RYDBERG RADIO SENSOR

A Rydberg sensor for detecting radio signals has a Rydberg vapour cell and input and output units for probe and control laser beams, where the input and output units split respective input laser beams into respective arrays to intersect oppositely within the vapour cell. The input and output units each contain an array of beamsplitters which preferably have successively increasing splitter ratio along the array, and preferably the beamsplitters are prisms arranged to abut one another and which are bonded to each other and to the vacuum cell to provide resilience to vibration in use. Data or signals from a respective array of photodetectors are passed to a computer processor to measure and discriminate an incident radio signal, for example at a specific frequency and incident angle, in preference to others.