Wavelength-Polarization Beam Splitter for Multimodal Microscopy

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Solution Overview

Problem

Existing multimodal microscopy setups face challenges in efficiently separating illumination and detection light due to spectral overlap, particularly when combining methods that require wavelength-dependent and polarization-dependent light separation, leading to significant loss of detection light.

Innovation Solution

A beam splitter with unique splitting characteristics that combines wavelength-dependent and polarization-dependent light separation, allowing for efficient separation of illumination and detection light in overlapping wavelength ranges by using a beam splitter with three distinct splitting characteristics across different wavelength bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a dichroic beam splitter is used for wavelength-dependent light separation, then light separation efficiency is improved for methods like multiphoton excitation, CARS, SHG, THG, but light loss occurs when combining with polarization-dependent methods like SRS

Engineering Contradiction:
Improvedetection light lossVSAvoidcompatibility with multiple microscopy methods
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent combines wavelength-dependent and polarization-dependent light separation characteristics into a single beam splitter component. This merged approach allows the beam splitter to handle both dichroic methods (multiphoton excitation, CARS, SHG, THG) and polarization-based methods (SRS) simultaneously, eliminating the need for separate beam splitters and reducing detection light loss while maintaining versatility across multiple microscopy techniques.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The beam splitter is designed with multi-functionality to perform both wavelength-dependent separation (for spectral discrimination in dichroic methods) and polarization-dependent separation (for isolating SRS signals). This universal component replaces the need for multiple specialized beam splitters, achieving high light efficiency across diverse microscopy methods while maintaining adaptability to different detection requirements.

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

2Adaptability or versatility

If a polarizing beam splitter is used for polarization-dependent light separation, then light separation is achieved for SRS microscopy, but significant detection light loss occurs when combining with wavelength-dependent methods

Engineering Contradiction:
Improvecompatibility with SRS and other microscopy methodsVSAvoiddetection light loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent merges polarization-dependent and wavelength-dependent separation capabilities into one beam splitter. This allows SRS microscopy (requiring polarization separation) to be combined with dichroic methods (requiring wavelength separation) without the significant light losses that would occur with separate polarizing beam splitters, achieving both versatility and high light efficiency simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The beam splitter exhibits different separation characteristics at different wavelengths: at the pump wavelength it provides polarization-dependent separation for SRS, while at the Stokes wavelength it provides wavelength-dependent separation for dichroic methods. This local differentiation of separation properties allows each microscopy method to operate optimally without compromising the other, minimizing overall detection light loss.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple beam splitters are used to support multiple microscopy methods, then adaptability is improved, but device complexity and light loss increase

Engineering Contradiction:
Improvesupport for multiple microscopy methodsVSAvoidnumber of beam splitters
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent consolidates multiple beam splitter functions into a single component that simultaneously provides both wavelength-dependent and polarization-dependent separation. This merging reduces the total number of beam splitters from two or more (separate dichroic and polarizing beam splitters) to one, simplifying the optical path while maintaining full support for multiple microscopy methods including SRS, multiphoton excitation, CARS, SHG, and THG.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single beam splitter is designed with universal functionality to handle diverse microscopy methods through its dual separation capabilities. It universally supports both polarization-based methods (SRS) and wavelength-based methods (dichroic methods) without requiring additional specialized components, thereby reducing device complexity while preserving adaptability across the full range of microscopy techniques.

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

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 high light efficiency in multimodal configurations by minimizing detection light loss, facilitating the combination of microscopy methods like SRS with multiphoton excitation, CARS, SHG, and THG without significant light loss.

Implementation Method 1

The beam splitter has a polarization-dependent second splitting characteristic with said one of transmitting and reflecting light of the first polarization state and the other of transmitting and reflecting light of a second polarization state in the intermediate wavelength range

Methodology Applied
Scientific EffectPolarization-dependent light separation: Polarisation

Implementation Method 2

The beam splitter has a first splitting characteristic with one of transmitting and reflecting light of at least a first polarization state in the illumination wavelength range excluding the intermediate wavelength range

Methodology Applied
Scientific EffectWavelength-dependent light separation: Reflection

Data Source

PatentEP4145211B1Optical apparatus
Publication Date: 2025.11.05 LEICA MICROSYSTEMS CMS GMBH
  • EP4145211B1 patent drawingFigure 1
  • EP4145211B1 patent drawingFigure 2
  • EP4145211B1 patent drawingFigure 3

AI summary

An optical apparatus (100) for examining a sample (102), comprises an illumination unit (104) configured to emit illumination light (106) in an illumination wavelength range (W3) onto the sample (102), and a detection unit (108) configured to collect detection light (122) in a detection wavelength range (W1+W2) from the sample (102). The illumination wavelength range (W3) and the detection wavelength range (W1+W2) partially overlap in an intermediate wavelength range (W2). A light separating device (114) is configured to separate the illumination light (106) and the detection light (122), wherein the light separating device (114) comprises a beam splitter (116). The beam splitter (116) has a first splitting characteristic with one of transmitting and reflecting light of at least a first polarization state (P-pol, S-pol) in the illumination wavelength range (W3) excluding the intermediate wavelength range (W2). The beam splitter (116) has a polarization-dependent second splitting characteristic with said one of transmitting and reflecting light of the first polarization state (P-pol, S-pol) and the other of transmitting and reflecting light of a second polarization state (S-pol, P-pol) in the intermediate wavelength range (W2). The beam splitter (116) has a third splitting characteristic with the other of transmitting and reflecting light of both the first polarization state (P-pol, S-pol) and the second polarization state (S-pol, P-pol) in the detection wavelength range (W1+W2) excluding the intermediate wavelength range (W2).