Offset Retroreflector Optics for Stable Beam Alignment
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Solution Overview
Problem
LASER resonators, interferometers, and spectrometers face challenges in maintaining stable beam alignment due to lack of rigid mechanical structures for reflectors, leading to positional and orientational instability of reflected beams, especially when retroreflectors are movable or tilted.
Innovation Solution
An optical arrangement where a retroreflector is offset transversely to the optical axis, and a second reflector attached to the mechanical structure reflects the beam back in a fixed parallel offset direction, decoupling the beam's position from the retroreflector's position and orientation, ensuring stability regardless of the retroreflector's distance or tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a retroreflector is arranged remotely from the light source to reflect the light beam, then the optical path length can be extended, but the alignment stability deteriorates due to lack of rigid mechanical structures
Solution Approach 1:
Instead of attempting to rigidly secure the remotely positioned retroreflector to maintain alignment, the invention inverts the approach by using the retroreflector's inherent property of reflecting light back parallel to the incident beam. The second reflector is then positioned to receive this reflected beam and direct it back through the optical system, eliminating the need for rigid mechanical attachment of the remote reflector while maintaining alignment stability
Solution Approach 2:
The invention introduces a second reflector as an intermediary element between the light source and the remotely positioned first retroreflector. This second reflector acts as a mediator that receives the beam reflected by the first retroreflector and redirects it back through the optical system, thereby decoupling the alignment stability from the mechanical rigidity of the remote structure
2Adaptability or versatility
If a retroreflector is movable in the direction of the laser beam, then the optical path can be adjusted, but the alignment stability deteriorates because the reflector cannot be rigidly attached
Solution Approach 1:
The invention inverts the conventional approach by positioning the movable retroreflector remotely and using a second reflector to redirect the reflected beam. This allows the retroreflector to be movable while the second reflector, which can be rigidly attached, ensures stable beam redirection back through the optical system
Solution Approach 2:
The second reflector serves as a stable intermediary that can be rigidly attached to mechanical structures, receiving the beam from the movable first retroreflector and directing it back through the optical path. This mediator approach allows optical path adjustment while maintaining alignment stability
3Adaptability or versatility
If the retroreflector is tilted relative to the optical axis, then the beam direction can be changed, but the reflected beam position deteriorates due to angular errors
Solution Approach 1:
The invention inverts the approach by using the retroreflector's property of reflecting light parallel to the incident beam direction, regardless of its tilt angle. The second reflector is then positioned to receive this parallel reflected beam and direct it back through the optical system, eliminating the angular error problem that would normally occur with tilted reflectors
Solution Approach 2:
The second reflector acts as an intermediary that receives the beam reflected by the tilted first retroreflector and redirects it back through the optical system. This intermediary approach allows the first retroreflector to be tilted for beam direction control while the second reflector ensures accurate beam positioning
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 arrangement maintains beam stability and direction, even with changes in the retroreflector's position or orientation, by predetermining the optical axis's position relative to the mechanical structure, enhancing positional stability and alignment in LASER systems.
Implementation Method 1
the first reflector is a retroreflector which is arranged with a transverse offset to the first optical axis, so that it reflects the light beam coming from the light source in the direction of a second optical axis which is offset parallel to the first optical axis
Implementation Method 2
the second reflector reflects the light beam reflected by the first reflector back to the first reflector in the direction of a third optical axis, wherein the third optical axis is offset parallel to the second optical axis by a fixed amount in a fixed transverse direction
Data Source
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AI summary
In the case of an optical arrangement (1) having a light source (2), which emits a light beam (3) in the direction of a first optical axis (4), wherein a spatial orientation of the first optical axis (4) is defined in relation to a mechanical structure (5) of the light source (2), having a first reflector (6) for the light beam (3) that is arranged at a distance from the light source (2) and having a second reflector (12) for the light beam (3') reflected by the first reflector (6), the first reflector (6) is a retroreflector (7) which is arranged with a transverse offset from the first optical axis (4) in such a way that it reflects the light beam (3) in the direction of a second optical axis (11) which has a parallel offset of two times the transverse offset in relation to the first optical axis (4) in the transverse direction of the transverse offset. The second reflector (12) is fastened to the mechanical structure (5) of the light source (2) and reflects the light beam (3) that was reflected by the first reflector (6) back to the first reflector (6) in the direction of a third optical axis (13), wherein the third optical axis (13) has a parallel offset with a fixed amount (14) in a fixed transverse direction in relation to the second optical axis (11). As a result, the light beam (3) is reflected by the first reflector (6) in the direction of a fourth optical axis (15) which has a parallel offset in relation to the first optical axis (4) with a fixed amount (14) counter to the fixed transverse direction.