Sulfur plasma lamps are a convenient, table-top system for the study of acoustics in dense, weakly ionized plasmas. Herein, we describe the construction and tuning of a passive waveguide circuit capable of igniting and sustaining the sulfur plasma and exciting acoustic modes within it.

We have constructed an actuator/encoder whose generated displacement is controlled through the resonance frequency of a microwave cavity. A compact, 10-μm-range, digitally controlled actuator executing frequency-coded displacement with picometer resolution is described. We consider this approach particularly suitable for metrologic-precision scanning probe microscopy.