We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is Holographic Grating?

By Paul Reed
Updated May 17, 2024
Our promise to you
WiseGeek is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WiseGeek, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A holographic grating is a pattern formed on a film by lasers used to diffract light, or separate light into its various wavelengths. Diffraction products are used in spectroscopy and astronomy where incoming light must be expanded or diffracted to show its spectrum. Spectroscopy is the science of using light to determine the chemical composition of substances, where each element has a particular light absorption behavior.

Diffraction gratings are holographic if made by interactions of lasers with a light sensitive coating, or photoresist. Ruled diffraction products are metal plates that have been ruled or cut with very fine diamonds, creating a pattern of lines that will separate light. A holographic grating can provide finer light diffraction because the lines are created by light, not by cutting a plate.

Lasers can be used to create gratings because of the principle of interference patterns. Light passing through air or space has the appearance of a wave, with peaks and valleys. Using a laser creates a single wavelength of coherent light, or light oriented in a single wave direction. Normal light is a variety of colors, or wavelengths, scattering in all directions. When two lasers are pointed at a photoresist plate, they form a series of interference lines as the light waves of each laser interact with the other.

An example of diffraction lines can be seen by looking at a bright light through the fingers of a hand. If the fingers are separated by a small amount, the light coming through will appear to have a series of very fine black lines running vertically between the fingers. These are diffraction lines caused by the fingers acting as a lens, causing the light to bend slightly and interact in the narrow space.

Clean and dark areas are important when creating a holographic grating, because dust or any stray light will cause defects in the final product. The lasers must have the same wavelength and be oriented at specific angles to each other. Plastic film or glass can be coated with photoresist, which reacts chemically to the presence of light. When the film or plate is developed, the diffraction lines appear as very fine sinusoidal or wave patterns.

A single laser holographic grating can be made, using mirrors and lenses to split the light beam. Some losses occur with each mirror and lens used in such a system. It is preferred to use two identical lasers to maintain the best quality.

Ruled gratings have inherent defects, because they are mechanically cut into metal plates. Slight differences in cutting depth or imperfections in the metal surface can affect the diffraction patterns. These products are useful when a more durable surface is needed and the differences between a ruled and holographic grating are understood.

WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.