|
|
Maslennikov, S., Vachtomin, Y., Antipov, S., Smirnov, K., Kaurova, N., Grishina, E., et al. (2004). NbN HEB mixers for frequencies of 2.5 and 3.8 THz. In Proc. Tenth All-Russian sceintific conference of student-physicists and young sceintists (VNKSF-10). Moscow.
|
|
|
|
Antipov, S. V., Vachtomin, Y. B., Maslennikov, S. N., Smirnov, K. V., Kaurova, N. S., Grishina, E. V., et al. (2004). Noise performance of quasioptical ultrathin NbN hot electron bolometer mixer at 2.5 and 3.8 THz. In Proc. 5-th MSMW (Vol. 2, pp. 592–594). Kharkov, Ukraine.
Abstract: To put space-based and airborne heterodyne instruments into operation at frequencies above 1 THz the superconducting NbN hot-electron bolometer (HEB) will be incorporated into heterodyne receiver as a mixer. At frequencies above 1.3 THz the sensitivity of the NbN HEB mixers outperform the one of the Schottky diodes and SIS-mixers, and the receiver noise temperature of the NbN HEB mixers increase with frequency. In this paper we present the results of the noise temperature measurements within one batch of NbN HEB mixers based on 3.5 mn thick superconducting NbN film grown on Si substrate with MgO buffer layer at the LO frequencies 2.5 THz and 3.8 THz.
|
|
|
|
Vachtomin, Y. B., Antipov, S. V., Kaurova, N. S., Maslennikov, S. N., Smirnov, K. V., Polyakov, S. L., et al. (2004). Noise temperature, gain bandwidth and local oscillator power of NbN phonon-cooled HEB mixer at terahertz frequenciess. In Proc. 29th IRMMW / 12th THz (pp. 329–330). Karlsruhe, Germany.
Abstract: We present the performances of HEB mixers based on 3.5 nm thick NbN film integrated with log-periodic spiral antenna. The double side-band receiver noise temperature values are 1300 K and 3100 K at 2.5 THz and at 3.8 THz, respectively. The gain bandwidth of the mixer is 4.2 GHz and the noise bandwidth is 5 GHz. The local oscillator power is 1-3 /spl mu/W for mixers with different active area.
|
|
|
|
Kaurova, N. S., Finkel, M. I., Maslennikov, S. N., Vahtomin, Y. B., Antipov, S. V., Smirnov, K. V., et al. (2004). Submillimeter mixer based on YBa2Cu3O7-x thin film. In Proc. 1-st conf. Fundamental problems of high temperature superconductivity (291). Moscow-Zvenigorod.
|
|
|
|
Ryabchun, S., Korneev, A., Matvienko, V., Smirnov, K., Kouminov, P., Seleznev, V., et al. (2004). Superconducting single photon detectors array based on hot electron phenomena. In Proc. 15th Int. Symp. Space Terahertz Technol. (pp. 242–247).
Abstract: In this paper we propose to use time domain multiplexing for large format arrays of superconducting single photon detectors (SSPDs) of the terahertz, visible and infrared frequency ranges based on ultrathin superconducting NbN films. Effective realization of time domain multiplexing for SSPD arrays is possible due to a short electric pulse of the SSPD as response to radiation quantum absorption, picosecond jitter and extremely low noise equivalent power (NEP). We present experimental results of testing 2×2 arrays in the infrared waveband. The measured noise equivalent power in the infrared and expected for the terahertz waveband is 10 – 21 WHz -1/2 . The best quantum efficiency (QE) of SSPD is 50% at 1.3 µm wavelength.
|
|
|
|
Goltsman, G., Korneev, A., Izbenko, V., Smirnov, K., Kouminov, P., Voronov, B., et al. (2004). Nano-structured superconducting single-photon detectors. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 520(1-3), 527–529.
Abstract: NbN detectors, formed into meander-type, 10×10-μm2 area structures, based on ultrathin (down to 3.5-nm thickness) and nanometer-width (down to below 100 nm) NbN films are capable of efficiently detecting and counting single photons from the ultraviolet to near-infrared optical wavelength range. Our best devices exhibit QE >15% in the visible range and ∼10% in the 1.3–1.5-μm infrared telecommunication window. The noise equivalent power (NEP) ranges from ∼10−17 W/Hz1/2 at 1.5 μm radiation to ∼10−19 W/Hz1/2 at 0.56 μm, and the dark counts are over two orders of magnitude lower than in any semiconducting competitors. The intrinsic response time is estimated to be <30 ps. Such ultrafast detector response enables a very high, GHz-rate real-time counting of single photons. Already established applications of NbN photon counters are non-invasive testing and debugging of VLSI Si CMOS circuits and quantum communications.
|
|
|
|
Finkel, M. I., Maslennikov, S. N., Vachtomin, Y. B., Svechnikov, S. I., Smirnov, K. V., Seleznev, V. A., et al. (2005). Hot electron bolometer mixer for 20 – 40 THz frequency range. In Proc. 16th Int. Symp. Space Terahertz Technol. (pp. 393–397). Göteborg, Sweden.
Abstract: The developed HEB mixer was based on a 5 nm thick NbN film deposited on a GaAs substrate. The active area of the film was patterned as a 30×20 μm 2 strip and coupled with a 50 Ohm coplanar line deposited in situ. An extended hemispherical germanium lens was used to focus the LO radiation on the mixer. The responsivity of the mixer was measured in a direct detection mode in the 25÷64 THz frequency range. The noise performance of the mixer and the directivity of the receiver were investigated in a heterodyne mode. A 10.6 μm wavelength CW CO 2 laser was utilized as a local oscillator.
|
|
|
|
Loudkov, D., Tong, C. Y. E., Blundell, R., Kaurova, N., Grishina, E., Voronov, B., et al. (2005). An investigation of the performance of the superconducting HEB슠mixer as a function of its RF슠embedding impedance. IEEE Trans. Appl. Supercond., 15(2), 472–475.
|
|
|
|
Loudkov, D., Tong, C. - Y. E., Blundell, R., Kaurova, N., Grishina, E., Voronov, B., et al. (2005). An investigation of the performance of the superconducting HEB mixer as a function of its RF embedding impedance. IEEE Trans. Appl. Supercond., 15(2), 472–475.
Abstract: We have conducted an investigation of the optimal embedding impedance for a waveguide superconducting hot-electron bolometric (HEB) mixer. Three mixer chip designs for 800 GHz, offering nominal embedding resistances of 70 /spl Omega/, 35 /spl Omega/, and 15 /spl Omega/, have been developed. We used both High Frequency Structure Simulator (HFSS) software and scale model impedance measurements in the design process. We subsequently fabricated HEB mixers to these designs using 3-4 nm thick NbN thin film. Receiver noise temperature measurements and Fourier Transform Spectrometer (FTS) scans were performed to determine the optimal combination of embedding impedance and normal-state resistance for a 50 Ohm IF load impedance. A receiver noise temperature of 440 K was measured at a local oscillator frequency 850 GHz for a mixer with normal state resistance of 62 /spl Omega/ incorporated into a circuit offering a nominal embedding impedance of 70 /spl Omega/. We conclude from our data that, for low noise operation, the normal state resistance of the HEB mixer element should be close to the embedding impedance of the mixer mount.
|
|
|
|
Zhang, W., Jiang, L., Lin, Z. H., Yao, Q. J., Li, J., Shi, S. C., et al. (2005). Development of a quasi-optical NbN superconducting HEB mixer. In Proc. 16th Int. Symp. Space Terahertz Technol. (pp. 209–213).
Abstract: In this paper, we report the performance of a quasi-optical NbN superconducting HEB (hot electron bolometer) mixer measured at 500 and 850GHz. The quasi-optical NbN superconducting HEB mixer is cryogenically cooled by a 4-K close-cycled refrigerator. Measured receiver noise temperature at 850 and 500GHz are 3000K and 2500K respectively with wire grid as beamsplitter, while the lowest receiver noise temperature is found to be approximately 1200K with Mylar film. The theoretical receiver noise temperature (taking into account the elliptical polarization of log-spiral antenna) is consistent with measured one. The receiver noise temperature and conversion gain with 15-μm Mylar film as the beamsplitter at 500GHz are thoroughly investigated for different LO pumping levels and dc biases. The stability of the mixer’s IF output power is also demonstrated.
|
|
