World's Most Sensitive Thermometer Uses Light And Is 3x More Precise

Ankita Katdare

The next time you fall sick and need a thermometer to measure the temperature you will be able to tell it 3 times more accurately than what the best thermometers we use today do - all thanks to the physics research team from the University of Adelaide's Institute for Photonics and Advanced Sensing (IPAS). What is now being called the "world's most sensitive thermometer", here we have a device that can measure temperature with a precision of 30 billionths of a degree. Moreover, these numbers point to temperature measured at room temperature. So, in cryogenic environments, in other words - at very low temperatures, these values will be more accurate than ever.

How does this all work?
Well the Adelaide research team made use of light to measure temperature. Basically, the the thermometer injects 2 colors of light (red and green) into a highly polished crystalline disk. Depending on the temperature of the crystal, the two colors travelled at somewhat different speeds inside it. After heating the crystal up, the researchers observed that the red light would be slowed than the green light. Later, they forced this light to circulate 1000s of times around the edge of the disk - just the way that sound concentrates and reinforces itself in a curve in a phenomena known as a "whispering gallery." This made them measure this minuscule difference in speed with great precision.

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To emphasize on the ingenuity of this concept and demonstrate how precise this new thermometer is, the researchers gave an example of a normal situation when we are testing the temperature of person with fever. We all have experienced that the temperature is always fluctuating. The reason behind is that all the atoms in any material are always in a state of fluctuation. And this is where the newly introduced super sensitive thermometer can play a significant role in measuring the variants in speed of atoms accurately.

The researchers at IPAS are certain that the ability to measure temperature at such a high degree of precision will revolutionize technologies used in industrial and medical applications. Those interested in this research work can take a look at the paper titled 'Nano-Kelvin Thermometry and Temperature Control: Beyond the Thermal Noise Limit' published in <a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.160801" target="_blank" rel="nofollow noopener noreferrer">403 Forbidden</a>.

What are your thoughts on precision in measurement and the new thermometer? Share with us in comments.

Source: <a href="https://www.adelaide.edu.au/news/news70922.html" target="_blank" rel="nofollow noopener noreferrer">World's best thermometer made from light</a>

S.mukherjee

These thermometers are not meant for measuring temperatures of human body. As we can see, the crystal is the sensor and they are using optics to calibrate temperature, they want to be precise and accurate to the level where normal thermometers fail. So, this instrument may be used for very high temperature measurement or very low temperature measurement. As far as I think, they will be used mainly for cryogenic systems because high temperature measurement would involve heat handling capacity of the crystal( i.e. it should not melt).

Due to its accuracy, such system would be handful for research work or places where temperatures are such that normal thermometers become insensitive.

What's the point measuring human body temperature to the precision of 5 digits. (Who wants 101.000006 F, 101F would do). And to remind, such a system would cost at least 100 times more than a normal thermometer or may be much more.