Regulated polarization degree of upconversion luminescence and multiple anti‐counterfeit applications
Dongping Wen, Ping Chen, Yi Liang, Xiaoming Mo, Caofeng Pan
Abstract
Abstract Polarization upconversion luminescence (PUCL) of lanthanide ions (Ln 3+ ) has been widely used in single particle tracking, microfluidics detection, three‐dimensional displays, and so on. However, no effective strategy has been developed for modulating PUCL. Here, we report a strategy to regulate PUCL in Ho 3+ ‐doped NaYF 4 single nanorods based on the number of upconversion photons. By constructing a multiphoton upconversion system for Ho 3+ , we regulate the degree of polarization (DOP) of PUCL from 0.590 for two‐photon luminescence to 0.929 for three‐photon upconversion luminescence (UCL). Furthermore, our strategy is verified from cross‐relaxation between Ho 3+ and Yb 3+ , excitation wavelength, excitation power density, and local site symmetry. And this regulation strategy of PUCL has also been achieved in Tm 3+ , with the DOP ranging from 0.233 for two‐photon luminescence to 0.925 for four‐photon UCL. Besides, multi‐dimensional anti‐counterfeiting display has been explored with PUCL. This work provides an effective strategy for regulating PUCL and also provides more opportunities for the development of polarization display, optical encoding, anti‐counterfeiting, and integrated optical devices.