Related Experiment Video
Updated: Feb 2, 2026

Author Spotlight: Fabrication of a Low-Cost, Fiber-Coupled, and Air-Spaced Fabry-Pérot Etalon
Published on: February 3, 2023
Crystallization-sapphire-derived-fiber-based Fabry-Perot interferometer for refractive index and high-temperature
Abstract:
A crystallization-sapphire-derived-fiber (CSDF)-based Fabry-Perot interferometer (FPI) for refractive index (RI) and high-temperature measurement is proposed and demonstrated. The FPI is formed by splicing sapphire-derived fiber (SDF) to the end face of a well-cleaved single-mode fiber (SMF). CSDF is generated hundreds of micrometers away from the fusion joint resulting from arc discharge and then cuts the SDF to the edge of the CSDF. The FPI consists of two cavities, one of which is formed by CSDF, and the other is SDF, between the SMF and CSDF. The fringe contrast of the reflection spectrum varying with the RI changes of the external environment is used for RI sensing, while the wavelength shifting is for the ambient temperature sensing. In the experiment, the refractive index and temperature sensitivities are about 233.8 dB/RIU in the RI range of 1.333-1.363 and 13.571 pm/°C in the temperature range of 20°C-1000°C.
Related Concept Videos
Measurement: Derived Units
Temperature Measurement Sites
Oral: When assessing oral temperature, the thermometer tip should be placed under the tongue in the posterior sublingual pocket. It offers accurate readings and can be...
Equipments Used to Measure Body Temperature
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,...
Ionic Crystal Structures
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Crystal Growth: Principles of Crystallization
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...

