Particle Tracking via Spatially Limited Light Intensity Minima
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for tracking particle movement in a sample at a spatial resolution beyond the diffraction limit require a high number of photons, leading to increased bleaching risk and limiting the duration and distance of tracking due to the stress on fluorescent molecules, with existing techniques like STED and RESOLFT microscopy requiring high intensities and specific fluorophores.
Innovation Solution
A method and apparatus that utilize a spatially limited minimum light intensity distribution to track particles by moving the intensity distribution relative to the sample, minimizing the rate of photons emitted and reducing bleaching risk, with the light intensity distribution formed by coherent beams and moved using beam deflecting means to maintain a minimal photon rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high number of photons are detected for each particle position to achieve spatial resolution beyond the diffraction limit, then the spatial resolution is improved, but the molecule is seriously stressed resulting in increased risk of bleaching
Solution Approach 1:
Instead of maximizing photon detection at each position (conventional approach), the patent inverts the approach by minimizing photon emission through intelligent illumination control. The system uses a spatial light modulator to create intensity distributions with minima at particle positions, detecting photons only when particles pass through these minima during scanning, thereby reducing total photon exposure while maintaining tracking capability
Solution Approach 2:
The patent implements periodic scanning of the illumination pattern across the sample. The intensity distribution is moved systematically to scan different regions, and photon detection is synchronized with this periodic scanning motion. This allows the system to accumulate positional information over multiple scanning cycles without requiring high photon rates at any single moment, reducing bleaching risk
2Measurement precision
If high intensities of fluorescence inhibiting light are applied in STED microscopy to achieve spatial resolution below diffraction limit, then the spatial resolution is improved, but the risk of bleaching fluorophores is relatively high
Solution Approach 1:
The patent changes the illumination parameter from high-intensity focused stimulation (STED) to low-intensity structured illumination with spatial minima. Instead of using high intensity to inhibit fluorescence everywhere except the focal point, the system uses a spatial light modulator to create intensity distributions where minima are positioned at particle locations, detecting photons only during brief moments when particles pass through these minima, thereby achieving sub-diffraction resolution with much lower overall intensity
Solution Approach 2:
The patent replaces the optical stimulation mechanism of STED (using high-intensity laser to induce stimulated emission) with a detection-based approach using spatially modulated illumination and photon counting. The system substitutes the active fluorescence inhibition mechanism with a passive detection scheme that relies on temporal correlation between particle motion and illumination pattern scanning
3Measurement precision
If continuous high-rate photon emission is required for tracking, then the tracking precision is improved, but the molecule may be transferred to a metastable dark state from which it cannot emit photons for an extended period
Solution Approach 1:
The system uses periodic scanning of the illumination pattern combined with temporal correlation of detected photons. By accumulating positional information over multiple scanning periods and correlating photon arrival times with the known illumination pattern motion, the system achieves high tracking precision without requiring continuous high-rate photon emission, allowing molecules to remain in fluorescent state for extended periods
Solution Approach 2:
The system performs preliminary scanning and positioning to identify particle locations before intensive measurement. The spatial light modulator pre-establishes the illumination pattern with minima at expected particle positions, and the system correlates detected photons with this predetermined pattern, allowing efficient tracking with minimal photon requirements
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
Enables tracking of particles at a spatial resolution below the diffraction limit with reduced bleaching risk, allowing for longer tracking periods and distances without the need for high photon emission, and simplifies the optical setup by using lower light intensities and eliminating the need for complex beam alignment.
Implementation Method 1
The process underlying the emission of photons by the particle being subjected to the light may be fluorescence
Implementation Method 2
The light intensity distribution is formed by coherent beams
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
For tracking a movement of a particle (2) in a sample (3), the particle (2) is driven by light (4) to emit photons, and the photons emitted by the particle (2) are detected. The light (4) applied to the sample (4) comprises an intensity distribution (18) with a spatially limited minimum (19); and the particle (2) is tracked with the minimum (19) of the intensity distribution (18) of the light by moving the intensity distribution (18) relative to the sample (3) such that a rate of photons emitted by the particle (2) remains minimal.