Tiny sensors surround us as more are packed into our phones, tablets, laptops, and more. Perhaps one of the best known examples is the accelerometer which tracks the movement of a proof mass to measure the forces on the sensor. Typically this is part of an electrical system, but researchers at the California Institute of Technology and the University of Rochester have devised a new optical accelerometer with multiple advantages over the current technology.
Like much else in the technology world, sensors are trying to be miniaturized, but there is the catch that components, like the proof mass, are more sensitive at larger sizes. That means the miniaturizing the sensor could impair its performance. The optical system the researchers developed though can be made just microns large thanks to its highly sensitive lasers. This new system is comprised of a laser, two cavities, and a proof mass. The laser light shines into the cavities, where it bounces back and forth before escaping. One of these cavities is tied to the proof mass, so as it moves, the cavity changes. This causes a change in how much light escapes the cavity, and that can be measured very precisely. Also, as the light bounces back and forth, it has the effect of negating fluctuations due to heat and softens the motion of the proof mass, for even more precision.
We may not see this technology used in any device for a while yet, because while it can be made from silicon, it requires a laser be integrated into the electronics, which is still something other researchers are trying to perfect. When that is accomplished though, we will see new devices with sensors more precise than almost anything you can find today.