Liquid crystal spatial light modulator is a device that can load information onto a one-dimensional or two-dimensional optical data field in order to make effective use of light's inherent speed, parallelism and interconnectivity. These devices can be controlled by time-varying drive signals or other signals to achieve amplitude and phase modulation of light. Pure phase type liquid crystal spatial light modulator its parallel to the column of rod-shaped liquid crystal molecules can be seen as a uniaxial crystal, driven by the external electric field makes the liquid crystal molecules to rotate, thereby changing the effective refractive index of liquid crystal molecules, to achieve the modulation of the phase distribution of the light field.
Space light modulator index parameters directly affect the application effect, our company has always been adhering to the “sincere cooperation for this, customer satisfaction for the big” purpose, always meet the actual needs of customers in mind. R & D team through the process of upgrading, index enhancement, the 2K73-P02 product upgrades, in the recent launch of the new 2K73-P02 (HR) phase-type spatial light modulator, the product has a high reflectivity, high light utilization, high diffraction efficiency, high phase linearity, high depth, good color holographic effect, compact structure and other highlights of the advantages.
Fig 1. FSLM-2K73-P02HR Spatial Light Modulator Diagram
Relying on the digital light field control technology, we are committed to the development of electronically addressable liquid crystal spatial light modulators, with product types covering more than 20 spatial light modulator products of transmissive and reflective types, and realizing the independent design and batch production of liquid crystal light valves, and then stepping into a new process of product iteration and excellence.
Fig. 2 Batch FSLM-2K73-P02(HR) liquid crystal light valve
New Product Highlights
● High Reflectivity & Light Utilization
For the problem of low reflectivity in the target band (420nm~650nm), the reflectivity is improved. 2K73-P02(HR) can achieve ≥95%±5% optical utilization in the target band and improve the incident laser energy utilization.
Fig. 3 Reflectance spectrum of LCOS light valve in 420-650 nm band
● High Diffraction Efficiency
Realizing 420nm~650nm band, the 32nd order diffraction efficiency is more than 90%, which ensures that the energy utilization of the beam after SLM modulation can reach the highest.
Fig. 4 Spot diffraction pattern after adding flashing grating
● High linear modulation characteristics & vortex beams
Realize the linearity of phase modulation curve ≥0.99 in 420nm~650nm band, ensure the phase delay varies linearly with the gray scale.
Fig. 5 Phase modulation power curve and linearity plot
The vortex beam directly affects the experimental effect. 2K73-P02(HR) products can realize that the vortex beam is well closed in the band of 420~650nm (test band: 457nm/532nm/637nm), so that it can obtain good application effect.
Vortex beam @ 457nm
Vortex beam @ 532nm
Vortex beam @ 637nm
● Color holography
Color holographic display refers to the color information display realized by using holography. Based on liquid crystal spatial light modulator holographic display system can dynamically carry holograms and realize holographic dynamic display. At the same time, the parameters can be flexibly configured and easy to operate. It has a very broad application prospect in the fields of national defense and military, medical and health care, education and teaching, scientific research, and innovative design.
Fig. 6 Color holographic display effect based on 2K73P02(HR)
● Compact structure, compatible with external and internal structures
Self-developed driver board based on flexible and programmable FPGA platform, can be from the control of computing graphics card real-time image data for solving and time sequence processing, while embedded frame synchronization module, to achieve the input and output synchronization function, in addition to the compact structure (about 80mm * 80mm), with the light valve to support the built-in one-piece and dumping a variety of structures to facilitate the fixation of the optical path in the light.
Fig. 7 Miniaturized FPGA driver board
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Model Number |
FSLM-2K73-P02 |
FSLM-2K73-P02HR（New product） |
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Modulation Type |
phase type |
phaseProduct Indicators type |
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Liquid Crystal Type |
reflex |
reflex |
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Number of Pixels |
2048*2048 |
2048*2048 |
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Image size |
6.4μm |
6.4μm |
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Effective Display Area |
0.73inch（13.1mm*13.1mm） |
0.73inch （13.1mm*13.1mm） |
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Spectral Range |
420-650nm |
420~650nm |
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Test wavelength |
532nm |
457nm |
532nm |
637nm |
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Linearity |
≥99% |
≥99% |
≥99% |
≥99% |
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Light Utilization |
50% |
≥93% |
≥93% |
≥93% |
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Diffraction efficiency |
L16:59.6% L32:65.2% |
L16:78.6% L32:90.4% |
L16:80.7% L32:91.6% |
L16:77.5% L32:90.6% |
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Reflectivity |
50% |
≥95% |
≥95% |
≥95% |
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Response Time |
43.5ms |
35.9ms |
44.8ms |
42.8ms |
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Gray Level |
8bit，256steps |
8bit，256steps/10bit，1024steps |
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Phase Modulation |
≥2π |
≥2π |
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Refresh frequency |
60Hz |
60Hz |
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Data Interface |
HDMI |
HDMI |
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Driver board size |
149.95mm*80.01mm |
80mm*80mm |
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Typical Applications
The optical utilization, diffraction efficiency, linearity, and phase stability of spatial light modulators are very important indicators that directly determine the application effect. It has a broad application prospect in laser processing, optical communication, beam shaping and other application fields.
● Laser Processing:
Ultra-fast laser processing technology promotes the development of laser manufacturing from traditional macro processing to ultra-precision processing. Although ultrafast laser processing technology has attracted more and more attention in the 3C electronic field by virtue of its powerful advantages, the single-focused ultrafast laser direct processing technology still suffers from the problems of small processing area and low efficiency, and it cannot satisfy the demands of large-format and high-precision processing at the same time. Spatial light modulator can be on the ultra-fast laser beam amplitude, phase or polarization and other optical parameters for regulation, with a certain optical path design can be in the material processing area to get an arbitrary light field intensity distribution.
1) Aberration correction
The existence of aberration will make the intensity distribution of the focused light field and the intensity distribution of the target light field deviate, affecting the three-dimensional distribution of the light field during processing, lowering the processing accuracy, raising the processing threshold, and even failing to process the target structure. Through the hologram, combined with the phase modulation function of SLM, the aberration can be corrected quickly and conveniently to improve the accuracy and quality of ultrafast laser processing.
Fig. 8 SLM-based aberration correction
2) Multi-focus parallel processing
Multi-focus parallel processing in different two-dimensional or three-dimensional position of the sample can exponentially improve the processing efficiency, but its preparation is more complex, and the use of inflexible. Spatial light modulator using hologram technology for phase modulation of incident light, can quickly generate a variety of target light field for multi-focus processing, and by switching the hologram to real-time modulation of the target light field, two-dimensional, three-dimensional structure of the rapid processing.
Multi-focused two-photon polymerization technology can also be used for human tissue engineering scaffolds, micro-needle arrays, cell culture media and other functional biological and medical micro-devices preparation, significantly improving the processing efficiency and precision. Ultra-fast laser multi-focus parallel processing technology can also be used to improve the writing speed of multi-dimensional optical storage, as well as parallel processing of materials such as silicon and stainless steel.
Spatial light modulators bring great convenience to ultrafast laser processing, where different hologram algorithms can be used to obtain different two-dimensional target light fields, so that the desired structures can be processed quickly and with high precision. The parallel processing of multi-focus arrays using spatial light modulators greatly improves the processing efficiency. The multifocal parallel processing technology can be combined with various optical field modulation techniques, such as aberration correction, spatial and temporal synchronous focusing, and structured light field, to realize ultrafast laser parallel processing in a variety of special application scenarios.
The above information comes from Zhihu “in the application of ultra-fast laser processing, space light modulator and so many ways to play”.
● Optical communication:
The phase modulation of incident light by software-controlled pixels in different areas of the liquid crystal spatial light modulator can control the beams of corresponding wavelengths in the area to be diffracted at a certain angle to different output ports in the direction of the ports. Since the deflection of the output beam at different angles is controlled by the diffraction effect of the liquid crystal spatial light modulator, the maximum deflection angle that can be achieved by the liquid crystal spatial light modulator and the number of ports of the input/output module within the angle range directly determine the number of ports of the wavelength selector switch.
Fig 10. Wavelength Selection Switch Schematic
● Beam shaping:
Bessel beams, vortex beams and array beams can be generated by loading different phase maps using spatial light modulators.
Bessel beam is a special non-diffracting beam with a small center spot and self-healing properties after interference during propagation, which has great application value in high-speed communication, non-destructive testing, material processing, 3D imaging and other fields;
A vortex beam is a beam with a helical phase wavefront with orbital angular momentum (OAM) that can carry different topological charges. Vortex beams have very broad application prospects in the fields of optical operation, high-capacity optical communication and super-resolution imaging;
Array beams can be generated by loading Dammann gratings in the SLM control software. A Dammann grating is a binary phase grating with unequal spacing and periodic repetition. It has a wide range of applications in the fields of femtosecond pulsed laser technology, laser detection, laser direct writing, three-dimensional measurement, three-dimensional imaging, particle manipulation, fiber optic communication, optical storage and so on.
Fig. 11 Measured effect of SLM-based beam shaping
More Expectations
CAS Microstar always adheres to the mission of “leading customers with technology, leading customers with service”, and insists on providing cost-effective products as well as high-quality personalized service. Our company is currently committed to research and development of more new types of space light modulators and the iterative upgrading of the original products, and strive to achieve a qualitative leap in the localization of space light modulators, so please look forward to our next technological upgrading!