Solid-State Slab Laser Amplifier Pump Light Redirection
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Solution Overview
Problem
Face-pumped slab laser amplifiers face limitations in heat extraction and pump power absorption due to the single-side pumping geometry, leading to inhomogeneous gain profiles and thermal gradients, which affect the seed beam distortion and efficiency.
Innovation Solution
A face-pumped solid-state slab laser amplifier design with a thin-plate geometry, featuring optically transparent heat spreaders and reflectors that allow multiple reflections of the pump light across the amplification element, ensuring efficient heat extraction and uniform pump energy distribution across the gain medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If face-pumping is used through one main face of the slab, then assembly simplicity and alignment ease are improved, but heat extraction capability and pump power absorption are limited due to single-side geometry
Solution Approach 1:
The patent transforms the single-side face-pumping geometry into a multi-dimensional configuration by introducing multiple reflectors that redirect pump light through the gain medium along different paths. This allows the pump to enter through one face while effectively utilizing the third dimension (depth) to create multiple reflection paths, thereby improving both heat extraction and pump absorption without compromising alignment simplicity.
Solution Approach 2:
The patent introduces optical reflectors as intermediary elements between the pump source and the gain medium. These reflectors act as mediators that redirect and distribute pump light throughout the gain medium, enabling enhanced pump absorption and heat extraction while maintaining the simplicity of face-pumping geometry and alignment procedures.
2Device complexity
If pump light path through the gain medium is shortened, then assembly simplicity is improved, but pump absorption efficiency and gain are reduced
Solution Approach 1:
The patent ensures continuous useful action of pump light through the gain medium by implementing multiple reflection paths. Instead of a single direct pass, the pump light continuously interacts with the gain medium through repeated reflections, maintaining high absorption efficiency while keeping the physical distance and assembly complexity low.
Solution Approach 2:
The patent employs periodic action by creating multiple reflection cycles of pump light through the gain medium. The reflectors are positioned to create periodic interactions between the pump light and gain medium, allowing sufficient absorption over multiple passes without requiring a physically long pump path or complex assembly.
3Use of energy by moving object
If pump intensity is concentrated at the entry side, then pump coupling efficiency is improved, but thermal gradients and gain inhomogeneity increase causing beam distortion
Solution Approach 1:
The patent applies local quality by using reflectors to create spatially distributed pump intensity throughout the gain medium. Instead of uniform or concentrated pumping at one location, the reflectors redirect pump light to create locally optimized intensity distributions that ensure uniform energy deposition and homogeneous gain across the entire gain medium volume.
Solution Approach 2:
The reflectors serve as intermediary elements that redistribute pump light intensity from the entry side throughout the entire gain medium. They mediate between the concentrated pump source and the gain medium to achieve uniform energy distribution, preventing thermal gradients and gain inhomogeneity while maintaining efficient pump coupling.
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 design enhances heat extraction efficiency and pump power absorption, reducing thermal gradients and seed beam distortion, while maintaining mechanical robustness and assembly simplicity.
Implementation Method 1
a solid-state heat spreader thermally connected to the first main face of the amplification element and substantially covering the surface of said first main face... featuring a good thermal conductivity
Implementation Method 2
a first reflector substantially covering and facing the first main face of the amplification element, and a second reflector substantially covering and facing the second main face of the amplification element... produce multiple reflections of said pump light across the amplification element
Implementation Method 3
In order to achieve high pump absorption, thus high gain, the path of the pump within the gain medium must be maximized
Data Source
AI summary
A laser amplifier device including an amplification element which includes a solid-state gain medium including a first main face and a second main face separated from each other by a distance which is smaller than the lateral dimensions. A heat spreader is thermally connected to, and substantially covering, the first main face. The heat spreader is optically transparent to a pump light and is in thermal contact with a heat sink. A first reflector substantially covers and faces the first main face and a second reflector substantially covers and faces the second main face; the reflectors being configured to reflect the pump light. The heat spreader and the first reflector are arranged such that the pump light passes through the heat spreader and through the first reflector and is reflected multiple times across the amplification element, between the first and second reflectors.