Multi-arm SIM Imaging with Fixed Diffraction Gratings
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Solution Overview
Problem
Existing structured illumination microscopy (SIM) systems face challenges with mechanical rotation stages that slow down imaging speed, reduce stability, and increase costs due to the need for precise rotation and high repeatability, while also having low optical efficiency due to the use of linear polarizers.
Innovation Solution
Implementing a multi-arm SIM system with fixed diffraction gratings oriented perpendicular to each other, eliminating the need for mechanical rotation and polarizers, and using a single linear motion stage to adjust phase shifts, which enhances speed, reliability, and optical efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical rotation stage is used to rotate the diffraction grating to change pattern orientation, then the system can achieve multiple orientation angles, but the imaging speed decreases and system stability is reduced
Solution Approach 1:
The system divides the illumination path into multiple independent arms (e.g., first arm with vertical grating, second arm with horizontal grating), each producing fringes at a fixed orientation. This segmentation eliminates the need for mechanical rotation while providing multiple orientations simultaneously, thereby improving imaging speed and stability.
Solution Approach 2:
Instead of rotating a single grating to change orientation (conventional approach), the invention inverts the approach by using multiple fixed gratings with different orientations that illuminate the sample simultaneously or sequentially without rotation, thus eliminating mechanical movement and improving speed.
2Measurement precision
If a mechanical rotation stage with high precision is used to ensure repeatability, then the pattern orientation accuracy is improved, but the system cost increases
Solution Approach 1:
The system uses multiple independent illumination arms with fixed gratings oriented at specific angles (e.g., 0°, 90°, 45°, 135°). Each arm contributes to the overall resolution without requiring precise rotation, thereby reducing mechanical complexity and cost while maintaining orientation accuracy.
Solution Approach 2:
The invention replaces the mechanical rotation stage with a multi-arm optical configuration using fixed diffraction gratings. This substitution eliminates complex mechanical components and their associated costs while achieving the same functional outcome through optical design.
3Reliability
If a linear polarizer is used to polarize the light source, then the interference pattern quality is improved, but the optical efficiency decreases
Solution Approach 1:
The invention extracts and eliminates the linear polarizer from the optical path by using diffraction gratings that work with unpolarized or partially polarized light. This removal maintains sufficient interference pattern quality while significantly improving optical efficiency by reducing energy loss.
Solution Approach 2:
The system changes the polarization parameter requirement by using diffraction-based interference instead of polarization-based interference. This allows the use of unpolarized or partially polarized light sources, improving optical efficiency while maintaining pattern quality through the diffraction grating design.
4Measurement precision
If multiple beams are combined to create interference fringe pattern, then the resolution is improved, but the modulation depth is reduced due to mixture of fringe spacings
Solution Approach 1:
The system segments the interference pattern generation into multiple independent arms, each producing fringes at a specific orientation with consistent spacing. By combining these segmented patterns from different arms rather than mixing multiple beams from a single grating, the system maintains high modulation depth while achieving enhanced resolution through the combination of orthogonal patterns.
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 approach improves imaging speed, reliability, and optical efficiency by eliminating mechanical rotation and polarizers, allowing for high-resolution imaging with reduced mechanical parts and costs.
Implementation Method 1
a first diffraction grating in a first orientation with respect to an optical axis of the system and a second diffraction grating in a second orientation with respect to the optical axis
Implementation Method 2
the interference between them can create a uniform, regularly-repeating fringe pattern where the spacing is determined by factors including the angle between the interfering beams
Data Source
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AI summary
The disclosure provides for structured illumination microscopy (SIM) imaging systems. In one set of implementations, a SIM imaging system may be implemented as a multi-arm SIM imaging system, whereby each arm of the system includes a light emitter and a beam splitter (e.g., a transmissive diffraction grating) having a specific, fixed orientation with respect to the system's optical axis. In a second set of implementations, a SIM imaging system may be implemented as a multiple beam splitter slide SIM imaging system, where one linear motion stage is mounted with multiple beam splitters having a corresponding, fixed orientation with respect to the system's optical axis. In a third set of implementations, a SIM imaging system may be implemented as a pattern angle spatial selection SIM imaging system, whereby a fixed two-dimensional diffraction grating is used in combination with a spatial filter wheel to project one-dimensional fringe patterns on a sample.