Vacuum-Chamber Photon Transfer Using Ionized Gas to Protect Yield

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Solution Overview

Problem

The yield of entangled photons is reduced due to surface degradation at the interface between the photon source and the vacuum space in quantum optical communication systems, primarily caused by deposition of material from the vacuum, which affects the entanglement maintenance in optical communication fibers.

Innovation Solution

Introducing ionized gas and/or gaseous radicals in the optical path between the photon source and the optical communication fiber within the vacuum space, using a gas excitation device to ionize and/or form radicals, which helps mitigate surface degradation and maintain entanglement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If photon transmission is used through vacuum space to provide thermal isolation, then thermal isolation is improved, but surface degradation at the interface reduces entangled photon yield

Engineering Contradiction:
Improvethermal isolationVSAvoidentangled photon yield
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

A gas layer is introduced as an intermediary medium between the photon source and the vacuum space. This gas layer acts as a protective barrier that prevents direct interaction between the vacuum environment and the photon source interface, thereby preventing material deposition while still allowing photon transmission. The gas serves as a mediator that resolves the contradiction between maintaining thermal isolation through vacuum and preventing surface degradation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the photon source is kept at cryogenic temperature to avoid decorrelation, then entanglement efficiency is improved, but thermal isolation requirements increase system complexity

Engineering Contradiction:
Improveentanglement efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system is segmented into distinct thermal zones: a cryogenic zone containing the photon source and a warmer zone containing the optical communication fiber. The vacuum chamber with its gas layer creates a thermal boundary that separates these zones, allowing each to operate at its optimal temperature independently. This segmentation enables cryogenic operation of the photon source without requiring the entire system to be cryogenic, thus reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If optical communication fiber is kept at environmental temperature for practical operation, then ease of operation is improved, but maintaining entanglement over distance becomes difficult

Engineering Contradiction:
Improveease of operationVSAvoidentanglement maintenance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The gas layer in the vacuum chamber serves as an intermediary that protects the entangled photons during their transition from the cryogenic photon source to the environmental temperature optical fiber. By preventing surface degradation at the interface, this intermediary ensures that the entanglement property is preserved during the temperature transition and subsequent transmission through the fiber at environmental temperature.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 introduction of ionized gas and/or gaseous radicals significantly reduces the degradation of entangled photon yield by preventing surface deposition, thereby enhancing the efficiency of entangled photon transmission.

Implementation Method 1

supplying ionized gas and/or gaseous radicals in a part of an optical path for the photon between the photon source and the optical communication fiber

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 2

a gas excitation device, configured to ionize and/or form radicals from gas in an excitation space that is in gas communication with the optical path in the vacuum space

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 3

the photon source must be kept at cryogenic temperature to avoid decorrelation due to thermal effects. This may be realized by placing the photon source in a vacuum chamber, in thermal contact with the cooled side of the cryogenic cooler

Methodology Applied
Scientific EffectCryogenic cooling: Cryogenics

Data Source

PatentEP4289104B1Quantum optical communication using photon transmission from a vacuum chamber
Publication Date: 2026.04.01 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4289104B1 patent drawingFigure 1~2
  • EP4289104B1 patent drawingFigure 3~4

AI summary

An entangled photon is produced by a photon source at cryogenic temperature in vacuum chamber and supplied to an optical communication fiber outside the vacuum chamber. Prior to generating the photon, ionized gas and/or gaseous radicals are supplied in a part of an optical path for the photon in a vacuum space between the photon source photon source and the optical communication fiber. This counteracts loss of entangled photon yield at entry of the photon from the photon source into the vacuum space.