Multi-dimensional degenerate four-wave-mixing spectroscopy using topological transformation

2014 Fiscal Year Final Research Report

• Project/Area Number: 25600105
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Optical engineering, Photon science
• Research Institution: Hokkaido University
• Principal Investigator: TODA YASUNORI 北海道大学, 工学(系)研究科(研究院), 教授 (00313106)
• Co-Investigator(Kenkyū-buntansha): ADACHI Satoru 北海道大学, 大学院・工学研究院, 教授 (10221722)
• Co-Investigator(Renkei-kenkyūsha): NAKAYAMA Masaaki 大阪市立大学, 大学院・工学研究院, 教授 (30172480)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 光物性 / コヒーレント分光 / 縮退四光波混合 / 光渦 / 軌道角運動量 / 励起子物理

Outline of Final Research Achievements

Spatiotemporal four-wave mixing (FWM) spectroscopy of semiconductor excitons was developed by using (A) variably controlled Laguerre-Gaussian (LG) pulses, (B) orbital angular momentum (OAM) resolved spectroscopy with high precision. The observed exciton OAM dynamics indicates that (1) near perfect OAM transfer to the exciton center-of-mass motion is achieved using the LG pulses with nonzero OAM, (2) imperfect conversion becomes significant when the excitation pulses include an OAM-free component (3) an extremely long OAM decay was observed in the bulk sample, which implies a small spatial variation of the exciton dephasing. Moreover, the topological charge dependence of the OAM dynamics suggests a robustness of the exciton OAM. For the application of the topological transformation, a novel spatially modulated optical feedback in a vertical-cavity surface-emitting laser was demonstrated for the first time, where the results show high selectivity of the OAM in the transverse mode.

Free Research Field

光物性