Semiconductor Disk Laser Pump Light Recirculation
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Solution Overview
Problem
Semiconductor disk lasers, particularly in the MIR wavelength range between 1.9 and 2.8 μm, face limitations in maximum output power and scalability of output power with the size of the pumped area.
Innovation Solution
A semiconductor disk laser design with a reduced total thickness of the active and window regions, where the pump light is guided through the active region at least twice, utilizing a reflection device with a high reflectivity element for the pump wavelength, and a heat spreader for improved heat dissipation, allowing for increased absorption efficiency and output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the total thickness of the active region and window region is reduced to less than three times the laser wavelength, then internal optical losses are reduced and power efficiency is enhanced, but the absorption path length for pump light is shortened
Solution Approach 1:
The pump light is guided through the active region multiple times (at least twice) by introducing a reflection device, effectively increasing the absorption path length in the vertical dimension without increasing the physical thickness of the semiconductor structure. This allows the pump light to interact with the active region repeatedly, maintaining high absorption efficiency while keeping the overall device thickness reduced for low optical losses.
Solution Approach 2:
A reflection device (such as a distributed Bragg reflector or mirror) is introduced as an intermediary element to redirect the pump light back through the active region. This mediator enables the pump light to traverse the thin active region multiple times, compensating for the shortened absorption path length that would otherwise result from the reduced thickness design.
2Temperature
If a heat spreader is added to improve heat dissipation, then thermal resistance is minimized and output power is increased, but device complexity increases
Solution Approach 1:
The heat spreader is merged with the existing semiconductor substrate or mounting structure, combining the thermal management function with the mechanical support structure. This integration approach improves heat dissipation without adding separate, complex thermal management subsystems, thereby minimizing the increase in device complexity.
Solution Approach 2:
The heat spreader is designed to serve multiple functions: it acts as both a thermal management component for heat dissipation and as a mechanical support structure for mounting the semiconductor device. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved thermal performance.
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 reduces internal optical losses, enhances power efficiency, and improves scalability by maintaining high output power while minimizing thermal resistance, achieving higher output powers and efficient heat dissipation.
Implementation Method 1
optically pumped semiconductor disk laser comprises a pump light source (3), at least one semiconductor body (2)... Within the active region, in the case of the semiconductor disk laser, pump radiation is absorbed and laser radiation is generated
Implementation Method 2
Within the active region, in the case of the semiconductor disk laser, pump radiation is absorbed and laser radiation is generated
Implementation Method 3
a reflection device (P), which has a first P-reflection element for the pump wavelength, wherein the first P-reflection element is embodied and arranged in such a way that pump light emerging from the pump light source (3) can be guided in at least two passes through the active region (7)
Implementation Method 4
a heat spreader for improved heat dissipation, allowing for increased absorption efficiency and output power
Data Source
AI summary
An optically pumped semiconductor disk laser including a pump light source, at least one semiconductor body (2), which semiconductor body (2) has at least one window region (8), an active region (7) and a reflection device (P), which reflection device has at least one first P-reflection element (P1) for the pump wavelength. The first P-reflection element (P1) is embodied and arranged such that pump light emerging from the pump light source (3) can be guided for at least two passes through the active region (7). A total thickness of the active region (7) and of the window region (8) in the direction of an optical axis of the semiconductor disk laser is less than three times the laser wavelength in the active region (7).