A binary light beam deflector is disclosed which includes a medium, such as water or quartz, which is transparent to an incident light beam. Two electroacoustic transducers are positioned to propagate acoustic waves of the same frequency through the medium so that each acoustic wave intercepts the incident beam at an angle equal to the Bragg angle. A radiofrequency oscillator is connected to one or the other of the transducers to cause deflection of the light beam in one or the other of two output directions. A plurality of the described deflectors may be arranged in cascade to provide any desired amount of deflection in binary steps.