Single-Sided Pump Laser Reflector Layout for Symmetric Absorption

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Solution Overview

Problem

Single-sided pumped laser devices exhibit asymmetric pump light distribution within the laser medium body, leading to inefficiency and sub-optimal laser mode performance due to thermal-optic distortions and misalignment of the resonant laser cavity.

Innovation Solution

An optical model is used to determine the curvature and relative spacings of reflectors and other components to achieve a symmetrical absorption profile by iteratively computing absorption values, adjusting spacings, and modifying surface shapes to align with a desired merit function, ensuring a symmetrical pump light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single-sided pumping is used to reduce device complexity and cost, then device complexity decreases, but pump light distribution symmetry deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidpump light distribution symmetry
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent intentionally introduces asymmetric optical elements (curved reflectors, cylindrical lenses) into the single-sided pumping system to compensate for the inherent asymmetry of single-sided pump geometry. By carefully designing the curvature and positioning of these elements, the system transforms the asymmetric pump input into a symmetric absorption distribution within the laser medium, resolving the contradiction between simplified structure and symmetric performance.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If single-sided pumping is used to reduce component quantity, then manufacturing cost decreases, but laser mode performance deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidlaser mode performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes specific geometric parameters of optical elements including reflector curvature radii, lens focal lengths, and component spacing to achieve symmetric absorption profiles. By precisely controlling these parameters, the system attains optimal laser mode performance while maintaining the cost advantages of single-sided pumping architecture.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If asymmetric pump light distribution occurs, then energy absorption efficiency decreases, but thermal-optic distortions increase

Engineering Contradiction:
Improveenergy absorption efficiencyVSAvoidthermal-optic distortions
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the potentially harmful asymmetric thermal distribution into a beneficial symmetric pattern by using optical elements to pre-shape the pump light distribution. The asymmetric single-sided pump geometry, which would normally create harmful thermal gradients, is transformed through curved reflectors and lenses to produce symmetric absorption and thus symmetric thermal distribution, eliminating thermal-optic distortions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 method results in a single-sided pumped laser device with improved efficiency and reduced thermal stress, achieving optimal laser mode performance and alignment by correcting asymmetry in pump light distribution.

Implementation Method 1

determine initial relative spacings of at least one reflector for the pump light with respect to the laser medium body and the laser pump

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

determining an absorption coefficient for a laser medium body

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

A method for making a single-sided pumped laser device having a symmetrical absorption pump profile within a laser medium body

Methodology Applied
Scientific EffectLaser: Laser

Data Source

PatentEP4429048B1Method for symmetrizing single-sided pump laser profiles
Publication Date: 2026.05.06 L3HARRIS TECH INC
  • EP4429048B1 patent drawingFigure 1A~1B
  • EP4429048B1 patent drawingFigure 2
  • EP4429048B1 patent drawingFigure 3

AI summary

A method for making a single-sided pumped laser device (20) may include determining initial relative spacings of a reflector (30) with respect to a laser medium body (28) having a known absorption coefficient, and to a laser pump (22) having known divergence angles of pump light (24) to be directed at a side of the laser medium body (28). A merit function defining a desired absorption profile of the pump light (24) passing through the laser medium body (28) may be determined. An optical model may be operated based on the merit function and the determined absorption coefficient, divergence angles and initial relative spacings to determine a curvature of the reflector (30), and adjusted relative spacings among the laser medium body (28), the laser pump (22), and the reflector (30). The laser medium body (28), the laser pump (22), and the reflector (30) may be assembled according to the determined curvature of the at least one reflector (30) and the adjusted relative spacings to make the single-sided pumped laser device (20) having a symmetrical absorption profile.