SAW Diffractive Modulator for Broad Light Steering
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Solution Overview
Problem
Existing diffractive modulators, such as acousto-optic modulators, face limitations including narrow beam steering angles, discretized steering, unintentional beam broadening, and excessive device volume, which restrict their effectiveness in light steering applications.
Innovation Solution
The proposed solution leverages the wavelength dependence of diffractive phenomena by combining radio frequency (RF) and wavelength-driven steering using diffractive structures like gratings and SAW modulators, along with chromatic dispersive elements to achieve broadened scanned angles and high angular dynamic range, enabling continuous light steering with a multiwavelength light source and controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional diffractive modulators are used for light steering, then light steering function is achieved, but beam steering angle is narrow
Solution Approach 1:
The patent applies parameter changes by simultaneously varying both the frequency of the RF drive signal and the wavelength of the incident light. This dual parameter modulation enables the system to achieve a broader beam steering angle range while maintaining steering precision through coordinated adjustment of both parameters, resolving the contradiction between steering angle width and steering precision.
Solution Approach 2:
The patent employs composite material structures in the diffractive modulator, combining multiple materials with different optical and acoustic properties. This composite structure enables enhanced light steering capability with broader angles while maintaining precision through the synergistic effects of different materials working together.
2Adaptability or versatility
If conventional diffractive modulators are used, then light steering is achieved, but steering angle selection is discretized
Solution Approach 1:
The patent implements continuous steering angle control by continuously varying the RF drive signal frequency and/or the incident light wavelength. This continuous parameter modulation eliminates the discretized stepping characteristic of conventional systems, enabling smooth, continuous steering angle selection across the entire range while maintaining high precision through the continuous nature of the control mechanism.
3Adaptability or versatility
If conventional diffractive modulators are used, then light steering function is provided, but beam broadening occurs unintentionally
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor the actual beam output and adjust the RF drive frequency and/or incident light wavelength accordingly. This feedback control compensates for unintentional beam broadening by dynamically tuning the parameters to maintain a focused beam while achieving the desired angular coverage, thus resolving the contradiction between angular coverage and beam direction precision.
4Adaptability or versatility
If conventional diffractive modulators are used, then light steering is achieved, but device volume is excessive
Solution Approach 1:
The patent transitions from conventional three-dimensional bulk acoustic wave modulators to surface acoustic wave modulators that operate in a planar, two-dimensional configuration. This dimensional change enables the light steering function to be achieved with significantly reduced device volume while maintaining full steering capability through the surface wave propagation mechanism.
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 approach enhances the angular dynamic range of light steering systems, allowing for fine control over a large range of angles, reducing perceptual artifacts, and improving the efficiency of light steering in applications like holographic displays.
Implementation Method 1
AOMs are a type of diffractive modulator that use diffraction to direct light
Implementation Method 2
surface acoustic waves (SAWs) diffract light propagating in the modulators' waveguides
Implementation Method 3
The system leverages the chromatic dispersive qualities of these structures to improve the angular dynamic range
Data Source
AI summary
A light steeling system and method for diffractive steering of electromagnetic radiation such as visible light is disclosed. Embodiments of the light steering system include leaky-mode SAW modulators as light modulator devices. The SAW modulators preferably include reflective diffractive gratings. The gratings are mounted to/patterned upon an exit face that opposes an exit surface of the SAW modulator, in one example. Steering of light signals emitted from the SAW modulators in these systems can be accomplished by varying wavelength of light signals introduced to the SAW modulators, and/or by varying frequency of RF drive signals applied to the SAW modulators. In addition, light field generators that incorporate SAW modulators of the proposed light steering system within displays of the light field generators are also disclosed.