Yb²⁺-Doped Silicate Glasses as Optical Sensor Materials for Cryogenic Thermometry

Area of Science:

• Materials Science
• Optical Engineering
• Condensed Matter Physics

Background:

• Optical sensors offer advantages over resistive probes for temperature monitoring.
• Cryogenic thermometry requires precise temperature measurement at very low temperatures.
• Ytterbium (Yb²⁺) ion photoluminescence (PL) is investigated for its potential in temperature sensing.

Purpose of the Study:

• To investigate the thermal behavior of Yb²⁺ ion photoluminescence in glass hosts for cryogenic thermometry.
• To evaluate the performance of Yb²⁺-doped aluminosilicate and aluminophosphosilicate glasses for temperature sensing.
• To determine the sensitivity and operating range of these optical sensors.

Main Methods:

• Fabrication of Yb²⁺-doped glass preforms using modified chemical vapor deposition (MCVD).
• Elongation of preforms into canes with Yb²⁺-doped cores.
• Photoluminescence (PL) and PL kinetics measurements under UV excitation (355 nm) from 2 to 300 K.
• Analysis using a modified two-level model to determine temperature sensitivity.

Main Results:

• All Yb²⁺-doped samples exhibited visible emission under UV excitation.
• Photoluminescence lifetime showed a temperature-dependent increase at low temperatures, followed by a decrease until room temperature.
• Aluminophosphosilicate glass compositions demonstrated higher sensitivity (S > 28.3 µsK^-1, S_r > 94.4% K^-1 at 30 K).
• The aluminophosphosilicate preform offered a wide operating temperature range of 10-300 K.

Conclusions:

• Yb²⁺-doped silicate glasses are promising materials for optical cryogenic thermometry.
• Aluminophosphosilicate glass hosts provide enhanced performance for cryogenic temperature sensing.
• The developed optical sensors offer a wide operating range and high sensitivity for low-temperature applications.