http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2012, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/aot/2012/581743/The porous silicon (PSi) layers were formed on p-type silicon (Si) wafer. The six samples were anodised electrically with 30 mA/cm2 fixed current density for different etching times. The structural, optical, and thermal properties of porous silicon on silicon substrates were investigated by photoluminescence (PL), photoacoustic spectroscopy (PAS), and UV-Vis-NIR spectrophotometer. The thickness and porosity of the layers were measured using the gravimetric method. The band gap of the samples was measured through the photoluminescence (PL) peak and absorption spectra, then they were compared. It shows that band gap value increases by raising the porosity. Photoacoustic spectroscopy (PAS) was carried out for measuring the thermal diffusivity (TD) of the samples.Kasra Behzad, Wan Mahmood Mat Yunus, Zainal Abidin Talib, Azmi Zakaria, Afarin Bahrami, and Esmaeil ShahriariCopyright © 2012 Kasra Behzad et al. All rights reserved.http://www.hindawi.com/journals/aot/2012/371390/We present a controlling technique of microporous structure by laser irradiation during self-organization process. Self-organization process is fabrication method of microstructure. Polymer solution was dropped on the substrate at high humid condition. Water in air appears dropping air temperature below the dew point. The honeycomb structure with regularly aligned pores on the film was fabricated by attaching water droplets onto the solution surface. We demonstrate that it was possible to prevent forming pores at the region of laser irradiation and flat surface was fabricated. We also demonstrated that a combination structure with two pore sizes and flat surface was produced by a single laser-pulse irradiation. Our method is a unique microfabrication processing technique that combines the advantages of bottom-up and top-down techniques. This method is a promising technique that can be applied to produce for photonic crystals, biological cell culturing, surface science and electronics fields, and so forth.Yukimasa Matsumura, Wataru Inami, and Yoshimasa KawataCopyright © 2012 Yukimasa Matsumura et al. All rights reserved.http://www.hindawi.com/journals/aot/2012/908976/We report a novel ultrabroadband high-energy femtosecond laser to be built in our laboratory. A 7-femtosecond pulse is firstly stretched by an eight-pass offner stretcher with a chirp rate 15 ps/nm, and then energy-amplified by a two-stage optical parametric chirped pulse amplification (OPCPA). The first stage as preamplification with three pieces of BBO crystals provides the majority of the energy gain. At the second stage, a YCOB crystal with the aperture of ~50 mm is used instead of the KDP crystal as the gain medium to ensure the shortest pulse. After the completion, the laser will deliver about 8 J with pulse duration of about 10 femtoseconds, which should be beneficial to the attosecond pulse generation and other ultrafast experiments.Jianqiang Zhu, Xinglong Xie, Meizhi Sun, Qunyu Bi, and Jun KangCopyright © 2012 Jianqiang Zhu et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/275682/A monochromatic continuous millimeter-wave imaging system coupled with an infrared temperature sensor has been used to investigate artistic objects such as painting artworks or antiquities preserved at the museum of Aquitaine. Especially, 2D and 3D analyses have been performed in order to reveal the internal structure of a nearly 3500-year-old sealed Egyptian jar.Ayesha Younus, Jean-Pascal Caumes, Simon Salort, Bruno Chassagne, Christophe Pradère, Alain Dautant, Anne Ziéglé, and Emmanuel AbrahamCopyright © 2011 Ayesha Younus et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/510186/We investigated carrier recombination dynamics in a low-temperature-grown GaAs (LT-GaAs)/AlGaAs/GaAs heterostructure by laser-combined scanning tunneling microscopy, shaken-pulse-pair-excited STM (SPPX-STM). With the AlGaAs interlayer as a barrier against the flow of photocarriers, recombination lifetimes in LT-GaAs of 4.0 ps and GaAs of 4.8 ns were successfully observed separately. We directly demonstrated the high temporal resolution of SPPX-STM by showing the recombination lifetime of carriers in LT-GaAs (4.0 ps) in the range of subpicosecond temporal resolution. In the carrier-lifetime-mapping measurement, a blurring of recombination lifetime up to 50 nm was observed at the LT-GaAs/AlGaAs boundary, which was discussed in consideration of the screening length of the electric field from the STM probe. The effect of the built-in potential on the signal, caused by the existence of LT-GaAs/AlGaAs/GaAs boundaries, was discussed in detail.Yasuhiko Terada, Shoji Yoshida, Osamu Takeuchi, and Hidemi ShigekawaCopyright © 2011 Yasuhiko Terada et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/547597/A new method for detecting the sound pressure in air, which uses the total internal reflection at the curved interface between glass and air, is proposed, and its application to microphone is discussed. The critical angle for total reflection changes by the refractive index of air, which depends on the air density. The density changes by the sound pressure. Therefore, the sound pressure is measurable by detecting the intensity of the reflected light from the total reflection area. The sound pressure sensitivity of the proposed method is investigated theoretically and experimentally. Experimental results show that the microphone using the method is feasible though its sensitivity is low in the present stage. When the sensitivity is improved dramatically for practical use, the microphone becomes very sensitive to the surrounding conditions. A method to compensate the fluctuation of atmospheric pressure or temperature is presented.Yasushi Suzuki and Ken'iti KidoCopyright © 2011 Yasushi Suzuki and Ken'iti Kido. All rights reserved.http://www.hindawi.com/journals/aot/2011/989515/We demonstrate that ultrashort optical pulses propagating in a nonlinear dispersive medium are naturally described through incorporation of analytic signal for the electric field. To this end a second-order nonlinear wave equation is first simplified using a unidirectional approximation. Then the analytic signal is introduced, and all nonresonant nonlinear terms are eliminated. The derived propagation equation accounts for arbitrary dispersion, resonant four-wave mixing processes, weak absorption, and arbitrary pulse duration. The model applies to the complex electric field and is independent of the slowly varying envelope approximation. Still the derived propagation equation posses universal structure of the generalized nonlinear Schrödinger equation (NSE). In particular, it can be solved numerically with only small changes of the standard split-step solver or more complicated spectral algorithms for NSE. We present exemplary numerical solutions describing supercontinuum generation with an ultrashort optical pulse.Sh. Amiranashvili and A. DemircanCopyright © 2011 Sh. Amiranashvili and A. Demircan. All rights reserved.http://www.hindawi.com/journals/aot/2011/213783/Cancer is one of the leading causes of death throughout the world. Advancements in early and improved diagnosis could help prevent a significant number of these deaths. Raman spectroscopy is a vibrational spectroscopic technique which has received considerable attention recently with regards to applications in clinical oncology. Raman spectroscopy has the potential not only to improve diagnosis of cancer but also to advance the treatment of cancer. A number of studies have investigated Raman spectroscopy for its potential to improve diagnosis and treatment of a wide variety of cancers. In this paper the most recent advances in dispersive Raman spectroscopy, which have demonstrated promising leads to real world application for clinical oncology are reviewed. The application of Raman spectroscopy to breast, brain, skin, cervical, gastrointestinal, oral, and lung cancers is reviewed as well as a special focus on the data analysis techniques, which have been employed in the studies.Michael B. Fenn, Petros Xanthopoulos, Georgios Pyrgiotakis, Stephen R. Grobmyer, Panos M. Pardalos, and Larry L. HenchCopyright © 2011 Michael B. Fenn et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/723901/We analyze numerically correspondence between the mechanical action, experienced by a spherical microparticle, and the internal energy flows in the light field incident on the particle. The inhomogeneous incident field is modelled by superposition of two plane waves; the mechanical action is calculated via the Mie theory for dielectric and conducting particles of different sizes and optical properties. It is shown that both spin and orbital components of the field momentum can produce the mechanical action whose value and sign depend on many additional details of the field-particle interaction. Besides, forces that are not associated with any sort of the energy flow (e.g., the gradient force owing to the inhomogeneous intensity and the polarization-dependent dipole force emerging due to inhomogeneous polarization) can strongly modify the observed mechanical action. The polarization-dependent mechanical action on particles can be treated as a form of the spin-orbit interaction of light.A. Ya. Bekshaev, O. V. Angelsky, S. V. Sviridova, and C. Yu. ZenkovaCopyright © 2011 A. Ya. Bekshaev et al. All rights reserved.http://www.hindawi.com/journals/aot/2012/727206/We present designs of all-optical reversible gates, namely, Feynman, Toffoli, Peres, and Feynman double gates, with optically controlled microresonators. To demonstrate the applicability, a bacteriorhodopsin protein-coated silica microcavity in contact between two tapered single-mode fibers has been used as an all-optical switch. Low-power control signals (<200 μW) at 532 nm and at 405 nm control the conformational states of the protein to switch a near infrared signal laser beam at 1310 or 1550 nm. This configuration has been used as a template to design four-port tunable resonant coupler logic gates. The proposed designs are general and can be implemented in both fiber-optic and integrated-optic formats and with any other coated photosensitive material. Advantages of directed logic, high Q-factor, tunability, compactness, low-power control signals, high fan-out, and flexibility of cascading switches in 2D/3D architectures to form circuits make the designs promising for practical applications.Sukhdev Roy, Purnima Sethi, Juraj Topolancik, and Frank VollmerCopyright © 2012 Sukhdev Roy et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/710628/We have developed a white organic light-emitting diode featuring a double emission layer comprising a blue light-emitting conductive polymer as a host material for Cadmium Selenide (CdSe) quantum dots as red light emitters and tris-(8-hydroxyquinoline) aluminium thin layer for green light emission. The Commission Internationale de l'Eclairage coordinates of the emitting light of the device were found to be (0.32, 0.40) which were only slightly changed over a range of applied voltages between 5 and 10 volts. The use of CdSe nanocrystalline quantum dots (surface-stabilized with hexadecylamine/trioctylphosphine oxide ligands) in the hybrid heterostructure with poly(9,9-di-n-octylfluorenyl-2,7-diyl) conductive polymer was studied for a variety of CdSe concentrations developing the performance of the device in means of overcoming segregation problems in the blend. Besides, constituents' ratio was further examined for the exploration of possible energy transfer from polymer host material to the CdSe quantum dots as a key factor for well-balanced emission in the electroluminescent devices.Ilker Oner, Elias Stathatos, and Canan VarlikliCopyright © 2011 Ilker Oner et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/105232/The polarized light transmittance of magnetic fluids under longitudinal magnetic field (parallels the propagation direction of the incident light) is simulated theoretically. The investigated samples are with different reduced thickness (d/λ) in a wide range. Theoretical simulations reveal that the sample reduced thickness has a significant influence on the polarized light transmittance. The thin and thick samples have distinctly different dependence of polarized light transmittance on magnetic field strength. Based on the reduced-thickness- and magnetic-field-dependent polarized light transmittance, several magnetic-fluid-based photonic devices are proposed and discussed.Shengli Pu, Xuekun Bai, and Lunwei WangCopyright © 2011 Shengli Pu et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/504530/The finite difference time-domain (FDTD) method is used to simulate the light absorption enhancement in a plasmonic metal-semiconductor-metal photodetector (MSM-PD) structure employing a metal nanograting with phase shifts. The metal fingers of the MSM-PDs are etched at appropriate depths to maximize light absorption through plasmonic effects into a subwavelength aperture. We also analyse the nano-grating phase shift and groove profiles obtained typically in our experiments using focused ion beam milling and atomic force microscopy and discuss the dependency of light absorption enhancement on the nano-gratings phase shift and groove profiles inscribed into MSM-PDs. Our simulation results show that the nano-grating phase shift blue-shifts the wavelength at which the light absorption enhancement is maximum, and that the combined effects of the nano-grating groove shape and phase shift degrade the light absorption enhancement by up to 50%.Narottam Das, Ayman Karar, Chee Leong Tan, Kamal Alameh, and Yong Tak LeeCopyright © 2011 Narottam Das et al. All rights reserved.http://www.hindawi.com/journals/aot/2012/471957/Under certain conditions, a surface plasmon wave along a metal-dielectric interface can be excited by an optical beam. The reflected optical beam will then undergo changes in both intensity and phase. As the level of intensity or phase change is quite sensitive to the coupling conditions such as the molecule concentration on the metal surface, this phenomenon has been utilized for label-free detection of biological species and characterization of molecular interactions during the last two decades. Currently, most of the commercial surface plasmon resonance (SPR) sensors rely on the detection of absorption dip in angular or wavelength spectrum. However, recent researches have shown that phase detection has the potential to achieve lower limit of detection (LoD) and higher throughput. This paper, thus, intends to review various schemes and configurations for SPR phase detection. The performance advantages and disadvantages of various schemes will be emphasized. It is hoped that this paper will provide some insights to researchers interested in SPR sensing and help them to develop SPR sensors with better sensitivity and higher throughput.Y. H. Huang, H. P. Ho, S. Y. Wu, and S. K. KongCopyright © 2012 Y. H. Huang et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/971267/Rare-earth and Bi-substituted iron garnet thin film materials exhibit strong potential for application in various fields of science and frontier optical technologies. Bi-substituted iron garnets possess extraordinary optical and MO properties and are still considered as the best MO functional materials for various emerging integrated optics and photonics applications. However, these MO garnet materials are rarely seen in practical photonics use due to their high optical losses in the visible spectral region. In this paper, we report on the physical properties and magneto-optic behaviour of high-performance RF sputtered highly bismuth-substituted iron garnet and garnet-oxide nanocomposite films of generic composition type (Bi, Dy/Lu)3(Fe, Ga/Al)5O12. Our newly synthesized garnet materials form high-quality nanocrystalline thin film layers which demonstrate excellent optical and MO properties suitable for a wide range of applications in integrated optics and photonics.Mohammad Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh, and Viacheslav KotovCopyright © 2011 Mohammad Nur-E-Alam et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/321807/We developed a small and compact system of diode lasers, which can be inserted into the lower tools of a bending press. The parts of the system allow easy plug and play operation and can be installed for any bending length. The diode laser, which is based on 200 W laser bars on microchannel cooler, allows the heating of sheet metals in the forming zone shortly before and during the bending process. There is no unnecessary heating of other parts of the bending equipment, no wear of the tool, and, if properly done, no damage of the surface of the metal. The power per bending length is 16 kW/m.F. Bammer, D. Schuöcker, T. Schumi, B. Holzinger, and G. HumenbergerCopyright © 2011 F. Bammer et al. All rights reserved.http://www.hindawi.com/journals/aot/2012/814745/The optical properties of afterglow nanoparticles were successfully improved by the addition of polyethylene glycol (PEG) to an afterglow colloidal solution. Afterglow nanoparticles—Sr2MgSi2O7: Eu2+, Dy3+—were prepared by laser ablation in liquid. The quantum yields and the decay curves were measured by a fluorescence spectrophotometer. An increase in the amount of PEG added to the solution increased the quantum yield of the nanoparticles and improved the afterglow property in the initial portion of the decay curve. However, the afterglow property did not change after a substantial amount of time had passed. The afterglow nanoparticles were capped with PEG molecules, and surface defects of the nanoparticles were passivated, which decreased the optical properties.Fumitaka Yoshimura, Mika Ishizaki, Fumihiro Wakai, Masahiko Hara, Osamu Odawara, and Hiroyuki WadaCopyright © 2012 Fumitaka Yoshimura et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/454829/Electrostatic levitation combined with laser heating is becoming a mature technique that has been used for several fundamental and applied studies in fluid and materials sciences (synthesis, property determination, solidification studies, atomic dynamic studies, etc.). This is attributable to the numerous processing conditions (containerless, wide heating temperature range, cooling rates, atmospheric compositions, etc.) that levitation and radiative heating offer, as well as to the variety of diagnostics tools that can be used. In this paper, we describe the facility, highlighting the combined advantages of electrostatic levitation and laser processing. The various capabilities of the facility are discussed and are exemplified with the measurements of the density of selected iron-nickel alloys taken over the liquid phase.Paul-François Paradis, Takehiko Ishikawa, Yuki Watanabe, and Junpei OkadaCopyright © 2011 Paul-François Paradis et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/265702/The finite-difference time-domain (FDTD) algorithm has been used in simulation-based designs of many optical devices, but it fails to reproduce high-Q whispering gallery modes (WGMs). On the other hand, the nonstandard (NS) FDTD algorithm can accurately compute WGMs and can be used to make simulation-based designs of WGM devices. Wavelength splitters using the coupled resonator optical waveguides (CROWs) based on WGM couplings have recently attracted attention because they are potentially ultracompact. In this paper, we design a CROW wavelength splitter using NS FDTD simulations and demonstrate high interchannel extinction ratios of over 20 dB.Naoki Okada, James B. Cole, Shigeki Yamada, Kensuke Ogawa, and Yoshifumi KatayamaCopyright © 2011 Naoki Okada et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/230615/A method for measuring frequencies of the terahertz (THz) radiation emitted by the antenna mounted on the photoconductive (PC) device is presented. Two laser beams with slightly different frequencies irradiate the PC device, producing a beat current of 1 THz in the photocurrent. A microwave signal is applied to the antenna electrode. The frequency of the THz wave is measured using the homodyne detection of the optical beat with the high-order harmonics of the microwave. It is being investigated that the high-order harmonics are produced by the PC device owing to its nonlinearity. Periodic peaks generated by the homodyne detection were observed in the photocurrent, as the microwave was swept from 16 to 20 GHz with a power of −40 dBm. Using the peak frequencies, the THz-wave frequency was determined to be 1030.3±3.73 GHz. The measurement error is estimated to be less than 0.43 GHz. The proposed method realizes a compact frequency meter in the THz region.Kengo Murasawa, Koki Sato, and Takehiko HidakaCopyright © 2011 Kengo Murasawa et al. All rights reserved.http://www.hindawi.com/journals/aot/2011/689289/We consider application of the discrete Fourier transform-spread orthogonal frequency-division multiplexing (DFT-spread OFDM) technique to high-speed fiber optic communications. The DFT-spread OFDM is a form of single-carrier technique that possesses almost all advantages of the multicarrier OFDM technique (such as high spectral efficiency, flexible bandwidth allocation, low sampling rate, and low-complexity equalization). In particular, we consider the optical DFT-spread OFDM system with polarization division multiplexing (PDM) that employs a tone-by-tone linear minimum mean square error (MMSE) equalizer. We show that such a system offers a much lower peak-to-average power ratio (PAPR) performance as well as better bit error rate (BER) performance compared with the optical OFDM system that employs amplitude clipping.Fanggang Wang and Xiaodong WangCopyright © 2011 Fanggang Wang and Xiaodong Wang. All rights reserved.http://www.hindawi.com/journals/aot/2010/138024/This paper addresses the problem of reconstruction of a monochromatic light field from data points, irregularly distributed within a volume of interest. Such setting is relevant for a wide range of three-dimensional display and beam shaping applications, which deal with physically inconsistent data. Two finite-dimensional models of monochromatic light fields are used to state the reconstruction problem as regularized matrix inversion. The Tikhonov method, implemented by the iterative algorithm of conjugate gradients, is used for regularization. Estimates of the model dimensionality are related to the number of degrees of freedom of the light field as to show how to control the data redundancy. Experiments demonstrate that various data point distributions lead to ill-poseness and that regularized inversion is able to compensate for the data point inconsistencies with good numerical performance.Vladislav Uzunov, Atanas Gotchev, and Karen EgiazarianCopyright © 2010 Vladislav Uzunov et al. All rights reserved.http://www.hindawi.com/journals/aot/2010/693530/In the present work, we have suggested a technical solution of a CO laser facility for industrial separation of uranium used in the production of fuel for nuclear power plants. There has been used a method of laser isotope separation of uranium, employing condensation repression in a free jet. The laser operation with nanosecond pulse irradiation can provide acceptable efficiency in the separating unit and the high effective coefficient of the laser with the wavelength of 5.3 μm. Receiving a uniform RF discharge under medium pressure and high Mach numbers in the gas stream solves the problem of an electron beam and cryogenic cooler of CO lasers. The laser active medium is being cooled while it is expanding in the nozzle; a low-current RF discharge is similar to a non-self-sustained discharge. In the present work, we have developed a calculation model of optimization and have defined the parameters of a mode-locked CO laser with an RF discharge in the supersonic stream. The CO laser average power of 3 kW is sufficient for efficient industrial isotope separation of uranium at one facility.Igor Y. Baranov and Andrey V. KoptevCopyright © 2010 Igor Y. Baranov and Andrey V. Koptev. All rights reserved.http://www.hindawi.com/journals/aot/2010/538541/Purpose. To evaluate to which extent individual Zernike terms can be corrected. Methods. Ablation time and fidelity was analysed using different fluence levels (range 90–2000 mJ/cm2) and aspheric ablation profiles. With optimal parameters, the extent to which individual Zernike modes can be corrected was evaluated. Results. The range 188–565 mJ/cm2 resulted as optimum fluence level with an optimum proportion range 50%–90% for high fluence. With optimal parameters, it corresponds to 2.4 s/D at 6 mm OZ, with fidelity variance of 53 μm RMS, and average ablation error of 0.5 μm for each location. Ablation simulation of coma Z[3,±1] showed 98,4% accuracy and 98% fit quality; trefoil Z[3,±3], 99,9% accuracy and 98% fit quality; spherical aberration Z[4,0], 96,6% accuracy and 97% fit quality; secondary astigmatism Z[4,±2], 97,9% accuracy and 98% fit quality. Real ablation on a flat plate of PMMA of coma Z[3,±1] showed 96,7% accuracy and 96% fit quality; trefoil Z[3,±3], 97,1% accuracy and 96% fit quality; spherical aberration Z[4,0], with 93,9% accuracy and 90% fit quality; secondary astigmatism Z[4,±2], with 96,0% accuracy and 96% fit quality. Conclusions. Ablation of aspherical and customised shapes based upon Zernike polynomials up to the the 8th order seems accurate using the dual fluence concept implemented at the AMARIS platform.Samuel Arba-Mosquera and Thomas HollerbachCopyright © 2010 Samuel Arba-Mosquera and Thomas Hollerbach. All rights reserved.http://www.hindawi.com/journals/aot/2010/656421/An alexandrite effect spectropyrometer is used to directly measure the thermal temperature of an argon gas plasma jet from a 100 kW DC plasma torch, and the directly measured thermal temperature of the plasma is 11178±382 K. By using the spectral correction function to delete the spectral lines and to correct its underlying spectrum of the relative spectral power distribution of the plasma jet, the remaining continuum spectral power distribution represents the thermal spectral emission of the plasma jet. The calculated thermal temperature of the corrected relative continuum spectral power distribution by the spectropyrometer is 10106 K ±345 K, which is the true thermal temperature of the plasma jet. The blackbody level (BL) of the thermal plasma jet is defined as the ratio of the true thermal temperature to the directly measured temperature, and the blackbody level is a measure of how well the thermal plasma jet approaches a blackbody. The accuracy of directly measured thermal temperature depends on the blackbody level, the higher the blackbody level, and the higher the thermal temperature measurement accuracy.Peir-Jyh Wang, Chin-Ching Tzeng, and Yan LiuCopyright © 2010 Peir-Jyh Wang et al. All rights reserved.http://www.hindawi.com/journals/aot/2010/783206/We propose an alternative method to design diffractive lenses free of spherical aberration for monochromatic light. Our method allows us to design diffractive lenses with the diffraction structure recorded on the last surface; this surface can be flat or curved with rotation symmetry. The equations that we propose calculate the diffraction profiles for any substratum, for any f-number, and for any position of the object. We use the lens phase coefficients to compensate the spherical aberration. To calculate these coefficients, we use an analytic-numerical method. The calculations are exact, and the optimization process is not required.Sergio Vázquez-Montiel, Omar García-Liévanos, and Juan Alberto Hernández-CruzCopyright © 2010 Sergio Vázquez-Montiel et al. All rights reserved.http://www.hindawi.com/journals/aot/2008/417976/The color image quality of presentation programs is evaluated and measured using S-CIELAB and CIEDE2000 color difference formulae. A color digital image in its original format is compared with the same image already imported by the program and introduced as a part of a slide. Two widely used presentation programs—Microsoft PowerPoint 2004 for Mac and Apple's Keynote 3.0.2—are evaluated in this work.Edison Valencia and María S. MillánCopyright © 2008 Edison Valencia and María S. Millán. All rights reserved.http://www.hindawi.com/journals/aot/2008/359760/Numerous models have been developed for calculating optimum decision rules for nitrogen fertilization based on remote sensing techniques. New technologies related to digital image analysis may provide an alternative method to estimate nutrient status faster and more efficiently than current techniques. A series of field studies was conducted to determine the applicability of digital image analysis for nitrogen demand estimates in broccoli plants. Digital images were taken under constant light conditions in various wavelength ranges (380–1300 nm) using a digital imager. Images were processed for the parameters a∗ and b∗ in the L∗a∗b∗ color system. The image analysis showed a close correlation between the nitrogen status of broccoli plants and the parameter b∗ of the L∗a∗b∗ color system especially in the wavelength ranges 510780 and 516780 nm. The relationship between nutrient concentration in leaf dry matter and the parameters b∗ was used to determine the N fertilizer demand within the cultivation period. Estimated N amounts were applied as top dressing four weeks after setting and were 100 kg ha−1 lower than the standard fertilizer rate. Calculated N balances indicated a total uptake of applied N amounts in the image-based N treatments without considerable yield loss. Thus, digital image analysis proved to be an effective means of determining nitrogen status and adjusting fertilizer applications to preserve or enhance crop quality and yield considering sustainability.Simone Graeff, Judit Pfenning, Wilhelm Claupein, and Hans-Peter LiebigCopyright © 2008 Simone Graeff et al. All rights reserved.http://www.hindawi.com/journals/aot/2008/583687/We analyze in this paper the benefits that can be derived from employing color image alignment techniques in the context of face segmentation or tracking based on texture (defined as the patch of intensities) template matching. By making full use of the decorrelated color information, improvements on the accuracy of the segmentation are demonstrated. This is intended to enhance the face segmentation algorithm by increasing its robustness to differences in images caused by various image acquisition devices or settings or by variations in the ambient illumination conditions.Mircea C. Ionita and Peter CorcoranCopyright © 2008 Mircea C. Ionita and Peter Corcoran. All rights reserved.http://www.hindawi.com/journals/aot/2008/719632/A possibility to connect nonprecise positioned fibers in photopolymerizable compositions is under discussion in this paper. The processes of optical synthesis of connective waveguiding structures forming in such mediums directly by the radiation leaving the edges of connecting fibers are investigated numerically and experimentally as well. It was shown that nonlinear interaction of the light beams allows to connect misaligned and transversally shifted fibers with high efficiency.Sergey Nikolayevich Mensov and Yuri Victorovich PolushtaytsevCopyright © 2008 Sergey Nikolayevich Mensov and Yuri Victorovich Polushtaytsev. All rights reserved.