SPIM Light Sheet Waist Positioning for Uniform Axial Resolution
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Solution Overview
Problem
Light sheet fluorescence microscopy (SPIM) systems face challenges in maintaining the thinnest possible light sheet waist while ensuring image quality, particularly in applications requiring fast imaging of medium-sized or large specimens, due to non-uniform light sheets causing poor axial resolution and variations in image quality.
Innovation Solution
The system dynamically varies the cross-section and position of the light sheet's waist along the illumination axis, synchronizes the light sheet with a rolling shutter detector, and uses a variable focus lens to maintain optimal axial resolution and field of view, allowing for better image homogeneity and reduced shadows within the specimen plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the waist of the light sheet is reduced using objectives with higher numerical apertures, then axial resolution is improved, but the Rayleigh range decreases quadratically causing non-uniform illumination and poor image quality
Solution Approach 1:
The patent applies dynamics by making the light sheet system movable and adjustable. Specifically, it uses a scanning light beam with a circular cross-section that rapidly scans the object to create a virtual light sheet, rather than relying on a stationary beam. The system dynamically adjusts the light sheet parameters including waist size and position along the propagation axis to maintain optimal illumination uniformity across the field of view while preserving axial resolution
Solution Approach 2:
The patent changes physical parameters of the light sheet by using objectives with higher numerical apertures in combination with dynamic scanning. It optimizes the balance between waist size and Rayleigh range by adjusting illumination parameters and synchronization with the rolling shutter detector, thereby improving axial resolution without sacrificing image quality uniformity
2Volume of stationary object
If a stationary light sheet with elongated cross section is used, then the illuminated volume is reduced, but the light sheet waist is maintained only within a small space causing resolution variations
Solution Approach 1:
The patent transforms the stationary light sheet into a dynamic virtual light sheet by rapidly scanning the illumination beam across the specimen. This scanning approach maintains the thin waist characteristics over a much larger propagation distance, providing uniform axial resolution across the entire field of view while keeping the illuminated volume minimal
3Area of stationary object
If the light sheet is scanned rapidly to create a virtual light sheet, then the field of view is extended, but synchronization with the rolling shutter detector is required to maintain image quality
Solution Approach 1:
The patent implements feedback control by synchronizing the light sheet scanning with the rolling shutter detector operation. The system coordinates the scanning speed and pattern with the detector's readout timing, ensuring that each row of pixels captures light from the correct position in the scanned light sheet, thereby maintaining image quality while extending the field of view
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 enhances the axial resolution and signal-to-noise ratio, enabling faster and more accurate 3D imaging of large specimens with improved uniformity and reduced photo bleaching, addressing the limitations of traditional SPIM systems.
Implementation Method 1
The optical elements are configured to at least in part transform the light from each of the plurality of illumination sources into a light sheet illuminating the microscopy specimen and to vary a position of a waist of the light sheet
Implementation Method 2
Light sheet fluorescence microscopy or selective plane illumination microscopy (SPIM) technology typically relies on illuminating of a specimen in thin optical slices, formed from laser light, exciting the fluorophores in the specimen and acquiring light emitted by the illuminated plane inside the specimen
Data Source
AI summary
A system for illuminating a microscopy specimen includes illumination sources each of which is configured to emit a light that travels along an illumination path to illuminate the microscopy specimen placed on an optical detection path of an optical microscope. The system also includes optical elements in the illumination path of each of the illumination sources. The optical elements are configured to at least in part transform the light from each of the illumination sources into a light sheet illuminating the microscopy specimen and to vary a position of a waist of the light sheet from each of the illumination sources that illuminates the microscopy specimen. The optical elements for each of the illumination sources are configured such that the waist of the light sheet from each of the illumination sources are spatially aligned and illuminate a substantially coincident portion of the microscopy specimen.