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Research Activities
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6. Superconducting Integrated Submm Spectrometer for Laboratory Applications Proposed Superconducting Integrated Submm spectrometer for laboratory applications can in situ detect radiation from a coolable rf source (4-100 K) within frequency range of 200 - 700 GHz at receiver noise temperature: below 500 K (direct detection sensitivity better than 10-13 W). The Superconducting Integrated Receivers (SIR) chip is a superconducting integrated circuit comprising a quantum-noise-limited SIS mixer and a tunable Josephson local oscillator (LO). We have developed a series of lightweight and compact ultra-sensitive submm SIRs with low power consumption (typically less than 50 µW), which are beneficial for imaging applications in radio-astronomical research and remote monitoring of the Earth atmosphere. SIRs are very attractive for laboratory studies as well; the integrated receiver has been developed and tested demonstrating noise temperature below 300 K at 520 GHz. It is known that frequency stabilization of a LO is necessary for accurate detection of narrow-band submm wave emission. To realize stability better than 1 ppm of the center frequency, the LO of the SIR has to be phase-locked to an external reference source. Such phase locking of a superconducting submm FFO with continuous frequency tuning is demonstrated for the first time for ANY type of Josephson oscillator over a wide frequency range (up to 700GHz) with a resolution given by the phase noise of the reference oscillator. These results are the basis for the development of 550-650 GHz integrated receiver for the Terahertz Limb Sounder (TELIS) intended for atmosphere study and scheduled to fly on a balloon in 2006. We propose to use the achievements of the TELIS project to develop a sensitive laboratory-purpose integrated spectrometer for the detection and spectral study of radiation from a variety of superconducting oscillators. We hope that this development will be a beneficial step towards wide use of superconducting receivers in many research laboratories and universities.
Prototype of the Integrated spectrometer (a).
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