Temperature dependence of photoluminescence intensity and spin contrast in nitrogen-vacancy centers

We report on measurements of the photoluminescence (PL) properties of single nitrogen-vacancy (NV) centers in diamond at temperatures between 4-300 K. We observe a strong reduction of the PL intensity and spin contrast between ca. 10-100 K that recovers to high levels below and above. Further, we find a rich dependence on magnetic bias field and crystal strain. We develop a comprehensive model based on spin mixing and orbital hopping in the electronic excited state that quantitatively explains the observations. Beyond a more complete understanding of the excited-state dynamics, our work provides a novel approach for probing electron-phonon interactions and a predictive tool for optimizing experimental conditions for quantum applications.Comment: Companion paper: arXiv:2304.02521 | Model: https://github.com/sernstETH/nvratemode

Stable laser and upgraded vacuum setup for an experiment with ultracold atoms

In questo lavoro ci si propone di descrivere la realizzazione di un sistema laser con cavit´a esterna e di un apparato da ultra-alto-vuoto, che verranno impiegati in un esperimento di miscele di atomi ultrafreddi che utilizza due specie atomiche di bosoni: 87Rb e 41K. Speciale attenzione viene rivolta verso le caratteristiche dello schema utilizzato e sul sistema di controllo in temperatura, che rendono questo sistema laser particolarmente stabile in frequenza e insensibile alle vibrazioni e variazioni di temperatura. Si sono poi analizzate le propriet´a dei materiali impiegati e delle procedure sperimentali adottate per la realizzazione del nuovo apparato da vuoto, al fine di garantire migliori prestazioni rispetto al sistema attualmente in uso

Nanoscale Imaging of Current Density with a Single-Spin Magnetometer

ISSN:1530-6984ISSN:1530-699

Nanoscale magnetic field imaging for 2D materials

Nanoscale magnetic imaging can provide microscopic information about length scales, inhomogeneity and interactions of materials systems. As such, it is a powerful tool to probe phenomena such as superconductivity, Mott insulating states and magnetically ordered states in 2D materials, which are sensitive to the local environment. This Technical Review provides an analysis of weak magnetic field imaging techniques that are most promising for the study of 2D materials: magnetic force microscopy, scanning superconducting quantum interference device microscopy and scanning nitrogen-vacancy centre microscopy. The ability to image nanometre-scale magnetization and current density is key to deciphering the physics of correlated states hosted in 2D layered materials. This Technical Review analyses the magnetic imaging techniques most amenable to these systems, compares their capabilities and limitations, and discusses their potential impact

Liquid chromatography miniaturised system for agrofood applications

A liquid chromatography Si-based miniaturised system for agrofood applications, in particular for wine quality assessment, has been realized. The system is mainly based on two modules: i.) a Si-based open tubular separation column with inlet/outlet for fluidic connections and ii.) a Pt three-electrode voltammetric sensor. An ASIC integrated read-out electronics has been developed. A modular package of the two modules has been properly realized. Laboratory tests have been carried out

Linear temperature microhotplate gas sensor array for automotive cabin air quality monitoring

The present work describes the experimental evaluation of an innovative gas sensor array for automotive cabin air quality applications. This integrated array presents as a main innovation aspect the simultaneous outputs, from a single chip packaged onto TO-12 socket, of eight different signals coming from a WO3 thin film structure heated in a linear temperature gradient mode, allowing an overall evaluation of gas sensing properties of metal oxide materials in a 100 �C-wide window, typically from 300 to 400 �C. Experimental results will be explained by means of PCA (principal component analysis) compounds identification for three different target gases of CO, NO2 and SO2 at different concentrations

A CMOS ASIC for differential read-out of ISFET sensors

We report on a CMOS ASIC especially taylored for the differential read-out of ISFET sensors, to be used for remote monitoring of water pollution and for biomedical diagnostic and analysis. The circuit design is based on switched-capacitors technique, which allows a high resolution to be achieved. The first chip prototypes have been fabricated in 0.8 m, 5V CMOS technology, and are currently being tested. Preliminary results from the electrical characterisation of the chip are reported, which validate the design approac

Development of a new portable microsystem for wine quality analysis

A MEMS-based Chromium doped WO3 sensors arrays has been mounted in a dedicated chamber with reduced dead volumes (50μl,equivalent to 3% of the column volume), connected to the splitter output and properly heated. Signal read-out has been provided by a dedicated electronic board, allowing the sensor bias,the ASIC power supply and biasing, the microheater temperature control and data acquisition to a PC by a standard USB connection with a dedicated software. Testing of system performances has been performed by comparing results of SPME/GC/MS and SPME/GC/MOX analysis, simultaneously performed with a traditional chromatograph equipped forthis purpose with a purged splitter