Mark F. Bocko

Associate Professor of Electrical Engineering
Ph.D., University of Rochester, 1984

Key Words:
superconducting electronics, quantum noise, tunneling, electromechanical transducers, gravitational wave detection

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My research focuses on exploiting superconductivity in a variety of electronic applications, especially high-frequency circuits, both digital and analog, and low-noise detectors of electromagnetic and mechanical signals.

A large portion of my research program at present concerns the development of low temperature superconducting digital circuits and analog to digital converters. We are working on signal processing circuits built from Josephson junctions which will be capable of digitizing analog signals at multi-Gigahertz rates and carrying out computations at clock rates approaching 100 GHz. This research program also involves many other members of the Electrical Engineering Department and researchers at the Westinghouse Science and Technology Center in Pittsburgh, PA.

Also active is a project to develop superconducting electromechanical transducers for resonant-bar gravitational wave detectors. We are using superconducting microstrip circuits which are operated at 150-200 MHz to build electromechanical readouts capable of achieving sensitivities of 10-17 meters or better. We are also studying multimode gravitational wave antennae and new types of optical and electron tunneling transducers.

I also have an ongoing experimental and theoretical program to investigate the quantum noise limits of superconducting quasiparticle mixers and to implement novel measurement techniques to attempt to circumvent the apparent quantum noise limit for the detection of weak electromagnetic signals.

Finally, we are exploiting the techniques of scanning tunneling microscopy to develop sensitive displacement measuring techniques suitable for implementation in miniaturized integrated sensors. At present we are focused on an investigation of the fundamental sources of noise present in such transducers.

A Few Representative Publications:

  1. "Multipump and Quasi-Stroboscopic Back-Action-Evasion Measurements for Resonant-bar Gravitational Wave Antennae," (with L. E. Marchese) Phys. Rev., D45, 1869, 1992.

  2. "A Phase Sensitive SIS Mixer to Circumvent the Quantum Limit," (with Z. Zhang and S. Martinet), IEEE Trans. on Magnetics, 27, 3391-3394, 1991.

  3. "The Scanning Tunneling Microscope as a High-Gain, Low-Noise Displacement Sensor," Rev. Sci. Instrum., 61, 3763-3768, 1990.