/demultiplexing, spectral analysis of guided modes, and precise beam steering by wavelength.

Buyer Guidance on FindLight

On FindLight, you can review detailed datasheets for available Holographic Plane Gratings, compare groove density, efficiency curves, wavelength coverage, and mechanical formats across suppliers, then request quotes directly with no registration required. For custom Holographic Plane Gratings—such as non-standard groove densities, custom coatings, or specific aperture sizes—you can use the quote request form to specify optical performance targets, mechanical constraints, and environmental requirements so vendors can respond with suitable configurations and lead times.