Generation of colorful Airy beams and Airy imaging of letters via two-photon processed cubic phase plates.

In this Letter, we demonstrate the observation of colorful Airy beams and Airy imaging of letters, which we called Airy letters here, generated through the continuous cubic phase microplate (CCPP) elaborately fabricated by femtosecond laser two-photon processing. The fabricated CCPP with both micro size (60 µm×60 µm×1.1 µm) and continuous variation of phase shows a good agreement with the designed CCPP. Chromatic Airy beams and Airy letters "USTC" are experimentally generated via the CCPP illuminated by white light. In addition, superior properties of Airy letters are explored, demonstrating that the Airy letters inherit the nondiffraction, self-healing, and transverse acceleration characteristics of Airy beams. Our work paves the way toward integrated optics, light separation, optical imaging, and defective information recovery.

Continuous cubic phase microplates for generating high-quality Airy beams with strong deflection.

Owing to the distinguishing properties of nondiffraction, self-healing, and transverse acceleration, Airy beams have attracted much attention in the past decade. To date, a simple approach for exquisitely fabricating cubic phase plates with both continuous variation of phase and micro size still remains challenging, which limits the generation of high-quality Airy beams for integrated micro-optics. Here, we report the elaborate design and fabrication of a continuous cubic phase microplate (CCPP) for generating high-quality Airy beams in micrometer scale. A CCPP with a precise size (60 µm×60 µm×1.1 µm) is fabricated by femtosecond laser direct writing, exhibiting a high optical efficiency (∼79%). The high-quality Airy beam generated via the CCPP demonstrates an unprecedentedly strong deflection (∼4.2 µm within a 90 µm propagation distance) as well as being diffraction-free. Our research on the design and fabrication of miniature Airy phase plates paves the way toward high-performance integrated optics, optical micromanipulation, and optical imaging.

The Productivity Dynamics of China's Environmentally Friendly Production Technologies in terms of Wastewater Treatment Techniques.

Low economic profit usually reduces the incentive of producers to operate their wastewater treatment technologies effectively. It is necessary to investigate the performance of environmentally friendly production technologies that reduce wastewater discharges and generate economic outputs simultaneously (EPTWs) in China over the past decade. In this paper, we apply the Malmquist-Luenberger productivity index widely used in the field of economics to evaluate the productivity change of EPTWs for 30 administrative provinces in China during 2003-2015. The pathways of the productivity change are further identified by decomposing the productivity index into two components: technological change and technical efficiency change. The results show that China's environmental productivity index associated with wastewater reduction had undergone a downward trend, and evident spatial disparities are observed among the 30 provincial regions. Moreover, the changes of China's environmental productivity over the whole studied period can mainly be attributed to technological progress, while the technical efficiency component has contributed little, although its annual contributing rate is in an increasing trend.