Large-Angle Optical Raster Scanning for Deep Tissue Imaging
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Solution Overview
Problem
Current nonlinear optical microscopes face challenges in extending the field of view (FOV) beyond one square millimeter while maintaining high 3D resolution and acquisition speed, often compromising on image quality or data acquisition speed to fulfill the Nyquist Criterion for sub-micron resolution.
Innovation Solution
A large-angle optical raster scanning system using a high-NA and low magnification objective lens, synchronized with a pulsed laser source of high repetition rate, and employing a GPU-accelerated interpolation algorithm to correct resonant scanner-induced distortions, allowing for equidistant sampling and enhanced data acquisition speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an increased scanning angle is used to extend the FOV, then the FOV is improved, but the optical resolution is degraded
Solution Approach 1:
The system uses dynamic scanning mirror technology with optimized scan lens parameters that adapt to large scanning angles, enabling the optical system to maintain resolution performance across the extended FOV through real-time optical path adjustment
Solution Approach 2:
The patent optimizes specific optical parameters including scan lens focal length, beam diameter, and scanning angle relationships to achieve a balance where large FOV is obtained without proportionally degrading resolution, by carefully controlling the ratio of scan angle to optical parameters
2Area of stationary object
If a low magnification and low NA objective is used to extend the FOV, then the FOV is improved, but the axial resolution is degraded
Solution Approach 1:
The system employs local quality optimization by using a high-NA objective lens specifically configured for the central imaging region, while the extended FOV is achieved through optimized scanning geometry rather than objective lens magnification, allowing high resolution where needed while expanding overall coverage
Solution Approach 2:
The patent transitions from extending FOV through objective lens magnification (optical dimension) to extending FOV through increased scanning angle and resonant scanner technology (mechanical scanning dimension), thereby preserving the high-NA objective's resolution capabilities while achieving large FOV through a different dimensional approach
3Manufacturing precision
If a high-NA objective is used to maintain high resolution, then the optical resolution is improved, but the FOV is limited
Solution Approach 1:
The system uses dynamic resonant scanning technology that enables the high-NA objective to scan across a large FOV at high speeds, overcoming the traditional FOV limitation by transitioning from static to dynamic imaging approaches with optimized scan parameters
Solution Approach 2:
The patent employs periodic resonant scanning motion to efficiently cover the extended FOV, using the natural resonant frequency of the scanning mirror to achieve rapid back-and-forth scanning that maintains high resolution while covering large areas through repeated periodic cycles
4Area of stationary object
If the FOV is extended beyond one square millimeter with sub-femtoliter resolution, then the FOV is improved, but the data acquisition speed is degraded due to Nyquist Criterion requirements
Solution Approach 1:
The system uses resonant scanning's periodic motion at high frequencies to dramatically increase the speed at which the beam can scan across the extended FOV, allowing Nyquist-compliant sampling rates to be achieved across large areas by leveraging the high-speed periodic scanning capability
Solution Approach 2:
The patent optimizes the relationship between scanning speed, pixel dwell time, and laser repetition rate to achieve parameter combinations that satisfy Nyquist sampling requirements across the extended FOV while maintaining high acquisition speeds through coordinated adjustment of multiple system parameters
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
The system achieves a FOV of at least one square millimeter with sub-femtoliter effective 3D resolution, exceeding the Nyquist Criterion, and maintains high acquisition speed, achieving diffraction-limited performance and high-resolution imaging across the entire FOV.
Implementation Method 1
one or more, i.e., 1st to nth, pulsed laser source(s) for emitting one or more laser beams
Implementation Method 2
a resonant scanning mirror optically coupled to the one or more pulsed laser source(s)
Implementation Method 3
a high-NA (numerical aperture) and low magnification objective lens... for raster scanning a volumetric tissue-sample
Implementation Method 4
a high-NA (numerical aperture) and low magnification objective lens... for collecting a sample-generated fluorescence signal which is guided to a photomultiplier tube (PMT) to produce an electrical signal
Data Source
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AI summary
The field of view (FOV) of a nonlinear optical microscope (NLOM) is expected to be large enough for employing high-speed raster scanning on a mesoscale volumetric biological sample. Concurrently, three-dimensional (3D) visualization of fine sub-micron biological structures requires high enough lateral and axial resolutions, enforcing a high numerical aperture (NA) objective lens to be employed, thereby limiting the FOV of an NLOM. The invention is directed to a laser scanning NLOM, or to a large-angle optical raster scanning system, for deep biological tissue imaging with a large FOV of more than one square millimeter, up to 1.6 ¡ 1.6 mm2, while simultaneously maintaining a sub-femtoliter effective 3D resolution by means of a high-NA and low magnification objective lens and further maintaining a high acquisition speed with synchronized sampling, limited by the repetition rate of a high repetition rate pulsed laser source, thereby exceeding Nyquist Criterion for resolving micro-optical resolution throughout a horizontal FOV of more than one millimeter.