Jinan Institute of Quantum Technology proposes new strategy for optical superlattice preparation
Recently, the Jinan Institute of Quantum Technology, in collaboration with Shandong University, designed and constructed a real-time monitoring device to probe the ferroelectric domain inversion dynamics of periodically poled lithium niobate (PPLN) crystals, and designed a new micro-nano electrode structure to obtain higher nucleation density for the preparation of highly accurate and flexible periodically poled lithium niobate crystals, which brings new opportunities for applications in quantum communication, photoelectric countermeasures, laser displays, bio-detection and other fields.
The research results were published in the internationally renowned journal Small (JCR I, IF=13.281). The first author of the article is Qilu Liu, a PhD student jointly trained by Jinan Institute of Quantum Technology and Shandong University, and the corresponding authors are Associate Researcher Dongzhou Wang, Researcher Hong Liu and Professor Yuanhua Sang of Shandong University.
Real-time monitoring device diagram and real-time monitoring results
Optical superlattice crystal is an important nonlinear optical frequency conversion crystal with the advantages of high frequency conversion efficiency, freedom of design, small size and low cost, which can realize laser output at any wavelength in the transmission range of the matrix crystal. Optical superlattice structures based on lithium niobate ferroelectric domains (periodically poled lithium niobate, PPLN) are important devices for nonlinear frequency doubling, frequency combining, differential frequency, and optical parametric oscillation applications, which are widely used in quantum communication, photoelectric countermeasures, single photon imaging and other technical fields. However, the realization of accurate superlattice structures has been a major obstacle for the preparation of specific optical applications due to the unclear domain structure modulation dynamics.
How to monitor the preparation process of lithium niobate optical superlattices in real time and explore the domain growth kinetics to obtain high precision superlattice structures is one of the key issues.
Finite element analysis of the local electric field of ordinary electrode and porous electrode structure
In order to study the kinetics of ferroelectric domain reversal and to monitor the polarization process at high temperature for the solid transparent electrode applied electric field polarization method, the team designed and constructed a simple real-time monitoring system for in situ observation of the lithium niobate cycle polarization process. For the high-precision monitoring of the real-time monitoring system, the authors discuss the domain nucleation, growth and global monitoring under different polarization states.
Combined with finite element analysis, domain nucleation and growth are closely related to the electric field distribution. The team proposes a porous electrode structure that can utilize the local electric field more efficiently and controllably, resulting in higher domain nucleation density and higher uniformity. High-quality PPLN crystals with 2 mm thickness were obtained using a porous electrode combined with a real-time monitoring system. The nonlinear optical conversion from 1064.2 to 3402.4 nm was achieved using single resonance optical parametric oscillation technique with a nonlinear optical efficiency of 26.2%. This work provides an effective way for the preparation of precision superlattice structures.
Comparison of structure and polarization results between normal and porous electrodes
This work was supported by the Natural Science Foundation of Shandong Province, Jinan High-tech Zone, State Key Laboratory of Crystal Materials of Shandong University, and the "5150" talent attraction and multiplication innovation talent project of Jinan City.
paper link：
[1]https://onlinelibrary.wiley.com/doi/10.1002/smll.202202761
