Four Kinds of Diffractive Optical Elements

Diffractive optical elements (DOEs) are designed to be utilized as multi-spot beam splitters when shaping beams and modifying beam profiles with lasers and high-power lasers. The use of various diffractive elements for beam splitting is beneficial when there is a need for an element to produce multiple beams or when a very exact power separation is required. Also, DOEs achieve specific positioning to create holes at accurate and defined distances.

Applications of DOEs range from biotechnology through printing material processing, contact-less testing, and sensing to technical optics and optical metrology. Diffractive optics offer extra value to laser systems. Incorporating DOEs in a laser beam’s optical field makes it possible to control the shape of the beam and change flexibility based on application needs. Below are the different types of DOEs available:

High-Efficiency Double Spot (HEDS) Beam Splitter

This DOE is designed to separate an incoming laser beam into a couple of identical beams with 97 percent efficiency, leading to over 48% with every beam. Such splitter comes in wavelengths between 193 nm and 10.6 μm. HEDS tends to be quite sensitive to centering; however, slightly modifications will not affect spot shape and overall efficiency.

Beam Sampler Elements

These diffractive elements are used to inline monitor high-power lasers. They come with a design that allows the use of the ± first diffraction order for beam measurement and the use of high diffraction orders for measurement with lower intensities. The intensity is lower than the main beam and its design can be customized.

Multi-spot Elements

These elements are used for splitting a collimated incident beam into many beams that have uniformed angles and intensity. One-dimensional or 1D elements are used for splitting beams along a straight line. Meanwhile, two-dimensional or 2D elements produce beams that are arranged into a matrix.

Multi-focus Elements

These are used for making multiple focus points along their optical axis. They are ideal for use in sensor technology and ophthalmology. Also, a lot of emerging focal points can be used for optimizing results in material processing.

Diffractive optics have a technical discipline that offers methods to design and implement DOE microstructure to manipulate light and photons, implementing desired function. Improvements in DO design and implementation have been achieved within the last few years. Manufacturers have been able to implement fabrication techniques proven to be dependable and cost-efficient. Diffractive optics can realize nearly the same optical functions as refractive optics like prisms, lenses, or aspheres; however, they tend to be smaller and lighter.

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