Thermally Enhanced PARS Imaging for Non-Contact Subsurface Detection
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Solution Overview
Problem
Conventional photoacoustic imaging techniques require physical coupling to the sample, which is inappropriate for various clinical applications such as ophthalmic imaging, intraoperative imaging, and endoscopic procedures.
Innovation Solution
A thermally enhanced photoacoustic remote sensing (TE-PARS) system that generates PARS signals below the sample surface, using multiple beams for excitation, signal enhancement, and interrogation, with optical detectors to capture these signals and a processing unit to interpret the results, enhancing absorption contrast and resolution beyond the diffraction limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional photoacoustic techniques are used, then acoustic signals can be detected, but physical coupling to the sample is required which limits clinical applicability
Solution Approach 1:
The patent replaces the mechanical coupling system (acoustic transducers requiring physical contact) with an optical detection system. The PARS technique uses optical beams to interrogate the sample and detect photoacoustic signals remotely through optical property changes, eliminating the need for physical coupling while maintaining detection capability.
Solution Approach 2:
The patent introduces optical properties (absorption, scattering) as an intermediary to transfer the photoacoustic signal information from the sample to the detector. Instead of directly detecting acoustic waves requiring contact, the system detects changes in optical properties that encode the photoacoustic signal, enabling remote sensing.
2Adaptability or versatility
If PARS technique is used to enable non-contact imaging, then clinical applicability is improved, but signal detection sensitivity may be reduced
Solution Approach 1:
The patent employs signal enhancement beams that modify physical parameters (temperature, pressure) of the sample to amplify the photoacoustic signal. By changing the thermal and mechanical state of the sample through controlled heating and pressurization, the signal strength is enhanced to compensate for the reduced sensitivity inherent in remote detection.
Solution Approach 2:
The patent uses periodic modulation of the excitation and signal enhancement beams to generate time-varying photoacoustic signals. This periodic action allows for frequency-domain detection and signal processing techniques that improve sensitivity by distinguishing the modulated signal from background noise.
3Measurement precision
If multiple beams are used for excitation and signal enhancement, then absorption contrast and resolution are improved, but device complexity increases
Solution Approach 1:
The patent designs optical components and beams that serve multiple functions simultaneously. For example, signal enhancement beams not only amplify the photoacoustic signal but also provide thermal contrast information. The optical system is configured to perform excitation, enhancement, and interrogation functions with integrated components, reducing overall system complexity despite the multi-beam approach.
Solution Approach 2:
The patent combines multiple beam functions and optical paths into integrated optical systems. Rather than separate independent systems for excitation and signal enhancement, the patent merges these functions into a coordinated multi-beam architecture that shares common optical components and control systems, thereby managing complexity through consolidation.
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-contact imaging with improved absorption contrast and resolution, suitable for clinical applications by leveraging temperature and pressure-induced material properties to enhance signal detection and sensitivity.
Implementation Method 1
nanosecond or picosecond laser pulses are directed into a sample causing the generation of thermo-elastic induced acoustic waves
Implementation Method 2
signal enhancement beam or collection of beams configured to modify the observation or generation of temperature and pressure signals
Implementation Method 3
monitoring changes in material optical properties that coincide with the photoacoustic excitation
Data Source
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AI summary
A method for visualizing details in a sample including directing an excitation beam to an excitation location below a surface of the sample, to generate signals in the sample; directing an interrogation beam toward the excitation location of the sample; directing a signal enhancement beam to the sample, to raise a temperature of a portion of the sample by 5 Kelvin or less, compared to a temperature of the portion of the sample in absence of the signal enhancement beam; detecting a portion of the interrogation beam returning from the sample that is indicative of the generated signals.