Non-contact Temperature Measurement Research Articles

Dual-mode optical thermometers via the thermochromic Bi3+, Eu3+ co-doped La2LiSbO6 phosphors for real-time chip temperature monitoring

In recent years, with the increasing demand for non-contact temperature measurement, it is urgent to develop a new type of phosphor with double emission centers, high sensitivity and good reliability. A series of Bi3+and Eu3+ co-doped La2LiSbO6 double emission center phosphors were successfully prepared. The response characteristics of Bi3+and Eu3+ at different temperatures in the range of 293–473k were calculated by fluorescence intensity ratio (FIR) technique. The optimal relative sensitivity Sr and absolute sensitivity Sa were 1.13 % K−1 and 1.27 % K−1, respectively. Hence, La2LiSbO6:Bi3+, Eu3+ phosphors have the capability of non-contact optical temperature measurement and are a promising material for application. The phosphor is combined with the optical fiber temperature sensor to monitor the real-time temperature of the computer central processing unit. The optical fiber temperature sensor system breaks through the limitations of traditional temperature measurement, and can be used in special environments such as small size and strong electromagnetic interference. It has become an ideal choice to replace the traditional temperature sensor.

Fabrication of CsPbBr3 nanocrystal/POSS-based copolymer films for non-contact temperature probes

Fluorescence-based non-contact temperature measurement has been attested a widely-used technique for temperature aware in rotating mechanical equipment, electrical devices, and other fields. Inspired by the thermal sensitivity of perovskite nanocrystals, we prepared a CsPbBr3/polyhedral oligomeric silsesquioxane (POSS)-based composite film with outstanding temperature-photoluminescence (PL) dependence, high reversibility, and high hydrophobicity. Perovskites nanocrystals with controllable nanocubic and nanoplate morphologies were synthesized by adjusting the temperature. Various CsPbBr3/POSS-based composite films with different CsPbBr3 morphologies and ratios were fabricated. The CsPbBr3 nanocubic and nanoplate based films possessed high hydrophobicity, UV stability, and thermal stability. Temperature dependence experiments revealed that PL spectral parameters of CsPbBr3/POSS-based composite films had obvious temperature change characteristics attributable to the CsPbBr3 morphology. The PL intensity and full width at half maximum (FWHM) of the CsPbBr3 nanoplate based film exhibited poor regularity with temperature. In contrast, the PL intensity of the CsPbBr3 nanocubic based film was related to temperature exponentially, and the FWHM had a strong linear relationship with temperature. Moreover, temperature dependence reversibility was realized for the CsPbBr3 nanocubic based film. Furthermore, the applicability of a CsPbBr3 nanocubic based temperature probe was verified by monitoring the temperature of a bearing cage on a spindle-bearing test platform. The CsPbBr3/POSS-based composites can be applied as temperature probes for non-contact temperature measurement of rotating components of mechanical equipment.

Thermal Field Monitoring When Exposing Soft Tissues to Low Temperatures: Thermography Prospects and Limitations

The review analyzes the existing tools for monitoring the dynamics of thermal fi elds when exposing the soft tissues to low temperatures. Features of contact and non-contact temperature measurements have been considered, their capabilities and limitations have been noted. There was substantiated the need to develop the procedures of intra-operative temperature control. Special attention has been paid to the non-contact non-invasive infrared thermography. This method has been shown to be applied for intra-operative monitoring of the movement of the ice lump edge on the surface of tissues, detection of a disordered thermal symmetry of the ice spot, thermal fi eld dynamics on the surface of tissues inside and outside the area of the operative zone. However, thermal imaging control of the dynamics of the primary necrosis zone and the ice ball edge in the volume of tissues is possible only under certain parameters of cryoimpact, for example, with a short-term cooling of tissues with a quasi-point nitrogen cryoapplicator. The possibility of using thermography at other stages of cryosurgery is also considered, i. e. as the method of additional diagnosis at the stage of surgery planning, as well as during the post-surgery period to control healing, scarring, etc.

APPLICATION OF THERMAL IMAGING CAMERAS FOR SMARTPHONE: SEEK THERMAL COMPACT PRO AND FLIR ONE PRO FOR HUMAN STRESS DETECTION – COMPARISON AND STUDY

Thermography as an innovative diagnostic technique with non-contact temperature measurement is used in many industries – science, industry, medicine, and security. When using thermography in the field of health, images and images sequences obtained from thermal imaging cameras allow to record the temperature distribution in order to further recognize whether the state of the body is consistent with the defined parameters or whether there are deviations. However, it is worth paying attention to the measurement accuracy of thermal imaging cameras, their specification, and image quality of thermograms. In the case of recording stress states, measurement discrepancies between thermal imaging cameras for smartphone may affect the final results. Therefore, this article focuses on the comparison of the possibility of recording and detecting stress using two smartphone thermal imaging cameras: SEEK THERMAL Compact Pro and FLIR ONE Pro. The specifications of both cameras were compared. At the same time, the possibility of recording stress using smartphone thermal imaging cameras was confirmed on the basis of an exemplary study. The results of the comparison and analysis show that smartphone thermography can be a quick registration and diagnostic method in behavioral-biomedical issues.

Steering Thermal Radiation

Thermal radiation is a physical phenomenon exhibiting dual characteristics of both light and heat. Sunlight, serving as the primary source of energy, emanates as thermal radiation from a high-temperature surface at 5,700 K. It is also responsible for the feeling of warmth experienced when individuals congregate and non-contact measurement of body temperature. Thus, thermal radiation exists everywhere in our daily life. However, in the early 20th century, thermal radiation posed a challenge to physicists. The endeavor to elucidate the spectrum of thermal radiation led to the concept of light as photons, therefore signaling the advent of quantum physics. It is known that thermal radiation uniformly emits, irrespective of its direction and polarization, with the spectrum dictated by Planck’s law. Yet, this commonplace should be modified when thermal radiation encounters the principle of nanophotonics. Herein lies the ability to modulate the intensity of thermal radiation across desired wavelengths, directions, and polarizations. In this article, we will delve into the latest research findings concerning the manipulation of thermal radiation and its promising applications.

Tunable and highly sensitive fluorescent thermometers from La2CaZrO6:Cr3+ with a time-resolved technology.

Non-contact optical temperature measurement can effectively avoid the disadvantages of traditional contact thermometry and thus, become a hot research topic. Herein, a fluorescence intensity ratio (FIR) thermometry using a time-resolved technique based on La2CaZrO6:Cr3+ (LCZO) is proposed, with a maximum relative sensitivity (Sr - FIR) of 2.56% K-1 at 473 K and a minimum temperature resolution of 0.099 K. Moreover, the relative sensitivity and temperature resolution can be effectively controlled by adjusting the width of the time gate based on the time-resolved technique. Our work provides, to our knowledge, new viewpoints into the development of novel optical thermometers with adjustable relative sensitivity and temperature resolution on an as-needed basis.

Особенности расчета температуры резания при высокоскоростном фрезеровании алюминиевых сплавов без применения СОЖ

Introduction. The calculation of temperature during high-speed milling of aluminum alloys is of interest, since temperature can act as one of the main limiting factors in choosing rational milling modes. This is especially important when milling thin-walled products used in aircraft construction, since its high values can lead to local warping of the structure. It is not possible to control the temperature factor in production conditions, which makes it necessary to develop a mathematical model for calculating temperature. The purpose of the work is to develop a methodology for predicting the cutting temperature during high-speed milling of aluminum alloy workpieces for cutting conditions, in which it is not possible to use cutting fluid. Methods. This paper presents experimental studies of the cutting temperature during high-speed milling of aluminum alloy workpieces without the use of cutting fluid using non-contact temperature measurement methods. The results obtained were used to determine the coefficients substituted into formulas for calculating temperatures on the front and back surfaces of the cutting blade. Results and discussions. Based on the results of experimental tests and theoretical modeling, a temperature graph is drawn up. A comparison of experimental studies of milling of aluminum alloy D16T, with changing cutting conditions (the cutting speed changed) with theoretical data, gave a satisfactory result. The average relative error when comparing experimental data with theoretical one is 6.05 %. Based on experimental data, it can be concluded that the comparison of experimental data for measuring cutting temperatures is in satisfactory agreement with the proposed method of theoretical calculation of temperatures. The advantage of this technique is that it allows, without time-consuming and costly experimental studies, theoretically calculate (forecast) the temperatures on the front and back surfaces of the cutting blade, as well as the cutting temperature, for those narrow milling conditions, where effective heat removal from the cutting zone is impossible. It can also be used for milling aluminum alloys, the mechanical and thermophysical properties of which differ.

Closed-loop high precision human tissue temperature measurements using a joint forward and inverse method

A closed-loop forward-inverse joint multi-layer temperature prediction method is introduced to overcome the limitations of non-contact microwave-based precise temperature measurements within human tissues. This approach merges an incoherent four-layer tissue forward model with a multi-frequency high-precision inversion algorithm. Random errors were incorporated into the forward model to construct a multi-layer human tissue dataset for performance validation and optimization of the inversion algorithm. The lack of precise temperature measurements in internal human tissues was addressed using an incoherent four-layer forward model that integrates the Pennes heat transfer equation with a fluid–solid coupling boundary modeling technique. Parameter differentiation analysis was conducted in the forward modeling step using incoherent electromagnetic transport equations. The proposed high-precision multi-frequency inversion process, added to the objective function, refines the XGBoost algorithm by assigning a penalty factor and adjusting for neighboring tissue temperature distributions. The Optuna framework was then utilized to optimize XGBoost hyper-parameter sets, resulting in the Opt-XGBoost inversion algorithm. This approach achieved a root mean square error of 0.033 °C and an average absolute error of 0.0256 °C in simulations involving forward modeling-generated data.

A correction method for radial distortion and nonlinear response of infrared cameras.

The key feature of non-contact temperature measurement provided by infrared (IR) cameras underpins their versatility. However, the accuracy of temperature measurements with IR cameras depends on imaging quality due to their non-contact nature, such as the lens, body temperature, and measurement environment. This paper addresses the correction of radial distortion and nonlinear response issues in IR cameras. To address radial distortion, we have designed a passive checkerboard calibration board specifically for infrared cameras. This board is used to calibrate the IR camera and derive the necessary camera parameters. Subsequently, these parameters are applied during the actual measurement process to rectify radial distortion effectively. Building on the radial distortion correction method mentioned above, we propose a multi-point segmented calibration approach that considers different temperature ranges and imaging regions. This method alleviates the issue of reduced temperature measurement accuracy due to variations in camera responses by computing gain and offset coefficient matrices for each temperature range. Experimental results demonstrate the effectiveness of the calibration board in correcting radial distortion in IR cameras, with a mean reprojection error of less than 0.16 pixels. Regarding the nonlinear response problem, the introduced method significantly reduces the relative error in temperature measurement. In the verification phase, spanning from 100 to 500 °C, the average relative error in temperature measurement decreases by 0.49% from 1.61% before and after correction, which highlights a substantial improvement in temperature measurement accuracy. This work gives a useful reference to improve the imaging quality and temperature measurement accuracy using infrared cameras.

Analysis of statistical uncertainties of non-contact temperature and emissivity measurements in the optical and near infrared ranges

The aim of this report is the analysis of the uncertainties of non-contact measurement of temperature and emissivity determined by the least sum of squares (LSS) method. Analytical expressions are obtained for the uncertainties of the temperature T and the emissivity ε by three methods: (1) linear regression using the Wien approximation, (2) non-linear regression with covariance matrix calculation using the Planck’s equation, and (3) hybrid method that combines linear and non-linear regression methods. It was found that the better the condition for the Wien’s approximation is fulfilled, the worse the accuracy of the emissivity measurement compared to the accuracy of the temperature measurement. The new optimal strategy is proposed to determine the T and the emissivity ε for non-contact measurements. It consists of three steps: (1) the temperature of the radiating body is found by the Wien approximation, TW; (2) the obtained value TW is used as an initial approximation for one-dimensional “hybrid” minimization. Minimization is carried out by one of the numerical methods of one-dimensional minimization. As a result, the values of ε0 and T0 are found at with the sum of the squared residuals, S0, reaches a minimum; (3) Measurement uncertainties are estimated using the covariance matrix method.

Predictors of sleep quality components in patients undergoing transarterial chemoembolisation: a cross-sectional study.

Patients undergoing transarterial chemoembolisation experience postembolisation symptoms and interferences affecting sleep quality, which require intervention. The study aimed to identify the predictors of sleep quality components in patients undergoing transarterial chemoembolisation. This study included two groups of participants: 50 patients undergoing transarterial chemoembolisation and 45 nurses caring for them. Data were collected from September to November 2022 using a structured questionnaire, and analysed using descriptive statistics, the t-test, analysis of variance, Spearman's rank correlation, and multiple regression analysis using the SPSS 27.0 program (IBM Corp., Armonk, NY, USA). The mean sleep quality score was 40.28±14.10. Heat sensation (t=-2.08, p=.043) and fatigue (t=-4.47, p<.001) predicted sleep fragmentation in 38.6% of the patients. Abdominal pain (t=-2.54, p=.014), vomiting (t=-2.21, p=.032), and the expected fatigue by the nurses (t=2.68, p=.014) predicted sleep length in 41.7% of patients. Abdominal pain (t=-2.05, p=.046) explained 42.9% of sleep depth. Based on the predictors of sleep quality components obtained in this study, strategies to improve sleep quality tailored to patients undergoing transarterial chemoembolisation should be developed. This study highlighted the need to bridge the gap between patients' and nurses' expected fatigue and its contribution to sleep fragmentation and sleep length. It also highlighted the importance of noncontact temperature measurement, controlling vomiting, and pain relief for improving sleep length in patients undergoing transarterial chemoembolisation.

Optical thermometry and multi-mode anti-counterfeiting based on Bi3+/Ln3+ and Ln3+ doped Ca2ScSbO6 phosphors

A series of novel Bi3+/Ln3+-activated Ca2ScSbO6 (CSSO) phosphors were synthesized by solid-state method and their luminescent behaviors were investigated in detail. Under the 302 nm excitation, the CSSO:Bi3+ shows remarkable near-ultraviolet photoluminescence with a peak emission at 365 nm. Eu3+-activated CSSO phosphor possesses high efficiency and no obvious reduction of emission intensity even after replacing Sc with Eu completely, which indicates a low-concentration quenching effect. In addition, its emission intensity at 423 K (I423K) still maintains 88 % compared with that of at room temperature (I298K), indicating good thermostability. In contrast, the CSSO:Bi3+ phosphor exhibits a significant reduction in emission intensity, maintaining only 49 % of its luminescence at 423 K (I423K/I298K). By codoping Bi3+ and Ln3+ (Ln = Eu, Tb, Dy, Sm), the energy transfer was observed from the Bi3+ to Ln3+ ions, endowing the CSSO:Bi3+, Ln3+ phosphors with tunable multicolor emissions. Leveraging the differing thermostabilities of the emission spectra for Bi3+ and Ln3+ ions, we designed and assessed a range of sensitive optical thermometers. Among these, the CSSO:Bi3+, Eu3+ phosphors exhibited the best performance, boasting maximum absolute and relative sensitivities of 9.96 % K−1 and 2.002 % K−1, respectively. Additionally, we displayed the multi-mode anti-counterfeiting function of synthesized phosphors, and a multi-color switching system was designed with the advantages of direct visualization and easy identification of encrypted information. These results indicate that Bi3+ and Ln3+ coactivated CSSO phosphor has the potential application for non-contact temperature measurement and anti-counterfeiting.

Reduction of response time of fire detection and containment systems in compartments

Bench tests were performed on promising sensors used in fire safety systems in compartments. Activation delay times of fire sensors and systems were analyzed during the thermal decomposition and suppression of burning construction and interior design materials typical of compartments: wood, particle board, fiberboard, linoleum, cardboard, different types of wallpaper, paper and plastic. The thermal decomposition and ignition characteristics were identified using commercially available fire detectors of different types and designs (thermal, smoke and flame detectors), contact and non-contact temperature measurement instruments, a gas detection system and video recording equipment. Devices with the highest efficiency in terms of response time and detection reliability were determined that are necessary and sufficient to identify the thermal decomposition of construction and interior design materials at an early stage of fire. When generalizing the experimental data, mathematical equations were derived to predict the integral characteristics of the processes under study. Promising methods of reducing the response time of fire sensors and systems in general were determined. Guidelines were proposed on upgrading the existing systems of fire prevention in buildings and developing new automatic ones to significantly accelerate the detection of fires in buildings and optimize their containment and suppression.

Feasibility of Noncontact Inductive Temperature Measurement Scheme Suitable for a Fixed or a Moving Conductive Target

Feasibility of Noncontact Inductive Temperature Measurement Scheme Suitable for a Fixed or a Moving Conductive Target

Color-tunable luminescence and temperature sensing properties of Bi3+/Sm3+ or Bi3+/Eu3+ codoped Ba2Gd2Ge4O13 phosphors.

Novel temperature-sensitive luminescent materials, Ba2Gd2Ge4O13 doped with Bi3+, Bi3+/Sm3+ or Bi3+/Eu3+ ions, have been prepared using a conventional solid-state reaction technique. The XRPD study has verified that all the synthesized germanates crystallize in the monoclinic system (space group C2/c, Z = 4). The crystal lattice of the compounds consists of zigzag chains of edge-sharing Me2O7 (Me = Bi3+, Eu3+ or Sm3+) dimers, [Ge4O13] units, and ten-coordinated Ba atoms. Under UV excitation the powders exhibit the luminescence corresponding to the 3P1 → 1S0 (310-550 nm) transition in Bi3+ and 4G5/2 → 6HJ (550-730 nm) in Sm3+ or 5D0 → 7FJ (570-720 nm) transitions in Eu3+ ions. Heating of Ba2Gd1.94Bi0.01Sm0.05Ge4O13 and Ba2Gd1.89Bi0.01Eu0.1Ge4O13 phosphors leads to an irregular decrease in the intensity of the main emission lines. It has been found that the fluorescence intensity ratio between a wide band in the 310-530 nm region and peaks at longer wavelengths may be successfully used as a temperature-dependent characteristic. Absolute/relative sensitivity values for Ba2Gd1.94Bi0.01Sm0.05Ge4O13 and Ba2Gd1.89Bi0.01Eu0.1Ge4O13 germanates reach 0.19% K-1/0.80% K-1 and 2.21% K-1/0.58% K-1, respectively. The above parameters indicate that Ba2Gd2Ge4O13:Bi3+/Sm3+ or Bi3+/Eu3+ samples can be used as potential luminescent materials for non-contact temperature measurement.

Upconversion luminescence and temperature measurement performance of Ho3+/Yb3+ and Tm3+/Yb3+ codoped Na5Rb7Sc2(WO4)9 phosphors

New series of Ho3+/Yb3+ and Tm3+/Yb3+ codoped Na5Rb7Sc2(WO4)9 upconversion phosphors crystallizing in the trigonal system (S.G. R32) have been prepared. The studied tungstates are promising materials for non-contact temperature measurements.

Multi-color tunable luminescence of SrMoO4: Tb3+, Eu3+ nanophosphors for dual-mode temperature monitoring and multi-dimensional high secure anti-counterfeiting

New lanthanide-doped nanoparticles with unique optical characterisics are highly desirable for non-contact thermal sensing and advanced optical anticounterfeiting. The fluorescence intensity ratio (FIR) nanothermometers with higher relative temperature sensitivity (Sr) offer several advantages over traditional contact-based temperature sensors, including high sensitivity, fast response times, and non-invasive measurement. Herein, we describe the synthesis of nanocrystalline SrMoO4:RE3+ (RE3+= Tb3+ and Eu3+) using co-precipitation method for various optical applications, such as temperature sensing and anti-counterfeiting. These phosphors nanoparticle emit multi-colors by varying the percentage of Eu3+ and Tb3+ ions incorporated into SrMoO4. The maximum absolute sensitivity for multi-mode non-contact temperature measurement based on FIR and the distinct thermal behaviour of Eu3+ and Tb3+ ions was reached at 0.055 K−1. The maximum relative sensitivity is reached at 1.8 % K−1, with a minimum temperature resolution δT of 0.043 K at 300 K and maximum δT of 0.272 K. The developed nanophosphors emit green light when it doped Tb3+ and emit red light when it doped with Eu3+, and both demonstrate distinct changes in their response to temperature variations. The color change with temperature elucidates a real base for potential application in advanced anti-counterfeiting. The co-precipitation method we used to synthesize the nanophosphors is easy to scale up for industrial applications. So, the developed nanophosphors with multicolor emissions is of scientific and technological relevence.

Luminescence and temperature sensing properties of Y2-x-yTmxSmyMgTiO6 phosphors

Double perovskite materials have become the first choice of luminescent matrix materials in recent years due to their advantages of more flexible, easy doping and stable performance. A series of Y2-x-yTmxSmyMgTiO6 (0 ≤ x ≤ 0.5, 0 ≤ y ≤ 0.2) phosphors were prepared by high temperature solid-state method using different concentrations of Tm3+ and Sm3+ as dopants. The X-ray diffraction spectrum (XRD), photoluminescence spectrum (PL), fluorescence lifetime curve and X-ray excitation luminescence spectrum (XEL) of the phosphors were measured. The measurement results show that the dopants Tm3+ and Sm3+ enter the host lattice and replace part of the position of Y3+. The Tm3+ -doped sample emits strong blue light (458 nm) under 360 nm excitation, and the Sm3+ -doped sample has obvious emission peaks at 568 nm, 605 nm, 652 nm and 715 nm under 409 nm excitation. The energy transfer behavior of Tm3+→Sm3+ exists in the double doped samples. The energy transfer mechanism is consistent with the mechanism of concentration quenching in the system. Tunable luminescence can be realized by changing the doping concentration and excitation wavelength, which has great application value in the field of LED lighting. The energy transfer process and energy transfer efficiency in the system can be determined from the fluorescence lifetime curve of the sample. The phosphor can be effectively excited by X-ray, and the sample has good heat resistance and radiation resistance, which can be applied to the field of X-ray imaging. In addition, the thermal excitation effects of temperature on the 4G5/2 → 6H5/2 (568 nm) and 4G5/2 → 6H7/2 (605 nm) characteristic transitions of Sm3+ are different. Optical temperature measurement can be realized by using the fluorescence intensity ratio of I568 nm/I605 nm. Good temperature measurement performance and temperature measurement range have obvious advantages in the field of non-contact optical temperature measurement.

Micro-infrared thermometry for characterizing microscale heating devices

Infrared thermometry is a non-destructive and non-contact temperature measurement technique that allows for real-time, full-field imaging. However, the limited spatial resolution of infrared detectors and the scarcity of mid- and far-infrared lenses have hindered its use in microscale applications. To address this, we introduce an infrared microscope that employs a bolometer-type infrared detector and a reflective objective lens, enabling high-resolution temperature measurements of microscale heating devices. The reflective objective lens used in the microscope introduces intensity reduction due to magnification and undesirable background radiation caused by its cavity effect. To mitigate these issues, we utilized a custom-built micro-blackbody for calibrating intensity reduction and eliminating background radiation. The proposed micro-infrared thermometry setup was characterized by MDTD and MRTD measurements, as well as an MTF curve with a pixel resolution of 6.7μm/pixel and a spatial resolution of 12.5μm. To evaluate the effectiveness of the micro-infrared thermometry, we fabricated a suspended microscale heating device that can exhibit a clear temperature distribution. The temperature distribution obtained using both the differential conversion and Fast Fourier-Transform methods to eliminate background radiation agreed well, with a maximum difference of 3.2°C and 4.1°C in the range from room temperature to 77°C and 145°C, respectively. Furthermore, we compared our experimental results with COMSOL simulations and found them to be reasonably consistent, with a maximum difference of 6.1°C and 7.0°C in the range from room temperature to 77°C and 145°C, respectively.

Upconversion luminescence and optical thermometry behaviors of Yb3+ and Ho3+ co-doped GYTO crystal

Optical thermometry based on the upconversion (UC) luminescence intensity ratio (LIR) has attracted considerable attention because of its feasibility for achievement of accurate non-contact temperature measurement. Compared with traditional UC phosphors, optical thermometry based on UC single crystals can achieve faster response and higher sensitivity due to the stability and high thermal conductivity of the single crystals. In this study, a high-quality 5 at% Yb3+ and 1 at% Ho3+ co-doped Gd0.74Y0.2TaO4 single crystal was grown by the Czochralski (Cz) method, and the structure of the as-grown crystal was characterized. Importantly, the UC luminescent properties and optical thermometry behaviors of this crystal were revealed. Under 980 nm wavelength excitation, green and red UC luminescence lines at 550 and 650 nm and corresponding to the 5F4/5S2 → 5I8 and 5F5 → 5I8 transitions of Ho3+, respectively, were observed. The green and red UC emissions involved a two-photon mechanism, as evidenced by the analysis of power-dependent UC emission spectra. The temperature-dependent UC emission spectra were measured in the temperature range of 330–660 K to assess the optical temperature sensing behavior. At 660 K, the maximum relative sensing sensitivity (Sr) was determined to be 0.0037 K−1. These results highlight the significant potential of Yb,Ho:GYTO single crystal for optical temperature sensors.Graphical abstract