Ratiometric optical thermometry based on upconversion luminescence with different multi-photon processes in...

Area of Science:

• Materials Science
• Optical Physics
• Chemical Engineering

Background:

• Upconversion (UC) luminescence is a promising technology for optical thermometry.
• Ratiometric optical thermometry offers advantages like anti-interference from excitation light source fluctuations.
• Developing novel thermometry methods with high sensitivity and stability is crucial for various applications.

Purpose of the Study:

• To develop a new ratiometric optical thermometry method based on UC luminescence in CaWO₄:Tm³⁺, Yb³⁺ phosphor.
• To utilize the ratio of different multi-photon processes for temperature sensing.
• To validate the proposed method and assess its performance, including sensitivity and anti-interference capabilities.

Main Methods:

• Fabrication and characterization of CaWO₄:Tm³⁺, Yb³⁺ phosphor.
• Development of a novel fluorescence intensity ratio (FIR) thermometry using the ratio of ³F_2,3 and ¹G₄ emission intensities of Tm³⁺.
• Analysis of power-dependent and temperature-dependent emission spectra to validate hypotheses and determine thermometric performance.

Main Results:

• A new FIR thermometry method was successfully developed and validated.
• The method demonstrated anti-interference from excitation light source fluctuations.
• The developed thermometry achieved a maximum relative sensitivity of 6.61% K^-1 at 303 K.

Conclusions:

• The proposed ratiometric thermometry based on UC luminescence with different multi-photon processes is feasible.
• This method provides a reliable approach for optical temperature sensing with enhanced stability.
• The study offers guidance for selecting appropriate UC luminescence processes for constructing anti-interference optical thermometers.