Acousto-Optic Deflector Collinear Beam Compensation
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Solution Overview
Problem
The angle shift and resulting beam displacement between incoming and diffracted beams in acousto-optic devices pose challenges in designing compact opto-mechanical systems, requiring compensation in upstream or downstream optomechanical design.
Innovation Solution
The implementation of mechanical degrees-of-freedom, such as manual or motorized tilt stages, on external angle control prisms allows for fine-tuning of the acousto-optic deflector configuration to achieve collinear incoming and diffracted beams across various wavelengths and acoustic frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the angle shift and beam displacement from acousto-optic devices are compensated in the optomechanical design, then the system achieves compact configuration, but the device complexity increases due to additional compensation components
Solution Approach 1:
The patent introduces angle control prisms as intermediary components between the laser source and acousto-optic device, and between the device and detector. These prisms act as mediators that compensate for beam angle shifts and displacement without requiring complex feedback control systems, thereby achieving compact configuration while managing device complexity through simple optical elements
Solution Approach 2:
The patent applies preliminary action by pre-adjusting the angle control prisms to compensate for expected beam angle shifts before the acousto-optic device operates. The prisms are positioned and oriented in advance to counteract the diffraction-induced angle changes, eliminating the need for real-time complex compensation and reducing overall system complexity
2Manufacturing precision
If angle control prisms are added to compensate for beam displacement, then the manufacturing tolerance sensitivity is reduced, but the device complexity increases
Solution Approach 1:
The angle control prisms serve as intermediary elements that simplify the compensation of manufacturing tolerances. Rather than requiring complex active control systems, the prisms provide passive optical compensation that reduces sensitivity to Bragg angle alignment variations with minimal added complexity
Solution Approach 2:
The patent utilizes parameter changes by adjusting the orientation and position parameters of the angle control prisms to compensate for variations in the acousto-optic device's Bragg angle. By changing the geometric parameters of the prism arrangement, the system achieves tolerance compensation without requiring complex active adjustment mechanisms
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 compensation scheme significantly reduces the sensitivity of Bragg angle alignment, achieving an 82-fold reduction in beam angle change, thereby enhancing the adaptability and resilience of the system to manufacturing tolerances.
Implementation Method 1
These AO devices are based on the diffraction of beams of light by a grating formed by an acoustic wave in the device crystal. Diffraction leads to the incoming beams and the diffraction orders having one or more angles between them. The angle θ is given by the Bragg condition sin(0)=λ*/d
Implementation Method 2
Acousto-optic modulators (AOM) may be used for gate control via amplitude, phase, and frequency modulation of laser beams. Acousto-optic deflectors (AOD) can be used for beam steering, as well as amplitude and phase modulation.
Implementation Method 3
This angle and/or a lateral displacement between the incoming beam and the diffracted beam can be mitigated by modifying the input and output facets of the AO crystal and by making use of the refraction at the air-crystal interface.
Data Source
AI summary
Aspects of the present disclosure may include a method and/or a system for providing an acousto-optic deflector (AOD), emitting, toward a first deflector plate, a source beam, deflect the source beam, via the first deflector plate, to generate a deflected source beam toward the AOD, diffract, via the AOD, the deflected source beam to generate at least one diffracted beam, toward a second deflector plate, and deflect the at least one diffracted beam, via the second deflector plate, to generate a deflected diffraction light, wherein the source beam and the deflected diffraction light are collinear or substantially collinear.