190-GHz radiation from a quasioptical Josephson junction array

摘要

At 190 GHz, 0.36 /spl mu/W has been detected from an 11/spl times/58 array of niobium Josephson junctions. The power is radiated directly into free space above the surface of the two-dimensional array of junctions. Detection is made by a commercial bolometer outside the array cryostat. The junctions in the array are closely spaced in the y-dimension, but spaced by more than one-half wavelength in the x-direction. This asymmetry results in mutual phase-locking between adjacent junctions suitable for the production of y-polarized radiation. The resonance anti asymmetry also results in a reasonable impedance match between the Josephson junctions and the free-space radiation mode.