Lamp-Pumped Slab Laser With Fluorescent Filters

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Solution Overview

Problem

Existing solid-state laser amplifiers face inefficiencies due to mismatched pump lamp spectra and incomplete beam extraction, limiting their practical applications.

Innovation Solution

A transverse face-pumped, lamp-driven slab laser design with a face-to-face beam propagation scheme and cavity fluorescent filters that convert non-useful lamp output to useful pump bands, allowing for higher efficiency and power handling by redirecting amplified radiation and increasing the number of passes through the gain material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If lamp pumped systems are used, then device complexity is reduced and cost is lowered, but efficiency is limited due to spectral mismatch

Engineering Contradiction:
Improvesystem complexityVSAvoidpump efficiency
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent introduces cavity fluorescent filters as an intermediary component between the pump lamp and the laser crystal. These filters convert the broad spectrum lamp output into specific wavelength bands that match the absorption spectrum of the laser crystal, thereby resolving the spectral mismatch problem while maintaining the simplicity and low cost of lamp pumping

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the spectral parameters of the pump light by using fluorescent filters to convert lamp emission at specific wavelengths to match the absorption bands of the laser crystal. This parameter transformation enables efficient energy transfer from the lamp to the crystal without requiring complex diode pump systems

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If beam passes through crystal only twice, then extraction is simple, but efficiency is limited due to incomplete energy extraction

Engineering Contradiction:
Improvebeam extraction complexityVSAvoidenergy extraction efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent transitions from a single-pass or double-pass linear beam trajectory to a multi-dimensional face-to-face bounce configuration. The beam enters through one face, bounces between opposing faces multiple times (more than two passes), and exits through the same entry face, effectively utilizing the crystal volume in multiple spatial dimensions to extract energy more completely

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements continuous beam circulation through the gain medium via multiple internal reflections. The beam repeatedly traverses the crystal along different paths, continuously extracting energy from the excited states until saturation is approached, thereby maximizing energy extraction efficiency

Inventive Principle:
Principle #20Continuity of useful action

3Use of energy by moving object

If diode pump lasers are used, then efficiency increases to 25%, but cost increases significantly

Engineering Contradiction:
Improvesystem efficiencyVSAvoidsystem cost
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent replaces expensive, complex diode laser pump sources with simpler, cheaper arc lamps that have shorter operational lifetimes. By combining these economical lamps with cavity fluorescent filters for spectral matching, the system achieves high efficiency at a fraction of the cost of diode-pumped systems

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The cavity fluorescent filters serve as an intermediary that enables the use of inexpensive arc lamps by converting their broad spectrum output to match the laser crystal absorption bands, achieving diode-level efficiency without diode-level cost

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves higher efficiency and power output compared to diode-pumped systems, with efficiencies approaching 40% and output power exceeding diode-pumped versions, while being less expensive to implement.

Implementation Method 1

cavity fluorescent filters that convert non-useful lamp output to useful pump bands

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

the crystal configured such that the laser beam is reflected within the crystal more than two times while being amplified by the crystal using said absorbed light energy

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

Implementation Method 3

said back face and top and bottom sides are configured to reflect a laser beam internally within said crystal

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3185373B1Slab laser and amplifier
Publication Date: 2021.04.07 CUNNINGHAM STEPHEN LEE
  • EP3185373B1 patent drawingFigure 1~2
  • EP3185373B1 patent drawingFigure 3
  • EP3185373B1 patent drawingFigure 4~5

AI summary

A laser device is disclosed, the laser device comprising: a pump light source (2; 22) comprising one or more lamps configured to emit light (20); and a slab crystal (1; 21) having a front face, a back face, and four sides such that said back face and said sides are configured to reflect a laser beam (16) internally within said crystal (1; 21), said crystal (1;21) being configured to absorb energy obtained from said emitted light (20), wherein the slab crystal (1; 21) is configured to receive an input laser beam (16; 17) in the front face of the crystal (1; 21), with the crystal (1; 21) configured such that the laser beam (16) is reflected within the crystal (1; 21) more than two times while being amplified by the crystal (1; 21) using said received light energy, and wherein the input laser beam (16; 17) is thereby converted by the crystal (1; 21) into an amplified laser beam (17') emitted from one of the faces of the crystal (1; 21). Also, a system comprising a plurality of laser devices is disclosed.