Facilitating remote chemical sensing with random Raman lasing

职务名称：通过随机拉曼激光促进遥感摘要非技术性描述：该提案的驱动动机是对化学特定遥感（间隔探测）和深层组织光学成像的日益增长的需求。从地面粉末的远程评估到光学生物医学成像，都需要评估混浊介质中材料的化学成分。振动光谱已被证明是成功的，在复杂介质中识别化学品。然而，信号的强度通常被认为是一个主要的限制。拟议的研究计划的目的是克服这些主要缺点，利用最近发现的受激拉曼发射在无序介质中的效果。它允许将信号增加106-109的惊人值，从而使距离目标几公里的粉末的简单和无缝的远程化学感测成为可能。拟议中的计划将对环境科学、生物医学科学和医学诊断成像以及国土安全产生深远影响。所提出的装置的新颖操作原理以及将用于装置设计和构造的技术和方法将对光散射效应重要的许多研究和应用领域产生积极影响。在随机散射组织中利用受激拉曼散射增强的生物医学成像设备的仅仅一个即将到来的应用可以通过提供对深层组织的化学成分的简单访问而潜在地影响超过10亿人的生活。从教育的角度来看，拟议的计划将为直接参与研究的学生提供无与伦比的培训和专业发展机会，显着推进他们未来的职业前景。特别是，该计划将使学生接触到多学科研究的“全周期”，从计算模拟到样品制备和表征，从观察到的现象的分析描述的初始制定到后续迭代仪器优化，从基本思想到现实生活中的实际应用。从推广的角度来看，该方案提出了几个针对学龄学生及其教师的目标。德克萨斯农工大学位于美国发展最快的地区，主要是西班牙裔人口聚居的地区，有几项活动将专门针对不同的学生群体。技术描述：拟议的计划建立在计算科学，工程，光学科学和化学的最新进展，通过散射介质引入遥感和生物医学成像的变革性方法。该计划是建立在这些初步结果，并有一个主要的研究目标，基本了解机制和有效的非线性光学相互作用在随机介质中的限制。为了实现这一目标，我们将：（1）从根本上了解随机介质中受激拉曼散射的机理、条件和局限性。我们将使用两个发达的计算和实验工具来调查介质的吸收和散射参数的影响，不均匀性和夹杂物的影响，以及广泛的激发参数，如波长，脉冲持续时间和光束形状，在随机介质中的受激拉曼散射的阈值和效率。（2）探索利用时间和空间整形的激光脉冲控制随机拉曼激光的可能性。在许多实际情况下，随机介质不会随时间发生明显变化。它创造了优化入射辐射的波前以增强介质内部的非线性相互作用的机会。（3）利用随机拉曼激光的概念进行遥感和深层组织生物成像。我们将使用目标1-2的结果来设计一个实用的系统，用于远程化学传感和深层组织生物成像。

Title: FACILITATING REMOTE SENSING VIA RANDOM RAMAN LASINGABSTRACTNontechnical Description: The driving motivation for this proposal is the growing necessity for chemically specific remote sensing (standoff detection) and deep tissue optical imaging. From remote assessment of powders on the ground to optical biomedical imaging, there is a need to evaluate the chemical composition of materials a turbid medium. Vibrational spectroscopy has proven to be successful in identifying chemicals in complex medium. However, the strength of the signal is often considered as a major limitation. The proposed research program aims at overcoming those major disadvantages by utilizing a recently discovered effect of stimulated Raman emission in disordered medium. It allows increasing the signal by an astonishing value of 106-109 making it possible simple and seamless remote chemical sensing of powders km's away from the target. The proposed program will have a profound effect on environmental science, biomedical science and medical diagnostic imaging, and homeland security. The novel operating principle of the proposed device and technology and methods, which will be used in the device design and construction, will positively affect a number of research and application areas where light scattering effects are important. Just a single impending application of biomedical imaging device utilizing stimulated Raman scattering enhancement in randomly scattering tissues can potentially affect the lives of more than a billion people by providing a simple access to the chemical composition of deep-laying tissues. From the educational standpoint, proposed program will provide unmatched opportunities for training and professional development of the students directly involved in the research, significantly advancing their future career prospects. In particular, the program will expose the students to the "full cycle" of multidisciplinary research, from computational simulations to sample preparation and characterization, from initial formulation of analytical description of the observed phenomena to the follow-up iterative instrument optimization, from a fundamental idea to a real-life practical application. From the outreach perspective, the program presents several thrusts aimed at school-aged students and their teachers. Texas A&M University is located in the middle of the fastest growing, predominantly Hispanic-populated region in the US, and several activities will be specifically targeting the diverse student population.Technical Description: The proposed program builds up on the recent advances in computational science, engineering, optical sciences and chemistry to introduce a transformative approach for remote sensing and biomedical imaging through scattering medium. The proposed program is built on those preliminary results and has a major research objective of fundamental understanding the mechanisms and limitations of efficient nonlinear optical interactions in random media. To accomplish this goal, we will: (1)Fundamentally understand the mechanism, conditions and limitations of stimulated Raman scattering in random media. We will use both the developed computational and experimental tools to investigate the effects of absorption and scattering parameters of the media, the effects of inhomogeneities and inclusions, as well as a broad range of excitation parameters, such as wavelength, pulse duration and beam shape, on the threshold and efficiency of stimulated Raman scattering in random media.(2)Explore the possibility of controlling random Raman lasing using temporally and spatially shaped laser pulses. In many practical situations, random media does not vary appreciably over time. It creates an opportunity to optimize the wavefront of the incident radiation to enhance the nonlinear interaction inside the medium.(3)Utilize the developed concept of random Raman lasing for remote sensing and deep tissue biological imaging. We will use the results of Aims 1-2 to design a practical system for remote chemical sensing and deep tissue biological imaging.