Zhejiang University's micro-level Micro-LED array achievements were selected into the top ten scient

On March 17, the High-tech Research and Development Center of the Ministry of Science and Technology (Basic Research Management Center of the Ministry of Science and Technology) released the top ten scientific advances in China in 2022. Qiu Jianrong's team from the School of Optoelectronic Science and Engineering of Zhejiang University discovered that femtosecond laser induced a new mechanism for micro-nano structures in complex systems was selected.

Femtosecond laser is a pulsed laser emitted in femtoseconds (1 femtosecond is one thousandth of a second), and energy is released instantaneously between femtoseconds. Stable and precise femtosecond laser can be used in many fields, such as myopia surgery. However, the mechanism of the interaction between femtosecond laser and matter is complex, and researchers have made a lot of efforts in order to understand the mechanism.

Qiu Jianrong's team and their collaborators discovered a new mechanism for femtosecond laser-induced formation of micro and nano structures in complex systems. Taking an oxide glass system containing chlorine-bromide-iodine ions as an example, 3D direct lithography of perovskite nanocrystals with controllable composition and band gap in the glass and tunable luminescence was realized, showing different colors such as red, orange, yellow, green and blue. Luminescence. The formed nanocrystals showed significant stability under ultraviolet irradiation, organic solution immersion and a high temperature environment of 250℃. It further demonstrated that this 3D micro-nano structure can be used in a micro-LED array with ultra-large capacity and long-life information storage and highly stable minimum pixel size at the micron level, realizing a 1080p-level dynamic stereoscopic color holographic display. This achievement reveals the laws of femtosecond laser-induced spatially selective mesoscopic scale phase separation and ion exchange, and opens up new technical principles for femtosecond laser three-dimensional extreme manufacturing.

In fact, Qiu Jianrong's team has long been engaged in research on the interaction between femtosecond lasers and materials, and has achieved a series of highly original and important breakthroughs, ranking in an international leading position. For example, they have discovered new phenomena and mechanisms such as femtosecond laser-induced refractive index changes, polarization dependent nanogratings, and periodic nano-holes along the direction of laser propagation, and pioneered spatially selective manipulation of ion valence states, direct writing of three-dimensional optical waveguides, precipitation and erasing new technologies such as functional nanocrystals, and some of the results have been applied in fields such as integrated optical circuits and optical communications.