Stacked Broadband Optical Emitters Using Optical Pumping
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Solution Overview
Problem
Existing broadband light emission sources for spectrometers and optoelectronic devices are often bulky, energy-intensive, and costly, with limitations in wavelength emission due to charge-carrier injection requirements, which restricts the composition and thickness of semiconductor layers and decreases radiative-recombination efficiency.
Innovation Solution
The use of photon injection/light pumping instead of charge-carrier injection in a stack of semiconductor layers with different compositions and/or quantum layer thicknesses to generate a multi-emission spectrum, eliminating the need for doping and electrical contacts, and allowing for customizable emission wavelengths and higher radiative recombination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If charge-carrier injection is used to enable light emission from each layer, then light emission can be achieved, but the layer thickness is restricted and wavelength composition is limited
Solution Approach 1:
The patent replaces charge-carrier injection (electrical method) with optical pumping (photonic method). Instead of injecting electrons and holes that must recombine radiatively, the invention uses photons from a light source to directly excite carriers in each quantum well, enabling independent control of each layer's emission without electrical contact constraints
Solution Approach 2:
The patent divides the broadband emission into multiple discrete quantum well layers, each optimized for specific wavelength ranges. The stack includes multiple quantum well regions with different compositions and thicknesses, allowing each layer to be independently pumped and optimized for its target wavelength without compromising other layers
2Reliability
If doping is used to achieve charge-carrier transport in each layer, then electrical conductivity is improved, but radiative-recombination efficiency decreases
Solution Approach 1:
The patent eliminates the need for doped semiconductor layers by replacing electrical injection with optical pumping. The quantum wells are undoped or lightly doped, and carriers are generated optically rather than electrically, preserving radiative recombination efficiency while achieving sufficient carrier transport through the optical excitation mechanism
Solution Approach 2:
The patent introduces photons as an intermediary to transfer energy to the quantum well layers. The light source emits photons that penetrate through the stack and excite carriers in each quantum well independently, serving as a non-intrusive mediator that avoids the harmful effects of heavy doping while achieving the desired carrier population
3Use of energy by moving object
If electrical contacts are made to the layered stack, then charge-carrier injection is enabled, but additional electrode-compatible surfaces are required
Solution Approach 1:
The patent replaces the electrical injection system (requiring electrodes and electrical contacts) with an optical pumping system. A light source is positioned to illuminate the quantum well stack through transparent or partially transparent layers, eliminating the need for complex electrode structures and electrical contact surfaces
Solution Approach 2:
The patent extracts and removes the electrical contact infrastructure from the device architecture. By using optical pumping, the invention eliminates electrodes, contact pads, and associated electrical connection structures, simplifying the device and reducing manufacturing complexity
4Ease of operation
If each layer is made thin to enable charge-carrier injection, then carrier transport is facilitated, but the emission wavelength range is restricted
Solution Approach 1:
The patent segments the emission spectrum into multiple quantum well layers, each with optimized thickness and composition for its target wavelength range. This segmentation allows each layer to be independently designed and pumped, achieving broad overall coverage while maintaining optimal conditions for each individual layer
Solution Approach 2:
The patent transitions from a single-layer design to a multi-layer stacked architecture, adding the dimension of vertical layering. Each layer in the stack can have different thicknesses and compositions, enabling the system to cover a broad wavelength range by combining multiple specialized layers rather than compromising a single layer
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 compact, power-efficient broadband optical emission sources capable of emitting over a wide spectrum, including near-IR, with increased flexibility in layer design and improved efficiency, reducing the need for additional electrode-compatible surfaces and allowing for customized wavelength composition and intensity.
Implementation Method 1
a light source (32) operable to provide pumping for stimulated photon emission from the stack
Implementation Method 2
the light emitted by the light source generates charge carriers in the one or more transition layers (30)
Implementation Method 3
the electrons and holes emit light upon combination
Data Source
Figure 1~2
Figure 1A~1B
Figure 1C
AI summary
The present disclosure describes broadband optical emission sources that include a stack of semiconductor layers, wherein each of the semiconductor layers is operable to emit light of a different respective wavelength; a light source operable to provide optical pumping for stimulated photon emission from the stack; wherein the semiconductor layers are disposed sequentially in the stack such that a first one of the semiconductor layers is closest to the light source and a last one of the semiconductor layers is furthest from the light source, and wherein each particular one of the semiconductor layers is at least partially transparent to the light generated by the other semiconductor layers that are closer to the light source than the particular semiconductor layer. The disclosure also describes various spectrometers that include a broadband optical emission device, and optionally include a tuneable wavelength filter operable to allow a selected wavelength or narrow range of wavelengths to pass through.