On-Chip Photoacoustic Sensor with Optical Transducer
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Solution Overview
Problem
Current photoacoustic imaging (PAI) technologies face challenges in collecting broadband photoacoustic signals with high sensitivity and wide-angle acceptance, limiting the field of view and resolution for image reconstruction.
Innovation Solution
A miniaturized on-chip PAI device integrates optical and acoustic modules, utilizing silicon photonics for flexible and scalable systems, featuring a sensor with an excitation light source, output coupler, resonators, and detectors to detect shifts in resonance frequencies caused by photoacoustic waves, enabling broad bandwidth and wide-angle signal collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ultrasound imaging transducers with narrow bandwidth are used, then the device complexity is reduced and ease of manufacture is improved, but the measurement precision and sensitivity of photoacoustic signals are significantly degraded
Solution Approach 1:
The patent replaces conventional mechanical ultrasound transducers with an optical detection system. A probe beam is directed at the ultrasound transducer, and the reflected or transmitted light is detected to measure the transducer's vibration. This optical detection method enables broadband signal detection with high sensitivity without the bandwidth limitations of conventional piezoelectric transducers.
2Measurement precision
If conventional ultrasound transducers with limited angle of acceptance are used, then the device complexity is reduced, but the field of view and resolution for image reconstruction are degraded
Solution Approach 1:
The patent introduces an optical intermediary (probe beam and detector system) that can capture acoustic vibrations from a wide angle. The light acts as a mediator to detect transducer surface vibrations across different angles, enabling wide-angle acceptance and improved field of view without complicating the transducer's mechanical structure.
3Ease of manufacture
If miniaturized on-chip integration is implemented, then the device complexity is reduced and scalability is improved, but the manufacturing precision requirements are significantly increased
Solution Approach 1:
The patent merges the optical detection components (probe beam source and detector) with the ultrasound transducer into a single integrated on-chip device. This consolidation allows the system to be fabricated using standard semiconductor manufacturing processes, achieving scalability while managing precision requirements through integrated design rather than separate component assembly.
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
The solution enhances the sensitivity and field of view for photoacoustic imaging, allowing for improved resolution and deeper tissue penetration, suitable for biomedical applications such as neural tissue imaging with spatial resolutions of 20 microns to 50 microns over a volume of 1 cubic millimeter.
Implementation Method 1
a nonlinear interaction between light and biological tissue causes the biological tissue to emit ultrasound waves generated by biological tissue in response to incident light
Implementation Method 2
The first resonator, which is in acoustic communication with the analyte medium, has a first resonance frequency that shifts in response to the photoacoustic wave
Data Source
AI summary
A microscale photoacoustic sensor uses the detection of ultrasound waves generated by a sample in response to incident light absorption to perform photoacoustic spectroscopy, imaging, and microscopy. The microscale photoacoustic sensor, including components to excite a sample and detect ultrasound waves, may be integrated onto a single chip. The microscale photoacoustic sensor may excite a sample using a metasurface collimator. The metasurface collimator includes an array of diffraction grooves to collimate an excitation beam uniformly out of the plane of the sensor to create a wide and homogeneous beam spot. The microscale photoacoustic sensor may detect ultrasound waves using an optical photoacoustic transducer. The optical photoacoustic transducer includes a resonator on a mechanical membrane to detect ultrasound waves with high sensitivity. The microscale photoacoustic sensor may be used in applications such as deep-tissue neural imaging or microfluidic biological screening.