学　术

　　为搭建我校博士后之间的学术交流平台，促进学术水平提升，学校博士后管理办公室组织开展博士后学术沙龙活动。本次沙龙由我校博士后王涛分享其研究成果，诚挚邀请感兴趣的师生参加。

　　一、时　间：2016年10月20日（周四）15：00

　　二、地　点：沙河校区通信楼818室

　　三、主办单位：电子科技大学博士后管理办公室

　　四、承办单位：基础与前沿研究院

　　　　　　　　　电子科技大学博士后联谊会

　　五、活动安排：

　　（1）主　题：Coherence Buildup and Nonlinear Dynamics in Mesoscale Lasers 

　　（2）主讲人：王涛  基础与前沿研究院博士后

　　（3）交流内容：

　　Coherent light sources are nowadays ubiquitous in scientific research and engineering applications. Lasers, a powerful coherence light source, have been miniaturized since the first device realized in 1960 by Th. Maiman. Physically, the onset and development of laser coherence is largely affected by the reduction in cavity size, but this does not become apparent until its volume reaches that of the smallest Vertical Cavity Surface Emitting Lasers (VCSELs). Thus the following questions arise: At what point in the buildup of laser emission does coherence set in? How does it develop? How do we define “threshold”? Is there a unique “threshold value” and does it exist at all for a nanolaser? What is the dynamical response to modulation in this uncharted territory?

　　In this work we explore the regime of laser operation around what is conventionally called “the threshold point” and obtain experimental answers to some of the questions from “mesoscale” lasers (i.e., lasers whose size is intermediate between the macroscopic and the nanoscopic scales). Correlation functions, temporal dynamics, phase space reconstruction, statistical indicators and spatially-resolved intensity and emission wavelength measurements are used as indicators to find the answers we are looking for. The dynamical response is investigated by applying a sinusoidal modulation to very small VCSELs, where we obtain the extreme events. Finally, the two-dimensional (2D) characterization of the emission properties in a plane transverse to the laser　beam shows the correlation between the buildup of coherence in the smallest device and the establishment of a laser mode (preceded by the stabilization of the emission wavelength). For somewhat larger devices, we pave the way to the spatial investigation of coherence buildup through the simultaneous 2D characterization of intensity distribution and emission wavelength obtained with the help of an instrument developed in the course of this work.

　　（4）主讲人简介：

　　Wang Tao博士于2012年在安徽大学取得材料学硕士学位，2013-2016年在法国科学院-尼斯大学共同资助的非线性研究所攻读博士学位。博士期间主要从事微腔激光器的干涉及非线性动力学研究。其代表工作是结合Correlation Functions 和时域Full Dynamics揭示了中尺度激光器的干涉演变过程，并通过调制研究了微腔激光器的非线性动力学性能。

　　Wang Tao博士的主要研究兴趣包括激光物理、光-物质相互作用以及相关非线性光动力学。在其PhD期间，参加PIERS，SPIE，CLEO等国际会议8次，给出口头报告7次。在2015年的PIERS会议上，获得Best Student Paper Award。已在Scientific Report, Applied Physics Letters, Review of Scientific Instruments等国际著名期刊上发表论文数篇。目前在基础与前沿研究院从事博士后研究工作。

　　　　　　　　　　　　　　　　　　　　电子科技大学博士后管理办公室

　　　　　　　　　　　　　　　　　　　　　　　2016年10月18日