This pdf file contains the front matter associated with SPIE Proceedings Volume 7792, including Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

The paper gives an overview on the actual roots of Lambert's ideas on photometry including the excerpts of original sources as found in the Scientific library of castle Friedenstein in Gotha and in the Rostock university library, both in Germany, as well as some ideas on the system theoretical consequences and shortcomings and elegance of the concept of an angular cosine distribution. Further some almost lost paragraphs of Lambert's work on multiple reflection in dioptric systems are presented in translated and commented form.

A set of light-scattering results is presented in the form of Mueller Matrices (MM) and their corresponding Polar Decomposition (PD) parameters. The system under analysis is a square microstructure on a flat substrate, in the form of either a rib or a groove (or several equally spaced, depending on the experiment). As it is well known, MM contains all information, and many works have been carried out trying to connect its properties with those of the scattering system. However, this is not as intuitive as the analysis allowed by other presentations of the results, based on the decomposition of MM matrix in a set of matrices, each representing the action of a particular (non-real) element, and acting sequentially on the incident beam. Our analysis is a quite conventional application of the Polar Decomposition. The resulting parameters reveal, for instance, that the substrate plays an important role in the origin of the depolarization. Concerning the polar components the main analysis is performed by means of the conventional diattenuation and retardance parameters. The number and position of the discontinuities in the retardation parameter is associated to the size of the defect. This, of course, can be also concluded from the observation of m00 element oscillations, but in the case of the PD retardation parameter it is possible to connect the geometrical shape of the scattering element (rib or groove) to a single condition established for the PD parameters.

By the use of an impedance boundary condition, the Wiener-Hopf method, and Green's second integral identity in the plane we obtain a Kirchhoff approximation for the reflection amplitude of a surface plasmon polariton incident from one metal surface onto its rough boundary with a co-planar surface of a second metal. An example of the use of this result is presented.

This paper presents calculations of a new formulation of the 3D Kirchhoff approximation which allows calculation of the scattering of vector waves from 2D rough surfaces containing infinite slopes. Results are presented for scattering from metal surfaces with rectangular surface structures. This type of surface has applications, for example, in remote sensing and in testing or imaging of printed circuits. Some preliminary calculations for rectangular-shaped grooves in a plane are presented for the 2D surface method.

Recently, we have undertaken an experimental study of nonstandard refraction of light from one- and twodimensional dielectric quasi-periodic surfaces. The mechanism underlying this effect is the large local slope of the quasi-periodic surface.

Analytic formulas are derived for the Jones matrix and the Mueller matrix for dipole scattering by an ellipsoid and by a system of ellipsoids with totally random orientation. The scattering Mueller matrix by an ellipsoid as a function of ellipsoid orientation was simulated and showed complicated structure. The average Jones matrix for an ensemble of randomly oriented ellipsoids is proportional to the Jones matrix for a sphere. The averaging of the Mueller matrices washes away all the complicated structures and reduces to a simple Mueller matrix only a little more complicated than that for a sphere. The polarization of the dipole scattering by such ensemble depends on the scattering angle and the polarizability ratio β of a single ellipsoid. Scattering in the direction perpendicular to the incident direction shows the largest effects on both linear polarization and depolarization, although it has minimal intensity. More anisotropy (larger β) of scattering particles results in larger depolarization.

A unique tunable polarimetric scatterometry system has been developed by upgrading a Schmitt Measurement Systems Complete Angle Scatter Instrument (CASI) to produce a Dual-Rotating-Retarder full-Mueller-matrix polarimeter. The system has been enhanced by automation, addition of multiple, tunable, laser light sources, an improved sample positioning and orientation interface, and enhanced data-analysis software. A primary application of this system is the characterization of novel nano- and micro-structured materials, such as photonic crystals, plasmonic structures and optical meta-materials, which often display very narrow-band performance. The ability to characterize these materials both at and away-from their resonances is a clear advantage. The specific project goals are to demonstrate (1) a novel nano- and micro-structured-material-characterization full-polarimetric-diffuse-ellipsometry technique suitable to measure desired material properties with stated uncertainty limits for novel optical material structures of interest, and (2) the incorporation of predictive computational codes that estimate the electro-magnetic property values for novel nano- and micro-structured-material designs and concepts of interest.

The use of ultra short range Lidar techniques for measuring volume scatter behaviour of semi-transparent materials is investigated. Modern integrated circuits allow the design of low cost solutions for short to ultra short range Lidar applications such as combined multi GHz interferometry and FMCW in power domain. Besides typical in-door applications such as range finders, refined an explicitly tuned configurations can serve as volume scatterometers as well. First system concepts and designs based on off the shelf components are presented. Further, as an appendix for the interested reader, we continue to publish the translation of a chapter on multiple reflections in dioptric systems from Lambert's Photometria.

The large variety of scatterometric applications and basic scatterometer principles demands design rules to fit the final instrument as well as the data processing and user interface into the requirements of the application in scope. In the current paper we concentrate on the optical design of scatterometers based on a combination of an elliptical mirror and a secondary imaging lens system. The design strategy involves the Scheimpflug principle on two different scales and demands various compromises concerning spot size and angular resolution. The strategy is demonstrated on a practical example.

Non-contact temperature measurement is a preferred technique for rotating, hazardous and inaccessible objects. A major challenge for IR thermometry is the dependence of metal emissivity on wavelength and temperature. Optical reflectivity of metals is known to depend on metal temperature, plasma frequency of metal, angle and wavelength of the incident light. A major challenge in reflectance based temperature measurement techniques is the dependence of the reflectance on the surface roughness of the target metal. Sudden change in surface roughness (related or unrelated to temperature) can lead to spurious changes in reflectance irrespective of the temperature. To mitigate the surface roughness effect, we have investigated the speckle pattern emanating from the surface irregularities on the metal. An initial measurement on the speckle pattern also shows an enhanced sensitivity in temperature measurement of the surface that is a function of the inherent surface properties of the metal.

Tissue is optically anisotropic and highly photon-scattering medium. It has long been treated as optically diffusive medium in bio-medical applications. The diffusion equation of isotropic photon-density wave (PDW) was widely applied to interpret the data of reflectance spectroscopy and biomedical imaging experiments. In our recent transmission Stokes imaging experiment of the rat liver samples, the Mueller matrix elements were measured and analyzed theoretically. The measured data of depolarization constant has shown that the optical property is not perfectly diffusive. Based upon our recently developed theoretical model of anisotropic and highly photon-scattering medium, the simulated results of anisotropy, photon-scattering and depolarization property for the reflectance/backscattering experiment are reported.

In the manufacturing process of stainless steel, it is essential to pickle the oxide layer of steel surface for high corrosion resistance and fine surface quality. Pickling liquor of stainless steel is commonly composed of mixed hydrofluoric and nitric acid. Real time monitoring of concentrations of each acid is crucial to optimize pickling process. It also reduces cost of production and decreases the generation of waste acid. We used non-contact near infrared spectroscopy technique and rapid analysis method, for the quantification of each acid in an on-line manner. Multivariate calibration such as partial least square regression method is employed for the better prediction results.

Bidirectional reflectance distribution has been measured from an atomic-force-microscope (AFM)-patterned surface for the first time. The AFM was used to generate a two-dimensional square array of sub-wavelength surface features from a single material at a scale large enough to permit optical characterization. A diamond nano-indentation AFM probe was used to produce a 325-μm by 200-μm array of indentations in a 120-nm-thick polystyrene film deposited on silicon. Indentation spacing of 400 nm produced well-defined surface features with a maximum height of 140 nm. The full size array was achieved by tiling together single arrays, limited in size by the AFM scanner range, through the use of the AFM's translation stage. An SMS Complete Angle Scatter Instrument (CASI) was used to measure in-plane bidirectional reflectance at incident angles ranging from 0 to 80 degrees. Because of the small array size, the CASI beam was focused to approximately 140 μm and recalibrated using a 10-μm AFM calibration standard. Two wavelengths were investigated, 633 and 544 nm, at both s and p incident polarizations. Negative-first-order diffraction peaks were observed that were consistent with feature spacing. An anomalous scatter peak, believed to be associated with guidedmode resonance of the structure, was also observed. This is the first demonstration of an AFM-patterned polymer surface to behave as a 2D photonic crystal. The ability to construct and image arrays of optically active nano-features has potential DoD applications in laser eye protection and anti-reflection coatings for high power laser optics.

A semi-empirical reflectance/scatterance model has evolved over the years to represent a diverse set of materials from coated substrates to optical windows. This model separates the BRDF/BSDF into four basic components, specular, near-specular, diffuse, and Lambertian (random diffuse) terms. The specular and near-specular components employ a Gaussian phase function and the Fresnel power reflection coefficient. The Lambertian component uses Kubelka-Munk theory for the total integrated reflectance and transmittance. The model features wavelength, angle, and full hemispherical dependencies. It is applied to a variety of samples, from painted surfaces to transparent windows, with good success. This parameterized modeling approach is attractive because algorithms that use the model can be computationally efficient. Previous work has only considered in-plane effects. The present paper now explicitly takes into account the out-of-plane contribution and improves the total integrated factors.

In recent years paper have been published on the limitations of the Rayleigh Rice vector perturbation theory relating scattering (given by the bidirectional reflectance distribution function or BRDF) to surface roughness (given by the power spectral density function or PSD). In addition to the restrictions that the surface be optically smooth, clean and front surface reflective, the Rayleigh-Rice relationship has been criticized because calculations of the PSD from the BRDF often produce a high frequency (high scatter angle) peak. Variations in the wavelength and/or incident angle produce variations in the peak, so it is clear that the peak is not truly a part of the surface PSD. Recently a change was suggested to the expression that removes the peak. This paper presents data proving that the original expression is correct and implies that the peak is the result of scatter from non-topographic sources. In other words the surface is not clean, or is not front surface reflective.

The laser based trajectory measurement system referred to in a corresponding paper already gave theoretical considerations on the backscatter power of projectiles dependent on the angle of illumination by a laser. This leads to the question about the real angular backscattering properties of projectiles. Therefore, the need for an investigation of various projectiles is obvious. This paper presents back scatter examples for typical projectiles illuminated and viewed from defined angles. For each projectile its back scatter is recorded twice: once specially prepared with a Lambertian surface and once with its original surface. The results of the measurements provide an objective assessment for various camera arrangements of a LIDAR system. Finally, suitable camera configurations are shown.

A recently published experiment called "dual photography" exploits Helmholtz reciprocity by illuminating a scene with a pixilated light source and imaging other parts of that scene with a camera so that light transport between every pair of source-to-camera pixels is measured. The positions of the source and camera are then computationally interchanged to generate a "dual image" of the scene from the viewpoint of the source illuminated from the position of the camera. Although information from parts of the scene normally hidden from the camera are made available, this technique is rather contrived and therefore limited in practical applications since it requires access to the path from the source to the scene for the pixilated illumination. We propose this limitation may be relieved and additional scene information may be recovered if the scattering properties of media in the scene are known. To this end, we have shown through simulation and experimentation that information not directly visible to either the camera or the source, but illuminated by a source scattered off another part of the scene, may be recovered in limited initial cases. This paper discusses the technique of using the bidirectional reflectance distribution function (BRDF) of a non-specular medium to allow a camera collocated with a laser source and scattered off that medium to recover scene information not directly visible to the camera.

Most recent bidirectional reflectance distribution function (BRDF) measurement systems are the image-based that consist of a light source, a detector, and curved samples. They are useful for measuring the reflectance properties of a material but they have two major drawbacks. They suffer from high cost of BRDF acquisition and also give inaccurate results due to the limited use of spectral bands. In this paper, we propose a novel multispectral HDR imaging system and its efficient characterization method. It combines two promising technologies: high dynamic range (HDR) imaging and multispectral imaging to measure BRDF. We perform a full spectral recovery using camera response curves for each wavelength band and its analysis. For this, we use an HDR camera to capture HDR images and a liquid crystal tunable filter (LCTF) to generate multi-spectral images. Our method can provide an accurate color reproduction of metameric objects as well as a saturated image. Our multi-spectral HDR imaging system provides a very fast data acquisition time and also gives a low system setup cost compared to previous multi-spectral imaging systems and point-based commercial spectroradiometers. We verify the color accuracy of our multi-spectral HDR imaging system in terms of human vision and metamerism using colorimetric and spectral metric.

In the 2009 sessions a laser based imaging system for geometrical measurement of projectile trajectories was presented. This system has been extended to be able to gather 3D data. Therefore the mathematical baseline is given and measurement errors are estimated. An approach is shown how the direction of a trajectories' origin could be ascertained using the current system. A simulation software has been developed to emulate test firings and measurements under certain assumptions and different configurations. As a first step, simulations on the sensor grid error were carried out. Accuracies for determination of the direction of a trajectories' origin dependent on the sensor grid errors were computed for a sample setup and will presented here.

Measured data of the angular distribution of light scattering by surfaces (bi-directional-reflection-transmittancefunction, BRTF) has use in many fields: among them are stray light in lens design, projection screens,1 advanced architectural glazings and validating of surface and material models. Existing measurement devices either use cameras to capture multiple outgoing directions (imaging gonio-photometers) or move the sensor around the sample (scanning gonio-photometers). Scanning gonio-photometers offer advantages from a physics point-of-view: e.g. angular resolution, angular coverage, no relaying optics, isotropic sensor response, dynamic range and spectral resolution. But they had been prone to slow measurement speed, up to rendering them de-facto impractical for batch processing or routine checks in some applications. A new design of a scanning, out-of-plane gonio-photometer is presented with optimised mechanical and electronic design, reduced scanning time, optimised sensors resulting in high dynamic range, low noise and extended measurement capabilities (e.g. VIS,IR,UV and polarisation). Since the unobstructed beam is used as reference, it does not need external reference standards for ab-initio BRTF values. Sample data and validation checks illustrate that this measurement design offers advantages and flexibility over previous concepts.

The wave front sensor used in this paper is based on Makyoh method: the studied sample is illuminated by a collimated light beam and the reflected beam is collected by a camera. Previously it was demonstrated that this method enables the determination of surface flatness in the nanometer range. For this purpose the deformation of an initially planar wave front is detected and evaluated using patterns projected on the surface. This paper demonstrates that the sensor can also be used without patterns for characterization of surfaces flatness in the sub-micrometer and micrometer ranges. The intensity distribution image obtained can be interpreted in terms of topography as follows: convex areas of the studied surface defocus the beam (dark regions on the image) while the concave areas focus it (bright regions). The main result of this work is the development of a new approach for the fast assessment of the surface quality. This approach estimates the areas and the intensities of bright regions on the image and gives the value of the maximum concavity on the studied surface. For evaluation of data a simulation of the reflected from the given profile was made. The setup parameters, e.g. distances between the optical components, were optimized with the parameters obtained from the 2D simulation of the wave front sensor. This paper demonstrates the feasibility of wave front sensing for the topography analysis of reflective surfaces such as bare wafers' surfaces, metallic thin films, etc. used in semiconductor industry.

Black coatings have important applications in space-borne infrared systems, absolute radiometers, and radiometric temperature measurements. Recently, researchers have demonstrated close-to-unity absorptance, with diffuse reflection, by using vertically aligned carbon nanotube (VACNT) arrays. The present study deals with the optical properties of highly absorbing VACNT arrays, with surface features from diffuse to specular. Three CNT arrays were fabricated using a thermal chemical vapor deposition (CVD) technique with different growth conditions to produce highly aligned multi-walled CNT arrays. The bidirectional reflectance distribution functions (BRDFs) were measured with a laser scatterometer at a wavelength of 635 nm. Sharp specular peaks can be seen from the BRDF plots for the relatively smooth sample; while for the relatively diffuse samples, the specular peaks are significantly lower. The directional-hemispherical reflectance (DHR) at wavelengths from 400 to 1000 nm was measured with an integrating sphere and a monochromator. Based on Kirchhoff's law, the absorptance was obtained from the DHR to be between 99.5% and 99.9% for all samples in the measured spectral region.

Numerical results for the spatial distributions of the light transmitted through metallic planar lenses composed of symmetric nanogroove arrays on the surfaces of a gold film deposited on a dielectric substrate are presented and explained. Both the near and far-field distributions of the intensity of light transmitted through such films, which are modeled by two aligned and reversed one-dimensional surface profile functions, are calculated by the use of a Green's function formalism. The focusing action obtained for different groove-width variations is investigated thoroughly. Results for an optimal transverse focus based on a quadratic variation of groove width across the array are also obtained, in addition to the effect of groove shape on the sharpness of planar lens focusing. Meanwhile, a significant dependence of the focal length on the wavelength of light incident from the air side through the gold film into a dielectric substrate is found for this detector configuration.

See manuscript PDF.

We have studied the interference of light produced by a pair of circularly symmetric Collett-Wolf beams, and found that the output radiation from the interferometer in the far-field is a beam with an intensity distribution that displays a narrow bright spot at its center that diverges with the distance from the sources much more slowly than the beam itself. This result suggests that the interference of a pair of symmetric Collett-Wolf beams can be used to produce a pseudo-nondiffracting beam. We have also studied the temporal average over an ensemble of realizations of the output power spectrum of the interference of light produced by a pair of circularly symmetric Collett-Wolf beams, which causes a change in the spectrum of the light as well.

Fringe projection techniques are widely used for geometry measurement of synchro rings inside a manufacturing chain, since a dense areal geometrical data set is needed to evaluate all the key features. Post-process machined parts exhibit optically incooperative surfaces towards triangulation techniques. Hence these parts can't be measured accurately using fringe projection systems. The optical incooperativity originates from the scattering characteristics of the surface. Polished surfaces exhibit a narrow angle of light refraction, whereas rough surfaces scatter the light over a hemisphere more homogenously. The angle range at which an incident light ray is scattered is the basis for a definition of optical cooperativity. The wider the range, the higher is the optical cooperativity of the surface. In order to produce optically cooperative surfaces of machined parts for the use of fringe projection measuring systems, we employ methods of surface treatment. One promising mechanical method under investigation to obtain optical cooperativity with technical surfaces is done by blasting the surface with fused alumina (EKF1000). The blasted surface leads to an increased roughness which can be controlled using the blast parameters, i.e. blast-pressure, blast-duration and the distance of the blaster to the part surface. In this paper the effects of different parameters of the blast-process on the surface roughness, the optical roughness and on the optical cooperativity vis-à-vis fringe projection techniques are examined. Optimal parameter settings result in a sub-micrometer change with respect to the object surface. Since the effects due to a variation of the parameters are dependant on the object material, we restrict our research to the case-hardening steel 1.7193 (16MnCrS5).

In the field of microelectronic industry, periodic structures are produced with spatial dimensions that can be less than 100 nm. Because of the material and process effects, these structures will most likely present some additional roughness. The optical far field characterization of these structures usually allows to deduce the shape parameters of the periodic structure. Measurements are performed thanks to an ellipsometric apparatus, associated with modelling and inversion algorithms. In this configuration the technique is called "scatterometry". This method does not permit to directly extract roughness parameters. This paper aims at describing how model and experimental tools can be used to characterize the roughness of gratings. The study needs a complete three-dimensional electromagnetic modelling of the structure but the calculations are very time consuming. Here, different theoretical models are associated in order to reduce the calculation time: rigorous numerical differential theory and Born approximation theory. The exact numerical model allows to treat the periodic part of the structure while the roughness is viewed as a perturbation and treated using a first order approximation. From an experimental point of view, the information on the periodic part of the structure lies in the diffraction orders, while the roughness signature is mainly found between diffraction orders. Practically, this model could be used in the semiconductor industry for a detailed roughness characterization, based on an optical measurement using the same test structures used for scatterometry.

Accurate characterization of the reflection and scatter properties of materials is critical for their use in optical systems. PASCAL (Polarization And Scatter Characterization and Analysis of Lambertian materials) makes BRDF (Bidirectional Reflection Distribution Function) measurements with a polarized light source and can measure with / without an analyzer in series with the detector in the 400 - 1700 nm wavelength range. The entire incident light beam is collected by the detector assembly. With the sample in place, a precision circular aperture is used to collect the light. BRDF is calculated on the basis of the incident power and geometric factors eliminating the need for a standard characterized at another laboratory. The measured uncertainties of the geometric factors are comparable to those of the National Institute of Standards and Technology (NIST) Spectral Tri-function Automated Reflectance Reflectometer (STARR) facility. Spectral definition is achieved with band pass filters. As in typical BRDF instruments, the detector rotates about the sample in the plane defined by the source beam and the azimuth rotation of the sample. Unique additional features of this instrument include the ability to vary the sample elevation and sample roll. Comparisons with measurements made at NIST are presented. Measurements with this instrument demonstrate the importance of sample orientation, roll, with variations of 2.5% observed. The roll dependence can vary with polarization. The minimum sample size measurable is 5 cm diameter with the maximum sample size of 22 X 27 cm.

Amorphous carbon is an important and ubiquitous material, yet the understanding of the optical properties as a function of frequency and temperature remains a challenge. In particular, a comprehensive physics-based model has been a long term need. Building on past work on diamond and pyrolytic graphite, a new model of the optical properties of soot is developed. The model includes frequency and temperature dependence. Current progress is presented.

We report the preliminary characterization results of a gold-coated concentrator used for longwave irradiance measurements[1]. Throughput measurements of the concentrator are conducted at 1.562 μm and 10.15 μm using two different approaches, one is referred to a transmittance measurement using the Complete Hemispherical Infrared Laserbased Reflectometer (CHILR)[2] of NIST, and the other one is a direct throughput measurement using an existing thermopile detector for longwave irradiance measurement. For the transmittance measurement using CHILR, two diffuse gold references are selected to generate a Lambertian source by shining a laser on them. Spatial variations of transmittance of the concentrator are also investigated by scanning the laser beam across the opening area of it with a gold diffuser. For the direct throughput measurement, a small diffuse gold integrating sphere of 25.4 mm in diameter is utilized to produce an ideal diffuse source. The thermopile detector measures the radiation passing through the concentrator from the small integrating sphere. The incoming irradiance is determined from signal outputs of the thermopile detector and ambient temperature changes. Comparing with the results from the two approaches, a consistent throughput of the concentrator is obtained about 91 % to 92 %. The error sources and uncertainty in the two measurements are also discussed.

Flatness/Curvature measurement is critical in many Si-wafer based technologies ranging from micro-electronics to MEMS and to the current PV industry. As the thickness of the wafer becomes smaller there is an increased tendency for it to warp and this is not conducive to both patterning as well as dicing. Monitoring of curvature/flatness is thus necessary to ensure reliability of device and its uses. A simple whole-field curvature measurement system using a novel computer aided phase shift reflection grating method has been developed and this project aims to take it to the next step for residual stress measurement. The system was developed from our earlier works on Computer Aided Moiré Methods and Novel Techniques in Reflection Moiré, Experimental Mechanics (1994) in which novel structured light approach was shown for surface slope and curvature measurement. This method uses similar technology but coupled with a novel phase shift system to accurately measure slope and curvature. In this research, the system is calibrated with reference to stress measurement equipment from KLA-Tencor. Some initial results based on a joint project with Infineon Technologies are re-examined. The stress distribution of the wafers are derived with the aid of Stoney's equation. Finally, the results from our proposed system are compared and contrasted with data obtained from KLA-Tencor equipment.

The optical scattering signature and the absorbance of a material are of interest in a variety of engineering applications, particularly for those pertaining to optical remote sensing. The John Hopkins University Applied Physics Laboratory has developed an experimental capability to measure in-plane bidirectional scattering distribution functions to retrieve optical properties of materials. These measurements are supported at high angular resolution with wavelengths that span the ultra-violet to the long-wave infrared. Models have been developed to fit Lambertian, diffuse, near-specular, and specular scattering at a range of incident angles. Useful material properties can then be determined through analysis of the modeled BSDF. Optical characterization results are shown for a variety of materials, including paints, metals, optical windows, and leaves.

This paper deals with a method to effectively compress the measured reflectance data of pearlescent paints. In order to simulate the coated surface realistically, it is requested to measure the reflectance of the pearlescent paints by using multiple wavelengths. The wavelength-based reflectance data requests a large amount of storage. However, we can reduce the size of the measured BRDF and retain the accuracy the data by using several factorization algorithms. In this paper, we analyze the decomposition of the measured BRDF of pearlescent paint and find the number of lobes or basis functions to retain the visual accuracy of the measured reflectance.

The measuring system based on photon correlation spectroscopy is improved through several means. The distribution of nanometer particle's sizes measured by new systems is more stable and accurate. All of the experiments are done in an ultra-clean chamber. The temperature is controlled and changes from about 13 degrees centigrade to 22 degrees centigrade. Fibers with different core diameters are used to transmit scattering light. The "Y" type fibers with different core diameters are used to transmit both the incident laser and the scattering light. The microscope objectives with different numerical apertures are used to collect and couple the scattering light into fiber. The software of real time correlation is tried to be used in the measuring system and it is compared with the static correlation. The Labview is used to integrate the software of correlation and inverse algorithms of nanometer particle sizes. Influences of incident laser with different power and mode are analyzed.

A novel optical method is proposed and demonstrated, for real-time dimension estimation of thin opaque cylindrical objects. The methodology relies on free-space Fraunhofer diffraction principle. The central region, of such tailored diffraction pattern obtained under suitable choice of illumination conditions, comprises of a pair of 'equal intensity maxima', whose separation remains constant and independent of the diameter of the diffracting object. An analysis of 'the intensity distribution in this region' reveals the following. At a point symmetrically located between the said maxima, the light intensity varies characteristically with diameter of the diffracting object, exhibiting a relatively stronger intensity modulation under spherical wave illumination than under a plane wave illumination. The analysis reveals further, that the said intensity variation with diameter is controllable by the illumination conditions. Exploiting these 'hitherto unexplored' features, the present communication reports for the first time, a reliable method of estimating diameter of thin opaque cylindrical objects in real-time, with nanometer resolution from single point intensity measurement. Based on the proposed methodology, results of few simulation and experimental investigations carried-out on metallic wires with diameters spanning the range of 5 to 50μm, are presented. The results show that proposed method is well-suited for high resolution on-line monitoring of ultrathin wire diameters, extensively used in micro-mechanics and semiconductor industries, where the conventional diffraction-based methods fail to produce accurate results.

We measured the topography of lens by using a technique of diffuse reflection (fringe projection technique) and by a method based on specular reflection technique (similar to Placido disk system). The obtained results with both techniques are compared with those obtained with a spherometer. The retrieval of the three-dimensional shape of the lens is an issue of great interest for wide medical application, particularly in ophthalmology.