题目：Tabletop ultrafast X-ray “laser” advance the nano-photonics to achieve unprecedented spatial and temporal resolution
报告人: 张晓世 博士（美国KMlabs 公司）
时间：3月19号（周二），下午2:30-3:30
地点: 物理馆512会议室

报告摘要：
Coherent X-ray source based on nonlinear upconversion of high harmonic generation has been widely used to probe ultrafast dynamics in chemical and biological systems, as well as study heat transportation and charge transfer in new nano-materials and nano-devices. This technology opens new doorways to develop and invent new energy resources and medicines. In our laboratory, we have developed advanced technology to produce high order harmonics in hollow core fiber of up to 5001st harmonic by combining 5001 Mid IR photons into one X-ray photon at 1.6 keV, which holds the world record in this extreme nonlinear conversion regime. We also invented all-photonic-phase-matching technology that has been implemented to enhance the nonlinear conversion by orders of magnitude.
Currently, we are developing new fiber technology, such as in micro-structured and photonics crystal fibers, to improve the conversion efficiency of high order harmonics generation. Our future goal is to combine all these technologies together to achieve bright coherent ultrafast X-rays “laser” that is continuously tunable from deep ultraviolet into the hard X-rays region. These technologies advance nano-photonics into the X-ray regime achieving unprecedented spatial and temporal resolution.

参考文献：
X.S. Zhang, 等“Multi-microjoule, MHz repetition rate Ti:Sapphire Ultrafast regenerative amplifier system”, Optics Express, Vol. 20 Issue 7, pp.7015-7021 (2012) .
 个人简介：
2007年，美国科罗拉多大学，JILA学院，博士学位。
2007年－2008年，在美国KMlabs 公司担任激光研发科学家。成功研发超快高功率再生放大器，光学参量放大器和真空紫外激光器。掌握了实现高功率和高稳定度激光器等的关键及核心工程技术。
2008年－2012年，在美国KMlabs 公司担任再生放大器产品经理。带领生产团队研发，生产并在全世界（欧洲，美洲，日本和中国等地）成功安装了三十多台大功率超快激光器系统。此间，还代表公司在世界各地参加高科技激光科研和应用的大型国际会展和国际会议。
2012年－现在，在美国KMlabs 公司担任资深科学家。带领团队研发高功率超快激光器，超快极紫外和软X射线光源等高新科技产品，并为公司的激光产品和技术保持世界领先地位提供技术支持。自2012年以来，个人成功获得美国能源部总共约一百三十万美元的研发基金支持，并担任首席科学家一职。掌握着目前世界上最先进的超快激光技术及其应用和此项技术发展的前景。在他领导下的科研团队为公司研发出多种具有商业价值的超快激光产品，其中，兆赫兹再生放大器和极紫外超快光源分别在2012年的Photonics West大会上进入到了Prism Award的Finalist，以及2009年的Laser Focus World创新奖。