New microsensors use laser light to give accurate and quick results

Researchers at the University of Rochester and the California Institute of Technology have been working on developing a super sensitive type of motion detector; an accelerometer, which uses laser light to give improved results on the microchips that we are already accustomed to using in our everyday lives.

In this new sensor, laser light is used instead of a traditional electrical circuit to measure movements, and it can pick up a motion signal up to tens of thousands of time faster than the motion sensors in use today. A laser beam is very sensitive to movement, and does not cause much background interference, making the signals it detects clearer to analyse.

The accelerometer is designed on a silicon chip, and an optical cavity of 20 millionths of a metre wide is used to channel laser light towards a tethered mass called a proof mass. As a result of working in such small dimensions, the laser beam actually pushes and pulls the proof mass as it works its way down the optical cavity, resulting in fewer mechanical vibrations, less thermal noise, and a cooling of the system – all of which means in can detect motion faster, and can work at a large range of frequencies.

This quick detection, coupled with the accuracy and sensitivity of the accelerometer, means that there could be wide use of such sensors, particularly in silicon microelectronics. Microchips are already found in airbags, GPS systems and in much of the camera and mobile technology in use today, and the new sensors could one day mean smaller, lighter and more accurate products in these areas.

More information about the research and device can be found in the online publication of Nature Photonics.