Higher order coefficient measurements in nonlinear absorption process

Intensity-dependent two-photon absorption in chalcogenide glasses has been experimentally observed. Analytical solution of the basic differential equation giving the intensity at the output of the sample is difficult to obtain in this case. A quasi-analytical solution is provided. Second and third-order nonlinear coefficients are deduced from experimental data using Runge–Kutta numerical integration on data obtained via Z-scan technique. Results of the measured higher-order nonlinear coefficients are given. Comparison of these results with those obtained by various approximate analytical solutions of the differential equation is made.

Saturation of the Kerr effect in carbon disulfide

Accurate measurements of the nonlinear index in carbon disulfide shows an unusual saturation law of the Kerr effect which can be used to built a model of light propagation describing the filamentation in this liquid

Optimization and limits of optical nonlinear measurements using imaging technique

We report on analytical calculations for a 4f coherent imaging system in presence of a phase object at the entry of the set-up. We give the results of the optimized parameters to be used in this system so as to increase the sensitivity of the measurement of the nonlinear refraction coefficient. Analytical and previously reported simulated image profiles are compared here. Our study also gives the limits of the nonlinear imaging technique with a phase object for relatively high nonlinear phase shifts

Optical and structural properties of new chalcohalide glasses

New class of chalcohalide glasses has been prepared in the GeS2–In2S3–CsI system with regard to their potential non-linear properties. The study of glass-forming region was undertaken to select glassy compositions, which present high non-linear (NL) optical properties with a low two-photon absorption. Thermal analyses, structural examination by Raman spectroscopy, non-linear optical measurements were investigated as a function of CsI contents. Introduction of CsI has shifted the band-gap edge towards the blue region of the absorption optical spectrum and therefore has limited the two-photon absorption. Their NL refractive index n2 are 60 times higher than silica glasses without any NL absorption. Moreover, second harmonic signal was observed in thermally poled samples similar to silica glass. However, this second order non-linearity is not temporally stable

Surface-Enhanced Raman Spectroscopy for Biomedical Applications: A Review

Surface-enhanced Raman scattering has recently become a powerful vibrational spectroscopic tool for numerous applications in physical, chemical, biological as well as medical science. Apart from a chemical enhancement process, plasmonic fields sustained by metal nanoparticles play a vital role in the surface enhancement phenomena. Thus most SERS based applications also involve metal nanostructures as substrates apart from the analyte molecules. High sensitivity, molecular selectivity, portability and low cost are some of the advantages of SERS over conventional spectroscopic methods that has led to its popularity. In particular, biomedical applications involving detection and sensing of biomolecules are now moving towards utilizing this new tool. This review provides an introduction of SERS for biomedical applications. The theory of SERS will be explained in the first section. A brief review on popular SERS substrates will be given in the subsequent section. The review will focus on certain biomedical applications such as glucose sensors, cancer detection and protein sensing using SERS

Nonlinear optical measurements using a 4 f coherent imaging system with phase objects

International audienc

Applications de l'imagerie à la mesure des coefficients non linéaires des verres infrarouges

Nous présentons une technique simple basée sur un système 4f pour caractériser des non linéarités. Nous montrons qu'il est possible de caractériser les non linéarités en analysant le profil d'intensité de l'image après un filtrage non linéaire induit dans le matériau placé dans le plan Fourier du montage. Les acquisitions expérimentales sont ajustée à l'aide d'un modèle théorique utilisant l'optique de Fourier pour obtenir les coefficients non linéaires. Parmi les avantages de cette méthode on compte un montage optique simple et une bonne sensibilité comparable aux autres techniques. D'autre part, en ajoutant un objet phase a l'entrée du système 4f, il est possible d'extraire le signe de l'indice de réfraction non linéaire. Différentes compositions des verres en chalcogénures ont été étudiées et caractérisées pour leurs propriétés linéaires et non linéaires.We present a simple technique based on a 4f coherent optical imaging system to characterize nonlinearities. We show that it is possible to characterize the nonlinearities by analyzing the intensity profile of the image after nonlinear filtering through the material under study in the Fourier plane of the set up. The experimental acquisitions are fitted by a simple theoretical model based on Fourier optics to obtain the nonlinear coefficient. The advantages of this method include simple optical setup, few-laser shots inside the material and a sensitivity comparable to other techniques. Further, by adding a phase object at the entry of the 4f system, it is possible to extract the sign and magnitude of the nonlinear optical refractive index of the material with only one intense laser shot and the sensitivity of the measurement can be increased. Several different compositions of chalcogenide glasses were studied and characterized for their linear and nonlinear properties.ANGERS-BU Lettres et Sciences (490072106) / SudocSudocFranceF

20th International Symposium on Optomechatronic Technology

This book presents peer-reviewed articles from the 20th International Symposium on Optomechatronic Technologies (ISOT 2019), held in Goa, India. The symposium brought together students, researchers, professionals, and academicians in the field of optomechatronics and related areas on a common platform conducive to academic interaction with business professionals

4f coherent imager system and its application to nonlinear optical measurements

International audienc

Linear and nonlinear optical characterization of tellurium based chalcogenide glasses

International audienc