On the quantum-limit of the noise temperature in balanced correlation receivers

2020 ◽  
Author(s):  
Ernest A. Michael ◽  
Massinissa Hadjara ◽  
Felipe E. Besser ◽  
Miguel I. Pina ◽  
Daniella Pollarolo ◽  
...  
Keyword(s):  
Noise Temperature ◽  
Quantum Limit

scholarly journals Series-connected array of superconductor–insulator–superconductor junctions in the 100 GHz-band heterodyne mixer for FOREST on the Nobeyama 45 m telescope

2018 ◽  
Vol 71 (Supplement_1) ◽  
Author(s):  
Taku Nakajima ◽  
Hirofumi Inoue ◽  
Yumi Fujii ◽  
Chieko Miyazawa ◽  
Hiroyuki Iwashita ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Quartz Substrate ◽  
Impedance Matching ◽  
Characteristic Impedance ◽  
Noise Temperature ◽  
Coupling Efficiency ◽  
Wide Frequency Range ◽  
Quantum Limit ◽  
Receiver Noise ◽  
Sis Junction

Abstract We have designed and experimentally evaluated a series-connected array of superconductor–insulator–superconductor (SIS) junctions in the 100 GHz-band mixer for the multi-beam receiver FOREST on the Nobeyama 45 m millimeter-wave telescope. The construction of the junction chip comprised a waveguide probe antenna, impedance-matching circuit, SIS array junction, and choke filter, which were made from a superconducting niobium planar circuit on a quartz substrate. The multi-stage impedance-matching circuit between the feed point and the SIS junction was designed as a capacitively loaded transmission line, and it comprised two sections with high (∼90 Ω) and low (∼10 Ω) characteristic impedance transmission lines. The structure of this tuning line was simple and easy to fabricate, and the feed impedance matched with the SIS junction in a wide frequency range. The signal coupling efficiency was more than 92% and the expected receiver noise temperature was approximately twice the quantum limit for 75–125 GHz based on quantum theory. The array junction devices with three to six connected junctions were fabricated and we measured their performance in terms of the receiver noise temperature and gain compression in the laboratory. We successfully developed an array junction device with a receiver noise temperature of ∼15–30 K and confirmed that the improvement in the saturation power corresponded to the number of junctions. The newly developed array junction mixer was installed in the FOREST receiver and it successfully detected the 12CO(J = 1–0) molecular line toward IRC +10216 with the Nobeyama 45 m telescope.

Nanostructured Ultrathin NbN Film as a Terahertz Hot-Electron Bolometer Mixer

2006 ◽  
Vol 935 ◽  
Author(s):  
Grigory Gol'tsman ◽  
Sergey Maslennikov ◽  
Matvey Finkel ◽  
Sergey Antipov ◽  
Natalia Kaurova ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Noise Temperature ◽  
Quantum Limit ◽  
Superconducting Film ◽  
Hot Electron ◽  
Signal Loss ◽  
X Ray Diffraction ◽  
Spiral Antenna ◽  
Gain Bandwidth ◽  
X Ray

ABSTRACTPlanar spiral antenna coupled and directly lens coupled NbN HEB mixer structures are studied. An additional MgO buffer layer between the superconducting film and Si substrate is introduced. The buffer layer enables us to increase the gain bandwidth of a HEB mixer due to better acoustic transparency. The gain bandwidth is widened as NbN film thickness decreases and amounts to 5.2 GHz. The noise temperature of antenna coupled mixer is 1300 and 3100 K at 2.5 and 3.8 THz respectively. The structure and composition of NbN films is investigated by X-ray diffraction spectroscopy methods. Noise performance degradation at LO frequencies more than 3 THz is due to the use of a planar antenna and signal loss in contacts between the antenna and the sensitive NbN bridge. The mixer is reconfigured for operation at higher frequencies in a manner that receiver's noise temperature is only 2300 K (3 times of quantum limit) at LO frequency of 30 THz.

scholarly journals Particle simulation of plasmons

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3303-3313 ◽  
Author(s):  
Wen Jun Ding ◽  
Jeremy Zhen Jie Lim ◽  
Hue Thi Bich Do ◽  
Xiao Xiong ◽  
Zackaria Mahfoud ◽  
...  
Keyword(s):  
Simulation Method ◽  
Electron Excitation ◽  
Particle Simulation ◽  
Quantum Limit ◽  
Free Electrons ◽  
Theoretical Approaches ◽  
Electromagnetic Responses ◽  
Electric And Magnetic Fields ◽  
Particle Simulations ◽  
Collective Oscillations

AbstractParticle simulation has been widely used in studying plasmas. The technique follows the motion of a large assembly of charged particles in their self-consistent electric and magnetic fields. Plasmons, collective oscillations of the free electrons in conducting media such as metals, are connected to plasmas by very similar physics, in particular, the notion of collective charge oscillations. In many cases of interest, plasmons are theoretically characterized by solving the classical Maxwell’s equations, where the electromagnetic responses can be described by bulk permittivity. That approach pays more attention to fields rather than motion of electrons. In this work, however, we apply the particle simulation method to model the kinetics of plasmons, by updating both particle position and momentum (Newton–Lorentz equation) and electromagnetic fields (Ampere and Faraday laws) that are connected by current. Particle simulation of plasmons can offer insights and information that supplement those gained by traditional experimental and theoretical approaches. Specifically, we present two case studies to show its capabilities of modeling single-electron excitation of plasmons, tracing instantaneous movements of electrons to elucidate the physical dynamics of plasmons, and revealing electron spill-out effects of ultrasmall nanoparticles approaching the quantum limit. These preliminary demonstrations open the door to realistic particle simulations of plasmons.

Knight shift in the extreme quantum limit in InSb

1972 ◽  
Vol 11 (8) ◽  
pp. 1077-1080 ◽  
Author(s):  
A. Willig ◽  
B. Sapoval
Keyword(s):  
Knight Shift ◽  
Quantum Limit

Noise temperature distribution of superconducting hot electron bolometer mixers

2020 ◽  
Vol 29 (5) ◽  
pp. 058505
Author(s):  
Kang-Min Zhou ◽  
Wei Miao ◽  
Yue Geng ◽  
Yan Delorme ◽  
Wen Zhang ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Noise Temperature ◽  
Hot Electron ◽  
Hot Electron Bolometer

scholarly journals A New 21-cm Line Survey of the LMC

1984 ◽  
Vol 108 ◽  
pp. 395-396
Author(s):  
K. Rohlfs ◽  
J. Kreitschmann ◽  
J. V. Feitzinger
Keyword(s):  
Noise Temperature ◽  
Beam Width ◽  
Main Beam ◽  
Corrugated Waveguide ◽  
Line Survey ◽  
Single Polarization ◽  
Switching Mode ◽  
Half Power ◽  
Channel Separation ◽  
Made In

The measurements were made in Feb. 1982 with the Parkes 64 m telescope using a corrugated waveguide horn with total half-power beam width of 15′, the first sidelobes being 19 dB down, resulting in an aperture efficiency ηA=0.53±0.007, a main beam efficiency of ηmb=0.80±0.005 and a ratio of source flux to antenna temperature of Γ=0.62±0.1 K/Jy (Murray, priv. comm.). A cooled two channel FET frontend used in the frequency switching mode with Δν = 2 MHz resulted in a system noise temperature at zenith of Tsyst = 40 K for one channel and Tsyst = 50 K for the other. Each frontend channel received a single polarization mode, and this radiation was then further analysed in a 2 × 512 channel autocorrelation spectrometer set at a channel separation of 3.906 KHz corresponding to a velocity resolution of V = 0.824 km s−1. Hanning smoothed this resulted in a σT = 0.05 K for the average of both polarization.

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