Researchers have designed a new optomechanical integrated device with a resolution of 45 femtometers in a measurement time of a fraction of a second. Crucially, the device has an ultrawide optical bandwidth of 80 nm, removing the requirement for a tunable laser.
The integrated device – optical sensor is based on an indium phosphide (InP) membrane-on-silicon (IMOS) platform, which is ideal for including passive components such as lasers or detectors. The sensor itself consists of four waveguides – structures that restrict light signals to a particular path and direction – with two waveguides suspended above two output waveguides. When a suspended waveguide is pushed towards the output waveguides on the InP membrane, the relative amount of signal carried by the output waveguides varies. Fabrication takes place via a series of lithography steps to define the waveguides and cantilever, and the final sensor consists of the transducers, actuator, and photodiodes.
One of the key advantages of this sensor is that it operates in a large range of wavelengths, which eliminates the need for an expensive laser on the device.