IEEE Transactions on Applied Superconductivity

Fabrication of high-T/sub c/ hot-electron bolometric mixers for terahertz applications

Michael J. Burns, Alan W. Kleinsasser, K. A. Delin, Richard P. Vasquez, Boris S. Karasik, William R. McGrath, Michael C. Gaidis

Published Jun 1, 1997• 11 citations

Publisher

Abstract

Superconducting hot-electron bolometers (HEB) represent a promising candidate for heterodyne mixing at frequencies exceeding 1 THz. Nb HEB mixers offer performance competitive with tunnel junctions without the frequency limit imposed by the superconducting energy gap. Although the performance of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// HEB mixers is not projected to be superior to that of Nb devices, which operate at low temperatures, they introduce the possibility of sensitive, low power heterodyne detectors operating at temperatures approaching 90 K for applications requiring portability and closed-cycle refrigeration. We report on the fabrication and characterization, both DC and RF, of high-T/sub c/ mixers based on ultra-thin (/spl les/20 nm) YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films patterned to micrometer dimensions and incorporated into 2.5 THz planar mixer circuits.

DOI: 10.1109/77.622168

Related papers

Fabrication of High-Tc Hot-Electron Bolometric Mixers for Submillimeter Heterodyne Applications

Michael J. Burns, Alan W. Kleinsasser, Boris S. Karasik +2 more

Superconducting hot-electron bolometers are the most promising candidate for heterodyne mixers at frequencies above 1 THz. These devices operate by heating of electrons in the superconductor, and thus have no energy gap related frequency limitation, such as exists in SIS mixers, for example. Nb hot-electron bolometric mixers have recently demonstrated superior performance to competing Schottky mixers at frequencies above 1 THz, but of course must be operated at liquid helium temperatures. YBa 2Cu307_,5 hot-electron bolometric mixers introduce the possibility of sensitive, low power heterodyne detectors operating at temperatures approaching 90 K for high-background applications, such as earth observing missions. We describe the fabrication of high-T, devices based on ultrathin (<20 nm) YBa2Cu307_ 5 films for use as 2.5 THz mixers.

Jan 1, 19970 citations

A~~~i~~~o~s

Michael J. Burns

Superconducting hot-electron bolometers (HEB) represent a promising candidate for heterodyne mixing at fre- quencies exceeding 1 Twz. M, WEB mixers offer performance competitive with tunnel junctions without the frequency limit imposed by the superconducting energy gap. Afthough the performance of YBazCu&-s HEB mixers is not projected to be superior to that of Nb devices, which operate at low tempera- tures, they introduce the possibility of sensitive, low power het- erodyne detectors operating at temperatures approaching 90 K for appl~ca~ions requiring portability and closed-cycle refrig- eration. We report on the fabrication and characterization, , of high-T, mixers based on ultra-thin (GO nm) YBa2Cu30~ films patterned to micrometer dimensions and incorporated into 2.5 TNZ planar mixer circuits.

Jan 1, 19970 citations

Low-noise and wideband hot-electron superconductive mixers for THz frequencies

Boris S. Karasik, Anders J. Skalare, Rolf A. Wyss +5 more

Superconductive hot-electron bolometer (HEB) mixers have been built and tested in the frequency range 1.1-2.5 THz. The mixer device is a 0.15-03 /spl mu/m microbridge made from a 10 nm thick Nb film. This device employs diffusion as a cooling mechanism for hot electrons. The double sideband noise temperature was measured to be /spl les/3000 K at 2.5 THz and the mixer IF bandwidth is /spl ap/9-10 GHz for a 0.1 /spl mu/m long device. The local oscillator (LO) power dissipated in the HEB microbridge was 20-100 nW. Further improvement of the mixer characteristics can be potentially achieved by using Al microbridges. The advantages and parameters of such devices are evaluated The HEB mixer Is a primary candidate for ground based, airborne and spaceborne heterodyne instruments at THz frequencies. HEB receivers are planned for use on the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) and the ESA Far Infrared and Submillimeter Space Telescope (FIRST). The prospects of a submicron-size YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) HEB are also discussed. The expected LO power of 1-10 /spl mu/W and SSB noise temperature of /spl ap/2000 K may make this mixer attractive for various remote sensing applications.

IEEE International Conference on Terahertz Electronics (THz)Nov 27, 20025 citations

Low-noise and wideband hot-electron superconductive mixer for terahertz frequencies

Boris S. Karasik, Anders J. Skalare, William R. McGrath +7 more

Superconductive hot-electron bolometer (HEB) mixers have been built and tested in the frequency range from 1.1 THz to 2.5 THz. The mixer device is a 0.15 - 0.3 micrometer microbridge made from a 10 nm thick Nb film. This device employs diffusion as a cooling mechanism for hot electrons. The double sideband noise temperature was measured to be less than or equal to 3000 K at 2.5 THz and the mixer IF bandwidth is expected to be at least 10 GHz for a 0.1 micrometer long device. The local oscillator (LO) power dissipated in the HEB microbridge was 20 - 100 nW. Further improvement of the mixer characteristics can be potentially achieved by using Al microbridges. The advantages and parameters of such devices are evaluated. The HEB mixer is a primary candidate for ground based, airborne and spaceborne heterodyne instruments at THz frequencies. HEB receivers are planned for use on the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) and the ESA Far Infrared and Submillimeter Space Telescope (FIRST). The prospects of a submicron-size YBa2Cu3O7-(delta ) (YBCO) HEB are discussed. The expected LO power of 1 - 10 (mu) W and SSB noise temperature of approximately equals 2000 K may make this mixer attractive for various remote sensing applications.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIENov 13, 19981 citation

Nonlinear THz mixing in YBa 2 Cu 3 O 7 thin film hot electron bolometers

Mark Lee, Chao Te Li, Bascom S. Deaver +3 more

Small volume high-Tc super-conducting YBa2Cu3O7 (YBCO) thin films are used as low power, very wide bandwidth mixers in the frequency range of 75 GHz to 2.5 THz. The YBCO films are patterned into lattice-cooled hot-electron bolometers (HEB) coupled to an integrated Au thin-film antenna and transmission line. Near 77 K, these mixers have responsivity as high as 780 V/W using only 8 nW of local oscillator (LO) power at 585 GHz. The responsivity can be shown to be truly bolometric. Direct heterodyne and homodyne down-conversion mixing using local-oscillator frequencies of 75 GHz and 585 GHz show overall conversion gains of -35 dB, which includes a -18 dB coupling loss, using only approximately 1 (mu) W of LO power. The gain bandwidth shows a simple Lorentzian roll-off with -3 dB point of 5 to 8 GHz. The large gain bandwidth and small power requirements make these high-Tc superconducting mixers an attractive alternative to existing Schottky diode and conventional superconducting receiver technologies.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEDec 22, 19981 citation

Development of terahertz superconducting hot-electron bolometer mixers

Andrew G. Semenov, Heiko Richter, H.-W. Hübers +3 more

We present recent results of the development of phonon cooled hot-electron bolometric (HEB) mixers for airborne and balloon borne terahertz heterodyne receivers. Three iomportant issues have been addresses: the quality of NbN films the HEB mixers were made from, the spectral properties of the HEB mixers and the local oscillator power required for optical operation. Studies with an atomic force microscope indicate, that the performance of the HEB mixer might have been effected by the microstructure of the NbN film. Antenna gain and noise temperature were investigated at terahertz frequencies for a HEB embedded in either log-spiral or twin-slot feed antenna. Comparison suggests that at frequencies above 3 THz the spiral feed provides better overall performance. At 1.6 THz, a power of 2.5 µW was required from the local oscillator for optimal operation of the HEB mixer.

Jan 1, 20040 citations