Random Laser Sensor for Non-Invasive Tissue Characterization
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Solution Overview
Problem
Existing methods for characterizing diffusive samples, particularly biological tissues, are invasive and alter sample properties due to the need for toxic external substances and inability to perform in vivo measurements.
Innovation Solution
A random laser sensor that forms a laser by an active medium and diffusing sample, using diffusion processes for optical feedback, allowing non-invasive analysis by separating the active medium from the sample and using stimulated emission for signal amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laser methods are used to characterize biological tissues, then detection sensitivity is improved, but the sample properties are altered due to injection of toxic external substances
Solution Approach 1:
The patent uses an optical fiber as an intermediary to deliver pump light to the active medium and collect the random laser signal from the diffusive sample. This intermediary approach allows the active medium to remain separated from the biological sample, enabling sensitive detection without direct contact that would require toxic substances.
Solution Approach 2:
The patent employs the biological sample itself as the diffusing medium in the random laser system, eliminating the need for external toxic substances. The sample's natural optical properties (scattering and absorption) are utilized to create the random laser effect, making the system self-sufficient and non-invasive.
2Object-affected harmful factors
If random laser technology is used with separated active medium and diffusing sample, then non-invasive measurement is enabled, but the optical feedback path becomes more complex
Solution Approach 1:
The patent combines the pump light delivery and signal collection functions into a single optical fiber. The same optical fiber that delivers the pump light also collects the random laser signal, simplifying the overall optical path while maintaining the separation between active medium and sample.
Solution Approach 2:
The patent utilizes the diffusive sample itself to provide optical feedback through multiple scattering events. The scattered light returns to the active medium, creating the necessary feedback loop for random laser action without requiring complex external feedback mechanisms.
3Adaptability or versatility
If active medium is kept separate from diffusing sample, then in vivo measurements become possible, but the pump and signal paths must pass through the medium being investigated
Solution Approach 1:
The patent uses the optical fiber to create a copy of the pump light path, delivering light to the active medium without the fiber itself needing to be in the sample. The fiber acts as a remote delivery system, allowing the pump signal to reach the active medium while the fiber remains outside the biological tissue.
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 non-invasive, in vivo characterization of biological tissues without altering sample properties, with enhanced sensitivity and portability for diagnostic and industrial applications.
Implementation Method 1
A random laser is formed by an active medium and the diffusing sample to be analysed, using diffusion processes for optical feedback, allowing non-invasive analysis by separating the active medium from the sample and using stimulated emission for signal amplification.
Implementation Method 2
the optical feedback is not constituted by a resonant cavity, as in a conventional laser, but rather by diffusion processes which, by increasing the path of light through the active medium, can increase the gain to the point of overcoming the losses and trigger a laser emission
Data Source
Figure 1~2
AI summary
Optical sensor, comprising a medium (5) for sending an excitation light beam (12) into a chamber (2) containing an active optical medium (3) capable of generating a light signal output from said chamber (2), wherein said chamber (2) is defined by a transparent wall adapted to separate the active medium (3) from a volume of a sample (14) comprising a dispersion of optical diffusion particles, wherein said wall is capable of propagating said input signal from the inside to the outside of the chamber to reach said diffusing particles, and to propagate a modified light signal (13) from the outside to the inside of the chamber, wherein the active medium (3) containing potentially toxic dyes is kept separate from the sample (14) allowing for in vivo sample analysis.