Development of advanced non-invasive dynamic photoacoustic and photothermal imaging technologies for biomedical and industrial diagnostics

这些拟议的研究项目构成了我在先进扩散波和光声技术中心（CADIPT）正在进行的研究项目的基础支持，旨在开发和有针对性地应用新的先进光声（PA），光热（PT）和光电子扩散波（DW）成像技术。在生物医学成像方面，建议研究的重点是3种PA和PT模式：1)波长调制差分光声雷达（WM-DPAR）；2)波长调制差分光热辐射测量法（WM-DPTR）；3)增强截断相关光热相干层析成像（TC-PCT）。光-超声（US） WM-DPAR和光-热波wm - dtr和TC-PCT的能量转换性质以及这些模式非常有效的信号基线抑制对早期诊断疾病非常有希望，并形成了设计本研究目标的主要标准。WM-DPAR具有低成本连续波（CW）激光波长调制，~ 2-3 cm深度分辨率，可集成到商用超声成像仪中，为超声图像增加光谱分子对比度增强。WM-DPTR工作于激光诱导黑体发射的中红外光谱范围内，仪器比PA更简单，没有耦合流体，便携性好。TC-PCT是一种高轴向分辨率（25um）的PT三维成像方法，也是基于激光诱导的中红外光子发射和~ 4mm深度分辨率。上述模式的应用主要在三个方面：1)微创临床兼容的WM-DPAR导管开发用于早期冠状动脉疾病（动脉粥样硬化）诊断；2)无创WM-DPTR大麻传感器，用于路边监测受损驾驶员四氢大麻酚（THC；大麻的精神活性成分）间质液（与血液密切相关）浓度；3)健康和肥胖/糖尿病小鼠在高脂饮食条件下，基于血红蛋白时间瞬变（梯度）的eTC-PCT成像实时无创测量棕色脂肪代谢。本文还提出了开发超高频外差锁相载波成像（UHF-HeLIC）成像技术，作为一种独特的非接触式非破坏性光电DW检测工具，用于半导体的整个表面区域，特别是快速生长的清洁能源超薄光伏硅太阳能电池技术。UHF-He LIC的一个独特之处在于，它可以取代需要成品电子器件的传统局部电气测试，采用全光非接触式测量，例如电流-电压特性，允许在任何和所有器件制造阶段进行快速的晶圆级检测，而无需电气引线。成像将识别并帮助最小化光电表面和体积陷阱，并评估超薄PV器件表面钝化和湿式清洁的有效性。

The proposed research projects constitute fundamental support of my ongoing research program at the Center for Advanced Diffusion-Wave and Photoacoustic Technologies (CADIPT) toward the development and targeted applications of new advanced photoacoustic (PA), photothermal (PT) and optoelectronic diffusion-wave (DW) imaging technologies pioneered in the CADIPT. In biomedical imaging the proposed research focuses on 3 PA and PT modalities: 1) Wavelength-Modulated Differential Photoacoustic Radar (WM-DPAR); 2) Wavelength-Modulated Differential Photothermal Radiometry (WM-DPTR); and 3) Enhanced Truncated-Correlation Photothermal Coherence Tomography (TC-PCT). The light-to-ultrasound (US) WM-DPAR and light-to-thermal-wave WM-DPTR and TC-PCT energy conversion nature and the very efficient signal baseline suppression of these modalities are very promising for diagnosis of diseases at very early stages and form the major criterion for designing the objectives of the proposed research. WM-DPAR features low-cost continuous wave (CW) laser-wavelength modulation, ~ 2-3 cm depth resolution, and can be integrated into commercial ultrasound imagers to add spectroscopic molecular contrast enhancement to the US image. WM-DPTR operates on laser induced blackbody emissions in the mid-infrared spectral range and features simpler instrumentation than PA, no coupling fluid and portability. TC-PCT is a high axial-resolution (25 um) PT 3D imaging method, also based on laser-induced mid-infrared photon emissions and ~4 mm depth resolution. Applications of the aforementioned modalities are proposed in three major areas: 1) Minimally- invasive clinically compatible WM-DPAR catheter development for early coronary artery disease (atherosclerosis) diagnosis; 2) A non-invasive WM-DPTR cannabis sensor for roadside monitoring of impaired driver tetrahydrocannabinol (THC; the psychoactive component of cannabis) interstitial fluid (strongly related to blood) concentration; and 3) Real-time noninvasive measurements of brown fat metabolism based on eTC-PCT imaging of hemoglobin time transients (gradients) in healthy and obese/diabetic mice, subjected to a high fat diet.. It is also proposed to develop Ultra-High Frequency Heterodyne Lock-In Carrierography (UHF-HeLIC) imaging as a unique non-contacting nondestructive optoelectronic DW inspection tool of entire surface areas of semiconductors, specifically rapid-growth clean energy ultrathin photovoltaic Si solar cell technologies. A unique feature of UHF-He LIC is that it can replace conventional localized electrical testing requiring finished electronic devices with all-optical noncontact measurements of e.g. current-voltage characteristics, allowing fast, wafer-level inspections at any and all device fabrication stages with no need for electrical leads. The imaging will identify and help minimize optoelectronic surface and bulk traps and assess the effectiveness of surface passivation and wet cleans in ultrathin PV devices.