When a team of researchers at the National Institute of Standards and Technology (NIST) Physical Measurement Laboratory (PML) first tested a new kind of pressure sensor two years ago, initial results showed it was faster and had higher resolution than the centuries-old mercury-based method for measuring pressure. The novel device, called a fixed length optical cavity (FLOC), works by detecting subtle changes in the frequency of light passing through a nitrogen gas-filled cavity about the size of a box of tissues.

Now the same research team has thoroughly vetted the FLOC against the U.S. mercury-based pressure standard, currently a world leader in pressure measurement. The verdict: The photonic sensor performs better than expected and in fact outperforms the traditional mercury system at low-pressure ranges. The work was carried out jointly by a team of NIST scientists from PML’s Sensor Science Division and Engineering Physics Division.

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