Zhang Zhifeng, Zhao Haoqi, Pires Danilo Gomes, Qiao Xingdu, Gao Zihe, Jornet Josep M, Longhi Stefano, Litchinitser Natalia M, Feng Liang
Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA 19104 USA.
Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708 USA.
Light Sci Appl. 2020 Oct 21;9:179. doi: 10.1038/s41377-020-00415-3. eCollection 2020.
On-chip integrated laser sources of structured light carrying fractional orbital angular momentum (FOAM) are highly desirable for the forefront development of optical communication and quantum information-processing technologies. While integrated vortex beam generators have been previously demonstrated in different optical settings, ultrafast control and sweep of FOAM light with low-power control, suitable for high-speed optical communication and computing, remains challenging. Here we demonstrate fast control of the FOAM from a vortex semiconductor microlaser based on fast transient mixing of integer laser vorticities induced by a control pulse. A continuous FOAM sweep between charge 0 and charge +2 is demonstrated in a 100 ps time window, with the ultimate speed limit being established by the carrier recombination time in the gain medium. Our results provide a new route to generating vortex microlasers carrying FOAM that are switchable at GHz frequencies by an ultrafast control pulse.
对于光通信和量子信息处理技术的前沿发展而言，携带分数轨道角动量（FOAM）的片上集成结构化光激光源是非常可取的。虽然之前已经在不同的光学设置中展示了集成涡旋光束发生器，但以低功率控制对FOAM光进行超快控制和扫描，以适用于高速光通信和计算，仍然具有挑战性。在此，我们基于由控制脉冲诱导的整数激光涡旋的快速瞬态混合，展示了来自涡旋半导体微激光器的FOAM的快速控制。在100 ps的时间窗口内演示了电荷0和电荷+2之间的连续FOAM扫描，其最终速度极限由增益介质中的载流子复合时间确定。我们的结果为生成携带FOAM的涡旋微激光器提供了一条新途径，该涡旋微激光器可通过超快控制脉冲在GHz频率下切换。
