Adaptive Optics Raman Microscopy Aberration Correction

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Solution Overview

Problem

Raman microspectrometry apparatuses face challenges such as complex calibration procedures, optical aberrations, and reduced signal-to-noise ratios due to the complexity of adaptive optics systems, which also introduce additional optical losses and are not reciprocal, making them less desirable for improving spatial and spectral resolution.

Innovation Solution

A Raman microscopy apparatus with a confocal hole and adaptive optics system configured to adapt the laser beam to the confocal hole shape, featuring wavefront detection and multiple adaptive mirrors for variable focusing and spatial modulation, placed on the Raman scattering beam path to correct aberrations and enhance signal quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If adaptive optics systems are implemented in Raman microscopy, then spatial resolution and signal quality improve, but device complexity and calibration difficulty increase

Engineering Contradiction:
Improvespatial resolutionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the adaptive optics system with the Raman microscopy apparatus by integrating a deformable mirror into the existing optical path. The deformable mirror is positioned in the illumination path between the laser source and the sample, allowing it to share the optical infrastructure with the Raman spectroscopy components. This merging approach enables aberration correction without requiring separate, independent optical systems, thereby improving spatial resolution while limiting the increase in overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The deformable mirror serves multiple functions: it corrects optical aberrations in the illumination path, shapes the laser beam profile, and can be used for wavefront sensing. By making the adaptive optics component multi-functional, the patent reduces the need for additional specialized devices, thus improving measurement precision without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If adaptive optics systems are implemented in Raman microscopy, then signal-to-noise ratio improves, but optical losses increase

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidoptical losses
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent applies adaptive optics specifically to the illumination path where aberrations most affect the Raman signal generation, rather than attempting to correct all optical paths uniformly. The deformable mirror is positioned to correct aberrations at the sample plane, which is the critical region for Raman scattering. This localized approach improves signal-to-noise ratio by ensuring optimal focus and beam quality at the sample, while minimizing unnecessary optical components and associated losses in other parts of the system.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If adaptive optics systems are implemented in Raman microscopy, then spatial resolution improves, but calibration complexity increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidcalibration complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a self-calibration mechanism where the system automatically determines the optimal deformable mirror configuration by analyzing the Raman signal quality and wavefront measurements. The control system iteratively adjusts the mirror shape to maximize signal intensity and minimize aberrations, eliminating the need for manual, time-consuming calibration procedures. This self-service approach enables high spatial resolution while reducing calibration complexity from a manual process to an automated routine.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If adaptive optics systems are implemented in Raman microscopy, then optical aberration correction improves, but system cost increases

Engineering Contradiction:
Improveoptical aberration correctionVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a deformable mirror with a relatively simple actuator structure that can be manufactured at lower cost compared to more complex adaptive optics solutions. The mirror uses a flexible membrane with a small number of actuators (e.g., 14-37 actuators) rather than hundreds, making it a more economical choice. This approach provides sufficient aberration correction for Raman microscopy applications while keeping the system cost manageable, effectively using a simpler, more affordable component to achieve the required performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

This configuration improves the spatial resolution and signal-to-noise ratio, allowing for more precise topographic analysis and reduced optical aberrations, while minimizing signal loss and optical alignment defects, enabling better Raman signal detection and analysis.

Implementation Method 1

adaptive optics systems are known whose optical characteristics of reflection or refraction can be electronically modified, for example, to correct in real time the effects of certain optical disturbances or aberrations

Methodology Applied
Scientific EffectOptical aberration correction:

Implementation Method 2

a sample is illuminated with an excitation beam, usually a laser beam, and the scattered light is observed at wavelengths different from the wavelength of the excitation laser beam

Methodology Applied
Scientific EffectRaman scattering: Scattering

Implementation Method 3

Raman microscopy apparatus with a confocal hole and adaptive optics system configured to adapt the laser beam to the confocal hole shape

Methodology Applied
Scientific EffectConfocal filtering:

Implementation Method 4

featuring wavefront detection and multiple adaptive mirrors for variable focusing and spatial modulation

Methodology Applied
Scientific EffectWavefront detection:

Implementation Method 5

Some adaptive optics systems are based on mirrors or micromirrors in which micro-actuators allow the reflective optical surface to be oriented or deformed

Methodology Applied
Scientific EffectDeformable mirror actuation:

Implementation Method 6

There are also adaptive optics systems that operate in transmission, such as liquid crystal modulators (SLMs or Spatial Light Modulators) that allow the spatial modulation of the intensity, phase, and/or polarization components of a beam

Methodology Applied
Scientific EffectSpatial light modulation:

Data Source

PatentEP3111178B1Optical microscopy system and method for raman scattering with adaptive optics
Publication Date: 2020.11.18 HORIBA FRANCE SAS
  • EP3111178B1 patent drawingFigure 1~4C

AI summary

The present invention relates to a Raman scattering optical microscopy apparatus comprising a laser source (10) adapted to emit a laser beam (11) at an excitation wavelength λ, a microscopy objective (14) adapted to receive the laser beam (11) and to focus the laser beam in an image plane of the microscope objective (14), the focused laser beam (21) being intended to illuminate a sample (20), an optical system adapted to collect an optical Raman scattering beam (22) and detection means (16, 17) adapted for detecting the Raman scattering beam (22) collected. More particularly, there is proposed according to the invention, a Raman scattering microscopy apparatus furthermore comprising an adaptive optics system (31, 32, 33) disposed on an optical path of the excitation laser beam (11), on an optical path of the Raman scattering beam (22) or on a common optical path of the excitation laser beam (11) and of the Raman scattering beam (22).