Femtosecond Optical Interactions in Glasses

来自康奈尔大学和康宁公司的一组科学家提出了一项关于超短光脉冲与光学玻璃相互作用的多学科研究。主要目标是发展对快速光学非线性的全面和系统的理解，这是各种光学器件和系统的物理基础。本文将在各种实验玻璃中研究由几个周期的电磁场激光脉冲激发的三阶非线性。由于玻璃具有典型的拉曼活性，因此必须考虑核对非线性光学响应的贡献。吸收和折射三阶非线性将用10-fs脉冲测量，具体目标是隔离电子和核对非线性响应的贡献。利用在这些研究中获得的单个过程的知识，将从理论上和实验上研究超短脉冲在玻璃中的非线性和色散传播。实验将利用各种玻璃中10至200飞秒的脉冲持续时间来研究群速度色散、受激拉曼散射、多光子吸收、电子非线性的有限弛豫时间和慢变包络近似的击穿的影响。提出的工作的第二个主题是玻璃的局部结构与玻璃中振动和电子激发的弛豫之间的关系。用时域和频域实验研究了短光脉冲激发下的振动模式的消相和电子杂质的弛豫；在每种情况下，结果都将与局部结构相关联。参与这项工作的研究生将参加一个创新的教育计划，其中包括一个多学科的课程，以及每年一个月在康宁工厂从事玻璃合成和表征工作的作业。这一经验将为学生在光学物理和玻璃材料科学方面提供广泛的基础，并为他们提供大量的工业研究机会。＊＊＊

9612255 Wise A multi-disciplinary investigation of the interactions of ultrashort light pulses with optical glasses is proposed by a team of scientists from Cornell University and Corning, Incorporated. The primary goal is to develop a thorough and systematic understanding of the fast optical nonlinearities that are the physical basis for a wide variety of optical devices and systems. Third-order nonlinearities excited by laser pulses consisting of only a few cycles of the electromagnetic field will be studied in a variety of experimental glasses. Since glasses are typically Raman-active, the nuclear contribution to the nonlinear optical response must also be considered. The absorptive and refractive third-order nonlinearities will be measured with 10-fs pulses, with the specific goal of isolating the electronic and nuclear contributions to the nonlinear response. Using the knowledge of individual processes gained in these studies, the nonlinear and dispersive propagation of ultrashort pulses in glasses will be investigated theoretically and experimentally. Experiments will utilize pulse durations ranging from 10 to 200 femtoseconds in a variety of glasses to study the effects of group velocity dispersion, stimulated Raman scattering, multiphoton absorption, the finite relaxation time of the electronic nonlinearity, and the breakdown of the slowly-varying envelope approximation. A secondary theme of the proposed work is the relation between the local structure of a glass and the relaxation of vibrational and electronic excitations in the glass. The dephasing of vibrational modes and the relaxation of electronic impurities excited by short optical pulses will be studied using both time- and frequency-domain experiments; in each case the results will be correlated with the local structure. Graduate students involved in this work will participate in an innovative education program that includes a multi-disciplinary course curriculum and assignments to work on t he synthesis and characterization of glasses at the Corning location for one month each year. This experience will provide the students with a broad foundation in the optical physics and material science of glasses as well as giving them substantial exposure to industrial research. ***