fluctuations in the electron system of a superconductor exposed to a photon flux - mylar film roll
In a conductor paired with electrons, the density of unpaired electrons should be zero when approaching zero temperature.
Therefore, based on the commitment of the highest sensitivity to the broken radiation detector, we demonstrated using an aluminum superconductive microwave oscillator.
Here, we show that the resonant cavity can also study the electronic system of the magnet-
Break the photon, microwave photon and temperature change.
Large range of radiation power (at 1. 54u2009THz)
It can be selected by carefully filtering the radiation from the black body source.
We have identified two systems.
At high radiation power, fluctuations in the electronic system caused by the random arrival rate of photons are solved, thus directly measuring the optical efficiency (48±8%)
Unprecedented detector sensitivity is shown.
At low radiation power, fluctuations are mainly controlled by excess quasi-particles, which are measured by their composite lifetime.
A layer of aluminum with a thickness of 100 kbps nm is deposited on the sapphire substrate as a ground plane of the microwave cavity.
The microwave cavity is a co-plane waveguide cavity, with a center band width of 3 μm and a slit width of 1. 5u2009μm.
The center band of the resonant cavity consists of the second layer of 50 nm thick Al.
The critical temperature of the 50 nm layer was measured as = 1.
24 k, the energy gap delta = 1. 76=188u2009μeV.
The resistivity from the normal state ,(=2.
2 μ Omega cm and 0 in the central belt.
28 μ Ω cm of the ground plane)
1 depth of radiant skin.
The 54Hz is 60 kHz nm in the central area and 21Hz nm in the ground plane. The X-
For layers that are thinner than the depth of the skin, the slot antenna is invalid, so the thickness of the ground plane layer is 100 nm.
The resistance of the midline microwave square is 0.
46 Omega and Omega 0 of the ground plane. 13u2009Ω.
Considering this effect, coupled with the participation ratio of the center line and the ground plane, we estimate that 90% of the radiation is absorbed by the center line.
The distribution of current along the length of the resonant cavity peaks at the antenna and follows sin ()
Zero at the beginning.
Therefore, the response rate follows sin ().
Since the diffusion length within a typical quasi-particle composite lifetime of 2 Kbps ms exceeds half of the length of the resonant cavity, the quasi-particles produced by optics can be moved to non-
Therefore, in order to calculate the number of quasi-particles in the sensitive volume, we take half of the volume of the center strip, = 0. 6 × 10 μm.
The signal from the microwave generator is first attenuated, sent through the sample and amplified with HEMT amp and room temperature amplifier at 4 k.
The output is mixed with the original signal using an IQ mixer whose output can be sampled at a maximum frequency of 2 mhz.
The fluctuation spectrum of the resonance amplitude is measured by recording the resonance amplitude as a time function and calculating the power spectral density.
As described in ref, peaks in time-domain streams that occur due to high energy effects are filtered out before the spectrum is calculated.
We use the amplitude direction, because the fluctuations in the phase direction are mainly caused by the two-level system noise in the medium around the resonant cavity (and ).
The light source used in the experiment is a black body made of a copper cone with a diameter of 40mm, coated with carbon-loaded epoxy (
EPOTEK 920 1 pound A part, carbon black with A weight of 3% and EPOTEK 3% 1 pound B part with A weight of 920)
Covered with 1mm SiC particles.
In this experiment, the temperature of the black body changes from 3-25 u2009 K.
There are three metal
Grid filter stack (
QMC instruments Cardiff)
The properties are given in.
As a function of the optical frequency, the measurement transmission of the entire filter stack ,()
, Also displayed in.
Since there is no aperture limit between the black body and the detector, the optical throughput is assumed to be (/)
At the speed of light.
The total radiation power before reaching the detector lens can now be calculated by the numerical integral Planck law and the filter properties measured at each black body temperature.
A polarized radiation power is given here.
Optical window around 1.
As shown, the black body temperature range of 54 hz and 3-25 hz k provides a large tuning range in terms of radiation power.
With this device, we can verify that the radiation power drops to 0.
1 The quasi-particle composite time measured by fW ().
With the decrease of microwave power, the increase of optical response and composite time, there is no sign of saturation, which indicates that the optical system performs well at lower radiation power.
The excess quasi-particles in the current device limit us to verify this.
Right in front of the detector, after the last optical filter, we place a polarizer to select the polarization of the antenna design.
The bias mirror consists of a copper mesh on the top of 1. 5-
Thick Mylar film.
The line width of the grid is 10 μm, and the line spacing is 20 μm.
Responsiveness/is obtained from a linear fit with the response measured as a function.
In places of interest, the temperature of the black body is swept slowly.
Each measurement point is integrated at 500 ms.
At very low radiation power (