Deterministic Single Photon Source Using Transported Electrons
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Solution Overview
Problem
Existing single photon sources for quantum information processing applications face challenges in providing single photons on demand with low uncertainty in timing and high reliability, as they often emit multiple photons or require slower clock rates to maintain single photon generation.
Innovation Solution
A deterministic single photon source is developed, comprising an electron excitation region with a potential well, an electron emitter, a light source, a photon emission resonant cavity, and a transport device, which excites and physically transports a bound surface state electron to induce precise photon emission, allowing for picosecond time resolution at gigahertz clock rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical sources emit very weak pulses to generate single photons, then single photon generation is achieved, but the timing uncertainty increases and the emission window becomes larger
Solution Approach 1:
The device is divided into separate excitation region and emission region, allowing independent optimization of each function. The quantum system is excited in one region and then transported to another region for photon emission, segmenting the timing-critical emission process from the excitation process.
Solution Approach 2:
The quantum system is excited in advance and then held in an excited state during transport. The excitation action is completed before the emission action, allowing precise control of when the photon will be emitted by controlling the transport timing.
2Productivity
If the delay between photon demand and emission is reduced to increase photon provision rate, then the operation rate increases, but the probability of delivering multiple photons increases
Solution Approach 1:
The system uses dynamic control of the transport device to precisely timing the arrival of excited quantum systems at the emission region. The transport duration and timing can be adjusted to ensure single photon emission while maintaining high operation rates.
Solution Approach 2:
The system can monitor the emission process and adjust the timing of subsequent excitations and transports to maintain single photon delivery probability while maximizing the photon generation rate.
3Measurement precision
If the excitation and emission regions are separated, then the timing precision is improved, but the device complexity increases
Solution Approach 1:
The transport device serves multiple functions: it transports the quantum system from excitation to emission region, controls the timing of photon emission, and can potentially serve as part of the photon collection optics. This multi-functionality reduces the need for separate dedicated components.
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 reliable and deterministic emission of single photons on demand with reduced statistical uncertainty in timing, enabling faster operation and higher photon generation rates while maintaining single photon integrity.
Implementation Method 1
a light source coupled to the electron excitation region for exciting the bound surface state electron from a ground state energy level to a first excited energy level, the light source being configured to excite the bound surface state electron to the first excited energy level using light energy that corresponds to the energy gap between the ground state energy level and a second excited energy level, and using light energy that corresponds to the energy gap between the second excited energy level and the first excited energy level
Implementation Method 2
a photon emission resonant cavity that is displaced from the electron excitation region, the photon emission resonant cavity having a resonance that corresponds to the energy gap between the first excited energy level and the ground state energy level
Implementation Method 3
a transport device coupled between the electron excitation region and the photon emission resonant cavity, the transport device comprising a plurality of electrodes for creating a movable potential well for physically transporting the bound surface state electron from the electron excitation region to the photon emission resonant cavity
Data Source
AI summary
A photon source capable of emitting, for example, a single photon or a single pair of photons on demand. The photon source may include an excitation region where a single instance of a quantum system is excited using excitation energy. A Stimulated Raman Adiabatic Passage (STIRAP) technique can be used for exciting the quantum system to a desired energy level. The photon source may include a photon emission region physically displaced from the excitation region. A transport device can be used for controllably moving an excited quantum system from the excitation region to the photon emission region. The photon emission region may include a resonant cavity tuned to the de-excitation frequency of the quantum system for inducing de-excitation of the quantum system and emission of a photon. The photon emission resonant cavity may be switchably coupled to an output port by a tunable resonant cavity coupling device.