Through-Hole Spatial Light Modulator for Fast Dense Phase Control
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Solution Overview
Problem
Conventional spatial light modulators, such as liquid crystal-type modulators, have a large pixel arrangement period and limited speed due to their configuration, making it difficult to achieve high-quality dynamic optical images when combined with photonic crystal laser elements.
Innovation Solution
A surface waveguide-type spatial light modulator with a substrate having through-holes and layered structures, including electroconductive and dielectric layers, allows for dynamic control of light phase distribution with a smaller pixel arrangement period, enabling faster operation by individual voltage adjustment for each through-hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid crystal-type spatial light modulator is used, then phase modulation capability is achieved, but pixel arrangement period becomes large and operation speed is limited
Solution Approach 1:
The patent replaces the liquid crystal mechanism with a piezoelectric mechanism. The piezoelectric element directly converts electrical signals to mechanical displacement, eliminating the need for liquid crystal molecules to reorient. This substitution enables faster response speeds while achieving finer pixel arrangement periods, as the piezoelectric actuator can be miniaturized more effectively than liquid crystal pixel structures.
Solution Approach 2:
The patent changes the fundamental operating parameter from liquid crystal optical anisotropy to piezoelectric mechanical displacement. By using the piezoelectric effect to directly modulate the optical path length through physical displacement of the reflective surface, the system achieves both faster operation speeds and smaller pixel dimensions, resolving the contradiction between speed and device complexity.
2Quantity of substance
If liquid crystal spatial light modulator is combined with photonic crystal laser element, then dynamic optical image control is enabled, but the number of effective pixels remains extremely small
Solution Approach 1:
The patent segments the phase modulation function into multiple independent piezoelectric actuators arranged in a grid pattern. Each piezoelectric element can be independently controlled to modulate the phase of light reflected from its corresponding region. This segmentation enables a high number of effective pixels (e.g., 100x100 or more) within a compact footprint, as each actuator occupies minimal space compared to liquid crystal pixel structures.
Solution Approach 2:
The patent transitions from two-dimensional liquid crystal pixel arrays to a three-dimensional structure utilizing vertical piezoelectric actuation. The piezoelectric elements are positioned beneath the reflective surface, with their displacement acting in the vertical dimension to modulate optical path length. This dimensional transition allows for higher pixel density in the horizontal plane while maintaining compact overall dimensions.
3Adaptability or versatility
If fixed arrangement of modified refractive index regions is used, then pre-designed optical image is achieved, but dynamic control of phase distribution is not possible
Solution Approach 1:
The patent implements dynamic phase modulation by replacing fixed refractive index modifications with actively controllable piezoelectric actuators. Each piezoelectric element can be independently driven by voltage signals, allowing real-time adjustment of the phase distribution across the optical beam. This dynamic control enables the system to adapt to different optical image requirements without physical reconfiguration, achieving versatility while maintaining a relatively simple layered structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration increases the number of effective pixels, allowing for high-quality dynamic optical images and improved speed by reducing the pixel arrangement period and eliminating speed limitations associated with liquid crystals.
Implementation Method 1
a piezoelectric element, which changes an optical path length of the reflected light by a piezoelectric action
Implementation Method 2
spatially controlling a phase distribution of the laser light by the piezoelectric action
Data Source
AI summary
This disclosure relates to a spatial light modulator, etc., the spatial light modulator being capable of dynamically controlling the phase distribution of light, and provided with a structure having a smaller pixel arrangement period and suitable for high-speed operation. The spatial light modulator includes a substrate. The substrate has a front surface, a back surface, and through-holes arranged one-dimensionally or two-dimensionally and penetrating between the front surface and the back surface. The spatial light modulator further includes layered structures each covering the inner walls of the through-holes. Each layered structure includes a first electroconductive layer on the inner wall, a dielectric layer on the first electroconductive layer and having optical transparency, and a second electroconductive layer on the dielectric layer and having optical transparency. At least one of the first and second electroconductive layers is electrically isolated for each group including one or more through-holes.