Quantum Dot Photon Source With Tunneling Barrier
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Solution Overview
Problem
Current entangled photon sources rely on parametric down conversion with optical non-linear crystals, which are not easily integrable with standard semiconductor materials, limiting their application in fields like quantum communication and computing.
Innovation Solution
A photon source using a quantum dot with an applied electric field and a barrier to extend carrier tunneling time beyond the exciton's radiative lifetime, enabling the emission of entangled photons through bi-exciton or higher order exciton decay, with specific configurations to minimize energy level splitting and optimize tunneling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If parametric down conversion with optical non-linear crystals is used to produce entangled photons, then entangled photon pairs can be generated, but the device complexity and difficulty of integration with standard semiconductor materials increases
Solution Approach 1:
The patent changes the fundamental parameters of the photon generation process by transitioning from optical non-linear crystals to semiconductor quantum dots with electric field control. This enables the use of standard semiconductor fabrication processes while maintaining entanglement generation capability through bi-exciton decay mechanisms
Solution Approach 2:
The patent replaces the optical-based parametric down conversion mechanism with an electrically-controlled semiconductor-based bi-exciton decay mechanism. This substitution enables integration with standard semiconductor electronics and simplifies device fabrication while preserving the entanglement generation function
2Stability of the object's composition
If carrier tunneling time is extended beyond exciton radiative lifetime using barriers, then neutral charge state stability is improved, but device complexity increases
Solution Approach 1:
The patent applies localized barrier structures with specific height and width parameters around the quantum dot to create regions of high tunneling resistance. These localized modifications preserve the overall simplicity of the device while achieving the required carrier confinement to stabilize neutral charge states during bi-exciton decay
Solution Approach 2:
The barrier structures serve as intermediary elements that mediate between the quantum dot and the external environment. They control carrier tunneling rates to match the exciton radiative lifetime, enabling stable neutral charge state formation without requiring complex external control mechanisms
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 solution enables the production of entangled photons using standard semiconductor materials, enhancing integration with other components and improving the stability of neutral charge states during exciton decay, thus effectively generating entangled photon pairs for applications in quantum communication, imaging, and computing.
Implementation Method 1
the quantum dot being suitable for emission of entangled photons during decay of a bi-exciton or higher order exciton
Implementation Method 2
electrical source being configured to apply a potential such that carriers are supplied to the quantum dot to form a bi-exciton or higher order exciton
Implementation Method 3
a barrier configured to increase the time which a carrier takes to tunnel to or from the quantum dot
Data Source
AI summary
A photon source comprising: a quantum dot; electrical contacts configured to apply an electric field across said quantum dot: and an electrical source coupled to said contacts, said electrical source being configured to apply a potential such that carriers are supplied to said quantum dot to form a bi-exciton or higher order exciton, wherein said photon source further comprises a barrier configured to increase the time which a carrier takes to tunnel to and from said quantum dot to be greater than the radiative lifetime of an exciton in the quantum dot, the quantum dot being suitable for emission of entangled photons during decay of a bi-exciton or higher order exciton.