NSF-Europe: Development of Efficient Three-Photon Materials based on Theoretical Modeling

这是位于布法罗的纽约州立大学激光、光子学和生物光子学研究所（UB）和瑞典先进分子材料中心（CAMM）之间的一个国际合作项目。本计画的目标是发展有效的三光子吸收材料以应用于光子学。瑞典小组将进行理论建模，以提供设计标准，这些标准将用于布法罗合成新型3光子发色团，表征它们并探索应用。利用他们在同步加速器研究方面的专业知识，瑞典合作者还将对这些材料进行基于同步加速器的光谱研究。其目的是实现更好地理解结构性质的关系，以确定这些功能的分子结构，导致增强3-光子吸收。近年来，在新的分子结构中实现了双光子吸收（2 PA）的显著增强，这引起了人们对探索基于三光子（3 PA）的应用的兴趣。对于3 PA工艺，可以使用更长的激发波长，例如用于光通信的那些。而且，其对输入光强度的立方依赖性提供了更强的空间限制，使得可以获得更高的成像对比度。最近UB报告观察到一个高度定向和上转换的受激发射，在1.3 μ m的一个新的有机发色团的解决方案，由一个强大的同时3-光子吸收。将采用两种趋同办法。首先，实验研究将调查一组系统衍生的有前途的结构的3-光子性质。第二种是利用瑞典合作者提出的三光子吸收量子化学模型（如少态模型），通过结构-性质关系的理论研究指导分子设计。预期的项目产出包括具有1.3-1.55微米强三光子吸收波长的新材料，以及探索它们在以下方面的实际应用：（1）光纤通信，（2）光功率限制和稳定，（3）上转换受激发射和激光，以及（4）基于三光子吸收的成像和数据存储。该项目解决了与电子和光子材料相关的基础研究问题，具有技术相关性。该项目的一个重要特点是大力强调教育，强调研究和教育的结合，包括少数民族，以及提供科学和教育效益的国际合作。短期和长期的工作人员和学生交流将补充各小组之间的电子通信。该研究成果有望促进材料的合理开发，其利用3光子过程进行频率上转换激光;短脉冲光通信;光功率限制和稳定;以及生物成像和生物光子学。该NSF项目由多学科活动办公室、材料研究部（电子材料）和国际办公室（西欧）共同资助，是NSF和欧洲之间的材料研究合作活动（NSF 02-135）。该项目是与瑞典先进分子材料中心合作进行的。

This is an internationally collaborative project between the Institute for Lasers, Photonics and Biophotonics at the State University of New York at Buffalo (UB) and the Center for Advanced Molecular Materials (CAMM) in Sweden. Project goals are to develop efficient 3-photon absorb-ing materials for photonic applications. The Swedish group will conduct theoretical modeling to provide design criteria that will be used in Buffalo to synthesize novel 3-photon chromophores, characterize them and explore applications. Using their expertise in synchrotron research, the Swedish collaborator will also conduct synchrotron-based spectroscopic studies of these materials. The aim is to achieve greater understanding of structure property relations so as to identify those features of molecular structures that lead to enhanced 3-photon absorption. Recent suc-cesses in reaching a substantial enhancement of 2-photon absorption (2PA) in new molecular structures have created interest in exploring 3-photon (3PA) based applications. For the 3PA process, a longer excitation wavelength such as those for optical communications can be used. Also its cubic dependence on the input light intensity provides a stronger spatial confinement so that a higher contrast in imaging can be obtained. Recently UB reported observation of a highly directional and up-converted stimulated emission, produced by a strong simultaneous 3-photon absorption at 1.3 um in a new organic chromophore solution. Two convergent approaches will be used. First, experimental studies will investigate the 3-photon properties of a group of systematically derivatized promising structures. Second is the molecular design guided by theoretical stud-ies of the structure-property relationship by using quantum chemical models of 3-photon absorp-tion (e.g. the few-state model) as proposed by the Swedish collaborators. Anticipated project outputs include new materials with strong 3-photon absorption wavelengths of 1.3-1.55-um and exploration of their practical application for (1) optical fiber communication, (2) optical power limiting and stabilization, (3) up-converted stimulated emission and lasing, and (4) 3-photon ab-sorption based imaging and data storage. %%% The project addresses fundamental research issues associated with electronic and photonic mate-rials having technological relevance. An important feature of the project is the strong emphasis on education, with emphasis on integration of research and education, including minorities, and an international collaboration providing both scientific and educational benefits. Short and long-term staff and student exchanges will supplement electronic communications between the groups. The outcome of this research is expected to stimulate rational development of materials, which utilizes 3-photon processes for frequency up-conversion lasing; short pulse optical com-munications; optical power limiting and stabilization; and bioimaging and biophotonics. This NSF project is co-funded by the Office of Multidisciplinary Activities, the Division of Materials Research (Electronic Materials), and the International Office (Western Europe) as a Cooperative Activity in Materials Research between the NSF and Europe (NSF 02-135). This project is being carried out in collaboration with the Center for Advanced Molecular Materials (CAMM) in Swe-den.***