Related papers: Low Noise Microwaves for Testing Fundamental Physi…
Feedback-based control of nano- and micromechanical resonators can enable the study of macroscopic quantum phenomena and also sensitive force measurements. Here, we demonstrate the feedback cooling of a low-loss and high-stress macroscopic…
Environmental noise coupling to mechanical experiments often introduces low-frequency fluctuations to the resonators, adding noise to measurements and reducing signal to noise. To counter these fluctuations, we demonstrate a dynamic…
Slow noise processes, with characteristic timescales ~1s, have been studied in planar superconducting resonators. A frequency locked loop is employed to track deviations of the resonator centre frequency with high precision and bandwidth.…
In modern high precision optical instruments, such as in gravitational wave detectors or frequency references, thermally induced fluctuations in the reflective coatings can be a limiting noise source. This noise, known as coating thermal…
Properties of calcium fluoride (CaF2) have been well researched at UV, visible and IR range of frequencies, but not at ultra high frequencies. In this work we report the loss tangent and the real part of relative permittivity of CaF2,…
We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milliKelvin temperatures. The setup relies on the combination of an interferometric ampli- fication…
We demonstrate a cryo-compatible, fully fiber-integrated, alignment-free optical microresonator. The compatibility with low temperatures expands its possible applications to the wide field of solid-state quantum optics, where a cryogenic…
We present a realisation of high bandwidth instrumentation at cryogenic temperatures and for dilution refrigerator operation that possesses advantages over methods using radio-frequency single electron transistor or transimpedance…
This paper presents an ultra-low noise L-band radio astronomical cryogenic receiver for FAST telescope. The development of key low noise microwave parts of Coupling-LNA and conical quad-ridge OMT and reasonable system integration achieve…
We report observations of the Schawlow-Townes noise limit in a cryogenic sapphire secondary frequency standard. The effect causes a fundamental limit to the frequency stability, and was measured through the novel excitation of a bimodal…
The quest to enhance the sensitivity of electron spin resonance (ESR) is an ongoing challenge. One potential strategy involves increasing the frequency, for instance, moving from Q-band (approximately 35 GHz) to W-band (approximately 94…
Signal to noise ratios (SNR) in magnetic resonance microscopy images are limited by acquisition times and the decreasing number of spins in smaller voxels. Significant SNR gains from cooling of the RF receiver are only realized when the…
We describe an experiment in which we have used a cold damping feedback mechanism to reduce the thermal noise of a mirror around its mechanical resonance frequency. The monitoring of the brownian motion of the mirror allows to apply an…
We describe the design and performance of a series of fast, precise current sensing noise thermometers. The thermometers have been fabricated with a range of resistances from 1.290 $\Omega$ down to 0.2 m$\mathrm{\Omega}$. This results in…
We present a cryogenic microwave noise source with a characteristic impedance of 50 $\Omega$, which can be installed in a coaxial line of a cryostat. The bath temperature of the noise source is continuously variable between 0.1 K and 5 K…
In low temperature transport measurements, there is frequently a need to protect a device at cryogenic temperatures from thermal noise originating in warmer parts of the experiment. There are also a wide range of experiments, such as high…
We present a compact current sensor based on a superconducting microwave lumped-element resonator with a nanowire kinetic inductor, operating at 4.2 K. The sensor is suitable for multiplexed readout in GHz range of large-format arrays of…
This paper presents the characterization of microwave passive components, including metal-oxide-metal (MoM) capacitors, transformers, and resonators, at deep cryogenic temperature (4.2 K). The variations in capacitance, inductance and…
We have designed and characterized a cryogenic amplifier for use in $^3$He NMR spectrometry. The amplifier, with a power consumption of $\sim 2.5$ mW, works at temperatures down to 4~K. It has a hi-impedance input for measuring a signal…
Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered…