Refractive Index

A nonlinear image technique for characterization of the optical nonlinearities is used to investigate the solid semiconductor ZnSe at 600 nm. The method based on a 4f nonlinear image technique with a phase object is used to obtain the diffraction pattern of the nonlinear filter in solid ZnSe located at the Fourier plane by a CCD camera. The nonlinear absorption coefficient and nonlinear refraction index were both obtained by fitting the nonlinear image. Good agreement between the experiment data and the simulated result are obtained indicating a sensitive and powerful method for nonlinear optical measurements.

In this paper, we present a simple algorithm for extraction of laser rate equation parameters based on a set of simple laboratory measurements. Commercial semiconductor DFB laser (Fujitsu FLD3F7CZ) with central wavelength 1310 nm is used to obtain the PI ...

In this paper, we propose an approach to the problem of simultaneous shape and refractive index recovery from multispectral polarisation imagery captured from a single viewpoint. The focus of this paper is on dielectric surfaces which diffusely polarise light transmitted from the dielectric body into the air. The diffuse polarisation of the reflection process is modelled using a Transmitted Radiance Sinusoid curve and the Fresnel transmission theory. We provide a method of estimating the azimuth angle of surface ...

High speed recordable media often show only marginal modulation at the lowest recording speeds. This reduction is caused by bumps formed in the polycarbonate substrate during writing. After treating sliced discs with NaOH, holes were found underneath the written marks in the bottom of the grooves only in the case of high speed recording. This effect can be explained by postulating an additional polycarbonate layer with a lower refractive index. Simulations show that this extra layer increases modulation at high recording speeds. The simulation coincides well with experimental results.

We describe the use of a multi-aperture Hartmann mask coupled to a slightly out-of-focus focal plane array imager to monitor atmospheric turbulence (‘seeing’) produced by refractive index fluctuations. The imager (a CCD) is located inside or outside the focal surface of the imaging system so that each sub-aperture of the Hartmann mask produces an image well separated from all of the other images produced by the mask. Since the depth of focus of the sub-apertures is an order of magnitude larger than that of the parent optical system, the individual images are still diffraction-limited. We obtain short (10 to 100 msec) exposures and monitor the position fluctuations of the images. Analysis of the position and intensity fluctuations of the images can be used to determine the atmospheric parameter r0, the wind direction and velocity, and, under some circumstances, the distance of the turbulent layer from the observing site.

Large size gold nanoparticles (GNPs) were directly deposited onto the indium tin oxide (ITO) glass surface by cyclic voltammetric method. The GNPs on ITO substrate were characterized by means of scanning electron microscopy (SEM), UV–vis spectroscopy and X-ray diffraction (XRD). The nucleation and growth steps were controllable in the GNPs deposition procedure. The addition of chloride ion in the electrolysis affected the size and density of GNPs on the ITO surface. The response of refractive index for various organic solvents was also investigated. The sensitivity of refractive index increased as GNPs became larger.