News.hust.edu.cn (Correspondent: Yang Zhenyu, Wang Yuxi, Wang Zhaokun) On November 2, Nature Communications published a collaborative paper online titled “Generalized Hartmann-Shack Array of Dielectric Metalens Sub-arrays for Polarimetric Beam Profiling” , authored by Professor Xia Jinsong from Wuhan National Laboratory for Optoelectronics and Professor Yang Zhenyu from the School of Optical and Electronic Information. Yang Zhenyu (PhD), Wang Zhaokun (PhD) and Wang Yuxi (PhD) fromWuhan National Laboratory for Optoelectronics are the co-first-authors; and Xia Jinsong and Yang Zhenyu are the corresponding authors.
When Maxwell predicted more than 150 years ago that light was a kind of electromagnetic wave, people began to realize that amplitude, polarization, phase and frequency are the basic parameters of light waves. But like our eyes, the current light detectors can only perceive the intensity of light, but they cannot perceive polarization and phase directly. Therefore, some discrete components often need to be added before the photo detector. For example, the traditional polarization detection system needs a polarizer and a quarter waveplate before the CCD, and the traditional Hartmann-Shack wavefront detection system needs an array of microlens before the CCD. This not only increases the weight, volume and complexity of the system, but also raises the difficulty of integrating systems. With the future development of high-performance, portable and wearable optical devices and systems, polarization and wavefront optical detection systems are increasingly expected to be small and light with multiple functions. In recent years, sub-wavelength dielectric hypersurface materials have attracted increasing attention. They can control the amplitude, phase and polarization of light waves flexibly with a low loss, so they have become the most promising solution to the above challenge.
Meanwhile, acquiring the amplitude, phase and polarization information of the beam is significant. The research team created a generalized array of Hartmann-Shack hypersurface lenses, which can measure the amplitude and phase gradient distribution of the beam and the spatial polarization distribution at the same time. The research team successfully fabricated a multidimensional optical parametric imaging chip with a silicon-based hypersurface material on the micro-nano processing and testing platform of Wuhan National Laboratory for Optoelectronics. The chip consists of array of polarization-sensitive hypersurface lenses with a numerical aperture of 0.32, an average focusing efficiency of 28% and a working wavelength of 1550 nm. They can complete the two-dimensional real-time measurement of the amplitude, phase and polarization of the bean with high accuracy. In this paper, the design concept of the multi-dimensional optical parametric imaging chip is expounded, and 18 beams with different polarization states are measured. In order to verify the chip’s ability to detect complex phase and polarization distribution, the researchers also detected different vector beams and vortex beams. The experimental results are in good agreement with the theoretical values. The research team applied for a national invention patent for this in early 2017 (application number: 201810111548.1). The research results can realize real-time imaging of multi-dimensional information, such as the intensity, polarization and phase of the beam, with simple techniques and high system integration. It has a promising prospect of being applied in many fields, such as optical detection and imaging.
The research is supported by the National Natural Science Fund, the “863 Program,” the Innovation Research Fund of the Huazhong University of Science & Technology and Wuhan National Laboratory for Optoelectronics.
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