HOT researchers are developing a variety of transducers for electromagnetic fields, converting signals from one domain into another. This includes devices that allow conversion of the microwave signals in a superconducting quantum processor to optical photons propagating in glass fiber networks. HOT researchers are developing several platforms to implement such transducers. One particularly interesting material for this task is Gallium Phosphide, a piezoelectric material with high refractive index and a large electronic bandgap. In the first year of HOT, partner IBM reports that they could for the first time fabricate optomechanical crystals from this material, using a newly developed process. Characterization of the devices yields optical resonances with excellent coherence, reaching quality factors as high as 65,000. The modes are strongly coupled to co-localised mechanical breathing modes. The underlying idea of the devices design is to exploit the piezoelectric effect to use small electrical signals to set the breathing mode into motion, which then modulates the light in the optical resonance. Devices developed by researchers at the University of Camerino work by a similar principle, but in the lower radio frequency (~1 MHz) regime, relevant for applications such as magnetic resonance imaging (MRI). They employ thin membrane resonators as intermediate mechanical elements. Instead of using a piezoelectric, the membranes are excited by electrostatic forces inside a capacitor. Camerino’s recent HOT study shows, that in this approach the membranes’ multimode nature can enhance the bandwidth of the transducer. To find out more about the possibilities for signals transducers, you can consult a progress article in Nature Nanotechnology, co-authored by HOT researchers, on nano-opto-electro-mechanical systems and their applications.