题目：Femtosecond-laser-written optical waveguides for optical communications and biophotonic applications
报告人：Prof. Ajoy K Kar（School of Engineering and Physical Sciences, David Brewster Building,
Heriot-Watt University, Edinburgh, EH14 4AS, Scotland.）
Abstract：
The short pulse durations (<100fs) and high peak powers (>1GW) available from modern mode-locked laser systems make them attractive for precision materials processing. By exploiting the high peak powers, it is possible to induce structural changes in normally transparent materials by depositing optical energy via nonlinear multi-photon absorption. Since the light-matter interaction is highly nonlinear, and the pulse durations are ultrafast, the deposition can be precisely controlled such that structural changes are induced only in the immediate focal volume, thus allowing the direct-write three-dimensional micro-modification of transparent materials.
The structural changes induced by the deposited optical energy may manifest themselves in a variety of ways e.g. refractive index changes, etch-rate changes and colour centre formation. Such changes in the properties of the material can in turn be used to create a variety of new and exciting integrated optical devices. The majority of our research in this area has been concerned with using the highly localised refractive index modification to directly inscribe optical waveguides in various dielectric materials. To date, we have demonstrated a number of active devices e.g. waveguide amplifiers and modelocked lasers, and have recently demonstrated the complete preservation of the nonlinear optical properties in waveguides inscribed in periodically poled LiNbO3 (PPLN).
The aim of this talk will be to present and discuss recent advances on femtosecond waveguide inscription on various photonic materials with applications in optical communications and biophotonics.
Prof. Ajoy K Kar简介：
Professor Ajoy Kar has over 25 years of experience in studies of the nonlinear optical properties of materials and their applications. After completing his MSc at Delhi he joined the University of Essex where he developed his interest in Lasers and Nonlinear Optics. His current projects involve amplifiers for telecommunications, ultrafast all-optical switching in novel optical fibres, ultrafast optical nonlinearities in semiconductors, ultrafast laser inscription of photonic devices that should result in novel optoelectronic devices, generation and propagation of white light continuum through atmosphere for novel LIDAR applications. He has pionnered the Photonics Education in the UK and Europe. He is also the course director of MSc in Optoelectronics and Laser Devices and has developed distance learning modules for the MSc. His current international research and teaching activities are being funded by UKIERI, Royal Society, Royal Society of Edinburgh and Daiwa foundations. He is also the founding member of Optoscribe.
时间： 2011年6月21日（星期二）上午10:30
地点：中国科学院物理研究所B楼二段404会议室
联系人：金奎娟 研究员（Tel：82648099）
主办单位：中国科学院光物理重点实验室
