Resonant Optical Cavity for Submicron Particle Detection

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Solution Overview

Problem

Conventional microscopy techniques face limitations in sensitivity and spatial resolution when observing submicron-sized particles, particularly biological samples, due to reduced light scattering and interference patterns.

Innovation Solution

A device and method utilizing a resonant optical cavity formed by a pair of reflectors with different refractive indices, where the sample is placed between the reflectors, allowing for high sensitivity and improved spatial resolution through modulation of the refractive index and holographic reconstruction algorithms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional microscopy is used to observe particles, then spatial resolution can be maintained, but sensitivity decreases for submicron-sized particles due to reduced light scattering

Engineering Contradiction:
Improvespatial resolutionVSAvoiddetection sensitivity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the optical parameters by using a resonant optical cavity with specific refractive index contrasts and wavelength selections to enhance light scattering from submicron particles, thereby improving detection sensitivity without sacrificing spatial resolution

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs resonant oscillation of the optical cavity at specific frequencies to amplify the interaction between light and particles, enhancing the scattering signal from submicron particles and improving detection sensitivity

Inventive Principle:
Principle #18Mechanical vibration

2Reliability

If the particle size becomes comparable to the wavelength of incident light, then sensitivity improves, but spatial resolution is limited

Engineering Contradiction:
Improvedetection sensitivityVSAvoidspatial resolution
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the optical path into distinct functional zones including the resonant cavity region and detection region, allowing independent optimization of sensitivity in the cavity and resolution in the detection plane

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from direct imaging to holographic imaging in the spatial frequency domain, allowing recovery of spatial resolution information that would otherwise be lost when particle sizes approach the wavelength scale

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If lensless imaging is used to simplify the optical system, then device complexity is reduced, but spatial resolution is limited due to interference patterns

Engineering Contradiction:
Improveoptical system complexityVSAvoidspatial resolution
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a resonant optical cavity as an intermediary element between the light source and the sample, which mediates the light-sample interaction to produce enhanced diffraction patterns that preserve spatial resolution information while maintaining the simplicity of lensless imaging

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

Enables the detection of submicron particles with enhanced sensitivity and spatial resolution, allowing for more contrasting diffraction patterns and improved signal-to-noise ratios, facilitating the detection of particles as small as 0.1 μm in size.

Implementation Method 1

the lower reflector being formed of at least two materials having different refractive indices, at the emission wavelength

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

the upper reflector being arranged opposite the lower reflector, so as to form a resonant optical cavity

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

the image sensor collects an image of a light wave transmitted by the sample... interference patterns between the incident light wave emitted by the source and transmitted by the sample, and diffraction waves, resulting from the diffraction of the incident light wave by particles present in the sample

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 4

a lower reflector, formed of at least two materials having different refractive indices, at the emission wavelength... an upper reflector, formed of at least two materials having different refractive indices

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3575774B1Method for observing particles, in particular submicron particles
Publication Date: 2023.08.30 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3575774B1 patent drawingFigure 1A~1C
  • EP3575774B1 patent drawingFigure 2A~2F
  • EP3575774B1 patent drawingFigure 3A~3F

AI summary

The invention is a device (1) for producing an image of at least one particle (6), disposed in a sample (7), comprising: - a light source (2), capable of emitting a light wave (3), called the incident wave, at an emission wavelength (λ), along a propagation axis (Z), towards the sample; - an image sensor (30); - a support (20), disposed between the light source (2) and the image sensor (30), the support defining a support plane (PS), for receiving the sample; the device being characterized in that: - the support (20) comprises a lower reflector, formed of at least two materials (21, 22) having different refractive indices, the lower reflector extending between the support plane and the image sensor; - the device includes an upper reflector, formed of at least two materials having different refractive indices (11, 12), the upper reflector extending between the support plane (PS) and the light source (2);- the device comprising a free space (8) between the upper reflector and the support, the free space being suitable for being occupied by the sample.;