Diffractive optics (DO), simply known as diffraction, are a tool used in designing an optical system, in most experimental and commercial systems. The applications of light is more than just illumination and communication. Besides these, other applications, including imaging and sensing require light that has to be manipulated in complex ways. This is done in compact systems, however. Diffractive Optical Element (DOE)s can address both these requirements at the same time. With DO, as the name says, the principal phenomenon applied is diffraction, instead of refraction.
Applications of Diffractive Optical Elements
There are a number of applications of a diffractive optical element. Here are certain important applications of DOEs:
- A Diffraction Optical Element provides a distinct and improved chromatic aberration (also known as chromatic distortion and spherochromatism).
- Diffractive Optics is found in long range distance sensors such LiDAR/LADAR (Light Detection and Ranging), short range distance sensors, position sensors, motion detection and projection systems.
- The applications of DO range from biotechnology through processes such as printing, material processing, and sensing.
- It adds value to LASER (Light Amplification and Stimulated Emission of Radiation) Systems.
- A DOE when incorporated in the optical field of a laser beam, the beam’s shape can be regulated and altered flexibly in accordance with the requirements of the application
Design and Fabrication of Diffractive Optical Elements
The design and fabrication of DOEs with accuracy and high diffraction efficiency is, so far, one of the most up-and-coming trends in the development of optics. These elements are extensively used in techniques such as optical metrology and laser technology. They are also widely used in displays, sensors etc. Although DOEs were fabricated by image pattern generators, especially designed for the jobs of semiconductor industry, the current variety of DOEs and microptical elements generates a stimulus for the development of modern equipment and new technologies, especially for optical tasks.
Fabrication of superior optics is delineated by its testing methods. In optics, spherical and plane wavefronts can be formed with high accuracy while interferometry makes sure of quality of fabricated surfaces with nanometer accuracy with the help of these wavefronts. Nevertheless, surfaces with shapes other than spherical and plane are necessary for different applications. These days, the generation of aspherical wavefronts using refractive and diffractive optical elements, and computer-generated holograms has become popular. These elements change the preliminary flat/spherical wavefront into an aspherical one. In other words, they function as wavefront correctors. With the development of direct laser and e-beam writing systems, diffractive patterns (providing wavefront formation with nanometer accuracy) were produced.