Hybrid Two-Photon Three-Photon Microscopy Volumetric Imaging
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Solution Overview
Problem
Current optical microscopy techniques struggle to record volumetric activity from large neuronal populations in scattering tissues at single-cell resolution and on physiological timescales.
Innovation Solution
A modular, hybrid two-photon (2p)-three-photon (3p) excitation microscopy system with spatiotemporal multiplexing, one-pulse-per-voxel excitation, synchronized detection, rapid remote scanning, and light sculpting using temporal focusing is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential point-by-point scanning of a diffraction-limited two-photon excitation spot is used, then spatial resolution is maintained, but image acquisition rate and imaging volume are severely limited
Solution Approach 1:
The patent segments the excitation process by using multiple independently controlled laser beams (two-photon and three-photon channels) that can simultaneously excite different regions of the sample. This parallel excitation approach divides the imaging task across multiple beams, dramatically increasing the acquisition rate while maintaining spatial resolution through precise beam control and focusing.
Solution Approach 2:
The patent extends imaging into the temporal dimension by employing pulsed laser excitation with precise timing control. By using time-gated detection and synchronized pulsing of multiple laser channels, the system captures spatial information across multiple time points, enabling volumetric imaging at high speeds without sacrificing resolution.
2Measurement precision
If sequential point-by-point scanning is used, then spatial resolution is maintained, but the size of 3D volumes that can be imaged at biologically relevant time scales is limited
Solution Approach 1:
The patent merges two-photon and three-photon excitation channels into a unified imaging system that operates simultaneously. This combination allows the system to capture both shallow and deep tissue signals in the same volume, effectively doubling the usable imaging volume while maintaining single-cell resolution through the complementary penetration depths of the two excitation modalities.
Solution Approach 2:
The patent creates a multi-functional imaging system that can simultaneously perform two-photon excitation, three-photon excitation, and coordinated detection across multiple channels. This universal platform handles diverse imaging requirements (surface and deep tissue, different fluorescence markers) within a single volumetric scan, maximizing the effective imaging volume without requiring multiple separate systems.
3Productivity
If hybrid two-photon (2p)-three-photon (3p) excitation scheme with spatiotemporal multiplexing is used, then volumetric recording speed and imaging volume are improved, but system complexity increases
Solution Approach 1:
The patent introduces specialized intermediary components including beam-combining optics, synchronized pulse generators, and time-gated detection intermediaries that mediate between the complex multi-channel excitation sources and the final detection system. These intermediaries coordinate the multiple laser channels and detection paths, managing the system complexity while enabling high-speed volumetric imaging through controlled synchronization and signal integration.
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 system enables high-speed, unbiased recording of neuronal activity at single-cell resolution within large volumes (up to 1,000×1,000×1,220 μm) at rates of up to 17 Hz in awake behaving mice.
Implementation Method 1
a first channel for outputting a two-photon excitation laser pulse
Implementation Method 2
a second channel for outputting a three-photon excitation laser pulse
Implementation Method 3
a photodetector configured to collect photons generated within the target volume in response to simultaneous excitation of the target volume by both the two-photon laser pulse and the three-photon laser pulse
Data Source
AI summary
A multi-photon imaging system includes a laser module having a first channel for outputting a two-photon excitation laser pulse and a second channel for outputting a three-photon excitation laser pulse. The system further includes a first optical path for guiding the two-photon laser pulse from the first channel of the laser module and a second optical path for guiding the three-photon laser pulse from the second channel of the laser module. A microscope is also provided for simultaneously receiving the two-photon laser pulse from the first optical path and the three-photon laser pulse from the second optical path, and simultaneously, or with well controllable delays, delivering the two-photon laser pulse and the three-photon pulse to a target volume. The system further includes a photodetector configured to collect photons generated within the target volume in response to simultaneous excitation of the target volume by both the two-photon laser pulse and the three-photon laser pulse.