Integrated Beam Collimation Optics for Asymmetric Laser Fields
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Solution Overview
Problem
Existing light beam collimation devices for high-power diode lasers and quantum cascade lasers face inefficiencies due to incomplete collimation of light radiation fields, leading to power loss when coupling into fiber optics, particularly with asymmetrical beam characteristics and non-circular cross-sections, which are not effectively focused by spherical lenses.
Innovation Solution
A device comprising a first and second collimation lens, arranged sequentially, with an additional optical element that aligns oblique propagation directions parallel to the beam direction, allowing complete collimation of the light radiation field by integrating the functions of collimation and focusing into a single optical element, such as a free-form surface on the second collimation lens, ensuring all components are aligned parallel to the beam direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate cylindrical collimation lenses are used for fast axis and slow axis, then collimation in principal planes is achieved, but oblique propagation directions are insufficiently collimated resulting in blurred fields and performance loss
Solution Approach 1:
The collimation device is segmented into multiple functional components: a first cylindrical collimation lens for fast axis collimation, a second cylindrical collimation lens for slow axis collimation, and a third optical element with oblique collimation surfaces. Each segment handles specific propagation directions, collectively achieving complete collimation of all light rays including oblique ones.
Solution Approach 2:
The solution adds a third dimension to collimation by introducing optical surfaces oriented at oblique angles (e.g., 45 degrees) relative to the principal planes. This third angular dimension captures and collimates light rays that propagate in directions between the fast and slow axes, which cannot be collimated by the two principal plane lenses alone.
2Measurement precision
If multiple separate collimation lenses are used to achieve complete collimation, then all light portions are aligned parallel, but device complexity and size increase
Solution Approach 1:
The first and second cylindrical collimation lenses are merged into a single integrated lens that performs both fast axis and slow axis collimation functions. This integration reduces the number of separate optical elements while maintaining complete collimation capability in the principal planes.
Solution Approach 2:
The integrated collimation lens is designed with multiple functional surfaces: cylindrical surfaces for fast and slow axis collimation, and oblique collimation surfaces for oblique direction collimation. This universal optical element performs multiple collimation functions simultaneously, reducing overall device complexity.
3Power
If spherical/aspherical lenses are used for focusing, then focusing capability is provided, but asymmetrical beam fields with non-circular cross-sections are not effectively focused
Solution Approach 1:
The collimation device introduces asymmetry through cylindrical lenses with different focal lengths and curvatures for the fast and slow axes. The first cylindrical lens has a focal length optimized for fast axis collimation, while the second cylindrical lens has a focal length optimized for slow axis collimation, matching the asymmetrical beam characteristics of diode lasers.
Solution Approach 2:
Different regions of the optical system are assigned different optical properties: the fast axis region uses cylindrical surfaces with specific curvature, the slow axis region uses cylindrical surfaces with different curvature, and oblique regions use inclined surfaces. Each region is optimized for its specific collimation requirements, achieving uniform collimation quality across all directions.
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 solution enhances the collimation efficiency, allowing a larger proportion of the light radiation field to be focused, thereby increasing performance and reducing power loss during coupling, with improved precision and reduced device size compared to separate collimation lenses.
Implementation Method 1
a first collimation lens for collimating the light radiation field in the first plane
Implementation Method 2
a second collimation lens for collimating the light radiation field in the second plane
Implementation Method 3
an additional optical element, which is configured such that portions of the light radiation field which are not yet aligned parallel by the first and second collimation are aligned parallel to the beam direction
Data Source
Figure 1~1a
Figure 2~3
Figure 3a~4
AI summary
The invention relate to a device for collimating a light radiation field of a light source (L) having a beam characteristic which is different in a first plane (FAC) from that of a second plane (SAC). The device comprises at least one first collimating lens (10) and a second collimating lens (20). The device has an additional optical element (30), in order to collimate the light radiation field in different planes to the first and to the second plane.