Phosphor thermometry at cryogenic temperatures

Abstract

The temperature dependence of the lifetimes of two phosphors, La2O2S:Eu and Mg4FGeO6:Mn, is presented from 300 to 11 and 140 to 8 K, respectively. Emission from the D35 state of La2O2S:Eu reveals a strong temperature dependence from 11 to about 130 K, where the signal becomes too weak to measure accurately. Emission from the F24 state of Mg4FGeO6:Mn changes throughout the temperature range measured. Both of these materials are used for higher temperature thermometry applications. This work illustrates their utility down to liquid helium temperatures.

Making Nd3+ a Sensitive Luminescent Thermometer for Physiological Temperatures—An Account of Pitfalls in Boltzmann Thermometry

“…was found using equation(2). The value agrees well with the result for the fast component from the double exponential fit (kr( 4 F5/2) + k nr em (298 K) = (242 ± 12) ms -1 ) as depicted inFigure 6Error!…”

“…In order to obtain a more precise value, upon selective excitation into the 4 F 5/2 level, the luminescence decay was recorded for the strongest 4 F 5/2 → 4 I 9/2 -related emission at 804 nm (see Figure 7a). A fast decay with an average (radiative and non-radiative) decay rate of k r ( 4 F 5/2 ) + k em nr (T = 298 K) = 204 ms −1 was found using Equation (2). The value agrees well with the result for the fast component from the double exponential fit (k r ( 4 F 5/2 ) + k em nr (298 K) = (242 ± 12) ms −1 ) as depicted in Figure 6c.…”

“…Temperature is an important control parameter that governs, e.g., the rate of chemical reactions, but also the optimum working efficiency of electronic devices or dynamics and viability of biological systems. As such, non-invasive, sensitive and remote temperature measurement techniques with the capability to spatially resolve temperature variations down to the micrometer range are becoming increasingly relevant [1][2][3][4][5][6][7]. Physiological temperature sensing is especially demanding in that regard as it even requires to accurately distinguish temperature fluctuations below 1 K. Luminescence nanothermometry is an appealing and rapidly emerging technique that meets those requirements and constantly improves [8][9][10][11][12][13][14].…”

MgTiO3:Mn4+ a multi-reading temperature nanoprobe

“…The decrease of the quantum yield with temperature in the case of the Cr 3+ (isoelectronic to the Mn 4+ ) is fully documented in the literature [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] and the same process occurs for the tetravalent manganese. [44][45][46] The maximal relative sensitivity is around 1.2% C À1 at À180 C and remains above 0.6% C À1 until 50 C (Fig. 3d), which can give an accurate temperature measurement in the low-temperature range, but also matching well with the physiological temperature range for biophotonic applications.…”

A Calibration System for Fluorescence Thermography

“…Optical fibers can be used to convey the light-signals in and out of the hightemperature environment. Allison, Cates and co-workers described specific calibration systems for both cryogenic [8,9] and high temperatures [10,11] in which the phosphor was either bonded onto a substrate or held in a removable tray. Alaruri et al presented a laser-based system for remote surface temperature monitoring of turbine parts where the phosphor was calibrated within a high temperature furnace [12].…”