Recently, the nano-photonic team led by Professor Cai Bin from the International Future Optical Laboratory achieved new progress in the area of nonlinear optical materials, and published a cover paper entitled “DAST Optical Damage Tolerance Enhancement and Robust Lasing via Supramolecular Strategy” in a famous journal ACS Photonics (SCI Area Ⅰ). Tian Tian, a doctor from School of Optical-electrical and Computer Engineering, was the first writer.
Organic nonlinear optical crystals have higher nonlinear coefficients than traditional nonlinear crystal (LiNbO3), and have caught a lot of attention in many application fields such as ultra-high-speed electro-optic modulation in simulation, detection, and communication of Tera-hertz wave and laser wavelength conversion. However, for a long time, influenced by low DAST laser induced damage threshold, many restrictions were imposed on its application and development.
In response to the above problems, a surface support rapid evaportion crystallization (SSREC) is developed to prepare DAST single nanoparticles. This experiment is low-cost, time-consuming and strong in controllability with simple equipment. Through SSREC method, we obtained the smallest single nanometer-sized DAST crystal (5 nm), which is much smaller than the Rayleigh scattering scale requirements of the optical communication band, and is suitable for the further preparation of DAST-polymer high-performance optical composite materials. The size of DAST nanocrystal distribed from 5 to 150 nm successfully achieved by changing the experimental temperature and adding sufactant. Experiments shown that DAST nanocrystals prepared by SSREC method not only have good crystal quality, but also have strong two-photon fluorescence, and SHG effect. Not only that, replacing the anionic surfactant with a resin-based sufactant with a high acidity value, we can also quickly assemble DAST nanoparticles into micron belt which can grow millimeter-level within one minute. The micron bely not only exhibited the property of DAST single crystal, but also its fluorescence spectrum was red-shifted significantly compared to DAST nanocrystals, and its fluorescence spectrum band was also widened.
The DAST@β-CD crystal prepared by this method not only has good lasing resistance, but also can provide a reference for the preparation of other types of nonlinear organic crystals, thereby promoting the organic nonlinear crystal materials application of optical signal conversion, terahertz signal generation and digital signal processing. This research was selected as cover paper (issue 8, volume 7, August, 2020) of ACS Photonics. Yuan Shuai, Li Min, and You Guanjun from school of Optical-electrical and Computer Engineering also offered a lot of help and guidance for promoting the research peoject.
Link to the paper: https://pubs.acs.org/doi/10.1021/acsphotonics.0c00602