HOLOEYE Photonics Redefines Industry Standards with Latest Optical Innovations

Posted  by GoPhotonics


HOLOEYE Photonics, a leading provider of diffractive optics (DOE), spatial light modulators (SLM) for phase and amplitude modulation and LCOS microdisplay components for monochrome and colour projection applications, continues to push the boundaries of innovation with its latest advancements in optical technology.

Founded in 2000, HOLOEYE has been at the forefront of innovation in the field of optics. The company's journey began with the introduction of its first commercial Spatial Light Modulator (SLM) LC in 2002. This marked the beginning of a series of milestones, including the launch of the high-end HD resolution SLM PLUTO in 2006.

In 2016, HOLOEYE achieved a significant breakthrough with the development of its first Diffractive Optics Element (DOE) for a high-volume consumer application, showcasing its commitment to pushing the boundaries of optical technology. This momentum continued with the launch of the first 4K resolution SLM GAEA in 2023, further solidifying the company's position as an industry leader.

Diffractive Optics

HOLOEYE's diffractive components, including beam-splitters, pattern generators, kinoforms, beam shapers, and gratings, utilize microstructure surface relief profiles for their optical function. These components offer unparalleled design flexibility, enabling the reshaping of light to almost any desired distribution through diffraction and subsequent propagation. The DOE only encodes the shape of the desired intensity pattern, but maintains other parameters of the incident light source (e.g. beam size, divergence, polarization).

One of the key advantages of HOLOEYE's diffractive optics is their ability to achieve optical functions that would be otherwise impossible or highly complex with traditional optical systems. Moreover, compared to refractive optical elements, these components are typically much thinner and lighter, making them an attractive replacement in a variety of applications.

Diffractive Beam Splitter

A Diffractive Beam Splitter splits incident laser beams into 1-dimensional or 2-dimensional arrays of beams. Typically used in conjunction with a focusing lens, these beam splitters generate arrays of focused spots at a certain distance behind the lens.

The arrangement of the spots is not limited to arrays in perpendicular x-y lattices. Also hexagonal or irregular lattices are possible. For more complex arrangement of spots, like for structured light pseudo-random spot patterns, the diffractive beam-splitters can also be referred to as Diffractive Pattern generators.

Diffractive Pattern Generators

Another remarkable offering is the Diffractive Pattern Generators, which leverage diffractive optics to create complex patterns with a high depth of field. These patterns, comprising numerous spots, can either overlap to function as a Diffractive diffuser or remain visible as individual spots, acting as Diffractive beam-splitters. Due to the high accuracy of the microstructures, the diffraction angles can be extremely precise, in particular when using a frequency stabilized laser source.

Diffractive Diffusers

HOLOEYE's Diffractive Diffusers stand out for their ability to shape the emitted angular power distribution of various light sources. With Diffractive Diffusers flexible shaping of the emitted angular power distribution of various light sources can be achieved. Diffractive Diffusers can be best used with VCSEL arrays, because they consist of many individual incoherent laser emitters. As a result, the angular far field diffracted light distribution is much less affected from interference-caused intensity modulations, and more uniform light distributions are obtained.

With tailored diffractive diffusers, HOLOEYE is able to create various light distributions for the application wavelength. By suppressing the zero order diffraction to well below 1% compared to the incident light even for large diffraction angles, the desired profiles can be obtained in very good approximation.

Diffractive Beam Shapers

Diffractive Beam Shapers transform incident laser beams with ideally Gaussian intensity profiles into desired intensity profiles at target planes or workpieces. While typically used to achieve uniform (‘flat-top’) circular or rectangular beam profiles, these beam shapers offer flexibility for creating other shapes and non-uniform profiles. Custom developments require precise information about the input beam intensity and phase profile, with the phase profile described by the radius of curvature of its wavefront for high-quality beams with M²<1.3.

In addition to their diffractive components, HOLOEYE specializes in Spatial Light Modulators (SLMs), which are used to modulate amplitude, phase, or polarization of light waves in space and time. These SLMs, based on translucent or reflective liquid crystal microdisplays, offer customizable solutions for a wide range of applications.

Spatial Light Modulators

Spatial light modulator (SLM) is a general term describing devices that are used to modulate amplitude, phase, or polarization of light waves in space and time. HOLOEYE´s Spatial Light Modulator systems are based on translucent (LCD) or reflective (LCOS) liquid crystal microdisplays.

The use of LC materials in SLMs is based on their optical and electrical anisotropy. A certain gray level represents a defined average voltage across the LC cell. This voltage leads to a variable tilt of the LC molecules due to their electrical anisotropy. As LC molecules also show optical anisotropy this tilt changes the refractive index of the LC molecules (for suitable incident polarization, dependent on device version) which causes a modified optical path length within the LC cell. The addressed gray level is now converted into a phase level.

HOLOEYE’s SLMs are based on vertical aligned nematic (VAN), parallel aligned nematic (PAN) or twisted nematic (TN) microdisplay cells. In a twisted cell, the orientation of the molecules differs by typically 45°/90° between the top and the bottom of the LC cell and is arranged in a helix-like structure in between. In VAN/PAN cells the alignment layers are parallel to each other, so the LC molecules have the same orientation.

Microdisplay Technology

HOLOEYE's commitment to innovation is further evidenced by its LCOS (Liquid Crystal on Silicon) microdisplay technology, which combines the advantages of IC/CMOS and liquid crystal technologies to deliver high-resolution projection applications. 

LCOS (Liquid Crystal on Silicon) is a reflective microdisplay technology based on a silicon backplane. This technology is a powerful combination of two well-developed technologies: IC/CMOS and Liquid Crystal (LC). LCOS has a significant advantage in high-end projection applications due to the maturity and potential of both IC/CMOS and LC technologies.

One of the key benefits of LCOS technology is its ability to produce microdisplays with extremely small pixels, high fill factor (pixel aperture ratio), and low fabrication costs. By utilizing standard CMOS processes, HOLOEYE can create microdisplays that deliver exceptional performance at a fraction of the cost.

LCOS Projection Developer Kits

HOLOEYE offers monochromatic and color field sequential microdisplays. For single panel color projection a color field sequential (CFS) display addresses three monochromatic images corresponding to the primary colors (RGB) in a repetitive sequence and is illuminated by a triggered light source.

HOLOEYE's latest innovations in diffractive optical components promise to reshape light manipulation across various industries, offering unprecedented precision and versatility in light shaping and distribution. With its continued dedication to pushing the boundaries of optical technology, HOLOEYE Photonics remains at the forefront of innovation, driving advancements that redefine what's possible in the field of optics.