INTEGRATED SUPERCONDUCTING RECEIVER AS A TESTER FOR SUB-MILLIMETER DEVICES AT 400-600 GHz

摘要

We report on design and first application of a laboratory-purpose tester which can in situ detect spectrum of sub-millimeter wave emission within frequency range of 400- 600 GHz from virtually any compact low-power source working within temperature range below 100 K. Both the receiver and the sample are placed in vacuum inside a laboratory test stick of diameter 50 mm, which is cooled down in a standard transport vessel for liquid helium. The sensor of the tester is designed on a base of the superconducting integrated receiver (SIR) chip working below 5 K. The chip sensor, beside the quasi-optical SIS mixer, contains an internal electronically tuned superconducting local oscillator, that provide low-noise operation at the level below 300 K DSB at central frequencies of 480-520 GHz as measured with a black body at the position of the test source. The signal detected by the SIS mixer is boosted by a helum-cold low-noise amplifier (G=20 dB, TN=10 K) within frequency range 1- 2 GHz and then by a second room temperature amplifier (G=53 dB, TN=90 K) both mounted within the same test stick. The output level is sufficient for direct application to most of standard RF recorders, e. g. for a spectrum analyzer. To detect weak signals, a compact chopper-wing has been designed and placed at the input of the receiver module. Details of design and main test data measured at DC and RF are reported.