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

建议的研究项目构成了我在高级扩散波和光声技术中心(CADIPT)正在进行的研究计划的基本支持，该计划旨在开发和有针对性地应用CADIPT首创的新的先进光声(PA)、光热(PT)和光电扩散波(DW)成像技术。在生物医学成像方面，建议的研究集中在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(WM-DPTR)；3)增强截断相关光热相干层析成像(TC-PCT)。光到超声(US)的WM-DPAR和光到热波的WM-DPTR和TC-PCT的能量转换特性以及这些模式的非常有效的信号基线抑制对于非常早期的疾病诊断非常有希望，并形成了设计拟议研究目标的主要标准。WM-DPAR具有低成本的连续波(CW)激光波长调制、约2-3厘米的深度分辨率，并可集成到商用超声成像仪中，为US图像添加光谱分子对比度增强。WM-DPTR在中红外光谱范围内工作在激光诱导的黑体发射上，具有比PA更简单的仪器设备，没有耦合流体和便携性。TC-PCT是一种高轴向分辨率(25um)的PT 3D成像方法，也基于激光诱导的中红外光子发射和~4 mm的深度分辨率。建议将上述模式应用于三个主要领域：1)临床微创兼容WM-DPAR导管的开发，用于早期冠状动脉疾病(动脉硬化)的诊断；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)间质液体(与血液密切相关)浓度；3)基于ETC-PCT对健康和肥胖/糖尿病小鼠血红蛋白时间瞬变(梯度)的实时无创性测量。 还建议开发超高频外差锁定载波成像(UHF-Helic)，作为一种独特的非接触式、无损的光电DW检测工具，用于半导体的整个表面积，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的一个独特功能是，它可以用电流-电压特性等全光学非接触测量取代要求成品电子器件的传统本地化电气测试，从而在任何和所有器件制造阶段实现快速的晶片级检测，而不需要电气引线。成像将识别并帮助最大限度地减少光电子表面和体陷阱，并评估超薄光伏器件表面钝化和湿法清洗的有效性。

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.