scholarly journals Ultrafast control of fractional orbital angular momentum of microlaser emissions

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhifeng Zhang ◽  
Haoqi Zhao ◽  
Danilo Gomes Pires ◽  
Xingdu Qiao ◽  
Zihe Gao ◽  
...  

Abstract 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.

Nanoscale ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 2227-2233 ◽  
Author(s):  
Shengtao Mei ◽  
Kun Huang ◽  
Hong Liu ◽  
Fei Qin ◽  
Muhammad Q. Mehmood ◽  
...  

The orbital angular momentum (OAM) of light can be taken as an independent and orthogonal degree of freedom for multiplexing in an optical communication system, potentially improving the system capacity to hundreds of Tbits per second.


Author(s):  
Zhen Qu ◽  
Ivan Djordjevic

We review recent progress in high-speed orbital angular momentum (OAM) multiplexed free-space optical communication systems. The outdoor atmospheric turbulence is emulated by an indoor turbulence emulator, which is based on split-step beam propagation method. Adaptive optics, channel coding, Huffman coding combined with LDPC coding, and spatial offset are used for turbulence mitigation; while OAM multiplexing and wavelength-division multiplexing (WDM) are applied to boost aggregate capacity.


Science ◽  
2020 ◽  
Vol 368 (6492) ◽  
pp. 763-767 ◽  
Author(s):  
Zhurun Ji ◽  
Wenjing Liu ◽  
Sergiy Krylyuk ◽  
Xiaopeng Fan ◽  
Zhifeng Zhang ◽  
...  

Applications that use the orbital angular momentum (OAM) of light show promise for increasing the bandwidth of optical communication networks. However, direct photocurrent detection of different OAM modes has not yet been demonstrated. Most studies of current responses to electromagnetic fields have focused on optical intensity–related effects, but phase information has been lost. In this study, we designed a photodetector based on tungsten ditelluride (WTe2) with carefully fabricated electrode geometries to facilitate direct characterization of the topological charge of OAM of light. This orbital photogalvanic effect, driven by the helical phase gradient, is distinguished by a current winding around the optical beam axis with a magnitude proportional to its quantized OAM mode number. Our study provides a route to develop on-chip detection of optical OAM modes, which can enable the development of next-generation photonic circuits.


2014 ◽  
Author(s):  
Ryan P. Scott ◽  
Roberto Proietti ◽  
Binbin Guan ◽  
S. J. Yoo

2018 ◽  
Vol 32 (24) ◽  
pp. 1850289
Author(s):  
Siqi Li ◽  
Mulong Liu ◽  
Xingyi Li ◽  
Zhiqiang Ge ◽  
Lingxuan Zhang

We have proposed an approach for rapid generation of perfect vortex beam without side lobes through a digital micromirror device (DMD). Employing this method, the amplitude and phase of far field can be controlled indirectly by changing the rotation state of each unit on the DMD. The perfect vortex beams of equal rings diameter independent of their topological charges are generated commendably and the side lobes are avoided. Moreover, we have demonstrated rapid switching among the generated orbital angular momentum modes at the speed of 10 kHz, which is much faster than that of the usual method realized by spatial light modulators (SLMs). The proposed method is very beneficial for the optical communication and trapping or manipulating the small particle based on orbital angular momentum modes.


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