Compensator System for Acousto-Optic Deflector Angular Dispersion
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Solution Overview
Problem
Existing 3D laser scanning technologies using acousto-optic deflectors face challenges with spatial and temporal dispersion, particularly when combined with multi-photon scanning, as prior art optical arrangements fail to sufficiently reduce angular dispersion, leading to limitations in scanning speed and resolution.
Innovation Solution
A compensator system comprising a first lens group, a compensator element with two surfaces acting like prisms with varying incidence and opening angles, and a second lens group is used to focus and separate beams by deflection angle, effectively reducing wavelength dependence and angular dispersion in acousto-optic deflectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If acousto-optic deflectors are used for rapid 3D laser scanning, then scanning speed is improved, but angular dispersion increases leading to reduced measurement precision
Solution Approach 1:
The optical system is segmented into multiple functional components: first lens group for focusing, compensator element with two surfaces for dispersion compensation, and second lens group for beam shaping. Each component addresses specific aspects of the angular dispersion problem while maintaining rapid scanning capability.
Solution Approach 2:
A compensator element is introduced as an intermediary component between the acousto-optic deflectors and the sample. This element with its two specially designed surfaces acts as a mediator that compensates for angular dispersion introduced by the deflectors, allowing high-speed scanning to maintain measurement precision.
2Measurement precision
If conventional mechano-optic deflecting means are used for XY scanning, then angular dispersion is minimized, but scanning speed is reduced due to mechanical inertia
Solution Approach 1:
The patent replaces mechanical scanning systems (galvanometric scanners with moving mirrors) with acousto-optic deflectors that use acoustic waves to deflect the laser beam. This substitution eliminates mechanical inertia, enabling much faster scanning speeds while the added compensator element addresses the angular dispersion introduced by the acoustic deflection.
3Adaptability or versatility
If acousto-optic deflectors with high acoustic frequencies are used, then deflection angle and scanning range are improved, but angular dispersion and wavelength dependence increase
Solution Approach 1:
The compensator element features two surfaces with specifically designed local properties - each surface has tailored curvature and orientation to compensate for angular dispersion at different stages of the optical path. This local optimization allows the system to maintain broad deflection angle range while correcting wavelength-dependent effects.
Solution Approach 2:
The system changes the acoustic frequency parameter dynamically to achieve different deflection angles and scanning ranges. The compensator element is designed to compensate for angular dispersion across this variable frequency range, allowing the system to adapt to different scanning requirements while maintaining measurement precision through parameter optimization.
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
The system enhances scanning speed and resolution by spatially separating beams with different angular dispersion, allowing for independent compensation of each beam, thereby improving the field of view and maintaining angular variation across different acoustic frequencies.
Implementation Method 1
a first lens group (22) arranged so as to focus the deflected electromagnetic beam (18) into a focal plane (FP)
Implementation Method 2
a compensator element (26) with two surfaces arranged between the first lens group (22) and the second lens group (24) so as to compensate for the angular dispersion of the deflected electromagnetic beam (18)
Implementation Method 3
a compensator element (26) with two surfaces acting like prisms with varying incidence and opening angles
Implementation Method 4
a second lens group (24) arranged downstream of the compensator element (26) so as to parallelise the spectral components (18a, 18b, 18c) of the deflected electromagnetic beam (18)
Implementation Method 5
rapid acousto-optic deflectors (AOD) have been proposed as an alternative to the conventional mechano-optic solutions
Data Source
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AI summary
The invention relates to a compensator system adapted to compensate for the angular dispersion of electromagnetic beams deflected by at least one acousto-optic deflector of an optical system, wherein the angular dispersion of each deflected beam is dependent on the deflection angle obtained by the deflecting acoustic frequency of the acousto-optic deflector, characterised in that the compensator system comprises: - a first lens group for spatially separating the deflected beams of different deflection angle and angular dispersion by focusing the beams substantially into the focal plane, - a compensator element having a first surface and a second surface, and being arranged such that the first surface of the compensator element lies substantially in the focal plane of the first lens group, and the first and second surfaces of the compensator element have nominal radiuses R1 and R2 that together work as prisms with tilt angles beta and prism opening angles alphap that vary with the distance from the optical axis so as to compensate for the angular dispersion of the spatially separated deflected beams, - a second lens group arranged so as to substantially parallelise the different wavelength components of each deflected beam exiting the compensator element while maintaining the angular variation of the beams deflected at different acoustic frequencies. The invention further relates to method for compensating for the angular dispersion of electromagnetic beams deflected by at least one acousto-optic deflector of an optical system, wherein the angular dispersion of each deflected beam is dependent on the deflection angle obtained by the deflecting acoustic frequency, characterised by - spatially separating the deflected beams of different deflection angle and angular dispersion by focusing the beams via a first lens group substantially into the focal plane of the first lens group, - compensating for the angular dispersion of the spatially separated deflected beams in accordance with the angular dispersion of the given beam, - substantially parallelising the spectral components of each deflected beam while maintaining the angular variation of the beams deflected at different acoustic frequencies.