http://www.hindawi.comThe latest articles from Hindawi Publishing Corporation© 2012, Hindawi Publishing Corporation. All rights reserved.http://www.hindawi.com/journals/ijo/2012/361818/In deep penetration laser welding, a keyhole is formed in the material. Based on an experimentally obtained bending keyhole from low- and medium-speed laser penetration welding of glass, the keyhole profiles in both the symmetric plane are determined by polynomial fitting. Then, a 3D bending keyhole is reconstructed under the assumption of circular cross-section of the keyhole at each keyhole depth. In this paper, the behavior of focused Gaussian laser beam in the keyhole is analyzed by tracing a ray of light using Gaussian optics theory, the Fresnel absorption and multiple reflections in the keyhole are systematically studied, and the laser intensities absorbed on the keyhole walls are calculated. Finally, the formation mechanism of the keyhole is deduced.Xiangzhong Jin, Yuanyong Cheng, Licheng Zeng, Yufeng Zou, and Honggui ZhangCopyright © 2012 Xiangzhong Jin et al. All rights reserved.http://www.hindawi.com/journals/ijo/2012/627018/We highlight the feasibility of experimental implementation of both inverted and noninverted wavelength conversion, 2R regeneration, and all-optical logic functions, such as OR, NOR, XOR, and XNOR optical gates by exploiting the self-polarization rotation in a semiconductor optical amplifier (SOA) device without changing the setup configuration. Switching between each optical function is done by only adjusting the input optical power level. In order to allow optimum control and preserve the polarization state of the injected and collected signals, the polarimetric measures have been carried out in free space.Youssef Said and Houria RezigCopyright © 2012 Youssef Said and Houria Rezig. All rights reserved.http://www.hindawi.com/journals/ijo/2012/431826/Higher-order squeezing in different optical processes such as seven-wave mixing and five-wave mixing has been studied. The total noise of a field state is a measure of the fluctuations of the field amplitude. It is shown that the minimum total noise (Tmin) of a higher-order squeezed state always increases with the increase in nonclassicality associated with higher-order squeezing. Thus, from Tmin, one can conclude that highly nonclassical states have large amplitude fluctuations.Savita Gill, Sunil Rani, and Nafa SinghCopyright © 2012 Savita Gill et al. All rights reserved.http://www.hindawi.com/journals/ijo/2012/173250/Finite difference beam propagation method is an accurate numerical procedure, used here to explore the switching dynamics of a nonlinear coherent directional coupler. The coupling lengths derived from this simulation are compared with coupled mode theories. BPM results for the critical power follow the trend of the coupled mode theories, but it lies in between two coupled mode theories. Coupled mode theory is sensitive to numerical approximations whereas BPM results practically do not depend on grid size and longitudinal step size. Effect of coupling-region-width and core-width variations on critical power and coupling length is studied using BPM to look at the aspects of optical power-switch design.Dharmadas KumbhakarCopyright © 2012 Dharmadas Kumbhakar. All rights reserved.http://www.hindawi.com/journals/ijo/2012/575429/Data exchange, namely bidirectional information swapping, provides enhanced flexibility compared to the unidirectional information transfer. To fulfill the rapid development of high-speed large-capacity optical communications with emerging multiplexing/demultiplexing techniques and advanced modulation formats, a laudable goal would be to achieve data exchange in different degrees of freedom (wavelength, time, polarization), for different modulation formats (OOK, DPSK, DQPSK, pol-muxed), and at different granularities (entire data, groups of bits, tributary channels). Optical nonlinearities are potentially suitable candidates to enable data exchange in the wavelength, time, and polarization domains. In this paper, we will review our recent works towards robust data exchange by exploiting miscellaneous optical nonlinearities, including the use of cSFG/DFG in a PPLN waveguide for time- (groups of bits) and channel-selective data exchange and tributary channel exchange between two WDM+OTDM signals, nondegenerate FWM in an HNLF for phase-transparent data exchange (DPSK, DQPSK), bidirectional degenerate FWM in an HNLF for multi-channel data exchange, and Kerr-induced nonlinear polarization rotation in an HNLF for tributary channel exchange of a pol-muxed DPSK OTDM signal. The demonstrated data exchanges in different degrees of freedom, for different modulation formats, and at different granularities, open the door for alternative approaches to achieve superior network performance.Jian Wang and Alan E. WillnerCopyright © 2012 Jian Wang and Alan E. Willner. All rights reserved.http://www.hindawi.com/journals/ijo/2012/916482/Absorption spectroscopy in the long wave infrared provides an effective method for identification of various hazardous chemicals. We present a theoretical design for plasmonic band-pass filters that can be used to provide wavelength selectivity for uncooled microbolometer sensors. The microfilters consist of a pair of input reflection gratings that couple light into a plasmonic waveguide with a central resonant waveguide cavity. An output transmission grating on the other side of the structure pulls light out of the waveguide where it is detected by a closely spaced sensor. Fabrication of the filters can be performed using standard photolithography procedures. A spectral bandpass with a full-width at half-maximum (FWHM) of 100 nm can be obtained with a center wavelength spanning the entire 8–12 μm atmospheric transmission window by simple geometric scaling of only the lateral dimensions. This allows the simultaneous fabrication of all the wavelength filters needed for a full spectrometer on a chip.J. M. Banks, P. D. Flammer, T. E. Furtak, R. E. Hollingsworth, and R. T. CollinsCopyright © 2012 J. M. Banks et al. All rights reserved.http://www.hindawi.com/journals/ijo/2012/803797/Pure triglycine sulphate (TGS) and LiSO4-doped TGS crystals were grown from aqueous solution by natural evaporation method. The grown crystals were characterized by UV-vis spectroscopy, electrical conductivity (σdc) measurement, dielectric studies, microhardness, and thermogravimetry/differential thermal analysis. Pure TGS and LiSO4-doped TGS crystals were found highly transparent and full faced. The direct current conductivity is found to increase with temperature as well as dopant concentrations. Curie temperature remains the same for pure and doped crystals, but dielectric constant and dielectric loss increase with dopant concentration. The Vicker’s microhardness of the LiSO4-doped TGS crystals along (001) face is found higher than that of pure TGS crystals. Etching studies illustrate the quality of the doped crystal. The experimental results evidence the suitability of the grown crystal for optoelectronic applications.Farhana Khanum and Jiban PodderCopyright © 2012 Farhana Khanum and Jiban Podder. All rights reserved.http://www.hindawi.com/journals/ijo/2012/505023/We review the “Deep Level Saturation Spectroscopy” (DLSS) as the nonlinear method to study the deep local defects in semiconductors. The essence of a method is determined by the processes of sufficiently strong laser modulation (up to saturation) of quasistationar two-step absorption of the probe light via deep levels (DLs). DLSS is based on nonequilibrium processes of the optically induced population changes for deep levels which lead to the changes in an impurity absorption. This method allows us the separation of the spectral contributions from different deep centers (even in the case of their full spectral overlap), on the basis of the difference of their optical activity (photon capture cross-sections) and of their electroactivity difference (carriers capture coefficients). As shown, DLSS is allowed to determine directly the main set of phenomenological parameters (cross-sections, concentration, bound energy, etc.) for deep local defects, their content and energy position in the band gap. Some important aspects of DLSS were shown also: the possibility to connect directly the measured data to the local centers which are participating in radiative recombination, and also the possibility to study directly the phonon relaxation processes in the localized states of deep defects.Vladimir GavryushinCopyright © 2012 Vladimir Gavryushin. All rights reserved.http://www.hindawi.com/journals/ijo/2012/786295/The lidar measurements (Tomsk: 56.5∘N; 85.0∘E) of the optical characteristics of the stratospheric aerosol layer (SAL) in the volcanic activity period 2006–2011 are summarized and analyzed. The background SAL state with minimum aerosol content, observed since 1997 under the conditions of long-term volcanically quiet period, was interrupted in October 2006 by series of explosive eruptions of volcanoes of Pacific Ring of Fire: Rabaul (October 2006, New Guinea); Okmok and Kasatochi (July-August 2008, Aleutian Islands); Redoubt (March-April 2009, Alaska); Sarychev Peak (June 2009, Kuril Islands); Grimsvötn (May 2011, Iceland). A short-term and minor disturbance of the lower stratosphere was also observed in April 2010 after eruption of the Icelandic volcano Eyjafjallajokull. The developed regional empirical model of the vertical distribution of background SAL optical characteristics was used to identify the periods of elevated stratospheric aerosol content after each of the volcanic eruptions. Trends of variations in the total ozone content are also considered.Oleg E. Bazhenov, Vladimir D. Burlakov, Sergey I. Dolgii, and Aleksey V. NevzorovCopyright © 2012 Oleg E. Bazhenov et al. All rights reserved.http://www.hindawi.com/journals/ijo/2012/826763/Optically good quality single crystals of pure and L-lysine monohydrochloride-doped KDP crystals have been grown by a slow evaporation method. The grown crystals have been subjected to optical and dielectric studies. The UV-Vis spectrum shows the transmitting ability of the crystals in the entire visible region and transmittance percentage is increased for the doped KDP crystals. From the dielectric study, it is found that the dielectric constant and the dielectric loss of L-lysine-doped KDP crystals were lower than the pure KDP crystals. Hence L-lysine-doped KDP crystals are found to be more beneficial from an application point of view as compared to pure KDP crystals.N. Kanagathara and G. AnbalaganCopyright © 2012 N. Kanagathara and G. Anbalagan. All rights reserved.http://www.hindawi.com/journals/ijo/2012/606892/We report on recent technological improvements concerning nonlinear patterning of lithium niobate and lithium tantalate in the micrometer and submicrometer scales using surface periodic poling for ferroelectric domain inversion. The fabricated samples were employed for frequency doubling via quasiphase-matching both in bulk and guided wave geometries, including forward and backward configurations and wavelength conversion in bands C and L. We also investigated short-period quasiperiodic samples with randomly distributed mark-to-space ratios.Alessandro C. Busacca, Salvatore Stivala, Luciano Curcio, and Gaetano AssantoCopyright © 2012 Alessandro C. Busacca et al. All rights reserved.http://www.hindawi.com/journals/ijo/2012/739413/We have carried out the calculation and experimental measurement of the field formed by optical schemes composed of an axicon and lens with strong spherical aberrations. The calculation is performed by the methods of geometrical optics and diffraction integral. A mechanism is revealed, which is responsible for increasing the intensity in the near-axial focus of the doublet. It is shown that the formed bottle beam has a small length and the field at the periphery is of two types: oscillating and smooth ones. The changeover of the field from the bottle beam to a z-dependent Bessel beam is traced. The last beam is characterized, in particular, by the Bessel-type structure of its Fourier spectrum.Vladimir N. Belyi, Larisa I. Kramoreva, Muhanna K. Al-Muhanna, and Nikolai A. KhiloCopyright © 2012 Vladimir N. Belyi et al. All rights reserved.http://www.hindawi.com/journals/ijo/2012/537949/The excitation wavelength of conventional Tb3+-activated phosphor is near 270 nm. This study describes novel green-emitting Tb3+-activated amorphous calcium silicate by ultraviolet excitation at 378 nm. The Tb3+-activated amorphous calcium silicate was prepared by heating a sample of Tb3+-activated calcium silicate hydrate (CSH) at 900°C for 30 minutes. The emission wavelength of the resulting phosphor was 544 nm. The optimum excitation wavelength within the range 300–400 nm was 378 nm. The Tb3+-activated amorphous calcium silicate emitted green by ultraviolet irradiation. The optimum initial Tb/Ca atomic ratio of this phosphor was about 0.5. A mechanism for the action of the phosphor is proposed, in which Tb3+ ions existing in the layer of the CSH lead to loss of water molecules and OH groups.Yoshiyuki Kojima, Masaaki Numazawa, Shinnosuke Kamei, and Nobuyuki NishimiyaCopyright © 2012 Yoshiyuki Kojima et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/374581/We report the results of a numerical and experimental analysis of femtosecond pulse propagation in a highly nonlinear photonic crystal fibre (PCF). The propagation of ultrashort pulses in PCF is studied taking into account the effects of dispersion, self-phase modulation, stimulated Raman scattering, and self-steepening. The interaction between linear and nonlinear effects is investigated in order to better understand the interplay of these effects leading to the supercontinuum generation. The initial stage of an ultra-wide-band supercontinuum generation under femtosecond pumping is pointed out. Details about the expansion of the blue and red sides of the supercontinuum due to transfer of energy to dispersive waves are revealed and experimentally confirmed. Our experimental results are compared to numerical solution of the nonlinear Schrödinger equation. Good agreement is found.Rim Cherif and Mourad ZghalCopyright © 2011 Rim Cherif and Mourad Zghal. All rights reserved.http://www.hindawi.com/journals/ijo/2011/737684/Sum-frequency generation of UV pulses exceeding 25 mJ and with beam quality M2∼5 has been demonstrated by mixing the third harmonic pulses of a flash lamp pumped 1.06 μm Nd:YAG laser with 1.7 μm pulses from an optical parametric oscillator pumped by the same laser in a compact setup.Oystein Farsund and Gunnar RustadCopyright © 2011 Oystein Farsund and Gunnar Rustad. All rights reserved.http://www.hindawi.com/journals/ijo/2011/714265/Experimental investigation of a compact 40-kV diode-type photoelectric DC gun driven by 100 fs laser pulses revealed that the space-charge-limited current density could exceed 30 kA/cm2 and that the density increased linearly with the accelerating voltage. We explained these important properties by the balance between the cathode surface field and the field produced by sheet-like electron bunches near the cathode surface. Our simple physical model agreed well with the experimental results.Hiroko Yamamoto, Hiroaki Hamabe, Shintaro Sone, Soichiro Yamaguchi, and Makoto R. AsakawaCopyright © 2011 Hiroko Yamamoto et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/164023/This paper reviews and presents a coherent approach to the design of compact vertical coupler (VC) in InP-based compound semiconductor with variable polarization dependence. As a polarization-independent (PI) coupler, the VC is shown to transfer light with more than 90% efficiency for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. As a polarization-mode splitter (PMS), the VC is shown to preferentially couple TE or TM modes with a contrast ratio of up to 20 dB. We further demonstrate the single-mesa VC, which simplifies the fabrication process and potentially could improve the process yield, and its integration with a multimode interferometer (MMI). The versatility makes the VC a compact and useful input-stage device that not only maximizes input/output coupling efficiency to small active devices but also provides a degree of polarization control before the actual device.Chee-Wei LeeCopyright © 2011 Chee-Wei Lee. All rights reserved.http://www.hindawi.com/journals/ijo/2011/263182/We present the first unique design of a polarization-independent dual-wavelength splitter for wavelengths around 1.3 μm and 1.55 μm that is potentially of great interest to passive optical network (PON) applications. The filter design is simple compared with the other architectures and is based on ridge-type lateral directional couplers that can be readily integrated with other planar waveguide devices. Two design examples, based on InP/InGaAsP and Si/SiGe waveguides, are given. This polarization-independent wavelength splitting is achieved by exploiting the polarization dependence of the waveguides to produce coupling lengths that are sensitive to polarization and wavelength. We show that, to split the wavelengths without splitting the polarizations, the coupling lengths must be sufficiently different for TE and TM and for the different wavelengths in order to give the correct required ratios between the TE and TM coupling lengths for the two wavelengths of interest. We also show that the same approach can be applied to the design of a polarization splitter. The crosstalk, optical bandwidth, and fabrication sensitivity for the wavelength filter are evaluated.Chee-Wei LeeCopyright © 2011 Chee-Wei Lee. All rights reserved.http://www.hindawi.com/journals/ijo/2011/629605/We investigate theoretically the generation of squeezed states in spontaneous and stimulated six-wave mixing process quantum mechanically. It has been found that squeezing occurs in field amplitude, amplitude-squared, amplitude-cubed, and fourth power of field amplitude of fundamental mode in the process. It is found to be dependent on coupling parameter “g” (characteristics of higher-order susceptibility tensor) and phase values of the field amplitude under short-time approximation. Six-wave mixing is a process which involves absorption of three pump photons and emission of two probe photons of the same frequency and a signal photon of different frequency. It is shown that squeezing is greater in a stimulated interaction than the corresponding squeezing in spontaneous process. The degree of squeezing depends upon the photon number in first and higher orders of field amplitude. We study the statistical behaviour of quantum field in the fundamental mode and found it to be sub-Poissonian in nature. The signal-to-noise ratio has been studied in different orders. It is found that signal-to-noise ratio is higher in lower orders. This study when supplemented with experimental observations offers possibility of improving performance of many optical devices and optical communication networks.Sunil Rani, Jawahar Lal, and Nafa SinghCopyright © 2011 Sunil Rani et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/683415/We report on a novel behavior of the electromagnetically induced absorption (EIA) resonance observed on the D2 line of Cs for atoms confined in cells with micrometric thickness. With the enhancement of light intensity, the EIA resonance amplitude suffers from fast reduction, and even at very low intensity (W < 1 mW/cm2), resonance sign reversal takes place and electromagnetically induced transparency (EIT) resonance is observed. Similar EIA resonance transformation to EIT one is not observed in conventional cm-size cells. A theoretical model is proposed to analyze the physical processes behind the EIA resonance sign reversal with light intensity. The model involves elastic interactions between Cs atoms as well as elastic interaction of atom micrometric-cell windows, both resulting in depolarization of excited state which can lead to the new observations. The effect of excited state depolarization is confirmed also by the fluorescence (absorption) spectra measurement in micrometric cells with different thicknesses.A. Krasteva, D. Slavov, and S. CartalevaCopyright © 2011 A. Krasteva et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/417075/The femtosecond nature of X-ray free electron laser (FEL) pulses opens up exciting research possibilities in time-resolved studies including femtosecond photoemission and diffraction. The recent developments of seeding X-ray FELs extend their capabilities by creating stable, temporally coherent, and repeatable pulses. This in turn opens the possibility of spectral engineering soft X-ray pulses to use as a probe for the control of quantum dynamics. We propose a method for extending coherent control pulse-shaping techniques to the soft X-ray spectral range by using a reflective geometry 4f pulse shaper. This method is based on recent developments in asymmetrically cut multilayer optic technology and piezoelectric substrates.A. Aquila, M. Drescher, T. Laarmann, M. Barthelmeß, H. N. Chapman, and S. BajtCopyright © 2011 A. Aquila et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/818302/We have developed an ultrasonic probe for fluorescence modulation to image fluorescence within biological tissues. The probe consists of a focused ultrasonic transducer mounted on actuators for mechanical fan scanning, which can be used in contact with the measuring object aiming for clinical application. The mechanical fan scanning employed in the probe has a beneficial feature of portability. As a result, fluorescent beads, which were localized with the diameter of 2 mm at 20 mm depth in a pork meat tissue, were detected with resolution of 3 mm. The system performance denotes the feasibility of development towards the final goal of ultrasonic fluorescence modulation tomography for clinical applications.Trinh Quang Duc, Shunsuke Kaneta, and Masaki KobayashiCopyright © 2011 Trinh Quang Duc et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/364594/We report the efficient enhancement of light emission from silicon crystal by covering the silicon surface with an ultrathin (several nm) SiO2 layer. The photoluminescence of Si band edge emission (1.14 μm band) at room temperature is enhanced by two orders of magnitude. Compared with a p-Si/n-Si diode, light emission from a p-Si/SiO2/n-Si diode by current injection via direct tunneling is enhanced by more than 3 orders of magnitude. The light-emission enhancement is attributed to the diminishment of nonradiation recombination at the surface/interface and to the space confinement of the carrier recombination. The simple structure and low operating bias (approximately 1 volt) of our light emitting diodes supply a new choice for realizing efficient current injection light source in silicon compatible with conventional ULSI technology.Shucheng Chu and Hirofumi KanCopyright © 2011 Shucheng Chu and Hirofumi Kan. All rights reserved.http://www.hindawi.com/journals/ijo/2011/581810/We theoretically study the problem of Raman gain maximization in uniform silicon photonic-crystal waveguides supporting slow optical modes. For the first time, an exact solution to this problem is obtained within the framework of the undepleted-pump approximation. Specifically, we derive analytical expressions for the maximum signal gain, optimal input pump power, and optimal length of a silicon Raman amplifier and demonstrate that the ultimate gain is achieved when the pump beam propagates at its maximum speed. If the signal’s group velocity can be reduced by a factor of 10 compared to its value in a bulk silicon, it may result in ultrahigh gains exceeding 100 dB. We also optimize the device parameters of a silicon Raman amplifier in the regime of strong pump depletion and come up with general design guidelines that can be used in practice.Ivan D. Rukhlenko, Malin Premaratne, and Govind P. AgrawalCopyright © 2011 Ivan D. Rukhlenko et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/825629/Early cancer detection has been playing an important role in reducing cancer mortality. Optical coherence tomography (OCT), due to its micron-scale resolution, has the ability to detect cancerous tissues at their early stages. For internal organs, endoscopic probes are needed as the penetration depth of OCT is about 1–3 mm. MEMS technology has the advantages of fast speed, small size, and low cost, and it has been widely used as the scanning engine in endoscopic OCT probes. Research results have shown great potential for OCT in endoscopic imaging by incorporating MEMS scanning mirrors. Various MEMS-OCT designs are introduced, and their imaging results are reviewed in the paper.Jingjing Sun and Huikai XieCopyright © 2011 Jingjing Sun and Huikai Xie. All rights reserved.http://www.hindawi.com/journals/ijo/2011/293684/The microcirculation is a complex system, and the visualization of microcirculation has great significance in improving our understanding of pathophysiological processes in various disease conditions, in both clinical and fundamental studies. A range of techniques are available or emerging for investigating different aspect of the microcirculation in animals and humans. This paper reviews the recent developments in the field of high-resolution and high-sensitive optical imaging of microcirculatory tissue beds, emphasizing technologies that utilize the endogenous contrast mechanism. Optical imaging techniques such as intravital microscopy, Capillaroscopy, laser Doppler perfusion imaging, laser speckle perfusion imaging, polarization spectroscopy, photo-acoustic tomography, and various implementations of optical coherence tomography based on Doppler and speckle contrast imaging are presented together with their prospectives and challenges.Hrebesh M. SubhashCopyright © 2011 Hrebesh M. Subhash. All rights reserved.http://www.hindawi.com/journals/ijo/2011/254154/Satellite quantum key distribution is a promising technique that overcomes the limited transmission distance in optical-fiber-based systems. The polarization tracking technique is one of the key techniques in the satellite quantum key distribution. With free-space quantum key distribution between an optical ground station and a satellite, the photon polarization state will be changed according to the satellite movement. To enable polarization based quantum key distribution between mobile terminals, we developed a polarization-basis tracking scheme allowing a common frame of reference to be shared. It is possible to orient two platforms along a common axis by detecting the reference optical signal only on the receiver side with no prior information about the transmitter's orientation. We developed a prototype system for free-space quantum key distribution with the polarization-basis tracking scheme. Polarization tracking performance was 0.092° by conducting quantum key distribution experiments over a 1 km free space between two buildings in a Tokyo suburb.Morio Toyoshima, Hideki Takenaka, Yozo Shoji, Yoshihisa Takayama, Masahiro Takeoka, Mikio Fujiwara, and Masahide SasakiCopyright © 2011 Morio Toyoshima et al. All rights reserved.http://www.hindawi.com/journals/ijo/2011/902158/Nanoradian Surface Profilers (NSPs) are required for state-of-the-art synchrotron radiation optics and high-precision optical measurements. Nano-radian accuracy must be maintained in the large-angle test range. However, the beams' notable lateral motions during tests of most operating profilers, combined with the insufficiencies of their optical components, generate significant errors of ∼1 μrad rms in the measurements. The solution to nano-radian accuracy for the new generation of surface profilers in this range is to apply a scanning optical head, combined with nontilted reference beam. I describe here my comparison of different scan modes and discuss some test results.Shinan QianCopyright © 2011 Shinan Qian. All rights reserved.http://www.hindawi.com/journals/ijo/2011/473910/Differences in the odd to even response for tin isotopes has been observed earlier in resonance ionization experiments, resulting in anomalous odd to even isotope ratios. I have used a theoretical approach known as the spectral simulation approach to understand the cause for such anomaly and the anomaly has also been experimentally verified and found to be in good agreement. The effects of laser parameters such as intensity, accuracy of the excitation laser wavelength and bandwidth on the determination of the tin isotope ratio have been analyzed theoretically and experimentally. The source for such anomalies was found to be the inaccuracy in the excitation laser wavelength. For the 5p2 (3P0) − 5p 6s (P310) (286.3317 nm) transition, an inaccuracy of the order of γL in the peak frequency of the excitation laser (γL=15 GHz) can cause anomalies as large as ∼31% (β=0.31). Use of a very large bandwidth laser (∼60 GHz) reduces the anomaly to as small as −0.003. Alternatively by employing a relatively narrow band laser (∼1.2 GHz), it has been observed that inaccuracy of the order of 3-4 γL in the laser peak frequency does not induce anomalies >0.05. The isotope ratio is sensitive to the inaccuracy in the excitation laser wavelength for an intermediate linewidth laser.Manda SankariCopyright © 2011 Manda Sankari. All rights reserved.http://www.hindawi.com/journals/ijo/2011/215404/A simple method for determining the stress fields in transparent glass artwork pieces is presented. The proposed method is based on the principles of photoelasticity combining imaging and quantitative measures with an image processing algorithm. The main goal was to develop a methodology to help glass artists to determine the ability of their work to resist the thermal shocks by giving them a hazard map based on the stress map of the glass piece.João M. P. Coelho, Catarina Silva, and Teresa AlmeidaCopyright © 2011 João M. P. Coelho et al. All rights reserved.