Z-scan characterization of the nonlinear refractive index of single crystal ZnSe in the 1.20-1.95 μm wavelength range

2005 ◽  
Author(s):  
Arkady Major ◽  
J. Stewart Aitchison ◽  
Peter W. E. Smith ◽  
Evgeni Sorokin ◽  
Irina T. Sorokina
Keyword(s):  
Refractive Index ◽  
Single Crystal ◽  
Wavelength Range ◽  
Nonlinear Refractive Index

Ellipsometric characterization of thin nanocomposite films with tunable refractive index for biochemical sensors

2011 ◽  
Vol 1352 ◽  
Author(s):  
P. Petrik ◽  
H. Egger ◽  
S. Eiden ◽  
E. Agocs ◽  
M. Fried ◽  
...  
Keyword(s):  
Refractive Index ◽  
Wavelength Range ◽  
Spectroscopic Ellipsometry ◽  
High Refractive Index ◽  
Optical Quality ◽  
Nanocomposite Films ◽  
Optical Parameters ◽  
Sensor Applications ◽  
Preparation Conditions

ABSTRACTCreating optical quality thin films with a high refractive index is increasingly important for waveguide sensor applications. In this study, we present optical models to measure the layer thickness, vertical and lateral homogeneity, the refractive index and the extinction coefficients of the polymer films with nanocrystal inclusions using spectroscopic ellipsometry. The optical properties can be determined in a broad wavelength range from 190 to 1700 nm. The sensitivity of spectroscopic ellipsometry allows a detailed characterization of the nanostructure of the layer, i.e. the surface roughness down to the nm scale, the interface properties, the optical density profile within the layer, and any other optical parameters that can be modeled in a proper and consistent way. In case of larger than about 50 nm particles even the particle size can be determined from the onset of depolarization due to light scattering. Besides the refractive index, the extinction coefficient, being a critical parameter for waveguiding layers, was also determined in a broad wavelength range. Using the above information from the ellipsometric models the preparation conditions can be identified. A range of samples were investigated including doctor bladed films using TiO2 nanoparticles.

scholarly journals Optical, microphysical and compositional properties of the Eyjafjallajökull volcanic ash

2014 ◽  
Vol 14 (19) ◽  
pp. 10649-10661 ◽  
Author(s):  
A. Rocha-Lima ◽  
J. V. Martins ◽  
L. A. Remer ◽  
N. A. Krotkov ◽  
M. H. Tabacniks ◽  
...  
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Refractive Index ◽  
Optical Properties ◽  
Elemental Composition ◽  
Wavelength Range ◽  
Volcanic Ash ◽  
Volcanic Eruptions ◽  
Mixed Modes

Abstract. Better characterization of the optical properties of aerosol particles are an essential step to improve atmospheric models and satellite remote sensing, reduce uncertainties in predicting particulate transport, and estimate aerosol forcing and climate change. Even natural aerosols such as mineral dust or particles from volcanic eruptions require better characterization in order to define the background conditions from which anthropogenic perturbations emerge. We present a detailed laboratorial study where the spectral optical properties of the ash from the April–May (2010) Eyjafjallajökull volcanic eruption were derived over a broad spectral range, from ultra-violet (UV) to near-infrared (NIR) wavelengths. Samples of the volcanic ash taken on the ground in the vicinity of the volcano were sieved, re-suspended, and collected on filters to separate particle sizes into fine and mixed (coarse and fine) modes. We derived the spectral mass absorption efficiency αabs [m2g−1] for fine and mixed modes particles in the wavelength range from 300 to 2500 nm from measurements of optical reflectance. We retrieved the imaginary part of the complex refractive index Im(m) from αabs, using Mie–Lorenz and T-matrix theories and considering the size distribution of particles obtained by scanning electron microscopy (SEM), and the grain density of the volcanic ash measured as ρ = 2.16 ± 0.13 g cm−3. Im(m) was found to vary from 0.001 to 0.005 in the measured wavelength range. The dependence of the retrieval on the shape considered for the particles were found to be small and within the uncertainties estimated in our calculation. Fine and mixed modes were also analyzed by X-ray fluorescence, exhibiting distinct elemental composition supporting the optical differences we found between the modes. This is a comprehensive and consistent characterization of spectral absorption and imaginary refractive index, density, size, shape and elemental composition of volcanic ash, which will help constrain assumptions of ash particles in models and remote sensing, thereby narrowing uncertainties in representing these particles both for short-term regional forecasts and long-term climate change.

Characterization of the nonlinear refractive index of the laser crystal Yb:KGd(WO4)2

2003 ◽  
Vol 77 (4) ◽  
pp. 433-436 ◽  
Author(s):  
A. Major ◽  
I. Nikolakakos ◽  
J.S. Aitchison ◽  
A.I. Ferguson ◽  
N. Langford ◽  
...  
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Laser Crystal
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