MEMS Microcavity Resonance Tuning for Stable Color Center Photon Extraction

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Solution Overview

Problem

Existing micro cavities for color centers in solid-state materials face challenges in achieving mechanical stability and position stability due to macroscopic dimensions, which are sensitive to mechanical vibrations, especially in cryogenic environments, making it difficult to optimize the extraction efficiency of single photons.

Innovation Solution

A micro-electromechanical system (MEMS) based micro cavity with movable mirrors connected to a solid-state substrate, allowing precise adjustment of resonance frequency by moving one mirror relative to another, using actuators like electrostatic fields, to enhance photon extraction efficiency and reduce sensitivity to vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If macroscopic optical fibers and piezo stages are used to position mirrors, then the micro cavity can be formed, but the system becomes sensitive to mechanical vibrations and achieves poor position stability

Engineering Contradiction:
Improveposition stabilityVSAvoidmechanical vibration sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces macroscopic mechanical positioning systems (optical fibers, piezo stages) with a MEMS-based micromirror that is directly integrated with the optical cavity. This substitution of mechanical systems at the micro-scale eliminates the vibration sensitivity inherent in macroscopic mechanical components while maintaining the ability to adjust mirror position and cavity length for resonance tuning.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The micromirror is nested within the optical cavity structure itself, with the MEMS actuator integrated into the cavity assembly. This nesting of the positioning mechanism within the optical system allows the mirror to be moved precisely without requiring external macroscopic positioning equipment, thereby reducing vibration sensitivity while maintaining position stability.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Productivity

If the cavity length is adjusted to match resonance frequency, then photon extraction efficiency improves, but mechanical stability becomes difficult to maintain in cryogenic environments

Engineering Contradiction:
Improvephoton extraction efficiencyVSAvoidmechanical stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent employs a dynamically adjustable MEMS micromirror that can be precisely positioned to tune the cavity resonance frequency to match the color center emission. This dynamic adjustment capability allows optimization of photon extraction efficiency while the integrated MEMS structure provides mechanical stability through its direct coupling to the cavity, even in cryogenic environments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent substitutes traditional macroscopic mechanical adjustment mechanisms with a MEMS-based micromirror that integrates positioning and stability functions. This substitution enables precise resonance tuning for high photon extraction efficiency while the micro-scale MEMS structure inherently provides better mechanical stability than macroscopic systems, particularly in cryogenic conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If mirrors are moved to tune resonance frequency with precision of 1-10 pm, then the color center coupling is optimized, but the system becomes highly sensitive to external vibrations

Engineering Contradiction:
Improveresonance frequency tuning precisionVSAvoidvibration sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces macroscopic mechanical positioning systems with a MEMS-based micromirror that achieves sub-10 pm precision in resonance frequency tuning. The micro-scale MEMS structure inherently provides better vibration isolation and mechanical stability than macroscopic systems, allowing high precision tuning without the vibration sensitivity that plagues larger mechanical systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The MEMS micromirror is nested within the optical cavity structure, with the actuator integrated into the cavity assembly. This nested configuration allows precise resonance tuning (1-10 pm) while the integrated MEMS structure provides mechanical stability and reduces sensitivity to external vibrations, as the positioning mechanism is part of the overall cavity system rather than an external macroscopic component.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 MEMS-based micro cavity improves photon extraction efficiency by aligning the resonance frequency with the color center, increasing the fraction of usable photons in the weak coupling regime and directing photons into optical modes, while being robust against mechanical vibrations.

Implementation Method 1

The MEMS structure comprises an actuator arranged to move the first mirror towards to or away from the second mirror to adjust the length of the micro cavity thereby controlling a resonance frequency of the micro cavity

Methodology Applied
Scientific EffectElectrostatic actuation: Electrostatics

Implementation Method 2

at least one of the first mirror and the second mirror comprises a curved surface

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

A micro cavity stimulates the emission of light that matches the resonance frequency of the micro cavity

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4692893A1Micro-electromechanical system based micro cavity for color centers
Publication Date: 2026.02.11 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP4692893A1 patent drawingFigure 1
  • EP4692893A1 patent drawingFigure 2
  • EP4692893A1 patent drawingFigure 3A~3B

AI summary

Micro-electromechanical system, MEMS, based micro cavity for color centers in a solid-state substrate comprising a MEMS structure, a first mirror, a solid-state substrate comprising an embedded color center; and a second mirror located opposite to the first mirror, wherein the solid-state substrate is located between the first mirror and the second mirror, at least one of the first mirror and the second mirror comprises a curved surface, and the MEMS structure comprises an actuator arranged to move the first mirror towards to or away from the second mirror to adjust a length of the micro cavity thereby controlling a resonance frequency of the micro cavity.