Overcoming acquisition time and resolution limits of photoacoustic imaging using dual comb scanning

这个博士项目研究了一种变革性的方法，该方法采用双光频梳来克服波长扫描时间的限制。频率梳是同时发射具有相等频率间隔的10 s-100 s波长音调的光源。通过开发一种新的双频梳和相关的实时信号处理技术用于光声传感，我们的目标是将传感信号采集时间减少两个数量级以上，使快速光声成像在医学和疾病研究中产生广泛的影响。我们的方法结合了双频梳状光谱的概念与基于法布里-珀罗超声检测的生物医学光声成像。光声双梳多外差检测与实时FPGA硬件处理相结合，能够以高分辨率和精度（可追溯到SI时间标准）快速读出传感器。学生将与导师一起研究以下课题：a）在我们初步研究的基础上，进一步改进用于光声成像的双频梳方法的建模，了解基本的采集时间和信噪比限制;B）使用双梳系统进行实验研究[5]和由光声组开发的法布里-珀罗超声传感器。进一步改进双梳设置，以实现不同传感器的灵活性（例如，具有不同精细度和热稳定性的传感器）;c）创新信号处理策略（例如，该项目将涉及分析和实验工作，将光学信号处理和光声传感方面的专业知识结合起来，以克服传统光声系统的时间采集限制。这里研究的新方法还允许用于增强成像分辨率的改进的SNR。

This PhD project research investigates a transformative method that employs dual optical frequency combs to overcome the limit due to the wavelength sweeping time. A frequency comb is a light source simultaneously emitting 10s-100s of wavelength tones with equal frequency spacing. By developing a new dual frequency comb and associated real-time signal processing technologies for photoacoustic sensing, we aim to reduce the sensing signal acquisition time by more than two orders of magnitude, enabling fast photoacoustic imaging for wide impact in medicine and disease studies. Our method combines the concept of dual-frequency comb spectroscopy with Fabry-Perot based ultrasound detection for biomedical photoacoustic imaging. Photoacoustic dual-comb multi-heterodyne detection in conjunction with real-time FPGA hardware processing enables the rapid read-out of the sensor with high resolution and precision (traceable to the SI-time standard). Therefore, it allows for a significantly improved signal acquisition time and improved signal to noise ratio.The student will work with the supervisor on the following subjects:a) Based on our preliminary studies, further improve the modelling of dual frequency comb approach for photoacoustic imaging, understanding the fundamental acquisition time and signal to noise ratio limits;b) Carry out experimental studies using the dual-comb system at EEE [5] and the Fabry-Perot ultrasound sensors developed by the photoacoustic group. Further improve the dual comb set up to enable flexibility for different sensors (e.g., sensors with different finesse and thermal stability);c) Innovate signal processing strategies (e.g., equalizers, calibration algorithms) for fast signal acquisition and improved resolution.This project will involve both analytical and experimental work, bringing together expertise in optical signal processing and photoacoustic sensing to overcome the time acquisition limit in conventional photoacoustic systems. The new method studied here also allows for an improved SNR for enhanced imaging resolution.