Multimodal self‐calibrating photothermal window utilizing transparent Pr ³⁺ –Er ³⁺ co‐doped Y ₂ Zr ₂ O ₇ ceramics

Abstract In response to the urgent demand for windows with multi‐mode self‐calibrated temperature feedback operating over a wide range in extreme environments, herein, Pr 3+ –Er 3+ co‐doped Y 2 Zr 2 O 7 (YZO) transparent ceramics were developed. After annealing treatment to remove defects, these ceramics exhibit high transparency and temperature‐dependent wide‐range photoluminescence, in which the in‐line transmittance is up to 77.8% at 760 nm (theoretical limit is 78%), and the luminescence band spans blue to red. Furthermore, based on the luminescence intensity ratio technology, a multi‐mode temperature sensing window using highly transparent YZO:Pr/Er ceramics was designed. The developed photothermal window shows relatively high sensitivity, in which absolute sensitivity ( S a ) and relative sensitivity ( S r ) reached 0.0105 K −1 at 363 K and 1.295% K −1 at 301 K, respectively. The developed thermometer could provide a reference for self‐calibrated thermometer window, and its wide spectral operating range ensures the reliability of temperature measurement, which has the potential to be used in some extreme conditions.