Tunable eletro-optical modulators based on a split-ring resonator

We present a novel design of an electro-optical modulator setup, consisting of a mechanically tunable cavity which allows the modulation frequency to be varied over a broad range. The design is based on the frequently used geometry of a split-ring resonator which allows for high-efficiency sideband generation. Normally such a configuration has the limitation of a narrow excitation band width ( approximately 20 MHz). Our adjustable setup offers broad-range tunability over several hundred megahertz while still keeping the modulation efficiency. Such a widely tunable modulator may find applications in a variety of experiments in atomic physics.