Variable-Astigmatism Beam Adaptation Device for Frequency Conversion
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Solution Overview
Problem
Complex optical systems face challenges in adjusting laser beam parameters such as lateral extent and divergence, particularly in achieving rotationally symmetrical or astigmatic beam shapes, due to variations in laser sources and optical components, which can lead to undesirable aberrations and optical component degradation from UV radiation.
Innovation Solution
A beam adaptation device comprising adjustable astigmatism lens units, divergence adjustment lenses, and a control system that allows for continuous variable adjustment of beam size and divergence, enabling the creation of desired beam parameters by tilting and positioning lenses along the beam axis, and using a frequency conversion unit with precompensation to minimize aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downstream optical systems are designed to compensate for aberrations in UV laser radiation, then the aberrations in amplitude and phase can be corrected, but the optical components experience gradual surface degradation from UV radiation
Solution Approach 1:
The patent applies preliminary action by pre-shaping the laser beam upstream before it enters the frequency conversion crystal. The beam is pre-compensated for astigmatism and non-circularity, so that after frequency conversion, the output beam is already corrected and requires minimal or no downstream compensation optics, thereby reducing UV exposure of correction components
Solution Approach 2:
The patent extracts the beam shaping and aberration compensation function from the downstream UV path and relocates it to the upstream visible/near-IR path, before frequency conversion. This removes the need for UV-exposed compensation optics
2Device complexity
If fixed telescope arrangements are used for beam shaping, then the system structure is simple, but the beam parameters cannot be adjusted
Solution Approach 1:
The patent transforms the fixed telescope arrangement into a dynamic, adjustable system by introducing motorized mirror mounts that can change the orientation and position of mirrors. This allows continuous adjustment of beam parameters (size, shape, astigmatism) while maintaining a relatively simple overall structure
Solution Approach 2:
The patent creates a universal beam adaptation device that can handle multiple beam types and produce various output configurations. The same adjustable telescope structure can compensate for different input beam characteristics and generate different output beam shapes, making it applicable to multiple laser systems and applications
3Ease of manufacture
If laser beam parameters vary between sources and systems, then component manufacturing is easier, but the output parameters cannot meet tight tolerances
Solution Approach 1:
The patent uses parameter changes by adjusting multiple beam parameters (size, divergence, astigmatism, orientation) through the adjustable telescope system. By independently controlling mirror positions and angles, the system can transform beams with varying input parameters into a standardized output that meets tight tolerances, regardless of manufacturing variations in upstream components
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 solution allows for precise adjustment of beam parameters, reducing aberrations and extending the lifespan of optical components by enabling flexible and tolerant adjustments, even in systems with non-identical components, and improving the quality of frequency-converted beams.
Implementation Method 1
a first astigmatism lens unit (27) for receiving the electromagnetic radiation (52A), which has a first lens (L1) that can be tilted with respect to the beam axis (25) for astigmatism adjustment
Implementation Method 2
a divergence adjustment lens unit with a second lens (L2) for adjusting the divergence, wherein the distance between the second lens (L2) and the first lens (L1) is adjustable along the beam axis (25)
Implementation Method 3
generating a frequency-converted beam in the frequency conversion crystal
Data Source
Figure 1A~2
Figure 3
Figure 4
AI summary
A beam adaptation device (21) for variable-astigmatism adjustment of electromagnetic radiation propagating along a beam axis (25) of the beam adaptation device (21) has a first astigmatism lens unit (27), which provides at least one first lens (L1) tiltable with respect to the beam axis (25) for the astigmatism adjustment, a divergence adaptation lens unit (31) with a second lens (L2) for adjusting the divergence, wherein the distance (d12) between the second lens (L2) and the first lens (L1) along the beam axis (25) is adjustable, and a second astigmatism lens unit (29) with at least one third lens (L3) tiltable with respect to the beam axis (25) for the astigmatism adjustment, wherein in particular to adjust the magnitude of the electromagnetic radiation on the third lens (L3), the distance (d23) between the second lens (L2) and the third lens (L3) along the beam axis (25) is adjustable. The beam adaptation device (21) can be used, for example, for astigmatic pre-compensation in frequency conversion.