讲座题目：Nonlinear optics with femtosecond pulse bursts
主讲人：Andrius Baltuška 教授
主持人：曾和平 教授
开始时间：2024-08-22 10:00
讲座地址：闵行校区光学大楼三楼报告厅
主办单位：精密光谱科学与技术国家重点实验室
报告人简介：
Andrius Baltuska教授，奥地利科学院院士，是强激光技术与强场物理领域的国际领军人物，长期致力于发展超强超快激光和光参量放大技术，相关研究有力促进了超短脉冲精密控制在超快光谱和高能物理中的前沿应用。其领导的维也纳技术大学光子学研究中心是国际超快超强光学领域的前沿阵地，围绕“超快超强激光技术与应用”主题，深入探究了超快超强激光脉冲与物质的相互作用中涉及到的全新的物理现象与规律，特别是在阿秒光场相干控制、极端非线形光学以及新兴的亚周期电子波包控制等前沿课题，取得一系列重大科学成果。此外，研究所还着力于开展超快高能激光在新型材料精密制造与加工方面的研究，为纳米结构制作、光子器件、高密件存储和医疗生物工程等领域提供了重要技术手段。
报告内容：
Bursts of high-intensity ultrafast laser pulses enable many exciting applications which cannot be driven by traditional types of ultrafast lasers. On the one hand, isolated femtosecond pulses, boosted to high energies from conventional chirped-pulse amplifiers, are ideal for nonlinear-optical frequency conversion, but lack spectral selectivity unless a complex technique of spectral focusing is employed during the up- or down-conversion of the fundamental optical frequency. On the other hand, cw mode-locked sources at MHz-GHz repetition frequencies, which offer high spectral selectivity and enable frequency comb spectroscopies, cannot be amplified to mJ pulse energy levels due to excessive average power of the laser source as well as due to optical load on the spectroscopic targets. Fortunately, operation in the burst mode solves these problems by limiting the average power but allowing one to reach high single-pulse intensity levels that are suitable for many nonlinear applications, including time- and frequency-resolved nonlinear spectroscopy on gas and condensed phase. In addition, high spectral selectivity, essential for resonant nonlinear spectroscopies, becomes available in carefully engineered bursts, where wavelength tunability is obtained by a direct electronic phase control with no moving parts in the laser system. The talk will present the technology of generating phase- and amplitude-controlled amplified pulse bursts, discuss the limits of energy scaling and solutions, demonstrate applications of burst-driving for parametric frequency conversion and present the blueprint for 3rd and higher-order resonant nonlinear spectroscopies.
