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Novel Photonic Pressure Sensor Surpasses Traditional Mercury Standard
For almost 400 years, mercury gauges have prevailed as the most accurate way to measure pressure. Though accurate and reliable, these instruments are bulky and their dependence on mercury, a neurotoxic substance, makes them undesirable. Now, a novel pressure-sensing device has surpassed the performance of the best mercury-based techniques in resolution, speed, and range - at a fraction of the size. Developed by an interdisciplinary team of NIST researchers, the instrument is called a fixed-length optical cavity (FLOC). It works by detecting subtle differences in the wavelength of light resonating in two channels: one filled with gas, the other in vacuum. A change in pressure alters the density of the gas, which lengthens or shortens the wavelength of light resonating in the gas-filled channel while light in the vacuum channel is unaffected. The FLOC system is poised to depose traditional mercury pressure sensors - also called manometers - as the standard used to calibrate commercial equipment. The new design is also a promising candidate for a factory-floor pressure instrument that could be used by a range of industries, including those associated with semiconductor, glass, and aerospace manufacturing.
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