Randomized whispering-gallery-mode microdisk laser arrays via cavity deformations for anti-counterfeiting labels

Optical physical unclonable functions (PUFs) have emerged as a promising strategy for effective and unbreakable anti-counterfeiting. However, the unpredictable spatial distribution and broadband spectra of most optical PUFs complicate efficient and accurate verification in practical anti-counterfeiting applications. Here, we propose an optical PUF-based anti-counterfeiting label from perovskite microlaser arrays, where randomness is introduced through vapor-induced microcavity deformation. The initial perovskite microdisk laser arrays with regular positions and uniform sizes are fabricated by femtosecond laser direct ablation. By introducing vapor fumigation to induce random deformations in each microlaser cavity, a laser array with completely uneven excitation thresholds and narrow-linewidth lasing signals is obtained. As a proof of concept, we demonstrated that the post-treated laser array can provide fixed-point and random lasing signals to facilitate information encoding. Furthermore, different emission states of the lasing signal can be achieved by altering the pump energy density to reflect higher capacity information. A threefold PUF (excited under three pump power densities) with a resolution of 5 x 5 pixels exhibits a high encoding capacity (1.43 x 1045), making it a promising candidate to achieve efficient authentication and high security with anti-counterfeiting labels.& COPY; 2023 Chinese Laser Press