Two-Photon Upconversion Process and its Application to Infrared Vision

Abstract

This Thesis describes the use of (NaYF4:Yb,Er) microparticles suspended in water and ethanol to convert 980 nm infrared light into 540 nm visible light through a nonlinear stepwise two-photon process. The potential for upconversion enhancement explored by placing IR-reflecting mirrors on four sides of the cuvette containing the microparticles. Additionally, we developed and fabricated microparticle-coated lenses for use as eyeglasses, allowing for the visualization of intense infrared light images converted to visible light. The results of this study have significant implications for the development of new technologies in fields such as infrared vision, optogenetics, imaging, telecommunications, and biomedicine. We also described the design, construction, and results obtained by our novel, compact, and affordable microspectrophotometer capable of accurately recording absorption and emission spectra of microscopic samples.