Micro active vortex laser

Recently, Dong Yibo, from the Photonic Chip Research Institute of Shanghai University of Technology, published his research findings titled "Nanoprinted Diffractive Layer Integrated Vertical Cavity Surface Emitting Vortex Lasers with Scalable Topological Charge" as the first author in the internationally renowned journal Nano Letters.

This achievement was jointly completed by the team of academician Gu Min and associate professor Fang Xinyuan of the Photonic Chip Research Institute and the Institute of Microelectronics of the Chinese Academy of Sciences. Academician Gu Min, associate professor Fang Xinyuan, associate researcher Pan Guanzhong and associate researcher Xun Meng of the Institute of Microelectronics of the Chinese Academy of Sciences are the corresponding authors of this article, and Shanghai University of Technology is the first unit.

With the rapid development of artificial intelligence and big data, the amount of data generated by humans every day is also increasing exponentially. Achieving high-capacity information reuse is an effective way to cope with future high data throughput applications. Vortex light with spiral phase wavefronts carries orbital angular momentum, and the infinite orthogonality of orbital angular momentum (OAM) can be used in various optical information multiplexing technologies to significantly improve information capacity, including optical communication, holography, optical artificial intelligence, optical encryption, optical storage, etc.

Vortex optical lasers have been widely studied as emission devices for orbital angular momentum optical information. Among them, achieving on chip and micro vortex lasers is crucial for the chip and integrated development of vortex light reuse technology, which can truly promote the industrial implementation of these technologies. However, existing active micro vortex lasers are difficult to generate high-order vortex light (topological charges are generally less than 5), and the key reason is the limited output area of the light source, which leads to insufficient resolution of the integrated orbital angular momentum phase structure and restricts the improvement of spatial bandwidth product. The higher the topological charge, the more channels it is possible to achieve orbital angular momentum information reuse. Therefore, this problem seriously restricts the capacity improvement of information reuse on orbital angular momentum chips.

In this study, the author proposes a vertical cavity surface emission vortex laser based on laser nano 3D printing integrated orbital angular momentum phase structure, which has the advantages of small volume, high speed, low threshold, circular light field, vertical light output, and arrayability. The author integrated a micro orbital angular momentum phase structure into the surface of a vertical cavity surface emitting laser through laser printing, thereby transforming the Gaussian beam emitted by the laser into a vortex beam after being modulated by the phase structure. The method of laser printing can expand the effective illumination area of the orbital angular momentum phase structure, thereby increasing the spatial bandwidth product. At the same time, laser 3D printing has higher manufacturing efficiency than previous methods, with a single device printing time of only about 20 minutes, compared to several hours with previous methods. In the article, the author implemented an addressable vortex laser array with topological charges ranging from 1 to 5, with a single device size of only about 100 micrometers × 100 microns.

In this article, the author further improved the spatial bandwidth product by designing a 3D structured, cascaded spiral phase plate (SPP), and successfully achieved a vortex beam with a maximum topological charge of 15. This study has solved the problem of increasing the topological charge of micro vortex optical lasers, and is expected to promote the miniaturization and integration development of orbital angular momentum information multiplexing technology.

This work has received support from units such as the National Natural Science Foundation of China and the Shanghai Municipal Science and Technology Commission.

Paper link: https://pubs.acs.org/doi/full/10.1021/acs.nanolett.3c02938

Source: Guangxing Tianxia