arXiv subjects

Claudio Dal Savio

Publications and source records attributed to Claudio Dal Savio.

3 recordsLinked to original sources

arXiv2023

Cooling power analysis of a small scale 4 K pulse tube cryocooler driven by an oil-free low input power Helium compressor

Here we report the performance of a small scale 4 K pulse tube cryocooler operating with a low input power reaching a minimum temperature of 2.2 K, as well as a cooling capacity of over 240 mW at 4.2 K. The compressor is air cooled and can be supplied by single phase power sockets. With an input power of about 1.3 kW the coefficient of performance reaches values of up to 185 mW/kW, which is among the highest currently reported values for small to medium power pulse tubes. The combination of an oil-free Helium compressor and low maintenance pulse tube cryocooler provides a unique miniaturized, energy efficient and mobile cooling tool for applications at 4 K and below.

cond-mat.mtrl-sci↗

arXiv2021

Open-cavity in closed-cycle cryostat as a quantum optics platform

The introduction of an optical resonator can enable efficient and precise interaction between a photon and a solid-state emitter. It facilitates the study of strong light-matter interaction, polaritonic physics and presents a powerful interface for quantum communication and computing. A pivotal aspect in the progress of light-matter interaction with solid-state systems is the challenge of combining the requirements of cryogenic temperature and high mechanical stability against vibrations while maintaining sufficient degrees of freedom for in-situ tunability. Here, we present a fiber-based open Fabry-Pérot cavity in a closed-cycle cryostat exhibiting ultra-high mechanical stability while providing wide-range tunability in all three spatial directions. We characterize the setup and demonstrate the operation with the root-mean-square cavity length fluctuation of less than $90$ pm at temperature of $6.5$ K and integration bandwidth of $100$ kHz. Finally, we benchmark the cavity performance by demonstrating the strong-coupling formation of exciton-polaritons in monolayer WSe$_2$ with a cooperativity of $1.6$. This set of results manifests the open-cavity in a closed-cycle cryostat as a versatile and powerful platform for low-temperature cavity QED experiments.

quant-ph↗

arXiv2014

Scanning probe microscopy in an ultra-low vibration closed-cycle cryostat

We report on state-of-the-art scanning probe microscopy measurements performed in a pulse tube based top-loading closed-cycle cryostat with a base temperature of 4 K and a 9 T magnet. We decoupled the sample space from the mechanical and acoustic noise from the cryocooling system to enable scanning probe experiments. The extremely low vibration amplitudes in our system enabled successful imaging of 0.39 nm lattice steps on single crystalline SrTiO$_{3}$ as well as magnetic vortices in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ superconductor. Fine control over sample temperature and applied magnetic field further enabled us to probe the helimagnetic and the skyrmion-lattice phases in Fe$_{0.5}$Co$_{0.5}$Si with unprecedented signal-to-noise ratio of 20:1. Finally, we demonstrate for the first time quartz-crystal tuning fork shear-force microscopy in a closed-cycle cryostat.

cond-mat.mtrl-sci↗