Speckle analysis of reconfigurable disordered photonic materials made of polymer dispersed liquid crystals
Year: 2026
Authors: Salvestrini S., Maestri F., Lio GE., Krajinic F., Savic-Sevic S., Muric B., Pantelic D., Jelenkovic B., Wiersma D.S., Nocentini S., Riboli F.
Autors Affiliation: European Lab Nonlinear Spect LENS, Sesto Fiorentino, Tuscany, Italy; CNR, Natl Inst Opt, INO, Sesto Fiorentino, Tuscany, Italy; CNR, Nanosci Inst, Pisa, Tuscany, Italy; Univ Belgrade, Sch Elect Engn, Belgrade, Serbia; Univ Belgrade, Inst Phys Belgrade, Belgrade, Serbia; Senzor Infiz, Dept Inst Phys, Belgrade, Serbia; Ist Nazl Ric Metrolog INRIM, Turin, Italy; Univ Firenze, Dipartimento Fis, Sesto Fiorentino, Tuscany, Italy.
Abstract: Photonic devices greatly benefit from the ability to reconfigure their optical properties. To achieve this with disordered optical materials, it is possible to make use of polymer dispersed liquid crystals (PDLCs) in which the scattering originates from randomly distributed liquid crystal droplets that respond to external stimuli, such as light, temperature, and magnetic or electric fields. In this work, we present a speckle-based analysis to investigate the reconfigurability of the dynamic and static scattering properties of dye-doped PDLCs, as a function of dye concentration and light intensity. Our findings allow us to distinguish between reversible and non-reversible molecular rearrangements after a light-induced phase transition, occurring on millisecond timescale. The degree of reversibility is quantified using cross-correlation analysis based on the Pearson correlation coefficient. As a proof-of-concept application, we exploit their non-reversible reconfiguration properties to create a cryptographic optical physical unclonable function whose behavior can progressively be erased in case of malicious attacks. We demonstrate a non-reversibility, assessed through the uniqueness metric, that ranges from 30% to 40% depending on dye content. Leveraging their intensity-dependent scattering properties, these disordered materials emerge as ideal candidates for advanced nonlinear information processing and secret-free security applications.
Journal/Review: APL PHOTONICS
Volume: 11 (2) Pages from: 20802-1 to: 20802-13
More Information: This work was partially supported by the project SERICS (No. PE00000014) under the MUR National Recovery and Resilience Plan funded by the European Union-Ne xtGenerationEU-and co-funded by the European Union-NextGenerationEU, Integrated infrastructure initiative in Photonic and Quantum Sciences-I-PHOQS (Nos. IR0000016, ID D2B8D520, CUP B53C22001750006) and by Horizon WIDERA 2021-ACCESS-03-01 BioQantSense (No. 101079355). S.N. acknowledges the financial support from project PRIN 2022 2022T3B4HS-PE11-Multi-step optical encoding in anticounterfeiting photonic tags based on liquid crystals (PHOTAG) financed in the framework of Piano Nazionale di Ripresa e Resilienza (PNRR). F.R. acknowledges the financial support from the Air Force Office of Scientific Research under Award No. FA8655-24-1-7005. This work was also partially supported by the Ministry of Science, and Technological Development and Innovation of the Republic of Serbia. We thank L. Pattelli and E. Pini for their help and discussion on the scattering properties analysis and V. Spinoso for the sample thickness measurements.KeyWords: Temperature; Displacement; Scattering; DynamicsDOI: 10.1063/5.0282151
