Related Experiment Video
Updated: Jan 18, 2026
08:44
Fabrication and Testing of Photonic Thermometers
Published on: October 24, 2018
6.2K
Practical primary thermometry via alkali-metal-vapour Doppler broadening
Nicola Agnew1, Veronika Vohnikova1, Erling Riis1
1Department of Physics, University of Strathclyde, Glasgow, Scotland, UK.
Summary
Doppler-broadening thermometry (DBT) offers calibration-free temperature measurements. This research demonstrates sub-kelvin accuracy with alkali-metal-vapour cells, paving the way for practical, long-term temperature sensing applications.
Area of Science:
- Atomic physics
- Metrology
- Thermometry
Background:
- Traditional thermometers require frequent recalibration, limiting their use in inaccessible environments.
- Doppler-broadening thermometry (DBT) presents a potential solution for calibration-free temperature measurements.
- Alkali-metal-vapour cells are explored as a medium for precise thermometry.
Purpose of the Study:
- To investigate the feasibility of Doppler-broadening thermometry (DBT) using alkali-metal-vapour cells.
- To assess the accuracy of absorption and frequency measurements during DBT scans.
- To evaluate the potential for practical, calibration-free temperature sensing devices.
Main Methods:
- Utilizing alkali-metal-vapour cells for Doppler-broadening thermometry.
- Conducting scans to measure absorption and frequency characteristics.
- Analyzing experimental data to determine temperature accuracy and fit residuals.
Main Results:
- Achieved sub-kelvin temperature accuracy.
- Experimental absorption-fit residuals were below 0.05%.
- Demonstrated proof-of-concept in a simple experimental setup.
Conclusions:
- DBT with alkali-metal-vapour cells is a viable method for accurate, calibration-free thermometry.
- The technology shows promise for practical applications, especially in environments requiring long-term, reliable measurements.
- Future improvements suggest a bright outlook for portable DBT devices.
Related Concept Videos
01:16Flame Photometry: Lab
856
In a flame photometer, when a solution like potassium chloride is aspirated into the flame, the solvent evaporates, leaving behind dehydrated salt. This salt dissociates into free gaseous atoms in their ground state. Some of these atoms absorb energy from the flame, leading to their excitation. The excited atoms return to the ground state, emitting photons at characteristic wavelengths. Because only electronic transitions are involved, the resulting emission lines are very narrow. The intensity...
856
01:27Atomic Spectroscopy: Effects of Temperature
845
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
845
01:22Gas Thermometers and the Kelvin Scale
6.0K
The definition of temperature in terms of molecular motion suggests that there should be a lowest possible temperature, where the average kinetic energy of molecules is zero (or the minimum allowed by quantum mechanics). Experiments confirm the existence of such a temperature, called absolute zero. An absolute temperature scale is one whose zero point is absolute zero. Such scales are convenient in science because several physical quantities, such as the volume of an ideal gas, are directly...
6.0K
01:02Flame Photometry: Overview
1.4K
Flame photometry, also known as flame emission spectrometry, is a technique used for the qualitative and quantitative analysis of elements present in a sample using a flame as the source of excitation energy. The concept of flame photometry was realized in the early 1860s by Kirchhoff and Bunsen, who discovered that specific elements emit characteristic radiation when excited in flames. The first instrument developed for this purpose was used to measure sodium (Na) in plant ash using a Bunsen...
1.4K
01:22Thermometers and Temperature Scales
7.1K
Any physical property that depends consistently and reproducibly on temperature can be used as the basis of a thermometer. For example, volume increases with temperature for most substances. This property is the basis for the common alcohol thermometer and the original mercury thermometers. Other properties used to measure temperature include electrical resistance, color, and the emission of infrared radiation.
As many physical properties depend on temperature, the variety of thermometers is...
As many physical properties depend on temperature, the variety of thermometers is...
7.1K
01:13Equipments Used to Measure Body Temperature
1.7K
Body temperature can be assessed using various devices and measured in Celsius or Fahrenheit.
Glass-bulb Thermometer:
Glass-bulb thermometers are hollow glass tubes with a bulb tip containing liquid such as ethanol or mercury. Historically, glass bulb mercury thermometers were the standard device to measure body temperature. Today, mercury thermometers are prohibited in many countries due to the hazardous effects of mercury and the risk of exposure if the glass bulb breaks. In general,...
Glass-bulb Thermometer:
Glass-bulb thermometers are hollow glass tubes with a bulb tip containing liquid such as ethanol or mercury. Historically, glass bulb mercury thermometers were the standard device to measure body temperature. Today, mercury thermometers are prohibited in many countries due to the hazardous effects of mercury and the risk of exposure if the glass bulb breaks. In general,...
1.7K