September 15, 2011

1 Min Read
Crystal Delivers Accurate Temperature Readings in Challenging Environments

Crystals have properties that researchers have discovered make them suitable to be used as highly accurate temperature gauges. Birefringence splits light through a crystal into two separate rays, and the size of the effect increases or decreases in proportion to the temperature of the crystal. But changes in the thickness and orientation of the crystal compromise the temperature-measuring ability, making them expensive to manufacture and unsuitable for use in situations where vibrations could affect the orientation of the crystal.

Researchers at the University of Warwick (Coventry, UK) and Oxford University have developed a low-cost, reproducible form of crystal that uses birefringence and is also resistant to vibration and interference called the Zero-Biregringence Optical Temperature Sensor (Z-BotS). By making modifications to the properties of crystalline lithium tantalite, the researchers can make its birefringence at almost zero in magnitude in all directions, and virtually independent of the crystal's thickness and position. The material is close to being optically isotropic like ordinary glass, but the slightest temperature change creates a rapid increase in birefringence, measuring temperatures from -184 to 1256 degrees Fahrenheit.

The technology will be especially valuable in electromagnetic, radio frequency, and high voltage environments, such as in the vicinity of MRI scanners in hospitals. And since only the crystal itself needs to be in the environment and the birefringence changes can be operated remotely, it opens up the possibility for many remote temperature sensing applications in challenging environments where the light source, measurement, and processing electronics could be situated remotely.

The invention is the subject of a patent application, and the team is seeking funding to develop the Z-BotS from its proof-of-concept stage to a miniaturized, commercially viable package.

Sign up for the QMED & MD+DI Daily newsletter.

You May Also Like