STED Microscope Illumination System Coaxial Beam Alignment
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Solution Overview
Problem
The complexity of STED microscope structures makes it difficult to achieve high-precision and long-time stable alignment of excitation and depletion light spots, limiting the instrument's reliability and imaging resolution.
Innovation Solution
An illumination system for STED optical microscopes is designed with a specific light path configuration using optical elements like polarization beam splitters, quarter-wave plates, dichroic elements, and a phase plate, which allows for compact beam steering and polarization control, enabling coaxial excitation and depletion light beams to form concentric spots, reducing the need for physical adjustments and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional STED microscope structure is used, then super-resolution imaging capability is achieved, but the structural complexity makes it difficult to maintain high-precision and stable alignment of excitation and depletion light spots
Solution Approach 1:
The patent combines the excitation light path and depletion light path into a single integrated illumination system. The laser source emits light that is split into two wavelengths, and both paths share common optical components including the objective lens and sample stage. This merging of previously separate systems reduces the number of independent alignment mechanisms and maintains stable relative positioning between excitation and depletion spots.
Solution Approach 2:
The illumination system is designed with multi-functional optical components that serve multiple purposes. The same optical path and components are used for both excitation and depletion light delivery, and the system can operate in different imaging modes (confocal and STED) using the same hardware platform. This universality reduces complexity while maintaining precision through consistent optical pathways.
2Reliability
If separate adjustment mechanisms are used for excitation and depletion light paths, then initial alignment can be achieved, but long-time stable alignment is difficult to maintain due to environmental variations
Solution Approach 1:
The patent merges the excitation and depletion light paths into a unified system where both beams traverse common optical components. This shared pathway ensures that environmental disturbances affect both beams equally, maintaining their relative alignment. The unified design eliminates the need for separate adjustment mechanisms that would drift independently, thereby improving long-term stability.
3Measurement precision
If complex optical paths are used to achieve precise beam control, then imaging resolution is improved, but the system becomes more sensitive to environmental variations
Solution Approach 1:
The patent combines excitation and depletion paths into a single integrated system with shared optical components. This merging reduces the total number of optical interfaces and adjustment mechanisms that could introduce sensitivity to environmental variations. The common pathway design ensures that thermal expansion, vibration, and other environmental factors affect both beams uniformly, maintaining resolution while reducing sensitivity.
4Manufacturing precision
If multiple optical elements are used for beam steering and polarization control, then light spot configuration precision is improved, but the physical adjustment requirements increase
Solution Approach 1:
The patent integrates beam steering and polarization control functions into a unified illumination system with shared optical components. The compact integrated design reduces the number of separate adjustment mechanisms required, while maintaining precise light spot configuration through coordinated control of the combined optical elements.
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 imaging resolution beyond the diffraction limit, allows for real-time imaging of subcellular structures, and maintains instrument reliability despite environmental variations, as demonstrated by improved resolution in STED imaging compared to confocal microscopy.
Implementation Method 1
a first quarter-wave plate and a first dichroic element, an optical path delay unit, a phase plate, a second dichroic element and a second quarter-wave plate, which are arranged in sequence in a transmission direction of the light path; after the light beam emitted from the illumination light source is optically filtered by the first optical filter and the second optical filter, a first light beam and a second light beam each having a certain wavelength are obtained; the first light beam and the second light beam are respectively split by the polarization beam splitter to form linearly polarized lights which, after being reflected, are incident onto the first quarter-wave plate and the first dichroic element in sequence; the first light beam forms circularly polarized light after passing through the first quarter-wave plate
Implementation Method 2
the first light beam forms circularly polarized light after passing through the first quarter-wave plate, and after being reflected by the first dichroic element, it passes through the first quarter-wave plate again to form linearly polarized light, which is then transmitted through the polarization beam splitter, reflected by the second dichroic element
Implementation Method 3
the first light beam and the second light beam are respectively split by the polarization beam splitter to form linearly polarized lights
Implementation Method 4
converted by the second quarter-wave plate into circularly polarized light to be incident onto a microscopic objective lens of a microscopic imaging system and converged, thus forming a first light spot at a focal plane of the microscopic objective lens
Implementation Method 5
a light beam emitted from the illumination light source is focused and irradiated onto a sample to excite fluorescent substance in the sample to emit fluorescence
Data Source
Figure 1
Figure 2~3
AI summary
An illumination system (10) for an STED optical microscope and an STED optical microscope. The illumination system (10) comprises an illumination light path consisting of an illumination light source and an optical element. The illumination light path comprises a first light filter (21), a second light filter (22), a polarizing light splitter (3), a first quarter wave plate (41), a first dichroic element (51), a light path delay unit (6), a phase plate (7), a second dichroic element (52), and a second quarter wave plate (42) arranged in sequence along the transmission direction of the light path. The light beam emitted from the illumination light source (1) is divided into two coaxial light beams after transmitted by the illumination light path. A first light beam (101) is incident to a microscope objective to form a first light spot, a second light beam (102) is incident to the microscope objective to form a second light spot, and the center of the first light spot coincides with that of the second light spot. Use of an integrated optical module design implements coaxial input and output of exciting light, depletion light, and confocal detection light path, and voids unstable temperature and vibration inherent in physical adjustment and mechanical adjustment mechanisms for geometrical relationships between the elements, thereby improving the reliability of an STED apparatus.