Mechanical and dimensional measurements

The latest publications in this offer are:

• September 10, 2025

  R6743

  Reference materials for nanometrology

  The continued development of nanotechnologies and nanomaterials requires reliable and comparable measurement results, so that robust quality control can be put in place to improve industrial production processes, meet regulatory requirements and ensure the safety of nanoproducts on the market.Nanometrology, the science of measurement on the nanoscale, therefore has a central role to play. Progress in this field will only be possible when the supply of reference nanomaterials and nanostructures is expanded.This article reviews the reference materials available on the nanometric scale, and also describes the needs in two priority fields: the nano-object industry (e.g. nanoparticles) and nano-electronics.

• September 10, 2025

  R6747

  Combined reference-free XRR-GIXRF analysis for thin films

  The property of elements to emit characteristic radiations following an excitation by X-rays called X-ray fluorescence is exploited for quantification. The equations describing this light-matter interaction are recalled as well as the experimental conditions necessary to overcome the reference standard needs.X-ray fluorescence can also be exploited by combining it with X-ray reflectivity for the study of thin layers of nanometric thickness. The approach presented here exploits fundamental parameters whose issues of accuracy and associated uncertainties are addressed from a metrological perspective.

• June 10, 2025

  R6180

  Experimental modal analysis

  Experimental modal analysis aims to identify the natural frequencies, damping ratios and mode shapes of a structure under given boundary conditions. Developed in the 1960s-1990s, experimental techniques and identification methods are now mature and available from industrial suppliers.Structural dynamics is nevertheless a complex discipline.This article aims to cover all the important knowledge to acquire a good mastery of experimental modal analysis.

• December 10, 2024

  R6738

  Laser damage to optical components

  The performance or lifespan of laser systems is often limited by the issue of laser-induced damage to optical components: under high laser flux, irreversible changes may occur, leading to a loss of optical performance or even destruction of the component. This issue has been studied since the invention of the laser and closely follows technological advancements in the field.This article aims, firstly, to present the main physical mechanisms that can lead to the degradation of an optic subjected to laser flux, focusing on the influence of laser parameters and the design and manufacturing of components on damage, and secondly, to present the measurement methods of laser flux resistance to evaluate operational limits for a given application

• December 10, 2024

  R6723

  Optical coherence tomography

  Optical coherence tomography (OCT) imaging is a label-free optical microscopy technique that allows the reconstruction of the 3D architecture of a sample using the properties of light interferences. OCT is used as a reference diagnostic tool in ophthalmology, especially because it allows imaging of the retina over large fields of view while maintaining high axial resolution.The use of OCT is progressively extending in many fields, such as biophotonics or metrology. This article first presents the principle of OCT and compares its different configurations. The article then focuses on a particular configuration, the full field OCT, offering a higher spatial resolution.

• October 10, 2024

  R6803

  Scanning magnetometry of nitrogen-lacune defects and its applications in nanomagnetism

  This article presents scanning nitrogen vacancy center magnetometry, an experimental technique allowing quantitative and non-perturbative imaging of complex nanoscale magnetic configurations, and used for example to study materials which are relevant for spintronics applications. This technique relies on a quantum sensor, the nitrogen vacancy center in diamond, which is integrated at the apex of the tip of an atomic force microscope.After a detailed experimental description of the magnetometer, the different measurement modes will be in- troduced, together with their applications and limitations. The analysis of the obtained maps is also discussed, in order to give a complete overview of the possiblities offered by this imaging technique

• October 10, 2024

  R6333

  Optical surface metrology by the CNRS Optics and Photonics Network

  Phase Shifting interferometry is the most widely method used for characterizations of optical surfaces, such as mirrors used in laser installations, beamlines in synchrotrons, and applications in astrophysics.The Réseau Optique et Photonique (ROP) of the Mission for Transverse and Interdisciplinary Initiatives (MITI) at CNRS has established a working group on comparative metrology, particularly in phase scanning interferometry. Five laboratories from academic institutions (CNRS, CEA, and universities) have joined to assess their capabilities in interferometric metrology

• July 10, 2024

  R1320

  Dimensional measurements using laser interferometry

  Laser interferometry is a technique allowing for contactless dimensional measurements of high precision with a dynamic range of several meters in air and nanometric resolution. It is used for calibrating translational displacements on machine tools or for characterizing motorized or piezoelectric micrometric mechanical actuators.The principles of homodyne, heterodyne, or frequency-scanning interferometry as well as various laser sources used for dimensional metrology are presented. The performances of different types of commercially available devices are detailed. The main industrial applications of laser interferometry used for dimensional measurement are also discussed.

• January 10, 2024

  R6724

  Acousto-optical imaging techniques in scattering media

  Optical imaging of scattering media is rapidly limited due to multiple-scattering process. This is the case for e.g. biological tissues for depth larger than the millimeter scale.Acousto-optic imaging is based on the coupling between light and ultrasound. As the latter are ballistic and merely attenuated in these media (ultrasound frequency < 20MHz), it is possible to obtain a local information, guided by the ultrasound. This bimodal technique provides two complementary information, i.e. an ultrasound and an optical image of the medium.This article introduces the principle of acousto-optic imaging and exhibits the different experimental configurations to perform this type of imaging.

• January 10, 2024

  R1307

  NMR scattering coefficients to describe complex materials

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