Self-Cooled Semiconductor Laser Using Anti-Stokes Photoluminescence
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Solution Overview
Problem
Conventional semiconductor lasers face challenges with internal heat generation due to quantum defect, leading to self-heating issues that limit power output and efficiency, and struggle with directional extraction of spontaneous emission, which is crucial for effective cooling and high-power applications.
Innovation Solution
The development of self-cooled semiconductor lasers with a ring laser design incorporating a waveguide directional output coupler and photonic crystal structures to enhance anti-Stokes photoluminescence, allowing for efficient directional extraction of spontaneous emission and reduced internal heating through colloidal quantum dot emitters and distributed Bragg reflectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional semiconductor lasers are used, then laser output is generated, but internal heat generation occurs due to quantum defect
Solution Approach 1:
The patent converts the harmful Stokes-shifted spontaneous emission (which normally contributes to heating) into a beneficial cooling mechanism by using it to pump anti-Stokes transitions in the active region. The spontaneous emission at longer wavelengths is absorbed and re-emitted at shorter wavelengths with higher energy, effectively removing heat from the system and creating a self-cooling effect that counteracts the quantum defect heating.
2Loss of energy
If conventional semiconductor lasers are used, then laser operation is achieved, but directional extraction of spontaneous emission is difficult
Solution Approach 1:
The patent applies local quality by creating specific structural features (photonic crystal patterns, distributed Bragg reflectors) at localized positions within the laser device to control the directional extraction of spontaneous emission. These localized structures modify the optical properties in specific regions to enhance extraction efficiency without requiring complete redesign of the entire device.
3Power
If power output is increased, then laser performance improves, but thermal rollover increases
Solution Approach 1:
The patent converts the harmful thermal effect into a beneficial cooling mechanism by utilizing the quantum defect to drive anti-Stokes transitions. The spontaneous emission that would normally heat the device is instead used to pump higher-energy transitions, creating a self-cooling effect that enables higher power output without thermal rollover and improves thermal stability.
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 approach enables improved power conversion efficiency, reduced thermal rollover, and enhanced directional control of spontaneous emission, effectively mitigating self-heating and increasing the power handling capacity of semiconductor lasers.
Implementation Method 1
Fluorescence then follows with a mean photon energy hvf higher than that of the absorbed photon, thus removing energy from the sample. The essential condition for achieving cooling in solids is availability of a high quantum efficiency anti-Stokes transition
Implementation Method 2
The excited ions in a host matrix (or carriers in a semiconductor material) absorb phonons during the thermalization process and reach quasi-equilibrium with the lattice
Implementation Method 3
a laser resonator with a waveguide bound by a slab photonic-crystal structure defined, through the photonic bandgap confinement effect
Implementation Method 4
distributed Bragg reflectors
Implementation Method 5
colloidal quantum dot emitters with high efficiency of anti-Stokes photoluminescence are inserted into nanocavities
Data Source
AI summary
A light-emitting device having a self-cooled semiconductor laser having a laser cavity.