The Kirchhoff approximation has been used for many years to calculate for the problem of scattering of light from rough surfaces. One of the limitations of the method is on the surface slopes for which the method can be used. For large surface slopes there is more shadowing and multiple scattering and the sampling of the surface, which is in constant intervals of the variable along the mean plane of the surface, becomes a problem. In this work, the Kirchhoff approximation is reformulated to permit the use of this method in surfaces with very high slopes. Results are presented for surfaces containing rectangular shaped grooves, surfaces which have infinite slope on the sidewalls of the grooves.

The effects of rough surface scattering on the detection and imaging of objects are important in many applications including the imaging of objects on or near ocean surfaces and the detection of objects buried under ground rough surfaces. This paper focuses on the following problems: (1) Scattering from wedge-like rough surfaces representing ocean surfaces with sharp crested waves. (2) Scattering by objects above or below the rough surfaces. (3) UWB confocal imaging of objects near rough surfaces. Finite-Difference Time-Domain (FDTD) method is used to obtain frequency domain as well as time domain responses. Numerical simulations of various representative cases are conducted to understand and gain insight into the scattering effects on object detection and imaging.

We proposal to apply two optical setups of a 1-D rough dielectric film on a glass substrate and a randomly weak dielectric film on a reflecting metal substrate for the measurement of high order correlation from rough surface scattering. The angular amplitude and intensity correlations are measured. Due to multiple scattering, when the input laser beam size is comparatively small or close to the travel pass length inside the film, C⁽²⁾ and C⁽³⁾ are measured by subtracting amplitude correlation from intensity correlation.

The coherence theory predicts that the correlation in the fluctuations of a source distribution can cause frequency shifts in the spectrum of the emitted radiation, even when the source is at rest relative to the observer. We have observed the changes in the spectrum of the light in the scattering from double passage configuration.

Scattering losses of guided waves that propagate in a planar waveguide are considered. Sources of scattering include random roughness at the cladding-core boundaries and random inhomogeneity of the waveguide core permittivity. A finite length segment of the waveguide channel has either random wall roughness or material inhomogeneity. The roughness is 1-D and the core inhomogeneity is 2-D and both are numerically generated to have a Gaussian autocorrelation. The length of the scattering segment (roughness or inhomogeneity) is varied from 0 to 160λ. Maxwell's equations in 2-D are solved in the frequency domain for both TE and TM polarization using modal expansion methods. Obtaining numerical solutions is facilitated by using perfectly matched boundary layers and the R-matrix algorithm. The guided waves are excited by a Gaussian beam incident on the waveguide aperture. For various parameters, numerical results are given for waveguide power loss per unit length of the imperfect waveguide segment.

We propose a method for designing a one-dimensional random perfectly conducting surface which, when illuminated normally by an s-polarized plane wave, scatters it with a prescribed angular distribution of intensity. The method is applied to the design of a surface that scatters light uniformly within a specified range of scattering angles, and produces no scattering outside this range; a surface that acts as a Lambertian diffuser; and a surface that suppresses single-scattering within a specified range of scattering angles. This method is tested by computer simulations, and a procedure for fabricating such surfaces on photoresist is described.

We propose a method for designing a two-dimensional random Dirichlet surface which, when illuminated normally by a scalar plane wave, scatters it with a prescribed circularly symmetric distribution of intensity. The method is applied to the design of a surface that scatters light uniformly within a circular region and produces no scattering outside that region, and a surface that acts as a Lambertian diffuser. The method is tested by computer simulations, and a procedure for fabricating such surfaces on photoresist is described.

Characterization of surface and interfacial morphology of magnetic materials is crucial to understand their properties. While AFM is unparalleled in directly determining surface morphology, x-ray scattering has distinct advantages for measuring both the surface and buried interfaces. However, x-ray scattering (XRS) requires modeling to extract roughness parameters. We review the techniques for performing and modeling XRS and show that the azimuthal transverse scattering geometry offers many advantages to in-plane scattering techniques, including a simplified modeling process and an extended scanning range in reciprocal space. To validate our modeling, the surface morphology of several magnetic thin films (d < 10 nm) is characterized using soft-x-ray scattering and carbon-nanotube tip atomic force microscopy (CNT-AFM). Results for out-of-plane XRS and CNT-AFM are within good quantitative agreement within their shared experimental bandpass.

We demonstrate a measurement of lithographic overlay using light scattering ellipsometry. In the limit of small amplitude surface topography, the polarization of light scattered by the two interfaces of a dielectric film can be decomposed into the roughness of each interface and the complex degree of phase correlation. For two identical but offset roughness functions, the degree of phase correlation will show oscillations, whose frequency in the spatial frequency domain will be given by the overlay distance Δx. The method is tested us-ing a shallow pseudorandom binary 1-D grating, photolithographically produced on a silicon wafer and again on a spin-on glass layer deposited onto the wafer.

This paper concerns a behavior of the total hemispherical reflectance (THR) of the Al-N coating in the course of mechanical and environmental tests. The Al-N coating has been designed to reduce the stray sunlight background in the satellite-borne optical instruments and charge-particles-analyzing apparatus operating in open space under intensive solar radiation. Usually, this problem arises when a density of instruments installed on the satellite is high and it is difficult to avoid getting to instrument the light reflected by neighboring devices. Resolution of this problem is also important in connection with development of the extra-atmosphere Far UV astronomy. The THR measurement results are presented for 10 wavelengths wihtin a range from 400 to 927 nm, and also at 121.6 nm, the most intensive line of the solar UV spectrum able to result in considerable contribution to the detector noise in space devices. The samples of the Al-N coating were exposed to standard mechanical loads including the vibratory loads, linear overloads, and impacts, to which the space equipment may be subjected when shipping to the space-vehicle launching site and also when lauching. The samples were also exposed to environmental tests simulating the vacuum, humidity, and cyclic temperature conditions, which may influence the space instruments while shipping, storing, launching, in flight, and under operating conditions. The THR measurements of the samples were made following exposure to each test. The THRs of tested samples at the wavelength of 121.6 nm were as low as 1.5-2%.

Principal Mueller matrices of scattering by a rough paint surface are measured. Null ellipsometry is used to measure the ellipsometric parameters and depolarization of scattering with small depolarization (< 0.2). Linear polarization, circular polarization, and principal Mueller matrix are obtained from the above measured quantities. Stokes method is used to measure the principle Mueller matrix for scattering with large depolarization (> 0.2), and all other polarization characteristics are derived from the principal Mueller matrix. Scattering is measured at fixed angle (2K) between the incident and detection directions, and variable sample orientation. The scattering and its polarization characteristics are symmetric with the off-specular angle (OSA). The measured linear polarization increases with increasing OSA, and may change sign for the cases of small K. The measured depolarization increases with increasing OSA more than linearly, and is larger for smaller K.

A device has been designed based on the diffraction that will permit to analyze in an objective and quick form, the quality of ophthalmic lenses. This device situated in the line of production will improve the process of fabrication. The device is based on the phenomenon of the diffraction that takes place in the defects when impacting the light of the laser. The device consists of an optical system, in charge of driving the light of the laser, under good conditions, on the lens to analyze, a sensor, adapted to the wavelength of the laser, that detects the presence of the defect through the produced diffraction and a mechanism in which the lens to inspect is located assures that the laser sweeps the whole surface of the lens. A control system connected to the previous systems regulates the whole process The image obtained can be used to analyze and characterize the type of defect. Using image processing we segment the images in order to classify the defects that appear in the surface of the lens.

Laser radar based on gated viewing uses narrow laser pulses to illuminate a whole scene for direct (incoherent) detection. Due to the time of flight principle and a very fast shutter with precisely controlled delay time, only light reflected in the range R (range slice ΔR) is detected by a camera. Scattered light which reaches the shutter outside a given exposure time (gate) is suppressed. Hence, it is possible to "look" along the optical axis through changing atmospheric transmissions (rain, haze, fog, snow). For each laser pulse, the grey value image ES(x,y) of the camera is captured by a framegrabber for subsequent evaluation. Image sequences from these laser radar systems are ideally suited to recognize objects, because of the automatic contrast generation of the technology. Difficult object recognition problems, detection, target tracking, or obstacle avoidance at bad weather conditions are favorite applications. In this paper we discuss improvements in the system modelling and simulation of our laser radar system. Formerly the system performance was calculated for the whole system using the signal-to-noise ratio (SNR), leading to a general estimation of the maximum range of target detection. Changing to a pixel oriented approach, we are now able to study the system response for targets with arbitrary two and even three dimensional form. We take into account different kinds of target reflectivity and the Gaussian nature of the illuminating laser spot. Hence it is possible to simulate gray value images (range slices) and calculate range images. This will lead to a modulation transfer function for the system in future. Finally, the theoretical considerations are compared with experimental results from indoor measurements.

Scatterometry is a powerful and fast measurement method to measure surfaces and its properties. The backscattered light from a coherently illuminated surface contains information about integral surface topography constants, material properties, surface defects and contamination. In this paper a generic system model of an angle resolved light scatter sensor (ARS sensor) will be discussed and exemplified by using the sensor system LARISSA (Large Dynamic Range Intelligent Scatter Sensor Approach). The system model consists of two parts - firstly in spatial domain and secondly in time (or frequency) domain. The part of the system model in spatial domain contains the characteristics of the optical map of the scattered light onto a detector system. The optical map will be discussed by using an elliptical mirror optics with regard to aberration effects. The part of the system model in time (or frequency) domain contains the characteristics of the conversion of scattered light into quantized signals. The basic steps of the conversion process will be considered. Furthermore, the characteristics in time domain of a single CMOS detector (photo diode) with logarithmical intensity characteristics will be discussed to estimate the opto electronic bandwidth limitation and the minimal exposure time for different applications. Based on the system model basic performance limits will be summarized and further design steps of the sensor system LARISSA will be outlined. This paper is a continuation of a previous paper.

The development of dynamical surface of long-wave oscillations viscous liquid with electrical charge is researched in the periodical restoring process of spatial deformation type crater. The possibility of using as a quality of leading parameter with the development - apparition process and the multiplying of spatial periodical deformed structures of dielectrical or mechanical parameter was determined. A mechanism of germination and a mechanism of multiplying exists in the process of apparition and development of dissipate structures. The applying of soluble surface active substance increases the development speed of dynamical surface. This allows registering the centers of germination or multiplication of new formation centers in the real time scale recording. The experimental calculations indicate that the developing speed of dynamical surface can give the values of 100 μm/s in the transversal plane and 0.2 (rel.un.) in the normal plane.

For the optical components in high power laser system, there are some special demands, therefore, there are some peculiar needs in evaluating, for example the testing in middle frequency segment is emphasized. Considering these special demands, power spectral density (PSD) is used as one of the important evaluating parameters. The paper summarizes the meaning of utilizing PSD, its calculation and demarcation methods. For measurement instrument, the paper chooses stitching interferometer to realize the testing of the optics of large scale. In order to test the frequency distortion in stitching, the paper applies PSD as the compared parameter. The results testifies that stitching can not introduce additional frequency distortion.

We obtain the reflection spectra of p-polarized light from metallic gratings fabricated by means of the interference technique. The gratings have constant period and heights are varied by changing the exposure time of the interference pattern on the sample. The experimental spectra show two minima due to the excitation of surface plasmons, and they are compared with the corresponding numerical results obtained with two models, the Rayleigh theory and the rigorous integral method. In order to demonstrate the validity of the Rayleigh hypothesis the amplitudes of the gratings are chosen close to the Rayleigh limit.

In this work we present the design of an instrument for measuring the scattering of light by a two-dimensional rough surface in the visible between 550nm and 830nm. An elliptical mirror is used to collect the light scattered by a 2D-surface which is placed at the first focus of the ellipse. A relay is placed near to the second focus of the ellipse to collect the light scattered by the surface in each direction, that is, parallel rays leaving the illuminated 2D surface at an arbitrary angle are brought to a point at the focal plane of the relay. The light is detected by a CCD camera. To cover 180 degrees field of view it is necessary to move the CCD linearly in two directions in the focal plane.

Recent studies have shown that the angular distribution of diffuse reflectance differs strongly between paper sheets with and without fibers present in the top surface layer. For fiber-containing surfaces, in contrast to pigment coated paper surfaces, there is a distinct forward scattering at angles much larger than the specular reflection angle. We have studied how this pronounced anisotropic reflectance distribution in the forward direction can be interpreted in terms of the internal structure of the fibers. We did this by comparing experimental BRDF measurements to Monte-Carlo simulations on a fiber web within the limits of geometrical optics. It was found that the 3rd reflection event, mainly corresponding to the first reflection from the fiber lumen, played a large role for the characteristic anisotropic reflectance distribution from fiber-containing surfaces. We also found that multiple reflections within a sheet tend to favor certain polar exit angles in such a way that the resulting distribution ends up anisotropic even after many reflections.

Novel data are presented of Bidirectional Reflectance Distribution Function (BRDF) and 8° directional/hemispherical reflective measurements of Martian regolith simulant JSC Mars-1. The scatterometer of the National Aeronautics and Space Administration's Goddard Space Flight Center (NASA's GSFC) Diffuser Calibration Facility (DCaF) was used for the measurements reported. The data were obtained with a monochromator-based light source in the UltraViolet (UV), Visible (VIS), and Near InfraRed (NIR) spectral regions. The BRDF measurements were performed at different angles of incidence, and over a range of in-plane and out-of-plane geometries. The 8° directional/hemispherical reflective measurements were calibrated using a gray Spectralon sample set of 7 plates. The results presented are NIST traceable through calibrated standard plates. The hemispherical and diffuse scatter data obtained from these studies are important for future Mars space and ground based observations.

A method for obtaining time-resolved diffraction data from laser-shocked solids was developed at the High-Energy beamline ID15 of the European Synchrotron Radiation Facility. This method combines the use of an appropriate timing electronics with a triple-axis diffractometer coupled to a short-pulsed laser source. Real time diffraction measurements were performed on single crystalline samples in order to monitor their compression under different loading conditions through the evolution of the Bragg reflection. As an example, we present results obtained from cadmium sulfide single crystals at stress values below and near the Hexagonal-Closed Packed to Rock Salt pressure-induced phase transition. These results clearly show two different behavior when the sample is compressed below and above its elastic limit.