Broadband light emission induced by laser absorption and optimized by thermal injection in Nd³⁺:Y₂SiO₅ ceramic powder

Abstract

Laser‐induced broadband (white) light emission has been studied in different particle systems for use in light‐emitting devices. The photoinduced phenomenon occurs above a certain excitation power threshold and it is generally studied under vacuum conditions. In this work, the phenomenon is studied in neodymium‐doped yttrium silicate ceramic powder synthesized by combustion method. White light is observed when the sample is excited in ambient air with a continuous‐wave near‐infrared (λ = 808 nm) laser powered above 1.3 W. When the temperature of the sample is externally raised above 200°C, white light is observed above 1.0 W and a large enhancement of the broadband emission intensity is observed.

Optical temperature sensor based on upconversion luminescence of Er3+ doped GdTaO4 phosphors

“…Upconversion (UC) luminescence refers to the conversion of electromagnetic waves from long to short wavelengths through multi‐photon processes where the absorption of infrared (IR) photons leads to visible emission, which has attracted a lot of attention on the bioimaging, 3‐D color display, printing ink, state‐of‐the‐art lighting, solar cell, fingerprint acquisition, anti‐counterfeiting, and so on 1‐7 . Particularly, based on the measurement of temperature‐dependent UC luminescence intensity of two thermally coupled energy levels of trivalent rare earth (RE 3+ ) ions, the non‐contact optical temperature sensor by using the fluorescence intensity ratio (FIR) technique still keeps a research hotspot in recent years owing to its advantages of fast response, high sensitivity and resolution 8‐13 .…”