Absolute instability of electromagnetic waves within large subcritically doped gallium arsenide samples

摘要

When an electromagnetic wave enters a medium having an effective negative resistance it may be expected to grow spatially. The present paper describes experimental work in which an electromagnetic wave propagates within a medium which is biased into a region of negative differential conductivity. Microwave emission is observed when round‐trip gain exists within the cavity formed by the specimen boundaries, and the factors which determine the form of the emission spectrum are studied. Finally, conclusions regarding the detailed mechanisms underlying the operation of this device are drawn.