Wavefront Control for Deep Imaging in Scattering Media
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Solution Overview
Problem
Current imaging methods in scattering media, such as biological tissues, face limitations in depth penetration due to scattering, leading to reduced resolution and imaging depth, and existing wavefront control technologies require measurable target signals that attenuate at deeper positions, making it difficult to focus light effectively.
Innovation Solution
A wavefront control apparatus and method that uses a detector to monitor signals within the medium and a controller to optimize the wavefront of light based on signals from multiple measurement positions, iteratively adjusting the wavefront to enhance signal intensity and extend imaging depth by forming optimized wavefronts for photoacoustic, fluorescent, or ultrasound modulated signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional imaging methods (confocal microscope, OCT) are used to remove scattered light and extract signal light, then imaging resolution is improved, but imaging depth is limited to shallow areas (1 mm or less)
Solution Approach 1:
The patent converts the harmful scattered light into a useful signal by using fluorescent particles as guide stars. The scattered light that would normally degrade image quality is instead utilized to excite fluorescent particles at deep positions, which then emit fluorescent light that serves as a signal for wavefront optimization. This allows the system to achieve both deep penetration and high resolution by transforming the scattering medium's harmful effect into a beneficial signaling mechanism.
Solution Approach 2:
Fluorescent particles are introduced as intermediary elements that mediate between the incident light and the detection system. These particles absorb incident light at deep positions within the scattering medium and re-emit fluorescent light, which then serves as a guide signal for wavefront shaping. The fluorescent particles act as a bridge that enables the system to target deep regions without requiring direct detection of light from those regions.
2Manufacturing precision
If wavefront optimization is performed using fluorescent signal or photoacoustic signal as target, then light can be focused inside scattering medium, but the target signal attenuates at deeper positions making optimization difficult
Solution Approach 1:
The system uses the scattered incident light itself to excite the fluorescent particles, rather than requiring a separate signaling mechanism. The fluorescent particles are excited by the same scattered light that would otherwise be lost, and the resulting fluorescent emission serves as the guide signal for wavefront optimization. This self-service approach allows the system to generate optimization signals from the scattered light field without requiring additional signal sources that would also attenuate with depth.
3Length of stationary object
If phase conjugate light technology is used to send light to specific position, then light focusing is achieved, but it requires measurable target signals that are unavailable at deep positions
Solution Approach 1:
The patent transforms the scattered light, which would normally be considered noise or harmful interference, into a useful excitation source for fluorescent particles. The scattered light that prevents conventional imaging from working at depth is instead utilized to generate fluorescent signals from guide stars, which then enable phase conjugate wavefront shaping to focus light at deep positions where previously no measurable signal was available.
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 signal intensity and extends the penetration depth of optical imaging, allowing for more effective measurement and imaging of optical properties at deeper positions within scattering media by iteratively optimizing the wavefront of light based on detected signals.
Implementation Method 1
a detector configured to detect a signal generated from a medium onto which light is irradiated
Implementation Method 2
there has recently been proposed a technology for efficiently sending the light to a specific position inside the scattering medium by properly shaping the wavefront of the light incident onto the medium
Implementation Method 3
I. M. Vellekoop, E. G. Van Putten, A. Lagendijk and A. P. Mosk, 'Demixing light paths inside disordered metamaterials,' Optics Express Vol. 16, No. 1, pp. 67-80 (2008) irradiates light onto a scattering medium, monitors fluorescent light generated from a fluorescent material in the medium with a CCD, and shapes an incident wavefront with a SLM
Data Source
AI summary
A wavefront control apparatus includes a detector configured to detect a signal generated from a medium onto which light is irradiated, and a controller configured to control a wavefront of the light based on an output of the detector. The controller performs first processing for forming a first wavefront of the light based on the signal generated from a first measurement position in the medium, and second processing for forming a second wavefront of the light based on the signal generated from a second measurement position different from the first measurement position in the medium onto which the light having the first wavefront is irradiated.