Optics

We propose a new sensing device based on all-optical nano-objects placed in a suspended periodic array. We demonstrate that the intensity-based sensing mechanism can measure environment refractive index change of the order of 1.8×10−6, which is close to record efficiencies in plasmonic devices.

In recent years, several New England projects have promoted professional development and curriculum design in optics and photonics. Funded in part by the Advanced Technological Education (ATE) program of the National Science Foundation (NSF), these projects have prepared middle and high school teachers, college faculty and career counselors from more than 100 New England institutions to introduce fiber optics, telecommunications and photonics technology education. Four of these projects will be discussed here: (1) The New England Board of Higher Education's (NEBHE) Fiber Optics Technology Education Project, (FOTEP) was designed to teach fiber optics theory and to provide laboratory experiences at the secondary and postsecondary levels. (2) Springfield Technical Community College's Northeast Center for Telecommunications Technologies (NCTT) is developing curricula and instructional materials in lightwave, networking and wireless telecommunications technologies. (3) The Harvard-Smithsonian Center for Astrophysics project ComTech developed a 12-week, hands-on curriculum and teaching strategies for middle and high school science and technology teachers in telecommunications and focused on optical communication (fiber optics). (4) NEBHE's project PHOTON is preparing middle, secondary and postsecondary instructors to introduce theory and laboratory experiences in photonics, including geometric and wave optics as well as principles of lasers and photonics applications.

We present both a computational and an experimental approach to the problem of biological aerosol characterization, joining the expertises reached in the field of theoretical optical scattering by complex, arbitrary shaped particles (multipole expansion of the electromagnetic fields ...

Wavelength scanning interferometry is a known technique to precisely measure the surface topography and plate thickness for transparent materials, such as glass. However, conventional methods have some problems in the practical applications that they require precise sample surface position adjustments relative to the reference surface, and highly accurate linear wavelength scanning. We propose a leastsquares model-fitting algorithm which estimates the surface topography and plate thickness from the interferograms obtained by arbitrary wavelength shift. The LD wavelength tuned by temperature control is measured by a wavelength meter, and the measured values are used in the data analysis. The validity of the proposed method is proved by computer simulations and actual experiments. The atual test results showed good agreement with those by a conventional method, and a onesigma repeatability of 2 nm was obtained.

In the past decades, spectral-domain optical coherence tomography (SD-OCT) has transformed into a widely popular imaging technology which is used in many research and clinical applications. Despite such fast growth in the field, the technology has not been readily accessible to many research laboratories either due to the cost or inflexibility of the commercially available systems or due to the lack of essential knowledge in the field of optics to develop custom-made scanners that suit specific applications. This paper aims to provide a detailed discussion on the design and development process of a typical SD-OCT scanner. The effects of multiple design parameters, for the main optical and optomechanical components, on the overall performance of the imaging system are analyzed and discussions are provided to serve as a guideline for the development of a custom SD-OCT system. While this article can be generalized for different applications, we will demonstrate the design of a SD-OCT s...

Tohoku University researchers have revealed more details about omnidirectional photoluminescence (ODPL) spectroscopy-a method for probing semiconducting crystals with light to detect defects and impurities. [32] Researchers have measured an optical clock's ticking with record-breaking accuracy while also showing the clock can be operated with unprecedented consistency. [31] The optical tweezer is revealing new capabilities while helping scientists understand quantum mechanics, the theory that explains nature in terms of subatomic particles. [30] In the perspective, Gabor and Song collect early examples in electron metamaterials and distil emerging design strategies for electronic control from them. [29] Lawrence Livermore National Laboratory (LLNL) researchers are working to make better electronic devices by delving into the way nanocrystals are arranged inside of them. [28] Self-assembly and crystallisation of nanoparticles (NPs) is generally a complex process, based on the evaporation or precipitation of NP-building blocks. [27] New nanoparticle-based films that are more than 80 times thinner than a human hair may help to fill this need by providing materials that can holographically archive more than 1000 times more data than a DVD in a 10-by-10-centimeter piece of film. [26] Researches of scientists from South Ural State University are implemented within this area. [25] Following three years of extensive research, Hebrew University of Jerusalem (HU) physicist Dr. Uriel Levy and his team have created technology that will enable computers and all optic communication devices to run 100 times faster through terahertz microchips. [24] When the energy efficiency of electronics poses a challenge, magnetic materials may have a solution. [23] An exotic state of matter that is dazzling scientists with its electrical properties, can also exhibit unusual optical properties, as shown in a theoretical study by researchers at A*STAR. [22]

Drawing of the hollow all-polymer Bragg fibers based on PMMA/PS and PVDF/PC materials combinations are demonstrated. Hole collapse during drawing effects the uniformity of a photonic crystal reflector in the resultant fiber. We first investigate how the core collapse effects fiber transmission properties. We then present modelling of fluid dynamics of hollow multilayer polymer fiber drawing. Particularly, hole collapse during

Visible Laser Light Communication System (VLLC) is a wireless communication system, using laser as the medium. In the data transfer process, it is possible to have optical interference where 2 laser beams coincide with one point on the reflector. Research on the effect of laser source interference has been carried out by several researchers including mitigation actions to reduce its effects. This experiment uses 2 optical distance sensors that produce a laser with a wavelength of 650 nm with a power <=4.1 mW and with the direction of the laser beam both of them cross each other. To determine the effect of the interference of two laser beams when crossing the communication process in the visible light communication system, a reflector is used which can capture the two laser beams and the reflector can be shifted gradually so that a condition can be obtained where the two laser beams meet at one point. From the measurements made at the points after the laser beam crossing, the meas...

The S-Bend structures are heavily exploited to join optical components. Reducing the power loss caused by the curve is the main objective in the design step of these components. However integrated optical circuits require S-Bend waveguide to be low loss and compact sized. In this paper, we present a contribution to link the curved structure to the straight waveguide by using the simulated bend function available in the Beam propagation tool of the Rsoft commercial software package. Simulation results confirm that this approach allows a reduction of the size of the curved structure with offset with relatively minimum of losses for photonic field.

We have developed a super compact optical fluorescence spectrometer. Our innovative design combines advantages of guided wave planar optics and free-space microoptics. This innovation allows for miniaturization that is not achievable with pure planar or pure free-space optics. A prototype device has volume of its optical part below 1cm3. The spectrometer covers 450nm-650nm spectral range, and provides spectral resolution of

Received XX Month XXXX; revised XX Month, XXXX; accepted XX Month XXXX; posted XX Month XXXX (Doc. ID XXXXX); published XX Month XXXX The simultaneous measurement of numerical aperture (NA) and mode field diameter (MFD) of single-mode fibers (SMF) was performed on several commercial fibers by means of digital image processing of the output light projected into a screen. In addition, the changes induced by core diffusion in an ultra-high (UH) NA fiber at several heat depositions from a CO2 laser source were measured. The measurement method demonstrated to be useful to monitor the adiabaticity of this process, by taking the product of the NA and MFD in order to verify if it remains constant. The method provides a cheap alternative to measure these optical fiber parameters by using simple optomechanical elements, readily available smartphone camera and can be easily implemented in the laboratory.

The generation of terahertz (THz) transients in photoconductive emitters has been studied by varying the spatial extent and density of the optically excited photocarriers in asymmetrically excited, biased low-temperature-grown GaAs antenna structures. We find a pronounced dependence of the THz pulse intensity and broadband (>6.0 THz) spectral distribution on the pump excitation density and simulate this with a three-dimensional carrier dynamics model. We attribute the observed variation in THz emission to changes in the strength of the screening field.

We analyze interactions between moving dissipative solitons in one- and multidimensional cubic-quintic complex Ginzburg-Landau equations with a linear potential and effective viscosity. The interactions between the solitons are analyzed by using balance equations for the energy and momentum. We demonstrate that the separation between two solitons forming a bound state decreases with the increase of the slope of the linear potential.

We present a model of energy consumption in IP networks. Using this model, we identify energy ldquohotspotsrdquo and estimate how energy consumption will grow with increasing network capacity. Todaypsilas Internet uses less than 1% of the available electricity supply. However, network energy consumption could grow substantially as access rates increase.