In the modern age, due to the rapid development of communication techniques, individuals can be secured by the application optical signal processing technology. In this paper, we have proposed a new technique that is using a multiplexing tactic for optical encrypting mechanism to secure the individuals for multiple users. Here in this paper, we are modifying the classical joint transform correlator to provide more security which is easy in implementation. Our proposed technique that is using encoding and decoding procedure provides more security than the previous techniques. In this approach, amplitude random mask was used for encoding as well as decoding procedure but in a holographic format that modulates the input information and enables us to recover the input information from modulated signal which is difficult for other people. For encoding process, we project the spectrum of the scattered beam of the amplitude random mask on the object that capture the object information in random manner and Fourier transformation gives the spectrum of the coded object. The split beam of the mask is multiplexed to the coming spectrum at the CCD plane for the decoding process unlike the classical joint transform architecture discussed. There is no need of the mechanical moment of the mask. This technique is more efficient than the techniques available in the literature because the advantage of the method introduced in this paper is the decryption performed using the same key code. We present a theoretical explanation, along with computer simulations results that support our proposal.
Fahimeh Abrinaei
A homemade Copper Vapor Laser (CVL) operating at 510 nm (green) and 578 nm (yellow) outputs was applied to vaporize the Mg metal target in the acetone liquid medium. The Mg plate surface was ablated under a 10 kHz repetition rate and maximum pulse energy of 3 mJ and 35 ns pulse duration. Structural, morphological, optical, and chemical-bond properties of synthesized Mg and MgO nanoparticles were investigated using the X-ray diffraction (XRD) analysis; scanning electron microscopy (SEM) observations, UV-VIS absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR) analysis, respectively. The XRD results confirmed the formation of both Mg and MgO nanoparticles. The crystallite size and the strain of final powder were estimated about 57 nm and 0.017 from XRD data calculated using the Williamson-Hall method. The Mg/MgO ratio was also calculated to be about 67% according to Alexander & Klug formula. The chemical bands of products were correctly identified using the FTIR characterization. The SEM images revealed the presence of spherical and plateletlike structures in a range of 50-80 nm in diameter that confirmed the XRD results. UV-VIS absorption spectrum of Mg/MgO nanoparticles synthesized by laser ablation of Mg target in acetone shows a broad peak at about 417 nm attributed to the plasmon absorption band at this wavelength. The derivative method was applied to measure the Eg equal to 2.3 eV for Mg/MgO nanoparticles synthesized in acetone medium under CVL ablation.
Reza Shoja Razavi
Direct Metal Deposition (DMD) is a metal deposition technique, which is well- known for high-quality and high-productivity level of fabrication. In the current economic situation with worldwide trend for developing new products, the importance of time and cost reduction increases day-by-day. To achieve this goal the man-machine-material interaction should be maximized. Direct Laser Metal Deposition (DLMD) is one of the most famous approaches for this. DLMD is one kind of 3D printing technology (additive manufacturing) together with laser cladding process. In DLMD, it is possible to fabricate fully functional metallic parts directly from CAD data, which involves a feeding of metal powders through a nozzle into a high power laser beam and creates a melt pool on the surface of the solid substrate upon which a metallic powder is injected. DLMD process are now acknowledged worldwide and is also known to all by several other names such as Laser Metal Deposition (LMD), Direct Laser Deposition (DLD), Laser Engineered Net Shaping (LENS), Direct Light Fabrication (DLF), Laser Deposition Welding (LDW) and Powder Fusion Welding (PFW). After development of this process in 1995, lot of researchers for several years work on various aspects of high quality deposition with dimensional accuracy such as good clad geometry, clad height, and microstructure study of the mechanical properties. An attempt has been made to focus on proper selection of the set up configuration for direct laser metal deposition to fulfill the requirement and help to achieve high quality deposition. Empirical-statistical models have been produced since the advent of LDMD as they avoid the complexity of analyzing the physical phenomena of the process itself. Direct metal deposition is typically described as having three “primary” process inputs of laser power, powder mass flow rate, and traverse speed. Most models have concentrated on relating these to final track geometry, typically using regression methods to relate input and response variables. Permitting materials to grow along specific orientation by means of directional solidification technique can optimize their structural or functional properties. Ni-based super alloys are the preferred material for turbine blades given their high temperature strength, microstructural stability, and corrosion resistance. Casting methods have been improved from conventional investment casting, which produces an Equiaxed (EQ) grain structure, to Directional Solidification (DS), which produces Columnar-Grain (CG) and Single Crystal (SC) structures. Although polycrystalline Ni-based super alloys are inherently strong, their properties can be further improved through processing. Ensuring crystal cohesion during solidification by avoiding the formation of cracks and pores is a major challenge in materials science. Under others, the safety of gas turbine components and of laser welds for the aerospace and automotive industries depends on it. Solidification cracking (also called hot cracking or hot tearing) is characterized by extended openings that form during solidification in the mushy zone.
Huang Lian
Jane Twain
Stephen Smith
Agatha Christie
Dimitrios Stasinopoulos1,2*, Konstantinos Giannakou3 and Dimitrios Lamnisos3
The aim of the present systematic review was to determine the effectiveness of High Intensity Laser Therapy (HILT) in the management of Lateral Elbow Tendinopathy (LET) and to provide recommendations based on this evidence. Methods: Randomized controlled trials (RCTs) identified by a search strategy in six databases were used in combination with reference checking. RCTs that included HILT, patients with LET, and at least one of the clinically relevant outcome measures were selected. A qualitative analysis of the selected studies was conducted using the Furlan system. Results: Three primary studies met eligibility criteria. All studies had a low risk of bias. There is no evidence for the effectiveness of HILT compared to bandage for the management of LET in the short-term. There is moderate evidence that HILT is more effective than LLLT for the management of LET in the short-term. Conclusion: HILT is a dose-response modality, and the optimal treatment dose has obviously not yet has been discovered. Further research with well-designed RCTs is required to provide meaningful evidence on the effectiveness (absolute and relative) of HILT for the management of LET.
Kaibo Zheng
A Free-Electron Laser (FEL) is a (fourth time) synchrotron light source making incredibly splendid and short beats of synchrotron radiation. A FEL capacities and acts from numerous points of view like a laser, yet rather than utilizing invigorated outflow from nuclear or sub-atomic excitations; it utilizes relativistic electrons as an addition medium. Synchrotron radiation is produced as a lot of electrons go through an attractive design (called undulator or wiggler). In a FEL, this radiation is moreover upgraded as the synchrotron radiation re-associates with the electron pack to such an extent that the electrons begin to produce soundly, accordingly permitting a dramatic expansion in general radiation force. [
Kamal Nain Chopra
Various types of unconventional lasers including Raman lasers, Spin lasers, Random lasers, macroscopic lasers, Nano lasers, and White
lasers. Have recently been the subjects of interest in the research institutes of the world? This Keynote Address is to present some of these
results in the fascinating field of unconventional lasers.
Francesco Enrichi
Optical Coherence Tomography (OCT) is an imaging strategy that utilizations low-soundness light to catch micrometer-goal, two-and three-dimensional pictures from inside optical dispersing media (e.g., natural tissue). It is utilized for clinical imaging and modern nondestructive testing (NDT). Optical intelligence tomography depends on low-lucidness interferometry, regularly utilizing close infrared light. The utilization of somewhat long frequency light permits it to enter into the dissipating medium. Confocal microscopy, another optical strategy, commonly infiltrates less profoundly into the example yet with higher goal.
Dirk Salvia*
A few plans have been exhibited to control the undesirable force journeys of enduring direct in EDFAs. These incorporate quick siphon control, interface control employing the addition of a remunerating sign, and gain clipping by an all-optical criticism circle. A large portion of these plans have zeroed in on accomplishing a shared objective: The greatest worth of the force journeys of the enduring channel ought to be not exactly a negligible part of a decibel for any conceivable change in channel stacking to limit the blunder blasts brought about by signal force drifters coming about because of a line disappointment or an organization reconfiguration. In this segment, we depict the beforehand referenced three plans to control the increase of the enhancer
Micheline Bejjani, Aicha Beya Far and Farid Flitti
In this study, optical properties of magnesium oxide (MgO) thin film deposited on germania (GeO2) and silica (SiO2) were studied as a function of wavelength in the range 0.3-1.1µm using matlab. Refractive indices, extinction coefficients, and absorption coefficients were investigated. The transmittance spectra of MgO thin films of different thicknesses deposited on the different substrates were also examined. The films were found to show high transmittance and low absorbance in the visible and near infrared region. However, the absorbance of the film was found to be high in the ultraviolet. The effects of interference on transmission spectra were also considered. The results give good reason for the applications of MgO thin films in optoelectronic devices.
Nilambar Muduli*, J.S.N Achary, Priya Sahu
Effect on generation of a tunable slow rate light can be estimated by fabricating circular and elliptical PCFs. Choosing the background material to be As2Se3 Chalcogenide glass for their investigation. In addition, we have also measured the maximum allowed pump power for undistorted output pulse, Brillouin gain and time delay using same PCFs structure. It reports that, Brillouin.gain is found to be 87.2 dB/m for circular PCF(C-PCF), 90 dB/m for elliptical PCF (E-PCF) and time delay reaches to 138.64ns C-PCF, 142ns for EPCF.
The above results seem to be measured using 1m long PCFs pumped with 100mW for both C-PCF and E-PCF. The simulating result of E-PCF is much more intensity for potential application in optical buffering, data synchronization, optical memories and signal processing etc over C-PCF.
Journal of Lasers, Optics & Photonics received 279 citations as per Google Scholar report
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