Random-Access STED Microscopy with Counter-Propagating Beams

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Solution Overview

Problem

Current multi-photon microscopy techniques face limitations in spatial resolution due to diffraction, hindering the detailed study of brain tissue and neuronal activity patterns, particularly in high-speed and three-dimensional imaging.

Innovation Solution

The implementation of a random-access stimulated emission depletion (RASTED) microscopy system, combining two-photon excitation with single-wavelength STED, utilizing counter-propagating light beams and acousto-optic deflectors for high-speed and super-resolution imaging, allowing for rapid focus adjustment and improved spatial resolution without compromising temporal resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional multi-photon microscopy is used, then temporal resolution is maintained, but spatial resolution is limited by diffraction

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

Solution Approach 1:

The patent combines two-photon excitation microscopy with stimulated emission depletion (STED) microscopy into a unified system. The excitation beam and depletion beam are integrated into a single optical path, allowing simultaneous operation of both modes. This merging enables the system to achieve super-resolution capabilities while maintaining the temporal resolution advantages of two-photon microscopy, resolving the contradiction between improved spatial resolution and system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The microscopy system is designed to operate in multiple modes: conventional two-photon excitation mode and STED super-resolution mode. By making the system universal and capable of switching between different operational states, the patent allows users to select the appropriate mode based on their specific imaging needs, thereby improving spatial resolution when required without permanently increasing system complexity for all operating conditions.

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

2Measurement precision

If STED technique is applied to improve spatial resolution, then diffraction limitation is overcome, but system complexity increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates the STED depletion functionality into the existing two-photon excitation microscope by adding a depletion beam path that shares optical components with the excitation path. This merging approach allows the system to achieve STED super-resolution without requiring completely separate optical systems, thereby improving spatial resolution while minimizing the increase in overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If random-access scanning is used for high-speed imaging, then temporal resolution is improved, but spatial resolution remains diffraction-limited

Engineering Contradiction:
Improvespatial resolutionVSAvoidimaging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines random-access scanning capability with STED super-resolution by integrating the depletion beam control into the random-access scanning system. This allows the system to rapidly switch between different regions of interest while maintaining super-resolution imaging, thereby improving spatial resolution without sacrificing the time efficiency benefits of random-access scanning.

Inventive Principle:
Principle #5Merging (Combining)

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-speed, super-resolution imaging of brain tissue and neuronal activity with enhanced spatial resolution, facilitating the analysis of complex brain functions and electrical signal transmission in neurons.

Implementation Method 1

Inertia-free acousto-optic deflectors (AODs) have been used to perform random-access imaging and rapidly vary focusing of a laser beam without mechanical movements

Methodology Applied
Scientific EffectAcousto-optic effect: Acousto-optic Effect

Implementation Method 2

A generation block (30) produces two light beams (110, 110b) having the same wavelength and synchronizable pulses, namely a first light beam (110) acting as a multi-photon excitation beam

Methodology Applied
Scientific EffectTwo-photon absorption:

Implementation Method 3

The basic principle of such a method is based on the inhibition of spontaneous fluorescence emission at predefined coordinates of the sample, such that adjacent elements emit sequentially over time by means of a stimulated emission process

Methodology Applied
Scientific EffectStimulated emission:

Data Source

PatentEP2976670B1Random access stimulated emission depletion (STED) microscopy
Publication Date: 2021.06.16 FOND INST ITAL DI TECH
  • EP2976670B1 patent drawingFigure 1~2
  • EP2976670B1 patent drawingFigure 3
  • EP2976670B1 patent drawingFigure 4~5

AI summary

Optical scanning system (80), comprising an optical system (3) for guiding a first and a second light beam (110, 110b), and deflector devices for deflecting first and second light beams in a directionally variable manner. The deflector devices comprise at least one acousto-optic deflector (100.1, 100.2; 100.3, 100.4), and the optical system is arranged in such a way that the first and second light beams are counter-propagating through the acousto-optic deflector, which is controllable for deflecting the first and second light beams simultaneously or in pulse sequence. STED microscopy apparatus comprising an optical scanning system based on acousto-optic deflectors.