Two-/multi-wavelength light excitation effects in optical materials: From fundamentals to applications

Abstract

Investigating the nature of two-/multi-wavelength light excitation effects in optical materials such as their mechanisms, materials composition, and opto-electronic behaviors is crucial for observing the photophysical and photochemical performance for their applications. Recently, this research area has received extensive attention owing to its remarkable optical performance, capability of tunable fluorescence emission, tailorable photochemical reaction, controllable electron population, and driving of novel photophysical and photochemical phenomena, which are promising for emerging applications in broad areas of spectroscopy, photophysics, photochemistry, opto-electronics, biophysics, as well as environmental and materials science. In this work, we review recent progress in the interdisciplinary studies of photoluminescence mechanisms, emitting centers, host material system, optical setups and characterization techniques, and application fields for the optical materials by two-/multi-wavelength light excitation effects. In the first part, we introduce the latest progress of two-/multi-wavelength light excitation effects in optical materials, from their fundamentals to their applications. In the second part, we present the dominant two-/multi-wavelength excited photoluminescence mechanisms, including excited state absorption, stimulated emission depletion (STED), ground state depletion, and more STED-inspired models. Moreover, we outline recent progress in optically active centers and host material classification, and their intrinsic connections between tunable microstructures and applications for different material systems based on two-/multi-wavelength light excitation effects. Optical measurement setups and characterization techniques for broad application fields are reviewed and summarized. By emphasizing the progress of emerging photoluminescence properties in optical materials and their application prospects based on two-/multi-wavelength light excitation effects, involving three-dimensional displays, lasers, STED super-resolution nanoscopy, photolithography and optical data storage, ultraviolet bacteriostatic agents, solar cells, and optical switches are explained. Finally, we discuss the present achievements and remaining questions and provide perspectives for future research directions.