WorldWideScience

Sample records for device-induced photon attenuation

  1. Uterine doughnut by intrauterine device-induced photon attenuation on three-phase bone scintigraphy: artifact

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Myung Hee; Jeong, Hwan Jeong; Lim, Seok Tae [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2007-02-15

    A 44-year-old female underwent three-phase bone scintigraphy for an evaluation of right hip joint pain. The blood-flow and blood-pool images show a pelvic blush with a photopenic center (doughnut) prior to bladder filling. On the three hour delayed image, the pelvic uptake disappeared. The scintigraphic findings indicated the possibility of an early pregnancy. However, plain radiography demonstrated an intrauterine device. A uterine doughnut developed as a result of photon attenuation of intrauterine device.

  2. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  3. Photon mass attenuation coefficients, effective atomic numbers and ...

    Indian Academy of Sciences (India)

    The attenuation coefficient data were then used to compute the effective atomic number and the electron density of TLD compounds. The interpolation of total attenuation cross-sections of photons of energy in elements of atomic number was performed using the logarithmic regression analysis of the data measured by ...

  4. Compensation for photon attenuation in PET

    International Nuclear Information System (INIS)

    Chintu Chen; Ordonez, C.E.; Xiaolin Yu.

    1992-01-01

    CT/MR and PET images usually are not in registration spatially because of differences in the imaging setup. CT, MR and PET imaging parameters that are used regularly for brain studies in their institution are compared, in addition, because the patient orientations in CT/MR and PET scanners are not the same, slice centers are positioned differently relative to the patients anatomy. For application of the new idea of using structural information from CT or MR images in PET image reconstruction for attenuation correction, image registration is required as a first step so that one can obtain a corresponding anatomic map for any selected PET image plane. The authors chose to use the surface-matching technique developed in their laboratories for image registration because this method is retrospective and accurate. After the PET and CT/MR scans are registered, they reslice the CT/MR images along the planes of the PET images. The differences in slice thickness and slice separation, as well as in image resolution between various image modalities are to be considered

  5. Simulation of Transmission and Attenuation of Photons in a Labyrinth

    Energy Technology Data Exchange (ETDEWEB)

    Hudek, K.

    2004-09-03

    Neutrons travel through tunnels and ducts (labyrinths) according to curves that are universally applicable, regardless of labyrinth geometry or particle energy. Photons were believed to follow this manner, but this has been found not to be the case. Photons transmit through labyrinths with a definite functional dependence upon both particle energy and labyrinth geometry. In the first leg of a two-legged labyrinth, photons attenuate according to the function: Dose = 1/1 + A {center_dot} x{sup 2}. In the second leg, photons attenuate according to the function: Dose = 1/1 + B {center_dot} x{sup 3} in which A and B are functions of energy and labyrinth geometry, and x is a dimensionless unit of d/sqrt(a) in which d is the distance from the labyrinth mouth and a is the cross-sectional area. Dose is an attenuation factor. The A and B values have not been analyzed sufficiently to determine their functional dependence upon energy and cross-sectional area, however they have been tabularized which allows for interpolation of the data for use in calculations. These results were determined by simulating a mono-energetic beam incident upon a two-legged labyrinth with angular spread to cover the mouth. Work was begun on utilizing a real spectrum to determine a functional dependence by placing an iron target at the mouth of the labyrinth, and striking it with an electron beam. However, the techniques used to gather the mono-energetic beam data were not sufficient to effectively gather a complete set of real spectrum data and analyze its functionality.

  6. Modeling transmission and scatter for photon beam attenuators.

    Science.gov (United States)

    Ahnesjö, A; Weber, L; Nilsson, P

    1995-11-01

    The development of treatment planning methods in radiation therapy requires dose calculation methods that are both accurate and general enough to provide a dose per unit monitor setting for a broad variety of fields and beam modifiers. The purpose of this work was to develop models for calculation of scatter and transmission for photon beam attenuators such as compensating filters, wedges, and block trays. The attenuation of the beam is calculated using a spectrum of the beam, and a correction factor based on attenuation measurements. Small angle coherent scatter and electron binding effects on scattering cross sections are considered by use of a correction factor. Quality changes in beam penetrability and energy fluence to dose conversion are modeled by use of the calculated primary beam spectrum after passage through the attenuator. The beam spectra are derived by the depth dose effective method, i.e., by minimizing the difference between measured and calculated depth dose distributions, where the calculated distributions are derived by superposing data from a database for monoenergetic photons. The attenuator scatter is integrated over the area viewed from the calculation point of view using first scatter theory. Calculations are simplified by replacing the energy and angular-dependent cross-section formulas with the forward scatter constant r2(0) and a set of parametrized correction functions. The set of corrections include functions for the Compton energy loss, scatter attenuation, and secondary bremsstrahlung production. The effect of charged particle contamination is bypassed by avoiding use of dmax for absolute dose calibrations. The results of the model are compared with scatter measurements in air for copper and lead filters and with dose to a water phantom for lead filters for 4 and 18 MV. For attenuated beams, downstream of the buildup region, the calculated results agree with measurements on the 1.5% level. The accuracy was slightly less in situations

  7. A new method for detecting hemoglobin directly in whole blood using photon attenuation techniques

    International Nuclear Information System (INIS)

    Medhat, M.E.

    2014-01-01

    The objective of the proposed work is focused on measuring iron concentration directly in whole blood as tool for estimating hemoglobin and anemic conditions in patients across the world. The investigated method depends on theory of photon attenuation through transmission of low energy in whole blood sample. The mathematical expressions for calculating hemoglobin and iron deficit on blood using photon attenuation are derived. Calculations are carried out for estimating concentration of iron in blood samples taken from children, adults and old patients and therefore measuring their hemoglobin and iron deficit from normal values. Theoretical mass attenuation coefficient values were obtained using the XCOM program. A high-resolution gamma-ray spectrometry based on high purity germanium detector was employed to measure attenuation of strongly collimated monoenergetic gamma beam through blood samples. (author)

  8. Variable photonic crystal fiber optical attenuator combining air hole reduction induced radiation and bending loss

    Science.gov (United States)

    Yokota, Hirohisa; Sano, Tomohiko; Imai, Yoh

    2018-02-01

    Recently, an optical attenuator has been important in fiber optic communication systems, because a transmission power in fiber has become higher due to a channel increment in wavelength division multiplexing transmission. A photonic crystal fiber (PCF) optical attenuator is fabricated by air hole diameter reduction in a part of PCF in which radiations are caused in the air hole diameter reduced part of PCF. A PCF optical attenuator has a high power resistance feature due to its radiation-induced operation of optical attenuation. In this paper, we proposed a variable PCF optical attenuator in which a bend was applied to the air hole diameter reduced part in PCF optical attenuator that was fabricated by CO2 laser irradiation. In PCF optical attenuator fabrication, the attenuation was adjusted by the reduced air hole diameter with laser irradiation time control. It was demonstrated that 10.6-13.5 dB of variable attenuation was obtained at 1550 nm-wavelength with 0°-90° bending angle applied to the air hole diameter reduced part in PCF optical attenuator.

  9. Attenuation correction strategies for multi-energy photon emitters using SPECT

    International Nuclear Information System (INIS)

    Pretorius, P.H.; King, M.A.; Pan, T.S.

    1996-01-01

    The aim of this study was to investigate whether the photopeak window projections from different energy photons can be combined into a single window for reconstruction or if it is better to not combine the projections due to differences in the attenuation maps required for each photon energy. The mathematical cardiac torso (MCAT) phantom was modified to simulate the uptake of Ga-67 in the human body. Four spherical hot tumors were placed in locations which challenged attenuation correction. An analytical 3D projector with attenuation and detector response included was used to generate projection sets. Data were reconstructed using filtered backprojection (FBP) reconstruction with Butterworth filtering in conjunction with one iteration of Chang attenuation correction, and with 5 and 10 iterations of ordered-subset maximum-likelihood expectation-maximization reconstruction. To serve as a standard for comparison, the projection sets obtained from the two energies were first reconstructed separately using their own attenuation maps. The emission data obtained from both energies were added and reconstructed using the following attenuation strategies: (1) the 93 keV attenuation map for attenuation correction, (2) the 185 keV attenuation map for attenuation correction, (3) using a weighted mean obtained from combining the 93 keV and 185 keV maps, and (4) an ordered subset approach which combines both energies. The central count ratio (CCR) and total count ratio (TCR) were used to compare the performance of the different strategies. Compared to the standard method, results indicate an over-estimation with strategy 1, an under-estimation with strategy 2 and comparable results with strategies 3 and 4. In all strategies, the CCR's of sphere 4 were under-estimated, although TCR's were comparable to that of the other locations. The weighted mean and ordered subset strategies for attenuation correction were of comparable accuracy to reconstruction of the windows separately

  10. TART calculations of neutron attenuation and neutron-induced photons on 5% and 20% borated polyethylene slabs

    International Nuclear Information System (INIS)

    Wuest, C.R.

    1993-01-01

    The coupled neutron/photon transport code TART has been used to calculate the attenuation of neutrons and the production of induced photons for neutrons incidents on 5% and 20% borated polyethylene slabs. The neutron attenuation lengths are found to be 2.4 cm and 2.9 cm for 5% and 20% borated polyethylene, respectively

  11. An Analytical-empirical Calculation of Linear Attenuation Coefficient of Megavoltage Photon Beams.

    Science.gov (United States)

    Seif, F; Tahmasebi-Birgani, M J; Bayatiani, M R

    2017-09-01

    In this study, a method for linear attenuation coefficient calculation was introduced. Linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. The calculation was done for Cerrobend as a common radiotherapy modifier and Mercury. The values of calculated linear attenuation coefficient with this new method are in acceptable range. Also, the linear attenuation coefficient decreases slightly as the thickness of attenuating filter (Cerrobend or mercury) increased, so the procedure of linear attenuation coefficient variation is in agreement with other documents. The results showed that the attenuation ability of mercury was about 1.44 times more than Cerrobend. The method that was introduced in this study for linear attenuation coefficient calculation is general enough to treat beam modifiers with any shape or material by using the same formalism; however, calculating was made only for mercury and Cerrobend attenuator. On the other hand, it seems that this method is suitable for high energy shields or protector designing.

  12. Calculation of photon attenuation coefficients of elements and compounds from approximate semi-analytical formulae

    Energy Technology Data Exchange (ETDEWEB)

    Roteta, M.; Baro, J.; Fernandez-Varea, J. M.; Salvat, F.

    1994-07-01

    The FORTRAN 77 code PHOTAC to compute photon attenuation coefficients of elements and compounds is described. The code is based on the semi analytical approximate atomic cross sections proposed by Baro et al. (1994). Photoelectric cross sections for coherent and incoherent scattering and for pair production are obtained as integrals of the corresponding differential cross sections. These integrals are evaluated, to a pre-selected accuracy, by using a 20-point Gauss adaptive integration algorithm. Calculated attenuation coefficients agree with recently compiled databases to within - 1%, in the energy range from 1 keV to 1 GeV. The complete source listing of the program PHOTAC is included. (Author) 14 refs.

  13. Calculation of photon attenuation coefficients of elements and compounds from approximate semi-analytical formulae

    International Nuclear Information System (INIS)

    Roteta, M.; Baro, J.; Fernandez-Varea, J. M.; Salvat, F.

    1994-01-01

    The FORTRAN 77 code PHOTAC to compute photon attenuation coefficients of elements and compounds is described. The code is based on the semi analytical approximate atomic cross sections proposed by Baro et al. (1994). Photoelectric cross sections for coherent and incoherent scattering and for pair production are obtained as integrals of the corresponding differential cross sections. These integrals are evaluated, to a pre-selected accuracy, by using a 20-point Gauss adaptive integration algorithm. Calculated attenuation coefficients agree with recently compiled databases to within - 1%, in the energy range from 1 keV to 1 GeV. The complete source listing of the program PHOTAC is included. (Author) 14 refs

  14. Verification of photon attenuation characteristics for 3D printer based small animal lung model

    International Nuclear Information System (INIS)

    Lee, Se Ho; Lee, Seung Wook; Han, Su Chul; Park, Seung Woo

    2016-01-01

    Since it is difficult to measure absorbed dose to mice in vivo, replica mice are mostly used as alternative. In this study, realistic mouse phantom was fabricated by using 3D printer (object500 connex3, Stratasys, USA). Elemental inks as material of 3D printer were selected corresponding to mouse tissue. To represent lung, selected material was partially used with air layer. In order to verify material equivalent, super-flex bolus was simply compared to verify photon attenuation characteristics. In the case of lung, Hounsfield unit (HU) of the phantom were compared with a live mouse. In this study, we fabricated mouse phantom by using 3D printer, and practically verified photon attenuation characteristics. The fabricated phantom shows tissue equivalence as well as similar geometry with live mouse. As more and more growing of 3D printer technique, 3D printer based small preclinical animal phantom would increase reliability of verification of absorbed dose in small animal for preclinical study

  15. Verification of photon attenuation characteristics for 3D printer based small animal lung model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Se Ho; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Han, Su Chul; Park, Seung Woo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2016-05-15

    Since it is difficult to measure absorbed dose to mice in vivo, replica mice are mostly used as alternative. In this study, realistic mouse phantom was fabricated by using 3D printer (object500 connex3, Stratasys, USA). Elemental inks as material of 3D printer were selected corresponding to mouse tissue. To represent lung, selected material was partially used with air layer. In order to verify material equivalent, super-flex bolus was simply compared to verify photon attenuation characteristics. In the case of lung, Hounsfield unit (HU) of the phantom were compared with a live mouse. In this study, we fabricated mouse phantom by using 3D printer, and practically verified photon attenuation characteristics. The fabricated phantom shows tissue equivalence as well as similar geometry with live mouse. As more and more growing of 3D printer technique, 3D printer based small preclinical animal phantom would increase reliability of verification of absorbed dose in small animal for preclinical study.

  16. Computation of the mass attenuation coefficient of polymeric materials at specific gamma photon energies

    Science.gov (United States)

    Mirji, Rajeshwari; Lobo, Blaise

    2017-06-01

    The gamma ray mass attenuation coefficients of ten synthetic polymeric materials, namely, polyethylene (PE), polystyrene (PS), polycarbonate (PC), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyethylene terephthalate (PET), Polyvinyl pyrrolidone (PVP), Polytetrafluoroethylene (PTFE), Polypropylene (PP) and Polymethyl methacrylate (PMMA) have been calculated using second order polynomial equation and logarithmic interpolation formula at selected gamma photon energies, in the energy range starting from 14.4 keV up to 1332 keV. It is important to note that second order polynomial equation fits very well with NIST data for all the polymeric materials considered here, for gamma photon energies ranging from 300 keV up to 2000 keV. Third order polynomial fitting is best suited for lower gamma photon energies (from 10 keV up to 200 keV).

  17. Single photon emission computed tomography using a regularizing iterative method for attenuation correction

    International Nuclear Information System (INIS)

    Soussaline, Francoise; Cao, A.; Lecoq, G.

    1981-06-01

    An analytically exact solution to the attenuated tomographic operator is proposed. Such a technique called Regularizing Iterative Method (RIM) belongs to the iterative class of procedures where a priori knowledge can be introduced on the evaluation of the size and shape of the activity domain to be reconstructed, and on the exact attenuation distribution. The relaxation factor used is so named because it leads to fast convergence and provides noise filtering for a small number of iteractions. The effectiveness of such a method was tested in the Single Photon Emission Computed Tomography (SPECT) reconstruction problem, with the goal of precise correction for attenuation before quantitative study. Its implementation involves the use of a rotating scintillation camera based SPECT detector connected to a mini computer system. Mathematical simulations of cylindical uniformly attenuated phantoms indicate that in the range of a priori calculated relaxation factor a fast converging solution can always be found with a (contrast) accuracy of the order of 0.2 to 4% given that numerical errors and noise are or not, taken into account. The sensitivity of the (RIM) algorithm to errors in the size of the reconstructed object and in the value of the attenuation coefficient μ was studied, using the same simulation data. Extreme variations of +- 15% in these parameters will lead to errors of the order of +- 20% in the quantitative results. Physical phantoms representing a variety of geometrical situations were also studied

  18. Calculation of photon attenuation coefficients of elements and compounds from approximate semi-analytical formulae

    International Nuclear Information System (INIS)

    Roteta, M.; Baro, J.; Fernandez-Varea, J.M.; Salvat, F.

    1994-01-01

    The FORTRAN 77 code PHOTAC to compute photon attenuation coefficients of elements and compounds is described. The code is based on the semi-analytical approximate atomic cross sections proposed by Baro et al. (1994). Photoelectric cross sections are calculated directly from a simple analytical expression. Atomic cross sections for coherent and incoherent scattering and for pair production are obtained as integrals of the corresponding differential cross sections. These integrals are evaluated, to a pre-selected accuracy, by using a 20-point Gauss adaptive integration algorithm. Calculated attenuation coefficients agree with recently compiled databases to within equal 1%, in the energy range from 1 KeV to 1 GeV. The complete source listing of the program PHOTAC is included

  19. Attenuation correction in pulmonary and myocardial single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Almquist, H

    2000-01-01

    The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiologic and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients observed without attenuation correctionwere artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 {+-} 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer {sup 133}Xe. Because of the low energy of {sup 133}Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study.

  20. Attenuation correction in pulmonary and myocardial single photon emission computed tomography

    International Nuclear Information System (INIS)

    Almquist, H.

    2000-01-01

    The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiologic and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients observed without attenuation correction were artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 ± 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer 133 Xe. Because of the low energy of 133 Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study

  1. Measurement of exposure buildup factors: The influence of scattered photons on gamma-ray attenuation coefficients

    Science.gov (United States)

    Mann, Kulwinder Singh

    2018-01-01

    Scattered photon's influence on measured values of attenuation coefficients (μm, cm2g-1) for six low-Z (effective atomic number) building materials, at three photon energies has been estimated. Narrow-beam transmission geometry has been used for the measurements. Samples of commonly used engineering materials (Cements, Clay, Lime-Stone, Plaster of Paris) have been selected for the present study. Standard radioactive sources Cs137 and Co60 have been used for obtaining γ-ray energies 661.66, 1173.24 and 1332.50 keV. The optical thickness (OT) of 0.5 mfp (mean free path) has been found the optimum optical thickness (OOT) for μm-measurement in the selected energy range (661.66-1332.50 keV). The aim of this investigation is to provide neglected information regarding subsistence of scattered photons in narrow beam geometry measurements for low-Z materials. The measurements have been performed for a wide range of sample-thickness (2-26 cm) such that their OT varies between 0.2-3.5 mfp in selected energy range. A computer program (GRIC2-toolkit) has been used for various theoretical computations required in this investigation. It has been concluded that in selected energy-range, good accuracy in μm-measurement of low-Z materials can be achieved by keeping their sample's OT below 0.5 mfp. The exposure buildup factors have been measured with the help of mathematical-model developed in this investigation.

  2. Attenuation analysis of neutrons and photons generated by 52-MeV protons transmitted through shielding materials

    International Nuclear Information System (INIS)

    Uwamino, Y.; Nakamura, T.

    1983-01-01

    Attenuation of neutrons and photons transmitted through grahite, iron, water and ordinary concrete assemblies were studied using gold foils for thermal neutron and an NE-213 organic scintillation detector with an (n-γ) discrimination technique for spectral measurements. Source neutrons and photons were produced by 52-MeV proton bombardment of a 21.4-mm-thick graphite target placed in front of the assembly. The distributions of the light output from the scintillator were unfolded by the revised FERDO code. These experimental results were used as benchmark data on neutron and photon penetration by neutrons energy above 15MeV. Multigroup Monte Carlo, one-dimensional ANISN and two-dimensional DOT-3.5 transport calculations were performed with the DLC-58/HELLO group cross sections to compare with the measurement and to evaluate the cross sections. The DOT code was also used for the estimation of room-scattered neutron and photon contribution to the measured spectra. The results of the ANISN calculation of neutrons and the three-dimensional Monte Carlo calculation agreed with the experimental values except for high energy neutrons transmitted through water and graphite. The agreement of both calculations was well within the accuracy of 7% in the measured attenuation coefficients. For photons, the ANISN calculation gave >20% overestimation of the attenuation coefficients in the case of deep penetration through the medium for which the photon mean-free-path is shorter than that of neutrons, such as in iron and concrete. The result of the DOT calculation of neutrons down to thermal energy agreed well with the gold foil measurement in the absolute value. (author)

  3. Flash-Bang Detector to Model the Attenuation of High-Energy Photons

    Science.gov (United States)

    Pagsanjan, N., III; Kelley, N. A.; Smith, D. M.; Sample, J. G.

    2015-12-01

    It has been known for years that lightning and thunderstorms produce gamma rays and x-rays. Terrestrial gamma-ray flashes (TGFs) are extremely bright bursts of gamma rays originating from thunderstorms. X-ray stepped leaders are bursts of x-rays coming from the lightning channel. It is known that the attenuation of these high-energy photons is a function of distance, losing energy and intensity at larger distances. To complement gamma-ray detectors on the ground it would be useful to measure the distance to the flash. Knowing the distance would allow for the true source fluence of gamma rays or x-rays to be modeled. A flash-bang detector, which uses a micro-controller, a photodiode, a microphone and temperature sensor will be able to detect the times at which lightning and thunder occurs. Knowing the speed of sound as function of temperature and the time difference between the flash and the thunder, the range to the lightning can be calculated. We will present the design of our detector as well as some preliminary laboratory test results.

  4. The use of filtering methods to compensate for constant attenuation in single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Gullberg, G.T.; Budinger, T.F.

    1981-01-01

    A back projection of filtered projection (BKFIL) reconstruction algorithm is presented that is applicable to single-photon emission computed tomography (ECT) in the presence of a constant attenuating medium such as the brain. The filters used in transmission computed tomography (TCT)-comprised of a ramp multiplied by window functions-are modified so that the single-photon ECT filter is a function of the constant attenuation coefficient. The filters give good reconstruction results with sufficient angular and lateral sampling. With continuous samples the BKFIL algorithm has a point spread function that is the Hankel transform of the window function. The resolution and statistical properties of the filters are demonstrated by various simulations which assume an ideal detector response. Statistical formulas for the reconstructed image show that the square of the percent-root-mean-square (percent-rms) uncertainty of the reconstruction is inversely proportional to the total measured counts. The results indicate that constant attenuation can be compensated for by using an attenuation-dependent filter that reconstructs the transverse section reliably. Computer time requirements are two times that of conventional TCT or positron ECT and there is no increase in memory requirements

  5. Megavoltage photon beam attenuation by carbon fiber couch tops and its prediction using correction factors

    International Nuclear Information System (INIS)

    Hayashi, Naoki; Shibamoto, Yuta; Obata, Yasunori; Kimura, Takashi; Nakazawa, Hisato; Hagiwara, Masahiro; Hashizume, Chisa I.; Mori, Yoshimasa; Kobayashi, Tatsuya

    2010-01-01

    The purpose of this study was to evaluate the effect of megavoltage photon beam attenuation (PBA) by couch tops and to propose a method for correction of PBA. Four series of phantom measurements were carried out. First, PBA by the exact couch top (ECT, Varian) and Imaging Couch Top (ICT, BrainLAB) was evaluated using a water-equivalent phantom. Second, PBA by Type-S system (Med-Tec), ECT and ICT was compared with a spherical phantom. Third, percentage depth dose (PDD) after passing through ICT was measured to compare with control data of PDD. Forth, the gantry angle dependency of PBA by ICT was evaluated. Then, an equation for PBA correction was elaborated and correction factors for PBA at isocenter were obtained. Finally, this method was applied to a patient with hepatoma. PBA of perpendicular beams by ICT was 4.7% on average. With the increase in field size, the measured values became higher. PBA by ICT was greater than that by Type-S system and ECT. PBA increased significantly as the angle of incidence increased, ranging from 4.3% at 180 deg to 11.2% at 120 deg. Calculated doses obtained by the equation and correction factors agreed quite well with the measured doses between 120 deg and 180 deg of angles of incidence. Also in the patient, PBA by ICT was corrected quite well by the equation and correction factors. In conclusion, PBA and its gantry angle dependency by ICT were observed. This simple method using the equation and correction factors appeared useful to correct the isocenter dose when the PBA effect cannot be corrected by a treatment planning system. (author)

  6. Characterization and attenuation study on tannin-added Rhizophora spp. particleboard at high energy photon and electron

    Science.gov (United States)

    Yusof, Mohd Fahmi Mohd; Hamid, Puteri Nor Khatijah Abd; Tajuddin, Abd Aziz; Abdullah, Reduan; Hashim, Rokiah; Bauk, Sabar; Isa, Norriza Mohd; Isa, Muhammad Jamal Md

    2017-01-01

    The effective atomic number of tannin-added Rhizophora spp. particleboards was determined based on elemental composition using Energy Dispersive X-ray Analysis (EDXA). The value of mass attenuation coefficients were measured using 137Cs and 60Co gamma energies. The attenuation properties of PDD curves and beam profile of tannin-added Rhizophora spp. particleboards were investigated using Gafchromic EBT2 film at 6 MV photon and 6 MeV electrons and compared to the value in water and solid water phantoms. The results showed that tannin-added Rhizophora spp. particleboards having effective atomic number close to the value of water. The mass attenuation coefficients were near to the value of water with χ2 values of 0.018 and 0.357 to 137Cs and 60Co gamma energies respectively. The PDD of tannin-added Rhizophora spp. particleboards at 6 MV photons showed good agreement within 3.21 and 5.91% to that in solid water phantoms and water respectively. The PDD at 6 MeV electrons showed a good agreement within 3.32 and 3.12% to that in solid water phantoms and water respectively. The depth of R50 and R90 in tannin-added Rhizophora spp. also showed a good agreement to that in water and solid water pahtoms. Lower surface dose was observed in tannin-added Rhizophora spp. particleboards at electron beams in comparison to solid water phantoms and water.

  7. On the Attenuation of Neutrons and Photons in a Duct Filled with a Helical Plug

    Energy Technology Data Exchange (ETDEWEB)

    Aalto, E.; Krell, Aa.

    1966-12-15

    Neutron and gamma ray attenuation has been studied in a cylindrical duct, length/diam. ratio 7, partly (36 vol.%) filled by a helical (screw-like) plug with adjustable number of turns. The total neutron leakage through the duct decreased by a factor of six from zero to 0.5 turn, and by an additional factor of three from 0.5 to 2 turns (saturation value). The leakage with less than 0.5 turn is governed by fast flux and above 0.5 turn by epithermal flux. It is observed that the attenuation calculation in a homogenized, infinite material combined with the predicted attenuation in a duct give the measured saturation attenuation. The length coordinates used must be slightly modified in this case. The attenuation of gamma in the saturation case (3 turns) equals that predicted without the duct attenuation in a homogenized infinite material.

  8. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

  9. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

  10. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

  11. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

  12. Mass attenuation and mass energy absorption coefficients for 10 keV to 10 MeV photons

    International Nuclear Information System (INIS)

    Joffre, H.; Pages, L.

    1968-01-01

    In this report are given the elements allowing the definition of the values of mass attenuation coefficients and mass energy absorption coefficients for some elements and mixtures, necessary for the study of tissue equivalent materials, for photons in the energy range 10 keV to 10 MeV. After a short reminding of the definitions of the two coefficients, follows, in table form, a compilation of these coefficients, as a function of energy, for simple elements, for certain mineral compounds, organic compounds, gases and particularly of soft tissues. (author) [fr

  13. A novel phantom design for emission tomography enabling scatter- and attenuation-''free'' single-photon emission tomography imaging

    International Nuclear Information System (INIS)

    Larsson, S.A.; Johansson, L.; Jonsson, C.; Pagani, M.; Jacobsson, H.

    2000-01-01

    A newly designed technique for experimental single-photon emission tomography (SPET) and positron emission tomography (PET) data acquisition with minor disturbing effects from scatter and attenuation has been developed. In principle, the method is based on discrete sampling of the radioactivity distribution in 3D objects by means of equidistant 2D planes. The starting point is a set of digitised 2D sections representing the radioactivity distribution of the 3D object. Having a radioactivity-related grey scale, the 2D images are printed on paper sheets using radioactive ink. The radioactive sheets can be shaped to the outline of the object and stacked into a 3D structure with air or some arbitrary dense material in between. For this work, equidistantly spaced transverse images of a uniform cylindrical phantom and of the digitised Hoffman rCBF phantom were selected and printed out on paper sheets. The uniform radioactivity sheets were imaged on the surface of a low-energy ultra-high-resolution collimator (4 mm full-width at half-maximum) of a three-headed SPET camera. The reproducibility was 0.7% and the uniformity was 1.2%. Each rCBF sheet, containing between 8.3 and 80 MBq of 99m TcO 4 - depending on size, was first imaged on the collimator and then stacked into a 3D structure with constant 12 mm air spacing between the slices. SPET was performed with the sheets perpendicular to the central axis of the camera. The total weight of the stacked rCBF phantom in air was 63 g, giving a scatter contribution comparable to that of a point source in air. The overall attenuation losses were <20%. A second SPET study was performed with 12-mm polystyrene plates in between the radioactive sheets. With polystyrene plates, the total phantom weight was 2300 g, giving a scatter and attenuation magnitude similar to that of a patient study. With the proposed technique, it is possible to obtain ''ideal'' experimental images (essentially built up by primary photons) for comparison with

  14. Mass attenuation coefficients of several bio-adhesive based oil palm particleboards at 16.59-25.26 keV photon energies

    Science.gov (United States)

    Abdu Mustapa, U. A.; Yusof, M. F. Mohd; Hamid, P. N. K. Abd; Hashim, R.; Ahmad, M. Z.; Aziz, M. Z. Abd

    2018-01-01

    Particleboards made of oil palm with addition of polylactic acid (PLA), starch, and fish oil were fabricated with target density of 1.0 g/cm3. The mass attenuation coefficients of the particleboards were measured using x-ray fluorescence (XRF) configuration in conjunction with niobium, molybdenum, palladium and tin metal plates that provided Kα1 photon energies between 16.59 and 25.26 keV. The results were compared to the calculated value of water using XCOM. The results showed that all particleboards having mass attenuation coefficients near to the value of water with the mass attenuation coefficient different less than 0.25. The method of fabrication did not give significant different to the mass attenuation coefficients of the particleboards. The results had indicated the potential of bio-adhesive based palm oil particleboards to be developed as phantoms for low energy photons.

  15. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 - 25.26 keV photon energy range

    Science.gov (United States)

    Mohd Yusof, Mohd Fahmi; Hamid, Puteri Nor Khatijah Abdul; Bauk, Sabar; Hashim, Rokiah; Tajuddin, Abdul Aziz

    2015-04-01

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941).

  16. Mass attenuation coefficient of tannin-added Rhizophora spp. particleboards at 16.59-25.56 keV photons, and 137Cs and 60Co gamma energies.

    Science.gov (United States)

    Yusof, Mohd Fahmi Mohd; Hamid, Puteri Nor Khatijah Abd; Tajuddin, Abd Aziz; Hashim, Rokiah; Bauk, Sabar; Isa, Norriza Mohd; Isa, Muhammad Jamal Md

    2017-09-01

    The aim of this study was to determine the suitability of tannin-added Rhizophora spp. particleboards as phantom materials in the application of low- and high-energy photons. The tannin-added Rhizophora spp. particleboards and density plug phantoms were created with a target density of 1.0 g/cm 3 . The elemental composition and effective atomic number of the particleboards were measured using energy dispersive X-ray analysis. The mass attenuation coefficient of the particleboards for low-energy photons were measured using the attenuation of X-ray fluorescence. The mass attenuation coefficients of high-energy photons were measured using the attenuation of 137 Cs and 60 Co gamma energies. The results were compared to the calculated value of water using XCOM calculations. The results showed that the effective atomic number and mass attenuation coefficients of tannin-added Rhizophora spp. particleboards were similar to those of water, indicating the suitability of tannin-added Rhizophora spp. particleboards as phantom materials for low- and high-energy photons.

  17. Effects of Siemens TT-D carbon fiber table top on beam attenuation, and build up region of 6 MV photon beam.

    Science.gov (United States)

    Sheykhoo, Asma; Abdollahi, Sara; Hadizadeh Yazdi, Mohammad Hadi; Ghorbani, Mahdi; Mohammadi, Mohammad

    2017-01-01

    This study deals with Monte Carlo simulations of the effects which the 550 TXT carbon fiber couch can have on the relevant parameters of a 6 MV clinical photon beam in three field sizes. According to the reports issued by the International Commission on Radiation Units and Measurements (ICRU), the calculated dose across a high gradient distribution should be within 2% of the relative dose, or within 0.2 cm of the isodose curve position in the target volume. Nowadays, the use of posterior oblique beam has become a common practice. It is clear that, in radiotherapy, the presence of the couch affects the beam intensity and, as a result, the skin dose. Firstly, Siemens linear accelerator validation for 6 MV photon beam was performed, and satisfactory agreement between Monte Carlo and experimental data for various field sizes was observed. Secondly, the couch transmission factor for the reference field size and depth was computed, and the skin dose enhancement by the couch was assessed. The largest impact of the carbon fiber couch effect was observed for the 5 × 5 cm 2 field size. Such evaluation has not been reported for this couch before. Despite providing minimal attenuation for the primary radiation, the assumption that carbon fiber couches are radiotranslucent is not valid, and the effects of couches of this type on the transmission factor, and on the skin dose should be carefully investigated for each field size and depth.

  18. Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 – 25.26 keV photon energy range

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Yusof, Mohd Fahmi, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, Sabar [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, Rokiah [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-29

    The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941)

  19. Mass attenuation and mass energy absorption coefficients for 10 keV to 10 MeV photons; Coefficients d'attenuation massique et d'absorption massique en energie pour les photons de 10 keV a 10 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Joffre, H.; Pages, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    In this report are given the elements allowing the definition of the values of mass attenuation coefficients and mass energy absorption coefficients for some elements and mixtures, necessary for the study of tissue equivalent materials, for photons in the energy range 10 keV to 10 MeV. After a short reminding of the definitions of the two coefficients, follows, in table form, a compilation of these coefficients, as a function of energy, for simple elements, for certain mineral compounds, organic compounds, gases and particularly of soft tissues. (author) [French] Dans ce rapport, sont donnes les elements permettant de determiner les valeurs des coefficients d'attenuation massique et d'absorption massique en energie pour certains elements et melanges necessaires a l'etude des materiaux equivalents aux tissus pour les photons dans le domaine d'energie allant de 10 keV a 10 MeV. Apres un bref rappel des definitions des deux coefficients, suit, sous forme de tableaux, un recueil de ces coefficients, en fonction de l'energie, pour les elements simples, certains composes mineraux, composes organiques, gaz, et, particulierement, pour les tissus mous. (auteur)

  20. An analytical solution to the shielding of Co 60 teletherapy rooms based on a semiempirical equation of photon attenuation

    International Nuclear Information System (INIS)

    Saez, D.G.; Hernandez, L.; Borroto, M.; Figueredo, M.

    1996-01-01

    A semiempirical equation of polynomial-exponential type is presented to describe the transmission data of Co-60 gamma radiation in finite materials of concrete and lead. This equation and the expression obtained for the relationship of scatter-to-incident exposure made easy the developing in computer of an analytical solution for shielding calculations of Co 60 teletherapy rooms, based on the procedures of the NCRP 49 and Simpkin's method. The standard error in the estimation of parameters is less than 1.7 % except for the attenuation of 150 'o' scattered radiation in concrete that resulted in 6.3 % for one of them. The shielding calculations were compared with the data in NCRP 49 for the same conditions with a correlation better than 99 %

  1. Clinical usefulness of scatter and attenuation correction for brain single photon emission computed tomography (SPECT) in pediatrics

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Itaru; Doi, Kenji; Komori, Tsuyoshi; Hou, Nobuyoshi; Tabuchi, Koujirou; Matsui, Ritsuo; Sueyoshi, Kouzou; Utsunomiya, Keita; Narabayashi, Isamu [Osaka Medical Coll., Takatsuki (Japan)

    1998-01-01

    This investigation was undertaken to study clinical usefulness of scatter and attenuation correction (SAC) of brain SPECT in infants to compare the standard reconstruction (STD). The brain SPECT was performed in 31 patients with 19 epilepsy, 5 cerebro-vascular disease, 2 brain tumor, 3 meningitis, 1 hydrocephalus and psychosis (mean age 5.0{+-}4.9 years old). Many patients was necessary to be injected sedatives for restraining body motion after Technetium-99m hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) was injected at the convulsion or rest. Brain SPECT data were acquired with triple detector gamma camera (GCA-9300 Toshiba Japan). These data were reconstructed by filtered backprojection after the raw data were corrected by triple energy windows method of scatter correction and Chang filtered method of attenuation correction. The same data was reconstructed by filtered backprojection without these corrections. Both SAC and STD SPECT images were analyzed by the visual interpretation. The uptake ratio of cerebral basal nuclei was calculated by the counts of the thalamus or lenticular nuclei divided by the cortex. All images of SAC method were excellent than that of STD method. The thalamic uptake ratio in SAC method was higher than that of STD method (1.22{+-}0.09>0.87{+-}0.22 p<0.01). The lenticular nuclear uptake ratio in SAC method was higher than that of STD method (1.26{+-}0.15>1.02{+-}0.16 p<0.01). Transmission scan is the most suitable method of absorption correction. But the transmission scan is not adequate for examination of children, because this scan needs a lot of time and the infants are exposed by the line source radioisotope. It was concluded that these scatter and absorption corrections were most suitable method for brain SPECT in pediatrics. (author)

  2. Clinical usefulness of scatter and attenuation correction for brain single photon emission computed tomography (SPECT) in pediatrics

    International Nuclear Information System (INIS)

    Adachi, Itaru; Doi, Kenji; Komori, Tsuyoshi; Hou, Nobuyoshi; Tabuchi, Koujirou; Matsui, Ritsuo; Sueyoshi, Kouzou; Utsunomiya, Keita; Narabayashi, Isamu

    1998-01-01

    This investigation was undertaken to study clinical usefulness of scatter and attenuation correction (SAC) of brain SPECT in infants to compare the standard reconstruction (STD). The brain SPECT was performed in 31 patients with 19 epilepsy, 5 cerebro-vascular disease, 2 brain tumor, 3 meningitis, 1 hydrocephalus and psychosis (mean age 5.0±4.9 years old). Many patients was necessary to be injected sedatives for restraining body motion after Technetium-99m hexamethylpropylene amine oxime ( 99m Tc-HMPAO) was injected at the convulsion or rest. Brain SPECT data were acquired with triple detector gamma camera (GCA-9300 Toshiba Japan). These data were reconstructed by filtered backprojection after the raw data were corrected by triple energy windows method of scatter correction and Chang filtered method of attenuation correction. The same data was reconstructed by filtered backprojection without these corrections. Both SAC and STD SPECT images were analyzed by the visual interpretation. The uptake ratio of cerebral basal nuclei was calculated by the counts of the thalamus or lenticular nuclei divided by the cortex. All images of SAC method were excellent than that of STD method. The thalamic uptake ratio in SAC method was higher than that of STD method (1.22±0.09>0.87±0.22 p 1.02±0.16 p<0.01). Transmission scan is the most suitable method of absorption correction. But the transmission scan is not adequate for examination of children, because this scan needs a lot of time and the infants are exposed by the line source radioisotope. It was concluded that these scatter and absorption corrections were most suitable method for brain SPECT in pediatrics. (author)

  3. Investigation of mass attenuation coefficient of almond gum bonded Rhizophora spp. particleboard as equivalent human tissue using XRF technique in the 16.6-25.3 keV photon energy.

    Science.gov (United States)

    Ababneh, Baker; Tajuddin, Abd Aziz; Hashim, Rokiah; Shuaib, Ibrahim Lutfi

    2016-12-01

    This paper reports the novel use of almond gum as a binder in manufacturing Rhizophora spp. particleboard. X-ray fluorescence spectroscopy was employed for analysis under photon energy range of 16.6-25.3 keV. Results showed that almond gum-bonded Rhizophora spp. particleboard can be used as tissue-equivalent phantom in diagnostic radiation. The calculated mass attenuation coefficients of the particleboards were consistent with the values of water calculated using XCOM program for the same photon energies, with p values of 0.056, 0.069, and 0.077 for samples A8, C0, and C8, respectively. However, no direct relationship was found between the percentage of adhesive and the mass attenuation coefficient. The results positively supported the use of almond gum as a binding agent in the fabrication of particleboards, which can be used as a phantom material in dosimetric and quality control applications.

  4. Experimental determination of B R-12 attenuation coefficients utilizing photon spectrometry;Deteminacao experimental de coeficientes de atenuacao de BR-12 atraves de espectrometria de fotons

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Jose N.; Terini, Ricardo A. [Pontificia Universidade Catolica de Sao Paulo (PUC-SP), Sao Paulo, SP (Brazil). Dept. de Fisica; Herdade, Silvio B. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia (IEE). Secao Tecnica de Desenvolvimento Tecnologico em Saude

    2009-07-01

    In tests for quality assurance in mammography, it is common to use breast phantoms, with different compositions. One of the most used is the BR-12 phantom. There are few published experimental data on the attenuation of BR-12. Generally, the available attenuation coefficients are calculated from the composition of the coefficients determined for its components. In this work, the spectrometric method was used, with a CdTe detector, for X- and {gamma}-rays from radioactive sources of {sup 133}Ba and {sup 241}Am. The spectra of direct and attenuated by 0.5 cm of BR-12 beams were measured. From the ratio of intensities obtained for these radiations, it was possible to determine values of the attenuation coefficients from Beer's law. Results show coherence with previous data. The values of such coefficients are useful, for example, for calculations of absorbed dose (in BR-12), which have been made on other research activities of this group. (author)

  5. Experimental apparatus to determine lead attenuation coefficients for photons of 0.511 MeV; Aparato experimental para determinar os coeficientes de atenuação no chumbo para fótons de 0,511 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Luis C.B.; Cardoso, Domingos O.; Gavazza, Sérgio; Morales, Rudnei K., E-mail: claudiovargasbrito@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Oliveira, Luciano S. R. [Instituto de Defesa Química Biológica Radiológica Nuclear (IDQBRN), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Radioactive gamma-emitting sources with higher energies than 1.022 MeV, may interact with matter by pair production process, generating two photons of 0.511 MeV in the positron annihilation, that may contribute to increase doses in both IOE´s or public. National regulatory agencies require a radiation protection plan and a shielding project to consider the influence of these photons in the licensing procedure. This work will present all steps for the development of the experimental apparatus for determination of the attenuation coefficients for photons with energy of 0.511 MeV in lead. (author)

  6. Photon-photon collisions

    International Nuclear Information System (INIS)

    Haissinski, J.

    1986-06-01

    The discussions presented in this paper deal with the following points: distinctive features of gamma-gamma collisions; related processes; photon-photon elastic scattering in the continuum and γγ →gg; total cross section; γγ → V 1 V 2 (V=vector meson); radiative width measurements and light meson spectroscopy; exclusive channels at large /t/; jets and inclusive particle distribution in γγ collisions; and, the photon structure function F γ 2

  7. Photon-photon collisions

    International Nuclear Information System (INIS)

    Burke, D.L.

    1982-10-01

    Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e#betta# scattering. Considerable work has now been accumulated on resonance production by #betta##betta# collisions. Preliminary high statistics studies of the photon structure function F 2 /sup #betta#/(x,Q 2 ) are given and comments are made on the problems that remain to be solved

  8. Photon-photon colliders

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, A.M.

    1995-04-01

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R&D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy.

  9. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1988-07-01

    Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of ..gamma gamma.. physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive ..gamma gamma.. reactions at high momentum transfer. 73 refs., 12 figs.

  10. Photon-photon collisions

    International Nuclear Information System (INIS)

    Field, J.H.

    1984-01-01

    The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e + e - storage rings. After a complete presentation of the helicity amplitude formalism for the general process e + e - → Xe + e - , various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range

  11. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  12. Photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of α/sub s/ and Λ/sup ms/ from the γ*γ → π 0 form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from γγ → H anti H, reconstruction of sigma/sub γγ/ from exclusive channels at low W/sub γγ/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z 0 and W +- beams from e → eZ 0 and e → nu W will become important. 44 references

  13. Attenuation and scatter correction in SPECT

    International Nuclear Information System (INIS)

    Pant, G.S.; Pandey, A.K.

    2000-01-01

    While passing through matter, photons undergo various types of interactions. In the process, some photons are completely absorbed, some are scattered in different directions with or without any change in their energy and some pass through unattenuated. These unattenuated photons carry the information with them. However, the image data gets corrupted with attenuation and scatter processes. This paper deals with the effect of these two processes in nuclear medicine images and suggests the methods to overcome them

  14. CONFERENCE: Photon-photon collisions

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Despite being difficult to observe, photon-photon collisions have opened up a range of physics difficult, or even impossible, to access by other methods. The progress which has been made in this field was evident at the fifth international workshop on photon-photon collisions, held in Aachen from 13-16 April and attended by some 120 physicists

  15. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  16. Photonic Hypercrystals

    Directory of Open Access Journals (Sweden)

    Evgenii E. Narimanov

    2014-10-01

    Full Text Available We introduce a new “universality class” of artificial optical media—photonic hypercrystals. These hyperbolic metamaterials, with periodic spatial variation of dielectric permittivity on subwavelength scale, combine the features of optical metamaterials and photonic crystals. In particular, surface waves supported by a hypercrystal possess the properties of both the optical Tamm states in photonic crystals and surface-plasmon polaritons at the metal-dielectric interface.

  17. Evaluation of attenuating materials: model for the distribution of scattered radiation

    International Nuclear Information System (INIS)

    Costa, Paulo R.

    1996-01-01

    A mathematical model for the behaviour of the distribution of photon scattered by attenuating media is presented. Shielding barriers or attenuating materials used in tests of quality control in radiology are proposed. Comparative results for Lucite are reported

  18. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  19. Attenuation correction in SPECT images using attenuation map estimation with its emission data

    Science.gov (United States)

    Tavakoli, Meysam; Naji, Maryam; Abdollahi, Ali; Kalantari, Faraz

    2017-03-01

    Photon attenuation during SPECT imaging significantly degrades the diagnostic outcome and the quantitative accuracy of final reconstructed images. It is well known that attenuation correction can be done by using iterative reconstruction methods if we access to attenuation map. Two methods have been used to calculate the attenuation map: transmission-based and transmissionless techniques. In this phantom study, we evaluated the importance of attenuation correction by quantitative evaluation of errors associated with each method. For transmissionless approach, the attenuation map was estimated from the emission data only. An EM algorithm with attenuation model was developed and used for attenuation correction during image reconstruction. Finally, a comparison was done between reconstructed images using our OSEM code and analytical FBP method before and after attenuation correction. The results of measurements showed that: our programs are capable to reconstruct SPECT images and correct the attenuation effects. Moreover, to evaluate reconstructed image quality before and after attenuation correction we applied a novel approach using Image Quality Index. Attenuation correction increases the quality and quantitative accuracy in both methods. This increase is independent of activity in quantity factor and decreases with activity in quality factor. In EM algorithm, it is necessary to use regularization to obtain true distribution of attenuation coefficients.

  20. Polychromatic photons

    DEFF Research Database (Denmark)

    Keller, Ole

    2002-01-01

    A review is given of the space-time wave mechanics of single photons, a subject with an almost century long history. The Landau-Peierls photon wave function, which is related nonlocally to the electromagnetic field is first described, and thereafter the so-called energy wave function, based...... on the positive-frequency Riemann-Silberstein vectors, is discussed. Recent attempts to understand the birth process of a photon emerging from a single atom are summarized. The polychromatic photon concept is introduced, and it is indicated how the wave mechanics of polychromatic photons can be upgraded to wave...... in a hyperfine spin transition shows an exponential falloff with the distance from the atomic nucleus. The length parameter in this falloff is the Bohr radius....

  1. Hallo photons calls photon; Allo photon appelle photon

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1997-09-01

    When a pair of photons is created, it seems that these 2 photons are bound together by a mysterious link. This phenomenon has been discovered at the beginning of the seventies. In this new experiment the 2 photons are separated and have to follow different ways through optic cables until they face a quantum gate. At this point they have to chose between a short and a long itinerary. Statistically they have the same probability to take either. In all cases the 2 photons agree to do the same choice even if the 2 quantum gates are distant of about 10 kilometers. Some applications in ciphering and coding of messages are expected. (A.C.)

  2. Dual photon absorptiometry: Validation of mineral and fat measurements

    International Nuclear Information System (INIS)

    Heymsfield, S.B.; Wang, J.; Sulet, M.; Lichtman, S.; Pierson, R.N. Jr.; Kehayias, J.; Lindsay, R.

    1989-01-01

    Photons passing through human tissue undergo attenuation in relation to the specific chemical substances with which they interact. By selecting two appropriate photon energies and recording their attenuation, the investigator can solve simultaneous equations that subdivide body mass into two components: soft tissue and bone mineral ash. The aim of this paper is to describe and to validate the estimates of body composition derived by dual photon systems. The initial studies largely involved dual photon absorptiometers, although the discussion will also include the more recently developed dual energy x-ray absorptiometers. 13 refs., 7 figs., 4 tabs

  3. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  4. Photon diffraction

    Science.gov (United States)

    Hodge, John

    2009-11-01

    In current light models, a particle-like model of light is inconsistent with diffraction observations. A model of light is proposed wherein photon inferences are combined with the cosmological scalar potential model (SPM). That the photon is a surface with zero surface area in the travel direction is inferred from the Michelson-Morley experiment. That the photons in slits are mathematically treated as a linear antenna array (LAA) is inferred from the comparison of the transmission grating interference pattern and the single slit diffraction pattern. That photons induce a LAA wave into the plenum is inferred from the fractal model. Similarly, the component of the photon (the hod) is treated as a single antenna radiating a potential wave into the plenum. That photons are guided by action on the surface of the hod is inferred from the SPM. The plenum potential waves are a real field (not complex) that forms valleys, consistent with the pilot waves of the Bohm interpretation of quantum mechanics. Therefore, the Afshar experiment result is explained, supports Bohm, and falsifies Copenhagen. The papers may be viewed at http://web.citcom.net/˜scjh/.

  5. Attenuation studies near K-absorption edges using Compton ...

    Indian Academy of Sciences (India)

    The results are consistent with theoretical values derived from the XCOM package. Keywords. Photon interaction; 241Am; gamma ray attenuation; Compton scattering; absorption edge; rare earth elements. PACS Nos 32.80.-t; 32.90.+a. 1. Introduction. Photon interaction studies at energies around the absorption edge have ...

  6. Quantum photonics

    CERN Document Server

    Pearsall, Thomas P

    2017-01-01

    This textbook employs a pedagogical approach that facilitates access to the fundamentals of Quantum Photonics. It contains an introductory description of the quantum properties of photons through the second quantization of the electromagnetic field, introducing stimulated and spontaneous emission of photons at the quantum level. Schrödinger’s equation is used to describe the behavior of electrons in a one-dimensional potential. Tunneling through a barrier is used to introduce the concept of non­locality of an electron at the quantum level, which is closely-related to quantum confinement tunneling, resonant tunneling, and the origin of energy bands in both periodic (crystalline) and aperiodic (non-crystalline) materials. Introducing the concepts of reciprocal space, Brillouin zones, and Bloch’s theorem, the determination of electronic band structure using the pseudopotential method is presented, allowing direct computation of the band structures of most group IV, group III-V, and group II-VI semiconducto...

  7. Green photonics

    International Nuclear Information System (INIS)

    Quan, Frederic

    2012-01-01

    Photonics, the broad merger of electronics with the optical sciences, encompasses such a wide swath of technology that its impact is almost universal in our everyday lives. This is a broad overview of some aspects of the industry and their contribution to the ‘green’ or environmental movement. The rationale for energy conservation is briefly discussed and the impact of photonics on our everyday lives and certain industries is described. Some opinions from industry are presented along with market estimates. References are provided to some of the most recent research in these areas. (review article)

  8. Compensation for nonuniform attenuation in SPECT brain imaging

    International Nuclear Information System (INIS)

    Glick, S.J.; King, M.A.; Pan, T.S.; Soares, E.J.

    1996-01-01

    Accurate compensation for photon attenuation is needed to perform quantitative brain single-photon-emission computed tomographic (SPECT) imaging. Bellini's attenuation-compensation method has been used with a nonuniform attenuation map to account for the nonuniform attenuation properties of the head. Simulation studies using a three-dimensional (3-D) digitized anthropomorphic brain phantom were conducted to compare quantitative accuracy of reconstructions obtained with the nonuniform Bellini method to that obtained with the Chang method and to iterative reconstruction using maximum-likelihood expectation maximization (ML-EM). Using the Chang method and assuming the head to be a uniform attenuator gave reconstructions with an average bias of approximately 6-8%, whereas using the Bellini or the iterative ML-EM method with a nonuniform attenuation map gave an average bias of approximately 1%. The computation time required to implement nonuniform attenuation compensation with the Bellini algorithm is approximately equivalent to the time required to perform one iteration of ML-EM. Thus, using the Bellini method with a nonuniform attenuation map provides accurate compensation for photon attenuation within the head, and the method can be implemented in computation times suitable for routine clinical use

  9. Efficient frequency downconversion at the single photon level from the red spectral range to the telecommunications C-band.

    Science.gov (United States)

    Zaske, Sebastian; Lenhard, Andreas; Becher, Christoph

    2011-06-20

    We report on single photon frequency downconversion from the red part of the spectrum (738 nm) to the telecommunications C-band. By mixing attenuated laser pulses with an average photon number per pulse telecommunications wavelengths.

  10. Photon Differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation...

  11. Photon Rao

    Indian Academy of Sciences (India)

    Volume 2 Issue 5 May 1997 pp 69-72 Feature Article. Molecule of the Month Molecular–Chameleon: Solvatochromism at its Iridescent Best! Photon Rao · More Details Fulltext PDF. Volume 16 Issue 12 December 2011 pp 1303-1306. Molecule of the Month - Molecular-Chameleon: Solvatochromism at its Iridescent Best!

  12. Photonics principles and practices

    CERN Document Server

    Al-Azzawi, Abdul

    2006-01-01

    Light The Nature of Light Light and Shadows Thermal Radiation Light Production Light Intensity Light and Colour Laws of Light Optics Plane Mirrors Spherical Mirrors Lenses Prisms Beamsplitters Light Passing through Optical Components Optical Instruments for Viewing Applications Polarization of Light Optical Materials Waves and Diffraction Waves Interference and Diffraction The Diffraction Grating Interferometers Spectrometers and Spectroscopes Optical Fibres Fibre Optic Cables Advanced Fibre Optic Cables Light Attenuation in Optical Components Fibre-Optic Cable Types and Installations Fibre-Optic Connectors Passive Fibre Optic Devices Wavelength Division Multiplexer Optical Amplifiers Optical Receivers Lasers Optical Switches Optical Fibre Communications Fibre Optic Lighting Testing Fibre Optic Testing Safety Photonics Laboratory Safety Miscellaneous Appendix A: Details of the Devices, Components, Tools, and Parts Appendix B: Alignment Procedure of a Conventional Ar...

  13. Simple parametrization of photon mass energy absorption ...

    Indian Academy of Sciences (India)

    More interestingly, it has been observed in the present work that in this energy range, both the mass attenuation coefficients and the mass energy absorption coefficients for such samples vary only with respect to energy. Hence it was possible to represent the photon interaction properties of such samples by a mean value of ...

  14. Photon detectors

    International Nuclear Information System (INIS)

    Va'vra, J.

    1995-10-01

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF 2 windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission

  15. Self-attenuation factors in gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Korun, M.

    1999-01-01

    The relation between the self-attenuation factors and the distribution function describing the number of photons detected in the full-energy peaks, as a function of their path length in the sample is presented. The relations between the self-attenuation factor and the moments of the distribution function, the average path length and the variance are also presented. The use of these relations is illustrated by applying them to self-attenuation factors describing attenuation in cylindrical samples. The results of the calculations are compared with the measured average path lengths and discussed in terms of the properties of the distribution function. (author)

  16. Photon factory

    International Nuclear Information System (INIS)

    Tanaka, J.; Huke, K.; Chikawa, J.

    1985-01-01

    The Photon Factory (PF) was established on April 1, 1978 at KEK. The PF is a synchrotron radiation facility, which has a 2.5 GeV electron storage ring fully dedicated to the SR usage and a 2.5 GeV electron linac supplying electrons and positrons to the PF ring and the accumulation ring of TRISTAN (30 GeV electron-positron colliding machine). The PF consists of three departments, injector linac, light source, and instrumentation department. The facility is described

  17. Ultrafast photon number resolving detector with a temperature stabilized si multi pixel photon counter

    Energy Technology Data Exchange (ETDEWEB)

    Song, Minsoo; Hong, Eugene; Won, Eunil; Yoon, Tai Hyun [Korea Univ., Seoul (Korea, Republic of)

    2008-11-15

    Quantum information science has been rapidly progressed and matured and matured thanks to the recent developments of the single photon detection technologies. Single photon detectors such as a Si avalanche photo diode(APD)in the infrared, an InGaAs/InP APD in the telecommunication band, and a super conducting transient edge sensor(TES)in the broad region of the spectrum have been widely used. Single photon detectors, however, operating at the ultraviolet to visible (370nm∼800nm)regions has not been actively investigated partly due to the lack of single photon and/or entangled photon sources and the lack of solid state single photon detectors. In this paper, we investigate the single photon detection characteristics of a Si multi pixel photon counter(MPPC), which has a high spectral responsivity between 300nm to 800nm, as a photon number resolving solid state detector. Figure 1 shows the schematic diagram of the single photon detection set up at 399nm by using a temperature stabilized Si MPPC. The output beam of the laser being properly attenuated is directed to the MPPC module, at which fixed number of photo electrons corresponding to incident individual photon are generated at Geiger mode of the Si APD pixels. The detected photo current is converted into a digital signal by using a fast analog to digital converter and a digital oscilloscope stores the time sequence of the photo currents. Figure 2 shows the accumulated charges collected by MPPC at∼10.deg.C showing a clear single photon and two photons peaks, respectively, separated by ∼5 sigma of the coincidence counts at the two output ports of a Mach Zender interferometer as a function of optical path length difference. The research was supported by Seoul R and BD program(NT070127)and by the KRISS.

  18. Ultrafast photon number resolving detector with a temperature stabilized si multi pixel photon counter

    International Nuclear Information System (INIS)

    Song, Minsoo; Hong, Eugene; Won, Eunil; Yoon, Tai Hyun

    2008-01-01

    Quantum information science has been rapidly progressed and matured and matured thanks to the recent developments of the single photon detection technologies. Single photon detectors such as a Si avalanche photo diode(APD)in the infrared, an InGaAs/InP APD in the telecommunication band, and a super conducting transient edge sensor(TES)in the broad region of the spectrum have been widely used. Single photon detectors, however, operating at the ultraviolet to visible (370nm∼800nm)regions has not been actively investigated partly due to the lack of single photon and/or entangled photon sources and the lack of solid state single photon detectors. In this paper, we investigate the single photon detection characteristics of a Si multi pixel photon counter(MPPC), which has a high spectral responsivity between 300nm to 800nm, as a photon number resolving solid state detector. Figure 1 shows the schematic diagram of the single photon detection set up at 399nm by using a temperature stabilized Si MPPC. The output beam of the laser being properly attenuated is directed to the MPPC module, at which fixed number of photo electrons corresponding to incident individual photon are generated at Geiger mode of the Si APD pixels. The detected photo current is converted into a digital signal by using a fast analog to digital converter and a digital oscilloscope stores the time sequence of the photo currents. Figure 2 shows the accumulated charges collected by MPPC at∼10.deg.C showing a clear single photon and two photons peaks, respectively, separated by ∼5 sigma of the coincidence counts at the two output ports of a Mach Zender interferometer as a function of optical path length difference. The research was supported by Seoul R and BD program(NT070127)and by the KRISS

  19. Quantum communications system with integrated photonic devices

    Energy Technology Data Exchange (ETDEWEB)

    Nordholt, Jane E.; Peterson, Charles Glen; Newell, Raymond Thorson; Hughes, Richard John

    2017-11-14

    Security is increased in quantum communication (QC) systems lacking a true single-photon laser source by encoding a transmitted optical signal with two or more decoy-states. A variable attenuator or amplitude modulator randomly imposes average photon values onto the optical signal based on data input and the predetermined decoy-states. By measuring and comparing photon distributions for a received QC signal, a single-photon transmittance is estimated. Fiber birefringence is compensated by applying polarization modulation. A transmitter can be configured to transmit in conjugate polarization bases whose states of polarization (SOPs) can be represented as equidistant points on a great circle on the Poincare sphere so that the received SOPs are mapped to equidistant points on a great circle and routed to corresponding detectors. Transmitters are implemented in quantum communication cards and can be assembled from micro-optical components, or transmitter components can be fabricated as part of a monolithic or hybrid chip-scale circuit.

  20. Resonance formation in photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Gidal, G.

    1988-08-01

    Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the ..gamma gamma..* production of spin-one resonances. 37 refs., 17 figs., 5 tabs.

  1. Analytical inversion formula for uniformly attenuated fan-beam projections

    International Nuclear Information System (INIS)

    Weng, Y.; Zeng, G.L.; Gullberg, G.T.

    1997-01-01

    In deriving algorithms to reconstruct single photon emission computed tomography (SPECT) projection data, it is important that the algorithm compensates for photon attenuation in order to obtain quantitative reconstruction results. A convolution backprojection algorithm was derived by Tretiak and Metz to reconstruct two-dimensional (2-D) transaxial slices from uniformly attenuated parallel-beam projections. Using transformation of coordinates, this algorithm can be modified to obtain a formulation useful to reconstruct uniformly attenuated fan-beam projections. Unlike that for parallel-beam projections, this formulation does not produce a filtered backprojection reconstruction algorithm but instead has a formulation that is an inverse integral operator with a spatially varying kernel. This algorithm thus requires more computation time than does the filtered backprojection reconstruction algorithm for the uniformly attenuated parallel-beam case. However, the fan-beam reconstructions demonstrate the same image quality as that of parallel-beam reconstructions

  2. Pressure surge attenuator

    Science.gov (United States)

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  3. RR photons

    CERN Document Server

    Camara, Pablo G; Marchesano, Fernando

    2011-01-01

    Type II string compactifications to 4d generically contain massless Ramond-Ramond U(1) gauge symmetries. However there is no massless matter charged under these U(1)'s, which makes a priori difficult to measure any physical consequences of their existence. There is however a window of opportunity if these RR U(1)'s mix with the hypercharge $U(1)_Y$ (hence with the photon). In this paper we study in detail different avenues by which $U(1)_{RR}$ bosons may mix with D-brane U(1)'s. We concentrate on Type IIA orientifolds and their M-theory lift, and provide geometric criteria for the existence of such mixing, which may occur either via standard kinetic mixing or via the mass terms induced by St\\"uckelberg couplings. The latter case is particularly interesting, and appears whenever D-branes wrap torsional $p$-cycles in the compactification manifold. We also show that in the presence of torsional cycles discrete gauge symmetries and Aharanov-Bohm strings and particles appear in the 4d effective action, and that ty...

  4. X-Ray Attenuation and Absorption for Materials of Dosimetric Interest

    Science.gov (United States)

    SRD 126 X-Ray Attenuation and Absorption for Materials of Dosimetric Interest (Web, free access)   Tables and graphs of the photon mass attenuation coefficient and the mass energy-absorption coefficient are presented for all of the elements Z = 1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x-ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV.

  5. Photonic time crystals.

    Science.gov (United States)

    Zeng, Lunwu; Xu, Jin; Wang, Chengen; Zhang, Jianhua; Zhao, Yuting; Zeng, Jing; Song, Runxia

    2017-12-07

    When space (time) translation symmetry is spontaneously broken, the space crystal (time crystal) forms; when permittivity and permeability periodically vary with space (time), the photonic crystal (photonic time crystal) forms. We proposed the concept of photonic time crystal and rewritten the Maxwell's equations. Utilizing Finite Difference Time Domain (FDTD) method, we simulated electromagnetic wave propagation in photonic time crystal and photonic space-time crystal, the simulation results show that more intensive scatter fields can obtained in photonic time crystal and photonic space-time crystal.

  6. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

    2005-01-01

    Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

  7. Photonic Crystals Towards Nanoscale Photonic Devices

    CERN Document Server

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

    2008-01-01

    Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

  8. Nuclear photonics

    Science.gov (United States)

    Habs, D.; Günther, M. M.; Jentschel, M.; Thirolf, P. G.

    2012-07-01

    With the planned new γ-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 1013 γ/s and a band width of ΔEγ/Eγ≈10-3, a new era of γ beams with energies up to 20MeV comes into operation, compared to the present world-leading HIγS facility at Duke University (USA) with 108 γ/s and ΔEγ/Eγ≈3ṡ10-2. In the long run even a seeded quantum FEL for γ beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused γ beams. Here we describe a new experiment at the γ beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for γ beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for γ beams are being developed. Thus, we have to optimize the total system: the γ-beam facility, the γ-beam optics and γ detectors. We can trade γ intensity for band width, going down to ΔEγ/Eγ≈10-6 and address individual nuclear levels. The term "nuclear photonics" stresses the importance of nuclear applications. We can address with γ-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, γ beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to μm resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of applications. We find many new applications in biomedicine, green energy, radioactive waste management or homeland security. Also more brilliant secondary beams of neutrons and positrons can be produced.

  9. Photon Shielding Features of Quarry Tuff

    Directory of Open Access Journals (Sweden)

    Vega-Carrillo Hector Rene

    2017-01-01

    Full Text Available Cantera is a quarry tuff widely used in the building industry; in this work the shielding features of cantera were determined. The shielding characteristics were calculated using XCOM and MCNP5 codes for 0.03, 0.07, 0.1, 0.3, 0.662, 1, 2, and 3 MeV photons. With XCOM the mass interaction coefficients, and the total mass attenuation coefficients, were calculated. With the MCNP5 code a transmission experiment was modelled using a point-like source located 42 cm apart from a point-like detector. Between the source and the detector, cantera pieces with different thickness, ranging from 0 to 40 cm were included. The collided and uncollided photon fluence, the Kerma in air and the Ambient dose equivalent were estimated. With the uncollided fluence the linear attenuation coefficients were determined and compared with those calculated with XCOM. The linear attenuation coefficient for 0.662 MeV photons was compared with the coefficient measured with a NaI(Tl-based γ-ray spectrometer and a 137Cs source.

  10. Photosynthetic efficiency of Chlamydomonas reinhardtii in attenuated, flashing light

    NARCIS (Netherlands)

    Vejrazka, C.; Janssen, M.G.J.; Streefland, M.; Wijffels, R.H.

    2012-01-01

    As a result of mixing and light attenuation, algae in a photobioreactor (PBR) alternate between light and dark zones and, therefore, experience variations in photon flux density (PFD). These variations in PFD are called light/dark (L/D) cycles. The objective of this study was to determine how these

  11. Evaluation of gamma-ray attenuation properties of bismuth borate glass systems using Monte Carlo method

    Science.gov (United States)

    Tarim, Urkiye Akar; Ozmutlu, Emin N.; Yalcin, Sezai; Gundogdu, Ozcan; Bradley, D. A.; Gurler, Orhan

    2017-11-01

    A Monte Carlo method was developed to investigate radiation shielding properties of bismuth borate glass. The mass attenuation coefficients and half-value layer parameters were determined for different fractional amounts of Bi2O3 in the glass samples for the 356, 662, 1173 and 1332 keV photon energies. A comparison of the theoretical and experimental attenuation coefficients is presented.

  12. Measurement of attenuation cross-sections of some fatty acids in the ...

    Indian Academy of Sciences (India)

    These quantities were obtained by utilizing experimentally measured values of mass attenuation coefficients ( μ m ) . A NaI(Tl) scintillation detector with 8.2% (at 662 keV) resolution was used for detecting of attenuated γ -photons. The variation in Zeff and Neff of fatty acids with energy is discussed. The experimental and ...

  13. Photonic crystals: towards nanoscale photonic devices

    National Research Council Canada - National Science Library

    Lourtioz, J.-M

    2005-01-01

    .... From this point of view, the emergence of photonic bandgap materials and photonic crystals at the end of the 1980s can be seen as a revenge to the benefit this time of optics and electromagnetism. In the same way as the periodicity of solid state crystals determines the energy bands and the conduction properties of electrons, the periodical structur...

  14. Photon-photon measurements in CMS

    CERN Document Server

    Chudasama, Ruchi

    2017-01-01

    We discuss the measurement of photon-photon processes using data collected by the CMS experiment in pp collisions at $\\sqrt{s}$ = 7 and 8 TeV and in PbPb collisions at $\\sqrt{s_{_{{\\rm NN}}}}= 5.02$ TeV.

  15. High energy photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.; Zerwas, P.M.

    1994-07-01

    The collisions of high energy photons produced at a electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions and extensions of the standard model. The luminosity and energy of the colliding photons produced by back-scattering laser beams is expected to be comparable to that of the primary e + e - collisions. In this overview, we shall focus on tests of electroweak theory in photon-photon annihilation, particularly γγ → W + W - , γγ → Higgs bosons, and higher-order loop processes, such as γγ → γγ, Zγ and ZZ. Since each photon can be resolved into a W + W minus pair, high energy photon-photon collisions can also provide a remarkably background-free laboratory for studying WW collisions and annihilation. We also review high energy γγ tests of quantum chromodynamics, such as the scaling of the photon structure function, t bar t production, mini-jet processes, and diffractive reactions

  16. Programmable Quantum Photonic Processor Using Silicon Photonics

    Science.gov (United States)

    2017-04-01

    mentioned above, increased infidelity in the single photon states produced by sources sharply increases the resource overhead for quantum repeaters...for a time-invariant cavity. Using a “dual Hong-Ou-Mandel” geometry shown in Fig. 3, we were able to ensure that the incoming and existing photon

  17. Photonic crystal light source

    Science.gov (United States)

    Fleming, James G [Albuquerque, NM; Lin, Shawn-Yu [Albuquerque, NM; Bur, James A [Corrales, NM

    2004-07-27

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  18. Photonic Design for Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Kosten, E.; Callahan, D.; Horowitz, K.; Pala, R.; Atwater, H.

    2014-08-28

    We describe photonic design approaches for silicon photovoltaics including i) trapezoidal broadband light trapping structures ii) broadband light trapping with photonic crystal superlattices iii) III-V/Si nanowire arrays designed for broadband light trapping.

  19. Photonic crystal pioneer

    Science.gov (United States)

    Anscombe, Nadya

    2011-08-01

    Over the past ten years, Crystal Fiber, now part of NKT Photonics, has been busy commercializing photonic crystal fibre. Nadya Anscombe finds out about the evolution of the technology and its applications.

  20. Photon mass attenuation coefficients, effective atomic numbers and ...

    Indian Academy of Sciences (India)

    The scattering and absorption of γ-radiations are related to the density and effec- tive atomic number of the material. The effective atomic number and the electron density of a composite material are very useful parameters in the dosimetric cal- culation of radiation dose in radiotherapy [12] and also in medical imaging, ...

  1. Photonic crystal fibers

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Hansen, K P; Nielsen, M D

    2003-01-01

    Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications...... of photonic crystal fibers with particular emphasis on recent advances in the field....

  2. Delayed photon selfinterference

    International Nuclear Information System (INIS)

    Kessel', A.R.; Moiseev, S.A.

    1993-01-01

    Delayed photon selfinterference on a sample containing resonant two-level atoms is considered when the difference in the lengths in two optical paths exceeds the photon 'length'. It is shown that a reading pulse of the electromagnetic field can induce photon echo

  3. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Olsen, Ole Fogh; Sporring, Jon

    2006-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features......, while eliminating noise. We call our method diffusion based photon mapping....

  4. A study of photon interaction parameters in lung tissue substitutes

    Directory of Open Access Journals (Sweden)

    H C Manjunatha

    2014-01-01

    Full Text Available The study of photon interaction with different composite materials has become a topic of prime importance for radiation physicists. Some parameters of dosimetric interest are the mass attenuation coefficient, effective atomic number, and electron density; these help in the basic understanding of photon interactions with composite materials. The photon interaction parameters such as mass attenuation coefficient (μ/ρ, effective atomic number (Z eff , and effective electron density (N el must be identical for the phantom material and their tissue. In the present study, we have evaluated the photon interaction parameters such as (μ/ρ, Z eff and N el of 13 lung tissue substitutes. The variations of these parameters of lung tissue substitutes with photon energy are graphically represented. The photon interaction parameters of lung tissue substitutes are compared with that of lung tissue. The variation of photon interaction parameters of the studied lung tissue substitutes is similar that of the lung. Logically, it can be shown that Alderson lung is good substitute for lung than the other substitutes.

  5. A study of photon interaction parameters in lung tissue substitutes.

    Science.gov (United States)

    Manjunatha, H C

    2014-04-01

    The study of photon interaction with different composite materials has become a topic of prime importance for radiation physicists. Some parameters of dosimetric interest are the mass attenuation coefficient, effective atomic number, and electron density; these help in the basic understanding of photon interactions with composite materials. The photon interaction parameters such as mass attenuation coefficient (μ/ρ), effective atomic number (Zeff), and effective electron density (N el) must be identical for the phantom material and their tissue. In the present study, we have evaluated the photon interaction parameters such as (μ/ρ), Z eff and N el of 13 lung tissue substitutes. The variations of these parameters of lung tissue substitutes with photon energy are graphically represented. The photon interaction parameters of lung tissue substitutes are compared with that of lung tissue. The variation of photon interaction parameters of the studied lung tissue substitutes is similar that of the lung. Logically, it can be shown that Alderson lung is good substitute for lung than the other substitutes.

  6. Electron attenuation lengths in fullerene and fullerides

    International Nuclear Information System (INIS)

    Li Hongnian; Wang Xiaoxiong; Ding Wangfeng

    2006-01-01

    Using X-ray photoemission measurements, we have determined the attenuation length of C 1s photoelectrons in C 60 film to be 21.5 A with the incident photon energy of Mg Kα radiation. The inelastic mean free path calculated with the TPP-2M algorithm coincides fairly well with the experimentally determined attenuation length, indicating the validity of the algorithm to fullerene and fullerides. The inelastic mean free paths for some fullerides, i.e. K 3 C 60 , K 6 C 60 , Ba 4 C 60 , Sm 2.75 C 60 and Sm 6 C 60 are calculated to help the quantitative analyses of the photoemission spectra for these compounds

  7. Photon correlation holography.

    Science.gov (United States)

    Naik, Dinesh N; Singh, Rakesh Kumar; Ezawa, Takahiro; Miyamoto, Yoko; Takeda, Mitsuo

    2011-01-17

    Unconventional holography called photon correlation holography is proposed and experimentally demonstrated. Using photon correlation, i.e. intensity correlation or fourth order correlation of optical field, a 3-D image of the object recorded in a hologram is reconstructed stochastically with illumination through a random phase screen. Two different schemes for realizing photon correlation holography are examined by numerical simulations, and the experiment was performed for one of the reconstruction schemes suitable for the experimental proof of the principle. The technique of photon correlation holography provides a new insight into how the information is embedded in the spatial as well as temporal correlation of photons in the stochastic pseudo thermal light.

  8. A multi-centre evaluation of eleven clinically feasible brain PET/MRI attenuation correction techniques using a large cohort of patients

    DEFF Research Database (Denmark)

    Ladefoged, Claes Nøhr; Law, Ian; Anazodo, Udunna

    2017-01-01

    Aim: To accurately quantify the radioactivity concentration measured by PET, emission data need to be corrected for photon attenuation; however, the MRI signal cannot easily be converted into attenuation values, making attenuation correction (AC) in PET/MRI challenging. In order to further improve...... acceptable degree, which is smaller than the quantification reproducibility in PET imaging....

  9. Electron and Photon ID

    CERN Document Server

    Hryn'ova, Tetiana; The ATLAS collaboration

    2017-01-01

    The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficiencies of the electron identification and isolation cuts are performed with the data using tag and probe techniques with large statis...

  10. XCOM: Photon cross sections on a personal computer

    International Nuclear Information System (INIS)

    Berger, M.J.; Hubbell, J.H.

    1987-07-01

    A computer program and data base are presented which can be used to calculate, with a personal computer, photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, in any element, compound or mixture, at energies from 1 keV to 100 GeV

  11. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  12. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  13. Single-photon imaging

    CERN Document Server

    Seitz, Peter

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncoooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist´s view from different domains to the forthcoming “single-photon imaging” revolution. The various aspects of single-photon imaging are treated by internati...

  14. Hybrid photon detectors

    CERN Document Server

    D'Ambrosio, C

    2003-01-01

    Hybrid photon detectors detect light via vacuum photocathodes and accelerate the emitted photoelectrons by an electric field towards inversely polarized silicon anodes, where they are absorbed, thus producing electron-hole pairs. These, in turn, are collected and generate electronic signals on their ohmic contacts. This review first describes the characteristic properties of the main components of hybrid photon detectors: light entrance windows, photocathodes, and silicon anodes. Then, essential relations describing the trajectories of photoelectrons in electric and magnetic fields and their backscattering from the silicon anodes are derived. Depending on their anode configurations, three families of hybrid photon detectors are presented: hybrid photomultiplier tubes with single anodes for photon counting with high sensitivity and for gamma spectroscopy; multi-anode photon detector tubes with anodes subdivided into square or hexagonal pads for position-sensitive photon detection; imaging silicon pixel array t...

  15. Tale of two photons

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    A very profitable spinoff from electron- positron collisions is two-photon physics. Rather than the electron and positron interacting directly via an exchanged photon, two virtual (transient) photons, one from each particle, get tangled up. With new electron-positron colliders appearing on the scene, a topical meeting on two-photon physics - 'From DAPHNE to LEP 200 and beyond' - held from 2-4 February in Paris, in the premises of the Ministry of Higher Education and Research, was particularly timely. Some 60 physicists, both experimentalists and theorists, participated, with some thirty speakers

  16. Photon virtual bound state

    International Nuclear Information System (INIS)

    Inoue, J.; Ohtaka, K.

    2004-01-01

    We study virtual bound states in photonics, which are a vectorial extension of electron virtual bound states. The condition for these states is derived. It is found that the Mie resonant state which satisfies the condition that the size parameter is less than the angular momentum should be interpreted as a photon virtual bound state. In order to confirm the validity of the concept, we compare the photonic density of states, the width of which represents the lifetime of the photon virtual bound states, with numerical results

  17. Photonic Integrated Circuits

    Science.gov (United States)

    Krainak, Michael; Merritt, Scott

    2016-01-01

    Integrated photonics generally is the integration of multiple lithographically defined photonic and electronic components and devices (e.g. lasers, detectors, waveguides passive structures, modulators, electronic control and optical interconnects) on a single platform with nanometer-scale feature sizes. The development of photonic integrated circuits permits size, weight, power and cost reductions for spacecraft microprocessors, optical communication, processor buses, advanced data processing, and integrated optic science instrument optical systems, subsystems and components. This is particularly critical for small spacecraft platforms. We will give an overview of some NASA applications for integrated photonics.

  18. Advanced Photon Source (APS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratoryprovides this nation's (in fact, this hemisphere's) brightest storage...

  19. Review on Dark Photon

    Directory of Open Access Journals (Sweden)

    Curciarello Francesca

    2016-01-01

    Full Text Available e+e− collider experiments at the intensity frontier are naturally suited to probe the existence of a force beyond the Standard Model between WIMPs, the most viable dark matter candidates. The mediator of this new force, known as dark photon, should be a new vector gauge boson very weakly coupled to the Standard Model photon. No significant signal has been observed so far. I will report on current limits set on the coupling factor ε2 between the photon and the dark photon by e+e− collider experiments.

  20. Biomedical photonics handbook

    CERN Document Server

    Vo-Dinh, Tuan

    2003-01-01

    1.Biomedical Photonics: A Revolution at the Interface of Science and Technology, T. Vo-DinhPHOTONICS AND TISSUE OPTICS2.Optical Properties of Tissues, J. Mobley and T. Vo-Dinh3.Light-Tissue Interactions, V.V. Tuchin 4.Theoretical Models and Algorithms in Optical Diffusion Tomography, S.J. Norton and T. Vo-DinhPHOTONIC DEVICES5.Laser Light in Biomedicine and the Life Sciences: From the Present to the Future, V.S. Letokhov6.Basic Instrumentation in Photonics, T. Vo-Dinh7.Optical Fibers and Waveguides for Medical Applications, I. Gannot and

  1. Liquid Crystals and Photonic Bandgap Fiber Components

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Scolari, Lara

    Liquid Crystal(LC)filled Photonic Crystal Fibers(PCFs) represent a promising platform for the design and the fabrication of tunable all-in fiber devices. Tunability is achieved by varying the refractive index of the LC thermally, optically or electrically. In this contribution we present important...... parts of the LC theory as well as an application of a LC infiltrated PCF subject to an external electrostatic field. The fiber is placed between two electrodes and the voltage is increased step by step leading to the reorientation of the LC in the fiber capillaries. This mechanism can be used to produce...... a swichable polarizer, and an on chip LC photonic bandgap fiber polarimeter is presented, which admits strong attenuation of one polarization direction while the other one is nearly unaffected....

  2. Two Photon Distribution Amplitudes

    International Nuclear Information System (INIS)

    El Beiyad, M.; Pire, B.; Szymanowski, L.; Wallon, S.

    2008-01-01

    The factorization of the amplitude of the process γ*γ→γγ in the low energy and high photon virtuality region is demonstrated at the Born order and in the leading logarithmic approximation. The leading order two photon (generalized) distribution amplitudes exhibit a characteristic ln Q 2 behaviour and obey new inhomogeneous evolution equations

  3. Photon beam position monitor

    Science.gov (United States)

    Kuzay, Tuncer M.; Shu, Deming

    1995-01-01

    A photon beam position monitor for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade "shadowing". Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation.

  4. Integrated microwave photonics

    NARCIS (Netherlands)

    Marpaung, D.A.I.; Roeloffzen, C.G.H.; Heideman, Rene; Leinse, Arne; Sales, S.; Capmany, J.

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A

  5. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Fogh Olsen, Ole; Sporring, Jon

    2007-01-01

    . To address this problem we introduce a novel photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way we preserve the important illumination features...

  6. ALICE Photon Multiplicity Detector

    CERN Multimedia

    Nayak, T

    2013-01-01

    Photon Multiplicity Detector (PMD) measures the multiplicity and spatial distribution of photons in the forward region of ALICE on a event-by-event basis. PMD is a pre-shower detector having fine granularity and full azimuthal coverage in the pseudo-rapidity region 2.3 < η < 3.9.

  7. Diffusion Based Photon Mapping

    DEFF Research Database (Denmark)

    Schjøth, Lars; Sporring, Jon; Fogh Olsen, Ole

    2008-01-01

    . To address this problem, we introduce a photon mapping algorithm based on nonlinear anisotropic diffusion. Our algorithm adapts according to the structure of the photon map such that smoothing occurs along edges and structures and not across. In this way, we preserve important illumination features, while...

  8. High energy photon response

    International Nuclear Information System (INIS)

    Cummings, F.M.; Yoder, R.C.; Endres, G.W.R.; Kathren, R.L.

    1981-01-01

    This study examines the response of the Hanford 4-chip and 5-chip dosimeter to high energy photons. The dose response of the Hanford Multipurpose Personnel Diometer (HMPD) to photons with energies greater than 0.65 MeV has been evaluated relative to the dose produced by photons from a 60 Co. source. The penetrating dose determined with the HMPD is compared to the 1 cm depth dose in tissue measured with an extrapolation chamber. The results of the study indicate that the HMPD can be used to estimate the 1 cm depth dose in tissue from photons with energies between 0.65 MeV and 3.0 MeV to within an accuracy of 15%. However, the 1 cm depth dose is underestimated by 38% when the dosimeter is irradiated in a beam of very high energy photons produced by bombarding a tungsten target with 25 MeV electrons

  9. Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Sanchez Bjarklev, Araceli

    Photonic crystal fibres represent one of the most active research areas today in the field of optics. The diversity of applications that may be addressed by these fibres and their fundamental appeal, by opening up the possibility of guiding light in a radically new way compared to conventional...... optical fibres, have spun an interest from almost all areas of optics and photonics. The aim of this book is to provide an understanding of the different types of photonic crystal fibres and to outline some of the many new and exciting applications that these fibres offer. The book is intended for both...... readers with a general interest in photonic crystals, as well as for scientists who are entering the field and desire a broad overview as well as a solid starting point for further specialized stuides. Teh book, therefore, covers bothe general aspects such as the link from classical optics to photonic...

  10. Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara

    This thesis deals with the fabrication and characterization of active photonic crystal waveguides, realized in III-V semiconductor material with embedded active layers. The platform offering active photonic crystal waveguides has many potential applications. One of these is a compact photonic...... crystal semiconductor optical amplier. As a step towards such a component, photonic crystal waveguides with a single quantum well, 10 quantum wells and three layers of quantum dots are fabricated and characterized. An experimental study of the amplied spontaneous emission and a implied transmission...... are presented in this thesis. A variation of photonic crystal design parameters are used leading to a spectral shift of the dispersion, it is veried that the observed effects shift accordingly. An enhancement of the amplified spontaneous emission was observed close to the band edge, where light is slowed down...

  11. Nonlinear Photonics 2014: introduction.

    Science.gov (United States)

    Akhmediev, N; Kartashov, Yaroslav

    2015-01-12

    International Conference "Nonlinear Photonics-2014" took place in Barcelona, Spain on July 27-31, 2014. It was a part of the "Advanced Photonics Congress" which is becoming a traditional notable event in the world of photonics. The current focus issue of Optics Express contains contributions from the participants of the Conference and the Congress. The articles in this focus issue by no means represent the total number of the congress contributions (around 400). However, it demonstrates wide range of topics covered at the event. The next conference of this series is to be held in 2016 in Australia, which is the home of many researchers working in the field of photonics in general and nonlinear photonics in particular.

  12. Ion photon emission microscope

    Science.gov (United States)

    Doyle, Barney L.

    2003-04-22

    An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

  13. Radiofrequency attenuator and method

    Science.gov (United States)

    Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Hall, Simon B [Palmerston North, NZ

    2009-01-20

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  14. Deconvolution based attenuation correction for time-of-flight positron emission tomography

    Science.gov (United States)

    Lee, Nam-Yong

    2017-10-01

    For an accurate quantitative reconstruction of the radioactive tracer distribution in positron emission tomography (PET), we need to take into account the attenuation of the photons by the tissues. For this purpose, we propose an attenuation correction method for the case when a direct measurement of the attenuation distribution in the tissues is not available. The proposed method can determine the attenuation factor up to a constant multiple by exploiting the consistency condition that the exact deconvolution of noise-free time-of-flight (TOF) sinogram must satisfy. Simulation studies shows that the proposed method corrects attenuation artifacts quite accurately for TOF sinograms of a wide range of temporal resolutions and noise levels, and improves the image reconstruction for TOF sinograms of higher temporal resolutions by providing more accurate attenuation correction.

  15. Single photons on demand

    International Nuclear Information System (INIS)

    Grangier, P.; Abram, I.

    2004-01-01

    Quantum cryptography and information processing are set to benefit from developments in novel light sources that can emit photons one by one. Quantum mechanics has gained a reputation for making counter-intuitive predictions. But we rarely get the chance to witness these effects directly because, being humans, we are simply too big. Take light, for example. The light sources that are familiar to us, such as those used in lighting and imaging or in CD and DVD players, are so huge that they emit billions and billions of photons. But what if there was a light source that emitted just one photon at a time? Over the past few years, new types of light source that are able to emit photons one by one have been emerging from laboratories around the world. Pulses of light composed of a single photon correspond to power flows in the femtowatt range - a million billion times less than that of a table lamp. The driving force behind the development of these single-photon sources is a range of novel applications that take advantage of the quantum nature of light. Quantum states of superposed and entangled photons could lead the way to guaranteed-secure communication, to information processing with unprecedented speed and efficiency, and to new schemes for quantum teleportation. (U.K.)

  16. Progress in neuromorphic photonics

    Science.gov (United States)

    Ferreira de Lima, Thomas; Shastri, Bhavin J.; Tait, Alexander N.; Nahmias, Mitchell A.; Prucnal, Paul R.

    2017-03-01

    As society's appetite for information continues to grow, so does our need to process this information with increasing speed and versatility. Many believe that the one-size-fits-all solution of digital electronics is becoming a limiting factor in certain areas such as data links, cognitive radio, and ultrafast control. Analog photonic devices have found relatively simple signal processing niches where electronics can no longer provide sufficient speed and reconfigurability. Recently, the landscape for commercially manufacturable photonic chips has been changing rapidly and now promises to achieve economies of scale previously enjoyed solely by microelectronics. By bridging the mathematical prowess of artificial neural networks to the underlying physics of optoelectronic devices, neuromorphic photonics could breach new domains of information processing demanding significant complexity, low cost, and unmatched speed. In this article, we review the progress in neuromorphic photonics, focusing on photonic integrated devices. The challenges and design rules for optoelectronic instantiation of artificial neurons are presented. The proposed photonic architecture revolves around the processing network node composed of two parts: a nonlinear element and a network interface. We then survey excitable lasers in the recent literature as candidates for the nonlinear node and microring-resonator weight banks as the network interface. Finally, we compare metrics between neuromorphic electronics and neuromorphic photonics and discuss potential applications.

  17. Fundamentals of microwave photonics

    CERN Document Server

    Urick, V J; McKinney , Jason D

    2015-01-01

    A comprehensive resource to designing andconstructing analog photonic links capable of high RFperformanceFundamentals of Microwave Photonics provides acomprehensive description of analog optical links from basicprinciples to applications.  The book is organized into fourparts. The first begins with a historical perspective of microwavephotonics, listing the advantages of fiber optic links anddelineating analog vs. digital links. The second section coversbasic principles associated with microwave photonics in both the RFand optical domains.  The third focuses on analog modulationformats-starti

  18. Single-Photon Optomechanics

    Science.gov (United States)

    Nunnenkamp, A.; Børkje, K.; Girvin, S. M.

    2011-08-01

    Optomechanics experiments are rapidly approaching the regime where the radiation pressure of a single photon displaces the mechanical oscillator by more than its zero-point uncertainty. We show that in this limit the power spectrum has multiple sidebands and that the cavity response has several resonances in the resolved-sideband limit. Using master-equation simulations, we also study the crossover from the weak-coupling many-photon to the single-photon strong-coupling regime. Finally, we find non-Gaussian steady states of the mechanical oscillator when multiphoton transitions are resonant. Our study provides the tools to detect and take advantage of this novel regime of optomechanics.

  19. Photonics: Technology project summary

    Science.gov (United States)

    Depaula, Ramon P.

    1991-01-01

    Photonics involves the use of light (photons) in conjunction with electronics for applications in communications, computing, control, and sensing. Components used in photonic systems include lasers, optical detectors, optical wave guide devices, fiber optics, and traditional electronic devices. The goal of this program is to develop hybrid optoelectronic devices and systems for sensing, information processing, communications, and control. It is hoped that these new devices will yield at least an order of magnitude improvement in performance over existing technology. The objective of the program is to conduct research and development in the following areas: (1) materials and devices; (2) networking and computing; (3) optical processing/advanced pattern recognition; and (4) sensing.

  20. Physics of photonic devices

    CERN Document Server

    Chuang, Shun Lien

    2009-01-01

    The most up-to-date book available on the physics of photonic devices This new edition of Physics of Photonic Devices incorporates significant advancements in the field of photonics that have occurred since publication of the first edition (Physics of Optoelectronic Devices). New topics covered include a brief history of the invention of semiconductor lasers, the Lorentz dipole method and metal plasmas, matrix optics, surface plasma waveguides, optical ring resonators, integrated electroabsorption modulator-lasers, and solar cells. It also introduces exciting new fields of research such as:

  1. Single photon ECT

    International Nuclear Information System (INIS)

    Maeda, Toshio; Matsuda, Hiroshi; Tada, Akira; Bunko, Hisashi; Koizumi, Kiyoshi

    1982-01-01

    The detectability of lesions located deep in a body or overlapped with a physiologically increased activity improve with the help of single photon ECT. In some cases, the ECT is superior to the conventional gamma camera images and X-ray CT scans in the evaluation of the location and size of lesion. The single photon ECT of the brain compares favorably with the contrast enhansed X-ray CT scans. The most important adaptation of the single photon ECT are the detection of recurrent brain tumors after craniotomy and the evaluation of ischemic heart diseases. (author)

  2. Fundamentals of photonics

    CERN Document Server

    Saleh, Bahaa E A

    2007-01-01

    Now in a new full-color edition, Fundamentals of Photonics, Second Edition is a self-contained and up-to-date introductory-level textbook that thoroughly surveys this rapidly expanding area of engineering and applied physics. Featuring a logical blend of theory and applications, coverage includes detailed accounts of the primary theories of light, including ray optics, wave optics, electromagnetic optics, and photon optics, as well as the interaction of photons and atoms, and semiconductor optics. Presented at increasing levels of complexity, preliminary sections build toward more advan

  3. Single-photon interference experiment for high schools

    Science.gov (United States)

    Bondani, Maria

    2014-07-01

    We follow the reductio ad absurdum reasoning described in the book "Sneaking a Look at God's Cards" by Giancarlo Ghirardi to demonstrate the wave-particle duality of light in a Mach-Zehnder interferometric setup analog to the conventional Young double-slit experiment. We aim at showing the double nature of light by measuring the existence of interference fringes down to the single-photon level. The setup includes a strongly attenuated laser, polarizing beam splitters, half-waveplates, polarizers and single-photon detectors.

  4. Quantum dots in photonic crystals for integrated quantum photonics

    Science.gov (United States)

    Kim, Je-Hyung; Richardson, Christopher J. K.; Leavitt, Richard P.; Waks, Edo

    2017-08-01

    Integrated quantum photonic technologies hold a great promise for application in quantum information processing. A major challenge is to integrate multiple single photon sources on a chip. Quantum dots are bright sources of high purity single photons, and photonic crystals can provide efficient photonic platforms for generating and manipulating single photons from integrated quantum dots. However, integrating multiple quantum dots with photonic crystal devices still remains as a challenging task due to the spectral randomness of the emitters. Here, we present the integration of multiple quantum dots with individual photonic crystal cavities and report quantum interference from chip-integrated multiple quantum dots. To solve the problem of spectral randomness, we introduce local engineering techniques for tuning multiple quantum dots and cavities. From integrated quantum dot devices we observe indistinguishable nature of single photons from individual quantum dots on the same chip. Therefore, our approach paves the way for large-scale quantum photonics with integrated quantum emitters.

  5. Microwave photonics shines

    Science.gov (United States)

    Won, Rachel

    2011-12-01

    The combination of microwave photonics and optics has advanced many applications in defence, wireless communications, imaging and network infrastructure. Rachel Won talks to Jianping Yao from the University of Ottawa in Canada about the importance of this growing field.

  6. Photonic fabrics take shape

    Science.gov (United States)

    Graham-Rowe, Duncan

    2007-01-01

    Electronics firms, fashion houses and medical-equipment suppliers are all busy developing textiles that blend photonics technology with materials science. Duncan Graham-Rowe reports on the striking results of their endeavours.

  7. Photonic Crystal Nanocavity Arrays

    National Research Council Canada - National Science Library

    Altug, Hatice; Vuckovic, Jelena

    2006-01-01

    We recently proposed two-dimensional coupled photonic crystal nanocavity arrays as a route to achieve a slow-group velocity of light in all crystal directions, thereby enabling numerous applications...

  8. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    Despite the general recession in the global economy and the collapse of the optical telecommunication market, research within specialty fibers is thriving. This is, more than anything else, due to the technology transition from standard all-glass fibers to photonic crystal fibers, which, instead...... of doping, use a microstructure of air and glass to obtain a refractive index difference between the core and the cladding. This air/glass microstructure lends the photonic crystal fibers a range of unique and highly usable properties, which are very different from those found in solid standard fibers......, leading to reduced mode confinement and dispersion flexibility. In this thesis, we treat the nonlinear photonic crystal fiber – a special sub-class of photonic crystal fibers, the core of which has a diameter comparable to the wavelength of the light guided in the fiber. The small core results in a large...

  9. Photonic Crystal Fibers

    National Research Council Canada - National Science Library

    Kristiansen, Rene E

    2005-01-01

    This report results from a contract tasking Crystal Fibre A/S as follows: Crystal Fibre will conduct research and development of large mode area, dual clad multi-core Yb-doped photonic crystal fiber...

  10. Photonic Quantum Information Processing

    International Nuclear Information System (INIS)

    Walther, P.

    2012-01-01

    The advantage of the photon's mobility makes optical quantum system ideally suited for delegated quantum computation. I will present results for the realization for a measurement-based quantum network in a client-server environment, where quantum information is securely communicated and computed. Related to measurement-based quantum computing I will discuss a recent experiment showing that quantum discord can be used as resource for the remote state preparation, which might shine new light on the requirements for quantum-enhanced information processing. Finally, I will briefly review recent photonic quantum simulation experiments of four frustrated Heisenberg-interactions spins and present an outlook of feasible simulation experiments with more complex interactions or random walk structures. As outlook I will discuss the current status of new quantum technology for improving the scalability of photonic quantum systems by using superconducting single-photon detectors and tailored light-matter interactions. (author)

  11. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S

    2015-01-01

    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  12. Principles of photonics

    CERN Document Server

    Liu, Jia-Ming

    2016-01-01

    With this self-contained and comprehensive text, students will gain a detailed understanding of the fundamental concepts and major principles of photonics. Assuming only a basic background in optics, readers are guided through key topics such as the nature of optical fields, the properties of optical materials, and the principles of major photonic functions regarding the generation, propagation, coupling, interference, amplification, modulation, and detection of optical waves or signals. Numerous examples and problems are provided throughout to enhance understanding, and a solutions manual containing detailed solutions and explanations is available online for instructors. This is the ideal resource for electrical engineering and physics undergraduates taking introductory, single-semester or single-quarter courses in photonics, providing them with the knowledge and skills needed to progress to more advanced courses on photonic devices, systems and applications.

  13. The photon collider at TESLA

    Czech Academy of Sciences Publication Activity Database

    Badelek, B.; Bloechinger, C.; Blümlein, J.; Boos, E.; Brinkman, R.; Burkhardt, H.; Bussey, P.; Carimalo, C.; Chýla, Jiří; Ciftci, A.K.

    2004-01-01

    Roč. 19, č. 30 (2004), s. 5097-5186 ISSN 0217-751X Institutional research plan: CEZ:AV0Z1010920 Keywords : photon collider * linear collider * gamma-gamma * photon-photon * photon electron * Compton scattering Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.054, year: 2004

  14. Photonics Explorer: revolutionizing photonics in the classroom

    Science.gov (United States)

    Prasad, Amrita; Debaes, Nathalie; Cords, Nina; Fischer, Robert; Vlekken, Johan; Euler, Manfred; Thienpont, Hugo

    2012-10-01

    The `Photonics Explorer' is a unique intra-curricular optics kit designed to engage, excite and educate secondary school students about the fascination of working with light - hands-on, in their own classrooms. Developed with a pan European collaboration of experts, the kit equips teachers with class sets of experimental material provided within a supporting didactic framework, distributed in conjunction with teacher training courses. The material has been specifically designed to integrate into European science curricula. Each kit contains robust and versatile components sufficient for a class of 25-30 students to work in groups of 2-3. The didactic content is based on guided inquiry-based learning (IBL) techniques with a strong emphasis on hands-on experiments, team work and relating abstract concepts to real world applications. The content has been developed in conjunction with over 30 teachers and experts in pedagogy to ensure high quality and ease of integration. It is currently available in 7 European languages. The Photonics Explorer allows students not only to hone their essential scientific skills but also to really work as scientists and engineers in the classroom. Thus, it aims to encourage more young people to pursue scientific careers and avert the imminent lack of scientific workforce in Europe. 50 Photonics Explorer kits have been successfully tested in 7 European countries with over 1500 secondary school students. The positive impact of the kit in the classroom has been qualitatively and quantitatively evaluated. A non-profit organisation, EYESTvzw [Excite Youth for Engineering Science and Technology], is responsible for the large scale distribution of the Photonics Explorer.

  15. Magnetic photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lyubchanskii, I L [Donetsk Physical and Technical Institute of the National Academy of Sciences of Ukraine, 72, R. Luxemburg St., 83114 Donetsk (Ukraine); Dadoenkova, N N [Donetsk Physical and Technical Institute of the National Academy of Sciences of Ukraine, 72, R. Luxemburg St., 83114 Donetsk (Ukraine); Lyubchanskii, M I [Donetsk Physical and Technical Institute of the National Academy of Sciences of Ukraine, 72, R. Luxemburg St., 83114 Donetsk (Ukraine); Shapovalov, E A [Department of Physics, Donetsk National University, 24, Universitetskaya St., 83055 Donetsk (Ukraine); Rasing, Th [NSRIM Institute, University of Nijmegen, 6525 ED, Nijmegen (Netherlands)

    2003-09-21

    In this paper we outline a new direction in the area of photonic crystals (PCs), or photonic band gap materials, i.e. one-, two-, or three-dimensional superstructures with periods that are comparable with the wavelengths of electromagnetic radiation. The main (and principal) characteristic of this new class of PCs is the presence of magnetically ordered components (or external magnetic field). The linear and nonlinear optical properties of such magnetic PCs are discussed. (topical review)

  16. ALICE photon spectrometer crystals

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Members of the mechanical assembly team insert the last few crystals into the first module of ALICE's photon spectrometer. These crystals are made from lead-tungstate, a crystal as clear as glass but with nearly four times the density. When a high-energy particle passes through one of these crystals it will scintillate, emitting a flash of light allowing the energy of photons, electrons and positrons to be measured.

  17. Photonics in switching

    CERN Document Server

    Midwinter, John E; Kelley, Paul

    1993-01-01

    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  18. Photon structure function

    International Nuclear Information System (INIS)

    Bardeen, W.A.

    1980-11-01

    Theoretical understanding of the photon structure function is reviewed. As an illustration of the pointlike component, the parton model is briefly discussed. However, the systematic study of the photon structure function is presented through the framework of the operator product expansion. Perturbative QCD is used as the theoretical basis for the calculation of leading contributions to the operator product expansion. The influence of higher order QCD effects on these results is discussed. Recent results for the polarized structure functions are discussed

  19. Photon Production at the LHC

    CERN Document Server

    Lafaye, Remi; The ATLAS collaboration

    2013-01-01

    We review the last results on photon production at LHC by the ATLAS and CMS experiments obtained in proton-proton collisions with a center of mass energy of 7 TeV. We discuss the impact of prompt photon and photon-jet differential cross-sections, on the parton distribution function of the proton. Di-photon differential cross-sections are also presented as a function of the di-photon invariant mass, transverse momentum, azimuthal separation, and cos theta*.

  20. Security and gain improvement of a practical quantum key distribution using a gated single-photon source and probabilistic photon-number resolution

    International Nuclear Information System (INIS)

    Horikiri, Tomoyuki; Sasaki, Hideki; Wang, Haibo; Kobayashi, Takayoshi

    2005-01-01

    We propose a high security quantum key distribution (QKD) scheme utilizing one mode of spontaneous parametric downconversion gated by a photon number resolving detector. This photon number measurement is possible by using single-photon detectors operating at room temperature and optical fibers. By post selection, the multiphoton probability in this scheme can be reduced to lower than that of a scheme using an attenuated coherent light resulting in improvement of security. Furthermore, if distillation protocol (error correction and privacy amplification) is performed, the gain will be increased. Hence a QKD system with higher security and bit rate than the laser-based QKD system can be attained using present available technologies

  1. Non-Poissonian photon statistics from macroscopic photon cutting materials.

    Science.gov (United States)

    de Jong, Mathijs; Meijerink, Andries; Rabouw, Freddy T

    2017-05-24

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and 'cutting' them into multiple low-energy excitations that can subsequently be extracted. The occurrence of photon cutting or quantum cutting has been demonstrated in a variety of materials, including semiconductor quantum dots, lanthanides and organic dyes. Here we show that photon cutting results in bunched photon emission on the timescale of the excited-state lifetime, even when observing a macroscopic number of optical centres. Our theoretical derivation matches well with experimental data on NaLaF 4 :Pr 3+ , a material that can cut deep-ultraviolet photons into two visible photons. This signature of photon cutting can be used to identify and characterize new photon-cutting materials unambiguously.

  2. Control algorithms for dynamic attenuators

    International Nuclear Information System (INIS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-01-01

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  3. CMOS-compatible photonic devices for single-photon generation

    Directory of Open Access Journals (Sweden)

    Xiong Chunle

    2016-09-01

    Full Text Available Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal–oxide–semiconductor (CMOS-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

  4. Photonics for life.

    Science.gov (United States)

    Cubeddu, Rinaldo; Bassi, Andrea; Comelli, Daniela; Cova, Sergio; Farina, Andrea; Ghioni, Massimo; Rech, Ivan; Pifferi, Antonio; Spinelli, Lorenzo; Taroni, Paola; Torricelli, Alessandro; Tosi, Alberto; Valentini, Gianluca; Zappa, Franco

    2011-01-01

    Light is strictly connected with life, and its presence is fundamental for any living environment. Thus, many biological mechanisms are related to light interaction or can be evaluated through processes involving energy exchange with photons. Optics has always been a precious tool to evaluate molecular and cellular mechanisms, but the discovery of lasers opened new pathways of interactions of light with biological matter, pushing an impressive development for both therapeutic and diagnostic applications in biomedicine. The use of light in different fields has become so widespread that the word photonics has been utilized to identify all the applications related to processes where the light is involved. The photonics area covers a wide range of wavelengths spanning from soft X-rays to mid-infrared and includes all devices related to photons as light sources, optical fibers and light guides, detectors, and all the related electronic equipment. The recent use of photons in the field of telecommunications has pushed the technology toward low-cost, compact, and efficient devices, making them available for many other applications, including those related to biology and medicine where these requirements are of particular relevance. Moreover, basic sciences such as physics, chemistry, mathematics, and electronics have recognized the interdisciplinary need of biomedical science and are translating the most advanced researches into these fields. The Politecnico school has pioneered many of them,and this article reviews the state of the art of biomedical research at the Politecnico in the field internationally known as biophotonics.

  5. Reconfigurable topological photonic crystal

    Science.gov (United States)

    Shalaev, Mikhail I.; Desnavi, Sameerah; Walasik, Wiktor; Litchinitser, Natalia M.

    2018-02-01

    Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.

  6. A practical attenuation compensation method for cone beam spect

    International Nuclear Information System (INIS)

    Manglos, S.H.; Jaszczak, R.J.; Floyd, C.E.; Greer, K.L.; Coleman, R.E.

    1987-01-01

    An algorithm for attenuation compensation of cone beam SPECT images has been developed and implemented. The algorithm is based on a multiplicative post-processing method previously used for parallel and fan beam geometries. This method computes the compensation from the estimated average attenuation of photons originating from each image pixel. In the present development, a uniform attenuation coefficient inside of the body contour is assumed, although the method could be extended to include a non-uniform attenuation map. The algorithm is tested with experimental projections of a phantom obtained using a cone beam collimator. Profiles through the reconstructed images are presented as a quantitative test of the improvement due to the compensation. The algorithm provides adequate compensation for attenuation in a simple uniform cylindrical phantom, and the computational time is short compared to that expected for iterative reconstruction techniques. Also observed are image distortions in some reconstructed slices when the source distribution extends beyond the edge of the cone beam axial field-of-view

  7. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir......-Wingreen-Landauer-type of conductance formula, which gives the photonic heat current through an arbitrary circuit element coupled to two dissipative reservoirs at finite temperatures. As an illustration we present an exact solution for the case when the intermediate circuit can be described as an electromagnetic resonator. We discuss...

  8. Graphene-based photonic crystal

    International Nuclear Information System (INIS)

    Berman, Oleg L.; Boyko, Vladimir S.; Kezerashvili, Roman Ya.; Kolesnikov, Anton A.; Lozovik, Yurii E.

    2010-01-01

    A novel type of photonic crystal formed by embedding a periodic array of constituent stacks of alternating graphene and dielectric discs into a background dielectric medium is proposed. The photonic band structure and transmittance of such photonic crystal are calculated. The graphene-based photonic crystals can be used effectively as the frequency filters and waveguides for the far infrared region of electromagnetic spectrum. Due to substantial suppression of absorption of low-frequency radiation in doped graphene the damping and skin effect in the photonic crystal are also suppressed. The advantages of the graphene-based photonic crystal are discussed.

  9. Quantum Flows for Secret Key Distribution in the Presence of the Photon Number Splitting Attack

    Directory of Open Access Journals (Sweden)

    Luis A. Lizama-Pérez

    2014-06-01

    Full Text Available Physical implementations of quantum key distribution (QKD protocols, like the Bennett-Brassard (BB84, are forced to use attenuated coherent quantum states, because the sources of single photon states are not functional yet for QKD applications. However, when using attenuated coherent states, the relatively high rate of multi-photonic pulses introduces vulnerabilities that can be exploited by the photon number splitting (PNS attack to brake the quantum key. Some QKD protocols have been developed to be resistant to the PNS attack, like the decoy method, but those define a single photonic gain in the quantum channel. To overcome this limitation, we have developed a new QKD protocol, called ack-QKD, which is resistant to the PNS attack. Even more, it uses attenuated quantum states, but defines two interleaved photonic quantum flows to detect the eavesdropper activity by means of the quantum photonic error gain (QPEG or the quantum bit error rate (QBER. The physical implementation of the ack-QKD is similar to the well-known BB84 protocol.

  10. Update on photon-photon collisions

    International Nuclear Information System (INIS)

    Arteaga-Romero, N.; Cochard, G.; Ong, S.; Amiens Univ., 80; Carimalo, C.; Kessler, P.; Nicolaidis, A.; Parisi, J.; Courau, A.

    1980-03-01

    This report is the continuation of the 'Update' of last year (L.P.C. 79-03, March 1979, in French). In Part I, the structure functions of the photon in QCD are examined. It is shown that, while large psub(T) hadron production is similar to some extent in γγ collisions and in hadron-hadron collisions, the point-like nature of the photon introduces new terms which are entirely calculable, providing new means to test the dynamics of strong interactions. In Part II, problems of analysis in γγ experiments are discussed. The pros and cons of various options with regard to the measurement of outgoing electrons (non-tagging, finite-angle tagging, tagging at 0 0 ) are compared. It is shown that (a) non-tagging may be applied to the study of a limited number of processes only; (b) finite-angle tagging counters allow for various possibilities (double-tagging, single-tagging, double anti-tagging), but none of them is entirely satisfactory; (c) the ideal measurement is double tagging at 0 0 , provided the problem of bremsstrahlung saturation of the tagging counters can be solved

  11. Photonic Floquet topological insulators

    Science.gov (United States)

    Rechtsman, Mikael C.; Zeuner, Julia M.; Plotnik, Yonatan; Lumer, Yaakov; Podolsky, Daniel; Dreisow, Felix; Nolte, Stefan; Segev, Mordechai; Szameit, Alexander

    2013-09-01

    Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on the surface. In two dimensions, surface electrons in topological insulators do not scatter despite defects and disorder, providing robustness akin to superconductors. Topological insulators are predicted to have wideranging applications in fault-tolerant quantum computing and spintronics. Recently, large theoretical efforts were directed towards achieving topological insulation for electromagnetic waves. One-dimensional systems with topological edge states have been demonstrated, but these states are zero-dimensional, and therefore exhibit no transport properties. Topological protection of microwaves has been observed using a mechanism similar to the quantum Hall effect, by placing a gyromagnetic photonic crystal in an external magnetic field. However, since magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatterfree edge states requires a fundamentally different mechanism - one that is free of magnetic fields. Recently, a number of proposals for photonic topological transport have been put forward. Specifically, one suggested temporally modulating a photonic crystal, thus breaking time-reversal symmetry and inducing one-way edge states. This is in the spirit of the proposed Floquet topological insulators, where temporal variations in solidstate systems induce topological edge states. Here, we propose and experimentally demonstrate the first external field-free photonic topological insulator with scatter-free edge transport: a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges. Our system is composed of an array of evanescently coupled helical waveguides arranged in a graphene-like honeycomb lattice. Paraxial diffraction of light is described by a Schrödinger equation where the propagation coordinate acts as `time'. Thus the waveguides

  12. Models for photon-photon total cross-sections

    International Nuclear Information System (INIS)

    Godbole, R.M.; Grau, A.; Pancheri, G.

    1999-01-01

    The paper presents here a brief overview of recent models describing the photon-photon cross-section into hadrons. It shall be showed in detail results from the eikonal minijet model, with and without soft gluon summation

  13. X-ray attenuation around K-edge of Zr, Nb, Mo and Pd: A ...

    Indian Academy of Sciences (India)

    coefficients with which the experimental values can be compared. The XCOM pack- age [24–26] is a very powerful and useful computer program and database which can be used to calculate, with a personal computer, photon cross-sections for scattering, photoelectric absorption and pair production. Total attenuation ...

  14. Handedness of direct photons

    International Nuclear Information System (INIS)

    Kopeliovich, B.Z.; Rezaeian, A.H.; Schmidt, Ivan

    2008-01-01

    The azimuthal asymmetry of direct photons originating from primary hard scatterings between partons is calculated. This can be accounted for by the inclusion of the color dipole orientation, which is sensitive to the rapid variation of the nuclear profile. To this end we introduce the dipole orientation within the saturation model of Golec-Biernat and Wuesthoff, while preserving all its features at the cross-section level. We show that the direct photon elliptic anisotropy v2 coming from this mechanism changes sign and becomes negative for peripheral collisions, albeit it is quite small for nuclear collisions at the RHIC energy. (author)

  15. Workplace photon radiation fields

    International Nuclear Information System (INIS)

    Burgess, P.H.; Bartlett, D.T.; Ambrosi, P.

    1999-01-01

    The knowledge of workplace radiation fields is essential for measures in radiation protection. Information about the energy and directional distribution of the incident photon radiation was obtained by several devices developed by the National Radiation Protection Board, United Kingdom, by the Statens Stralskyddsinstitut, Sweden, together with EURADOS and by the Physikalisch-Technische Bundesanstalt, Germany. The devices are described and some results obtained at workplaces in nuclear industry, medicine and science in the photon energy range from 20 keV to 7 MeV are given. (author)

  16. Recent developments in the theory of photon-photon collisions

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1984-09-01

    Over the past few years the field of photon-photon collisions has emerged as one of the best testing grounds for QCD, particularly in the area of exclusive and inclusive hard scattering processes, exotic resonance production, and detailed tests of the coupling of real and virtual photons to the quark current. In this summary of contributed papers, I will briefly review recent theoretical progress in the analysis of two-photon reactions and possible directions for future work. 29 references

  17. A microcomputer-based gamma attenuation monitor for flowing liquids

    International Nuclear Information System (INIS)

    Everett, S.; Malcolme-Lawes, D.

    1984-01-01

    Many industrial processes involve large-scale flows of liquid mixtures or solutions in situations where it is desirable for the composition of the flow to be monitored. The attenuation (Isub(x)/I 0 ) of a beam of gamma photons can be used to provide a moderately sensitive means of monitoring mixture composition. Several applications of this technique to solid systems have been reported, and we have recently shown how the technique may be applied to monitoring the composition of a flowing liquid binary mixture. This paper describes a microcomputer-based apparatus which may be used to record the attenuation of a collimated beam of gamma photons by a liquid mixture flowing through a pipe. The apparatus and some example results obtained with trial mixtures are discussed. However, the sensitivity of the technique is determined both by the difference in u (the linear absorption coefficient of the matter concerned) for the materials which make up the mixture, and by the precision with which Isub(x)/I 0 may be monitored. For this reason we first consider the precision obtainable in the measurement of the intensity of a gamma photon beam. (author)

  18. Development of a new technic for breast attenuation correction in myocardial perfusion scintigraphy using computational methods

    International Nuclear Information System (INIS)

    Oliveira, Anderson de

    2015-01-01

    Introduction: One of the limitations of nuclear medicine studies are false-positive results that lead to unnecessary exams and procedures associated to morbidity and costs to the individual and society. One of the most frequent causes for reducing the specificity of myocardial perfusion imaging (MPI) is photon attenuation, especially by breast in women. Objective: To develop a new technique to compensate the photon attenuation by women breasts in myocardial perfusion imaging with 99m Tc-sestamibi, using computational methods. Materials and methods: A procedure was proposed which integrates Monte Carlo simulation, computational methods and experimental techniques. Initially, were obtained the chest attenuation correction percentages using a phantom Jaszczak and breast attenuation percentages by Monte Carlo simulation method, using the EGS4 program. The percentages of attenuation correction were linked to individual patients' characteristics by an artificial neural network and a multivariate analysis. A preliminary technical validation was done by comparing the results of the MPI and catheterism (CAT), before and after applying the technique to 4 patients. The t test for parametric data, Wilcoxon, Mann-Whitney and X 2 for the others were used. Probability values less than 0.05 were considered statistically significant. Results: Each increment of 1 cm in the thickness of breast was associated to an average increment of 6% on photon attenuation, while the maximum increase related to breast composition was about 2%. The average chest attenuation percentage per unit was 2.9%. Both, the artificial neural network and linear regression, showed an error less than 3% as predictive models for percentage of female attenuation. The anatomical-functional correlation between MPI and CAT was maintained after the use of the technique. Conclusion: Results suggest that the proposed technique is promising and could be a possible alternative to other conventional methods employed

  19. Photon states in anisotropic media

    Indian Academy of Sciences (India)

    Rosen) cor- relations as codified in Bell's inequalities have been tested for the polarization-entangled states of two photons. Similarly, quantum teleportation and quantum encryption have also been accomplished using photon polarization states.

  20. Mass attenuation coefficients of X-rays in different barite concrete used in radiation protection as shielding against ionizing radiation

    Science.gov (United States)

    Almeida Junior, T. Airton; Nogueira, M. S.; Vivolo, V.; Potiens, M. P. A.; Campos, L. L.

    2017-11-01

    The probability of a photon interacting in a particular way with a given material, per unit path length, is usually called the linear attenuation coefficient (μ), and it is of great importance in radiation shielding. Plates of barite concrete with different thickness were fabricated in order to determining their mass attenuation coefficients at different energies. The plates were irradiated with ISO X-ray beams (N60, N80, N110 and N150), generated by Pantak HF320 X-ray equipment, at the IPEN laboratory. The mass attenuation coefficients of barite concrete have been measured using X-ray attenuation for different thicknesses of barite concrete qualities of the ISO. The attenuator material issued from different regions of Brazil. The experimental procedure in this research was validated by comparison between the experimental measurements of mass attenuation coefficients and coefficients determined by the same atomic composition, using as a tool to XCOM. The highest value of (μ/ρ) found experimentally was in the energy of 48 keV, in ISO 60 N quality, being 1.32(±0.49) for purple barite; 1.47(±0.41) for white barite and 1.75(±0.41) for cream barite. The determination of the chemical composition of the barite samples was of fundamental importance for the characterization of these materials. It can be seen that both calculated and measured data for the linear attenuation coefficients increase with the increasing materials density, as it is expected. It can be concluded that the photon attenuation coefficients depends on the photon energy and the materials density is the main contribution to the photon attenuation coefficients, which is important for radiation shielding.

  1. Channel analysis for single photon underwater free space quantum key distribution.

    Science.gov (United States)

    Shi, Peng; Zhao, Shi-Cheng; Gu, Yong-Jian; Li, Wen-Dong

    2015-03-01

    We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater free space QKD is feasible in the clearest ocean water.

  2. Photon strength functions

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1976-01-01

    Methods for extracting photon strength functions are briefly discussed. We follow the Brink-Axel approach to relate the strength functions to the giant resonances observed in photonuclear work and summarize the available data on the E1, E2 and M1 resonances. Some experimental and theoretical problems are outlined. (author)

  3. Photonic band structure computations.

    Science.gov (United States)

    Hermann, D; Frank, M; Busch, K; Wolfle, P

    2001-01-29

    We introduce a novel algorithm for band structure computations based on multigrid methods. In addition, we demonstrate how the results of these band structure calculations may be used to compute group velocities and effective photon masses. The results are of direct relevance to studies of pulse propagation in such materials.

  4. ALICE Photon Spectrometer

    CERN Multimedia

    Kharlov, Y

    2013-01-01

    PHOS provides unique coverage of the following physics topics: - Study initial phase of the collision of heavy nuclei via direct photons, - Jet-quenching as a probe of deconfinement, studied via high Pτ ϒ and π0, - Signals of chiral-symmetry restoration, - QCD studies in pp collisions via identified neutral spectra.

  5. What is a Photon?

    Indian Academy of Sciences (India)

    IAS Admin

    We discuss the absorber theory of radiation as put forward by Wheeler and Feynman. We show that it gives a better understanding of the photon compared to the usual quantum electrodynamics. (QED) picture. All the fifty years of conscious brooding have brought me no closer to answer the question, `What are light quanta ...

  6. Magnetic photon scattering

    International Nuclear Information System (INIS)

    Lovesey, S.W.

    1987-05-01

    The report reviews, at an introductory level, the theory of photon scattering from condensed matter. Magnetic scattering, which arises from first-order relativistic corrections to the Thomson scattering amplitude, is treated in detail and related to the corresponding interaction in the magnetic neutron diffraction amplitude. (author)

  7. Biomedical photonics handbook biomedical diagnostics

    CERN Document Server

    Vo-Dinh, Tuan

    2014-01-01

    Shaped by Quantum Theory, Technology, and the Genomics RevolutionThe integration of photonics, electronics, biomaterials, and nanotechnology holds great promise for the future of medicine. This topic has recently experienced an explosive growth due to the noninvasive or minimally invasive nature and the cost-effectiveness of photonic modalities in medical diagnostics and therapy. The second edition of the Biomedical Photonics Handbook presents fundamental developments as well as important applications of biomedical photonics of interest to scientists, engineers, manufacturers, teachers, studen

  8. Limits on the photon mass

    International Nuclear Information System (INIS)

    Vasseur, G.

    1996-03-01

    Is the photon mass strictly null as it is told in quantum electrodynamics. In fact, a coherent theory can be build with a massive photon. Experiences have been regularly led to try to make obvious an eventual non null photon mass. Superior limits more and more strict have been found. Here is given a general survey of the consequences of a non null photon mass, different methods to measure it and the achieved limits. (author). 30 refs., 1 fig

  9. Nonlinear photonic quasicrystals

    International Nuclear Information System (INIS)

    Freedman, B.; Bartal, G.; Segev, M.; Lifshitz, R.; Christodoulides, D.; Fleischer, J.

    2005-01-01

    Full Text:Quasicrystals are structures with long-range order and no periodicity, whose unique structural and physical properties have intrigued scientists ever since their discovery and initial theoretical analysis more than two decades ago. The lack of periodicity excludes the use of well-established theoretical and experimental tools for the analysis of quasicrystals, including such notions as the Brillouin zone and Bloch theorem. Instead, the quasiperiodic atomic arrangement gives rise to unique properties such as a hierarchy of effective Brillouin (or Jones) zones, yielding a fractal-like band structure, and the existence of unique phason degrees of freedom. Generally, in atomic quasicrystals it is very difficult to directly observe the evolution of electronic wave-packets propagating through the structure, or the dynamics of the structure itself. Photonic quasicrystals, on the other hand, are macroscopic objects and hence their internal wave dynamics can be locally excited and directly imaged. Here, we employ optical induction to create 2D photonic quasicrystals, and explore wave transport phenomena in quasicrystals in ways that were impossible until now. We demonstrate linear tunneling-transport of light initiated at different crystal sites, and observe the formation of lattice solitons when the light is made sufficiently intense. We experiment with dynamical photonic quasicrystals, in which crystal sites interact with one another, and directly observe dislocation dynamics: creation, healing, and local structural rearrangement due to phason flips. Our experiments show that photonic quasicrystals are an excellent model system through which one can study the universal features of wave dynamics in quasiperiodic structures, that should apply not only to photonics, but also to other systems such as matter waves in quasiperiodic traps, generic pattern-forming systems as in parametrically-excited surface waves, liquid quasicrystals, as well as the more familiar

  10. Hydrogenated amorphous silicon photonics

    Science.gov (United States)

    Narayanan, Karthik

    2011-12-01

    Silicon Photonics is quickly proving to be a suitable interconnect technology for meeting the future goals of on-chip bandwidth and low power requirements. However, it is not clear how silicon photonics will be integrated into CMOS chips, particularly microprocessors. The issue of integrating photonic circuits into electronic IC fabrication processes to achieve maximum flexibility and minimum complexity and cost is an important one. In order to minimize usage of chip real estate, it will be advantageous to integrate in three-dimensions. Hydrogenated amorphous silicon (a-Si:H) is emerging as a promising material for the 3-D integration of silicon photonics for on-chip optical interconnects. In addition, a-Si:H film can be deposited using CMOS compatible low temperature plasma-enhanced chemical vapor deposition (PECVD) process at any point in the fabrication process allowing maximum flexibility and minimal complexity. In this thesis, we demonstrate a-Si:H as a high performance alternate platform to crystalline silicon, enabling backend integration of optical interconnects in a hybrid photonic-electronic network-on-chip architecture. High quality passive devices are fabricated on a low-loss a-Si:H platform enabling wavelength division multiplexing schemes. We demonstrate a broadband all-optical modulation scheme based on free-carrier absorption effect, which can enable compact electro-optic modulators in a-Si:H. Furthermore, we comprehensively characterize the optical nonlinearities in a-Si:H and observe that a-Si:H exhibits enhanced nonlinearities as compared to crystalline silicon. Based on the enhanced nonlinearities, we demonstrate low-power four-wave mixing in a-Si:H waveguides enabling high speed all-optical devices in an a-Si:H platform. Finally, we demonstrate a novel data encoding scheme using thermal and all-optical tuning of silicon waveguides, increasing the spectral efficiency in an interconnect link.

  11. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  12. Calculation of gamma-ray attenuation parameters for locally developed shielding material: Polyboron

    Directory of Open Access Journals (Sweden)

    Ripan Biswas

    2016-01-01

    Full Text Available In the present study, the mass attenuation coefficient (μm has been calculated analytically for a locally developed shielding material, polyboron, and compared with the values obtained from the WinXCom code, a Windows version of the XCOM database at the photon energy range 0.001 MeV–20 MeV. A good agreement has been observed between these two values. The linear attenuation coefficients (μ and relaxation lengths (λ have also been calculated from the obtained μm values and their variations with photon energy have been plotted. For comparison, other four shielding materials- ordinary concrete, pure polyethylene, borated polyethylene and water have also been studied. The obtained result shows that μm, μ and λ strongly depends on the photon energy, chemical composition and density of the shielding materials. The values of μm and μ of polyboron have been found greater than those of pure polyethylene and borated polyethylene but less than those of ordinary concrete and water at low photon energy range; and at the intermediate photon energy range (0.125 MeV–6 MeV, all the sample materials have approximately the same μm values. It has also been noticed that polyboron has the medial relaxation length (λ over the entire photon energy range. The total mass attenuation coefficient (μm and linear attenuation coefficient (μ, Half Value Layer (HVL and Tenth Value Layer (TVL of the five sample materials for some common gamma sources have been worked out and the transmission curves have been plotted. The curves exhibit that the transmission factor of the sample materials decreases with the increase in shielding thickness. The results of this study can be utilized to comprehend the shielding effectiveness of this locally developed material.

  13. Few-photon optical diode

    OpenAIRE

    Roy, Dibyendu

    2010-01-01

    We propose a novel scheme of realizing an optical diode at the few-photon level. The system consists of a one-dimensional waveguide coupled asymmetrically to a two-level system. The two or multi-photon transport in this system is strongly correlated. We derive exactly the single and two-photon current and show that the two-photon current is asymmetric for the asymmetric coupling. Thus the system serves as an optical diode which allows transmission of photons in one direction much more efficie...

  14. Photon production at the LHC

    CERN Document Server

    Lafaye, R

    2013-01-01

    We review the last results on photon production at the LHC by the ATLAS and CMS experiments obtained in proton-proton collisions with a center of mass energy of 7 TeV in 2010 and 2011, corresponding to a maximum integrated luminosity of 5 fb−1. We compare the prompt photon and photon-jet differential cross-sections to theoretical predictions and discuss their impact on the parton distribution functions of the proton. Di-photon differential cross-sections are also presented as a function of the di-photon invariant mass, transverse momentum, azimuthal separation, and cos theta*.

  15. Physics with Photons in ATLAS

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    The fine granularity ATLAS electromagnetic calorimeter provides a precise measurement of the photon energy and direction, as well as efficient rejection of background from fake photons, while the high precision inner detector allows also the reconstruction of photons that convert into electron-positron pairs.Isolated photons are measured using well-defined infrared-safe isolation criteria corrected for underlying event and the effects of additional proton-proton collisions. Differential cross sections for inclusive photons and diphotons are presented, and the spectrum of diphoton production is used to search for the Higgs boson in this decay channel.

  16. Photonic band gap materials

    Science.gov (United States)

    Cassagne, D.

    Photonic band gap materials Photonic band gap materials are periodic dielectric structures that control the propagation of electromagnetic waves. We describe the plane wave method, which allows to calculate the band structures of photonic crystals. By symmetry analysis and a perturbative approach, we predict the appearance of the low energy photonic band gaps of hexagonal structures. We propose new two-dimensional structures called graphite and boron nitride. Using a transfer matrix method, we calculate the transmission of the graphite structure and we show the crucial role of the coupling with external modes. We study the appearance of allowed modes in the photonic band gap by the introduction of localized defects in the periodicity. Finally, we discuss the properties of opals formed by self-organized silica microspheres, which are very promising for the fabrication of three-dimensional photonic crystals. Les matériaux à bandes interdites photoniques sont des structures diélectriques périodiques qui contrôlent la propagation des ondes électromagnétiques. Nous décrivons la méthode des ondes planes qui permet de calculer les structures de bandes des cristaux photoniques. Par une analyse de la symétrie et une approche perturbative, nous précisons les conditions d'existence des bandes interdites de basse énergie. Nous proposons de nouvelles structures bidimensionnelles appelées graphite et nitrure de bore. Grâce à une méthode de matrices de transfert, nous calculons la transmission de la structure graphite et nous mettons en évidence le rôle fondamental du couplage avec les modes extérieurs. Nous étudions l'apparition de modes permis dans la bande interdite grâce à l'introduction de défauts dans la périodicité. Enfin, nous discutons les propriétés des opales constituées de micro-billes de silice auto-organisées, qui sont très prometteuses pour la fabrication de cristaux photoniques tridimensionnels.

  17. Photon activation analysis

    International Nuclear Information System (INIS)

    Segebade, C.; Weise, H.P.; Lutz, G.J.

    1988-01-01

    This book is written to give, in a concentrated form, an overview of the application of photonuclear reactions to activation analysis. Is is intended to accompany the analyst's work in the photon activation analysis laboratory as a practical usable reference. Emphasis is placed upon analytical qualitative and quantitative data which are based upon experimentally obtained results. Therefore, both a source of general information on photon activation analysis and a laboratory manual are combined in this book. The results of the authors' laboratory work and a large amount of literature data are evaluated and presented as completely as possible by the authors. Special knowledge of photonuclear physics is not required; only a very elementary theoretical introduction is given. More detailed information on the physical and mathematical theory should be sought in the special literature which is cited in the relevant chapters. (orig./RB)

  18. Photons in a ball

    Energy Technology Data Exchange (ETDEWEB)

    Mueck, Wolfgang [Universita degli Studi di Napoli ' ' Federico II' ' , Dipartimento di Fisica ' ' Ettore Pancini' ' , Naples (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Naples (Italy)

    2015-12-15

    The electromagnetic field inside a spherical cavity of large radius R is considered in the presence of stationary charge and current densities. R provides infra-red regularisation while maintaining gauge invariance. The quantum ground state of physical photons forming the magnetic field is found to be a coherent state with a definite mean occupation number. The electric field, which is determined by the Gauss law constraint, is maintained by a minimum uncertainty coherent state, according to the projection operator approach to the quantisation of constrained systems. The mean occupation number of this state is proportional to the square of the total charge. The results confirm formulae obtained previously from a calculation with a finite photon mass for infra-red regularisation. (orig.)

  19. Photons in a ball

    Energy Technology Data Exchange (ETDEWEB)

    Mück, Wolfgang, E-mail: mueck@na.infn.it [Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli “Federico II”, Via Cintia, 80126, Naples (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Via Cintia, 80126, Naples (Italy)

    2015-12-11

    The electromagnetic field inside a spherical cavity of large radius R is considered in the presence of stationary charge and current densities. R provides infra-red regularisation while maintaining gauge invariance. The quantum ground state of physical photons forming the magnetic field is found to be a coherent state with a definite mean occupation number. The electric field, which is determined by the Gauss law constraint, is maintained by a minimum uncertainty coherent state, according to the projection operator approach to the quantisation of constrained systems. The mean occupation number of this state is proportional to the square of the total charge. The results confirm formulae obtained previously from a calculation with a finite photon mass for infra-red regularisation.

  20. Natural photonic crystals

    Science.gov (United States)

    Vigneron, Jean Pol; Simonis, Priscilla

    2012-10-01

    Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

  1. Essentials of photonics

    CERN Document Server

    Rogers, Alan; Baets, Roel

    2008-01-01

    Photons and ElectronsHistorical SketchThe Wave Nature of LightPolarizationThe Electromagnetic SpectrumEmission and Absorption ProcessesPhoton Statistics The Behaviour of Electrons LasersSummaryWave Properties of LightThe Electromagnetic SpectrumWave RepresentationElectromagnetic WavesReflection and RefractionTotal Internal ReflectionInterference of LightLight WaveguidingInterferometersDiffractionGaussian Beams and Stable Optical ResonatorsPolarization OpticsThe Polarization EllipseCrystal OpticsRetarding WaveplatesA Variable Waveplate: The Soleil-Babinet Compensator Polarizing PrismsLinear BirefringenceCircular BirefringenceElliptical BirefringencePractical Polarization EffectsPolarization AnalysisThe Form of the Jones MatricesLight and Matter Emission, Propagation, and Absorption ProcessesClassical Theory of Light Propagation in Uniform Dielectric Media Optical Dispersion Emission and Absorption of LightOptical Coherence and CorrelationIntroductionMeasure of Coherence Wiener-Khinchin TheoremDual-Beam Interfe...

  2. Photonics an introduction

    CERN Document Server

    Reider, Georg A

    2016-01-01

    This book provides a comprehensive introduction into photonics, from the electrodynamic and quantum mechanic fundamentals to the level of photonic components and building blocks such as lasers, amplifiers, modulators, waveguides, and detectors. The book will serve both as textbook and as a reference work for the advanced student or scientist. Theoretical results are derived from basic principles with convenient, yet state-of-the-art mathematical tools, providing not only deeper understanding but also familiarization with formalisms used in the relevant technical literature and research articles. Among the subject matters treated are polarization optics, pulse and beam propagation, waveguides, light–matter interaction, stationary and transient behavior of lasers, semiconductor optics and lasers (including low-dimensional systems such as quantum wells), detector technology, photometry, and colorimetry. Nonlinear optics are elaborated comprehensively. The book is intended for both students of physics and elect...

  3. Photon cross sections in the X-ray range: present status

    International Nuclear Information System (INIS)

    Gerward, Leif

    1993-01-01

    The present state of knowledge of photon cross sections in the energy range 1-100 keV is presented. Recent sources of experimental and theoretical data are given as well as other useful tools for the calculation of X-ray attenuation in matter. (author). 43 refs

  4. Three-photon micromasers

    International Nuclear Information System (INIS)

    Obada, A.S.F.; Abu Sitta, A.M.M.; Yasin, O.M.

    1993-01-01

    A non-degenerate 3-photon micromaser is analyzed. A 4-level atom is taken and 3 models of the field are considered. The model is solved for the case of resonance and the master equation for the density matrix is obtained. Semi-analytical solutions are obtained under specified approximations. Three modes can exist depending on the time of interaction. (author). 10 refs, 2 figs

  5. Active Photonic Devices

    Science.gov (United States)

    Della Valle, Giuseppe; Osellame, Roberto

    The chapter is devoted to active photonic devices fabricated by fs-laser writing. After a brief introduction focused on the role played by fs-laser written active devices, Sect. 10.2 briefly reviews the spectroscopical properties of the most interesting active ions so far exploited, namely erbium, ytterbium, neodimium, and bismuth. In Sect. 10.3 the main figures of merit for an active waveguide, namely the internal gain, the insertion loss, the net gain, and the noise figure are introduced and the experimental procedure for accurate gain measurement is also detailed. A thorough review of the active photonic devices demonstrated with the femtosecond laser microfabrication technique is presented in Sects. 10.4, 10.5, and 10.6, where several active waveguides and amplifiers, prototypal lasers, as well as more functionalized laser devices (operating under single longitudinal mode or stable mode-locking regime) are illustrated, respectively. Finally, conclusions and future perspectives of femtosecond-laser micromachining of active photonic devices are provided.

  6. Photon-activation therapy

    International Nuclear Information System (INIS)

    Fairchild, R.G.; Bond, V.P.

    1982-01-01

    Photon Activation Therapy (PAT) is a technique in which radiation dose to tumor is enhanced via introduction of stable 127 I in the form of iodinated deoxyuridine (IdUrd). Stimulation of cytotoxic effects from IdUrd is accomplished by activation with external (or implanted) radiation sources. Thus, accumulations of this nucleoside in actively competing cellpools do not preclude therapy in so far as such tissues can be excluded from the radiation field. Calculations show that 5% replacement of thymidine (Tyd) in tumor DNA should enhance the biological effectiveness of a given photon radiotherapy dose by a factor of approx. 3. Proportionally higher gains would result from higher replacements of Tyd and IdUrd. In addition, biological response is enhanced by chemical sensitization with IdUrd. The data indicate that damage from photon activation as well as chemical sensitization does not repair. Thus, at low dose rates, a further increase in therapeutic gain should accrue as normal tissues are allowed to repair and regenerate. A samarium-145 source has been developed for PAT, with activating x-ray energies of from 38 to 45 keV. Favorable clinical results can be expected through the use of IdUrd and protracted irradiations with low energy x-rays. In particular, PAT may provide unique advantages at selected sites such as brain, or head and neck tumors

  7. Slotted Photonic Crystal Sensors

    Science.gov (United States)

    Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

    2013-01-01

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

  8. Photonic Molecule Lasers Revisited

    Science.gov (United States)

    Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J.

    2014-05-01

    Photonic molecules (PMs) formed by coupling two or more optical resonators are ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission. We will extend our recent study and present new results for a number of promising geometries. The authors acknowledge financial support from NSERC (Canada) and the CERC in Photonic Innovations of Y. Messaddeq.

  9. Attenuation Effects of MR Headphones During Brain PET/MR Studies.

    Science.gov (United States)

    Ferguson, Aaron; McConathy, Jonathan; Su, Yi; Hewing, Debra; Laforest, Richard

    2014-06-01

    PET/MR offers potential advantages over PET/CT that are currently under investigation. One of the challenges of PET/MR is attenuation correction, as there is no simple correlation between MR signal intensity and the attenuation of 511-keV photons detected in PET. Currently, dedicated MR sequences are used to segment voxels into categories that are then assigned a predetermined attenuation coefficient. MR hardware such as the imaging table, coils, and headphones are also sources of attenuation. The purpose of this study was to evaluate the effect of MR-compatible headphones on average activity concentration measured with PET/MR. We also present a practical approach to correct for the attenuation effect of headphones using a CT-derived attenuation map. Phantom studies were performed using a 3-L cylindric phantom containing 55 MBq of (18)F-FDG and water. Images were acquired on a PET/MR device in 2 settings-one with the PET/MR headphones on and one with the headphones off. Phantom images were analyzed to compare activity concentration with headphones on and off. A high-resolution CT and (57)Co transmission scan was obtained to construct a PET attenuation map of the headphones. The resulting attenuation map was registered to the phantom data to evaluate the ability to correct for headphone attenuation. One human subject was scanned to evaluate the clinical impact of headphone attenuation and the accuracy of the proposed correction. Activity concentrations measured in the phantom were reduced by as much as 13.2% with headphones on compared with headphones off. Using the modified attenuation maps that account for attenuation from the headphones resulted in a decrease in the headphone attenuation effect from a maximum of 13.2% to 1.9%. Comparable attenuation effects were observed in the human brain and were similarly reduced with correction using the modified attenuation maps. MR-safe headphones were a source of attenuation on our PET/MR phantom and human studies

  10. Two media method for linear attenuation coefficient determination of irregular soil samples

    International Nuclear Information System (INIS)

    Vici, Carlos Henrique Georges

    2004-01-01

    In several situations of nuclear applications, the knowledge of gamma-ray linear attenuation coefficient for irregular samples is necessary, such as in soil physics and geology. This work presents the validation of a methodology for the determination of the linear attenuation coefficient (μ) of irregular shape samples, in such a way that it is not necessary to know the thickness of the considered sample. With this methodology irregular soil samples (undeformed field samples) from Londrina region, north of Parana were studied. It was employed the two media method for the μ determination. It consists of the μ determination through the measurement of a gamma-ray beam attenuation by the sample sequentially immersed in two different media, with known and appropriately chosen attenuation coefficients. For comparison, the theoretical value of μ was calculated by the product of the mass attenuation coefficient, obtained by the WinXcom code, and the measured value of the density sample. This software employs the chemical composition of the samples and supplies a table of the mass attenuation coefficients versus the photon energy. To verify the validity of the two media method, compared with the simple gamma ray transmission method, regular pome stone samples were used. With these results for the attenuation coefficients and their respective deviations, it was possible to compare the two methods. In this way we concluded that the two media method is a good tool for the determination of the linear attenuation coefficient of irregular materials, particularly in the study of soils samples. (author)

  11. Study of the mass attenuation coefficients and effective atomic numbers in some gemstones

    International Nuclear Information System (INIS)

    Medhat, M.E.

    2012-01-01

    The total mass attenuation coefficients for natural beryl, corundum, garnet, pearl, and tourmaline gemstones were measured at 81, 356.5, 661.6, 1173.2, and 1332.5 keV photon energies. The samples were irradiated with 133 Ba, 137 Cs and 60 Co radioactive point sources using gamma ray transmission method. Total atomic and electronic cross-sections, effective atomic numbers and electron densities were determined experimentally and theoretically. The experimental values were compared with the calculated values for all samples. The calculations were extended for total photon interactions in a wide energy range (1 keV-100 GeV) using WinXCom program of the most commonly irradiated gemstones with different sources of ionized radiation. The values of these parameters have been found to vary with photon energy and chemical composition of the gemstones. All variations of these parameters against energy are shown graphically for total photon interactions. (author)

  12. INDIA: Photon multiplicity detector

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Full text: The team of Indian scientists from Calcutta's Variable Energy Cyclotron Centre, Bhubaneswar Institute of Physics, Panjab (Chandigarh), Rajasthan (Jaipur) and Jammu in collaboration with GSI Darmstadt have contributed a large and highly granular preshower photon multiplicity detector (PMD) for the WA98 experiment at the CERN SPS proton synchrotron. This experiment studies high energy collisions of lead ions and will measure both charged particle and photon multiplicity in a large overlap region. The motivation for measuring photon multiplicity in ultra-relativistic heavy ion collisions stems from theoretical predictions of changes in the relative production of photons and charged particles in the phase transition of hadronic matter to quarkgluon plasma and its subsequent hadronization. The photon multiplicity detector consists of a matrix of scintillator pads placed in light-tight boxes and mounted behind the lead converter plates. The light from the scintillator pads is transported to the readout system using wavelength shifting (WLS) fibres. Developing on the team's earlier experience with a smaller version for the WA93 experiment (September 1991, page 16), several modifications were incorporated to improve light collection and transport. Use of improved WLS fibres, short WLS pieces to minimize self-absorption, and thermal splicing with long clear fibres were some of the important changes incorporated. Tests showed signficantly improved light collection. The scintillator pads were fabricated at all the five collaborating centres in India and the complicated assembly in the detector box modules carried out at the Variable Energy Cyclotron Centre, Calcutta. More than 400 lead converter plates were machined in Calcutta to rigorous tolerances of 0.2 mm. The assembled detector box modules and lead plates were shipped to CERN in spring 1994 for tests and installation. The WA98 PMD consists of over 50,000 scintillator pads of sizes varying from 15 to

  13. Photonic crystal based polarization insensitive flat lens

    Science.gov (United States)

    Turduev, M.; Bor, E.; Kurt, H.

    2017-07-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a/λ  =  0.280 and a/λ  =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25λ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  14. Interstitial photonic radiosurgery for brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Osami; Muragaki, Yoshihiro; Iseki, Hiroshi; Hori, Tomokatsu; Takakura, Kintomo [Tokyo Women' s Medical Coll. (Japan). Neurological Inst.

    1999-12-01

    The photon radiosurgery system (PRS) is a developed of the Photo-electron Corp. of Walham, Mass. The heart of this system is a thin needle, 3 mm in diameter and 100 mm long, from whose tip low-energy X-ray photon are isotropically emitted. This apparatus is a compact radiosurgery system that irradiates soft X ray from the tip of its small probe (weight of the machine=1.9 Kg). The PRS can be used either with a stereotactic frame or during a craniotomy as interstitial radiotherapy. The PRS is able to irradiate 15 Gy at the portion of 1.5 cm from the center for about 20 minutes and avoid severe damage to surrounding normal brain because of steep dose distribution curve. Because this system emits low-energy photons, almost the x-rays are attenuated in the patient. For a treatment of this system, dose rates outside the patient are close to background radiation levels. No special shielding of the patient or health care personnel is required. Basic examination of this system was done. C 6 cell line of Glioma was irradiated by PRS in vitro. A majority of tumor cells were died after 24 hrs. This time we estimated the effect of the PRS for brain tumors. We underwent the PRS to 72 patients from June 1995 to May 1999. Sixty-eight patients underwent intraoperative irradiation after removal and 4 patients had interstitial irradiation after stereotactic biopsy. All 16 cases of primary anaplastic astrocytomas survived and demonstrated good Karnofski performance scale. Median survival tomes of 17 primary cases of glioblastoma is 14 month. Two cases of malignant lymphoma showed complete remission in CT scan 24 hours after intraoperative radiosurgery using PRS and 2 cases of germ cell tumor demonstrated dramatic decrease of tumor size in a short period. There was no definite newly neurological deficit. The intraoperative radiosurgery using PRS is useful adjuvant therapy for brain tumors. (author)

  15. Large Mode Area Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Nielsen, Martin Dybendal

    2004-01-01

    . As a result of fabrication optimisation, a single-mode fiber with an effective area of 130 m2 and attenuation of 0.48 dB/km at the 1550 nm wavelength is reported. Based on the general consideration of the introducing chapters, 5 different examples of large-mode area PCFs are presented. The first is a large......The photonic crystal fiber (PCF) is a novel single-material optical waveguide realized by an arrangement of air-holes running along the full length of the fiber. Since the proposal of the PCF in 1996, the technology has developed into being a well-established area of research and commercialisation....... The work presented in this thesis deals with the optical properties of large-mode area PCFs for which the mode-field diameter, typically, is an order of magnitude larger than the free-space optical wavelength. Special emphasis is put on the description of relevant mechanisms of attenuation in these fibers...

  16. Simple and efficient absorption filter for single photons from a cold atom quantum memory.

    Science.gov (United States)

    Stack, Daniel T; Lee, Patricia J; Quraishi, Qudsia

    2015-03-09

    The ability to filter unwanted light signals is critical to the operation of quantum memories based on neutral atom ensembles. Here we demonstrate an efficient frequency filter which uses a vapor cell filled with (85)Rb and a buffer gas to attenuate both residual laser light and noise photons by nearly two orders of magnitude with little loss to the single photons associated with our cold (87)Rb quantum memory. This simple, passive filter provides an additional 18 dB attenuation of our pump laser and erroneous spontaneous emissions for every 1 dB loss of the single photon signal. We show that the addition of a frequency filter increases the non-classical correlations and the retrieval efficiency of our quantum memory by ≈ 35%.

  17. First Swiss bachelor in Photonics

    Science.gov (United States)

    Leutenegger, Tobias; Studer, Bruno

    2015-10-01

    Swissmem, the Swiss association of mechanical and electrical engineering industries, founded a new photonics group in 2013. This reflects the importance of this key technology for Switzerland. Swissmem requested from the Swiss Universities of Applied Sciences to introduce a new bachelor program to fulfill the increasing demand of the Swiss industry of young academics in the field of photonics. Optech Consulting is investigating the Swiss photonics market since many years on behalf of Swissphotonics, the Swiss national thematic network for photonics. The study concluded that the total production volume of the Swiss photonics industry in the year 2013 was 3 billion Swiss francs and a slight growth is expected for 2014. The University of Applied Science HTW Chur is located in the Eastern part of Switzerland. This area of the Rhine valley is a technology cluster of innovative companies in the field of optics and electronics. The industry is growing and the R&D departments of the worldwide active companies are lacking well-educated photonics engineers. The HTW Chur is dedicated to establish the first Swiss bachelor in Photonics. Supported by strong industrial players and an excellent network, the HTW Chur developed different job descriptions and a complete curriculum, which reflect the needs of the Swiss photonics industry. Almost 60% of the ECTS of this national degree program are assigned to photonics specific courses and the practical projects are organized in close collaboration with the photonics industry. Curriculum, job descriptions and the industrial needs will be discussed in detail in this paper.

  18. Frequency Agile Microwave Photonic Notch Filter in a Photonic Chip

    Science.gov (United States)

    2016-10-21

    AFRL-AFOSR-JP-TR-2016-0087 Frequency Agile Microwave Photonic Notch Filter in a Photonic Chip Benjamin Eggleton UNIVERSITY OF SYDNEY Final Report 10...REPORT TYPE      Final 3.  DATES COVERED (From - To)      14 May 2014 to 13 May 2016 4.  TITLE AND SUBTITLE Frequency Agile Microwave Photonic Notch Filter...in a Photonic Chip 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-14-1-4030 5c.  PROGRAM ELEMENT NUMBER 61102F 6.  AUTHOR(S) Benjamin Eggleton, David

  19. Beamline fast and automatic attenuation system for X-Ray detectors at Synchrotron Soleil

    Science.gov (United States)

    Renaud, G.; Garreau, Y.; Betinelli, P.; Tournieux, A.; Bisou, J.; Monteiro, P.; Elattaoui, X.

    2013-03-01

    Attenuators are commonly used on beamlines to control incident photon flux. Attenuators are mainly controlled by software. In some experimental cases using various diffraction techniques, this architecture is not fast enough to manage high flux variation. The fast attenuation system inserts and extracts filters quickly, allowing very fast beam attenuation at the maximum rate allowed by the filter mechanism and the beam detector response. To build the solution, we used an off-the-shelf CPCI General Purpose board (GPIO) from TEWS that is based on a SPARTAN-3 Xilinx FPGA: We have developed a daughter board and an embedded VHDL program. The logic is dedicated to maintaining incident detector photon flux within an acceptable range for optimized measurements and protecting the X ray detector against over-exposure. This system is part of a continuous scan process. Some low level process logic is also embedded in order to optimize data exchange. During continuous scanning, this process allows each experimental data item collected to be associated with its corresponding photon flux value. This system is in operation on the SIXS beamline and will be soon installed on the DIFFABS beamline. This paper describes the principle and the results obtained with this solution and the possible improvements and perspectives (interfacing more complex detectors such as XPad).

  20. Beamline fast and automatic attenuation system for X-Ray detectors at Synchrotron Soleil

    International Nuclear Information System (INIS)

    Renaud, G; Garreau, Y; Betinelli, P; Tournieux, A; Bisou, J; Monteiro, P; Elattaoui, X

    2013-01-01

    Attenuators are commonly used on beamlines to control incident photon flux. Attenuators are mainly controlled by software. In some experimental cases using various diffraction techniques, this architecture is not fast enough to manage high flux variation. The fast attenuation system inserts and extracts filters quickly, allowing very fast beam attenuation at the maximum rate allowed by the filter mechanism and the beam detector response. To build the solution, we used an off-the-shelf CPCI General Purpose board (GPIO) from TEWS that is based on a SPARTAN-3 Xilinx FPGA: We have developed a daughter board and an embedded VHDL program. The logic is dedicated to maintaining incident detector photon flux within an acceptable range for optimized measurements and protecting the X ray detector against over-exposure. This system is part of a continuous scan process. Some low level process logic is also embedded in order to optimize data exchange. During continuous scanning, this process allows each experimental data item collected to be associated with its corresponding photon flux value. This system is in operation on the SIXS beamline and will be soon installed on the DIFFABS beamline. This paper describes the principle and the results obtained with this solution and the possible improvements and perspectives (interfacing more complex detectors such as XPad).

  1. Exact equations for soil particle-size analysis by gamma-ray attenuation

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Elimoel Abraao; Bacchi, Osny Oliveira Santos; Reichardt, Klaus [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab, de Fisica do Solo

    1999-03-01

    Soil particle-size analysis by gamma-ray attenuation was first suggested in 1992 and improved in 1997 by diminishing the measurement time and adapting it for automation. It is here demonstrated that when the mass attenuation coefficient {mu}{sub w} and the density D{sub w} are replaced by {mu}{sub s} and D{sub s} (where the subscripts w and s stand for water and solution) in the approximate equations used to estimate the concentration of suspended particles, they become exact. The demonstration is based by treating the dispersant and water solution as one single medium, instead of treating them as two media In this way, six variables are reduced to only three. Physical considerations suggest that the precision in this analysis could be improved if other types of solutions and of photon energies would be used, so that the attenuation by the particles would differ more significantly from the attenuation by the solution. (author)

  2. Photonic crystals in epitaxial semiconductors

    CERN Document Server

    La Rue, R M de

    1998-01-01

    The title of the paper uses the expression "photonic crystals". By photonic crystals, we mean regular periodic structures with a substantial refractive index variation in one-, two- or three- dimensional space. Such crystals can $9 exist naturally, for example natural opal, but are more typically fabricated by people. Under sufficiently strong conditions, i.e., sufficiently large refractive index modulation, correct size of structural components, and $9 appropriate rotational and translational symmetry, these crystals exhibit the characteristics of a photonic bandgap (PBG) structure. In a full photonic bandgap structure there is a spectral stop band for electromagnetic waves $9 propagating in any direction through the structure and with an arbitrary state of polarization. This behavior is of interest both from a fundamental viewpoint and from the point of view of novel applications in photonic devices. The $9 paper gives an outline review of work on photonic crystals carried out by the Optoelectronics Researc...

  3. All-photonic quantum repeaters

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  4. The Photon Collider at Tesla

    Science.gov (United States)

    Badelek, B.; Blöchinger, C.; Blümlein, J.; Boos, E.; Brinkmann, R.; Burkhardt, H.; Bussey, P.; Carimalo, C.; Chyla, J.; Çiftçi, A. K.; Decking, W.; de Roeck, A.; Fadin, V.; Ferrario, M.; Finch, A.; Fraas, H.; Franke, F.; Galynskii, M.; Gamp, A.; Ginzburg, I.; Godbole, R.; Gorbunov, D. S.; Gounaris, G.; Hagiwara, K.; Han, L.; Heuer, R.-D.; Heusch, C.; Illana, J.; Ilyin, V.; Jankowski, P.; Jiang, Y.; Jikia, G.; Jönsson, L.; Kalachnikow, M.; Kapusta, F.; Klanner, R.; Klassen, M.; Kobayashi, K.; Kon, T.; Kotkin, G.; Krämer, M.; Krawczyk, M.; Kuang, Y. P.; Kuraev, E.; Kwiecinski, J.; Leenen, M.; Levchuk, M.; Ma, W. F.; Martyn, H.; Mayer, T.; Melles, M.; Miller, D. J.; Mtingwa, S.; Mühlleitner, M.; Muryn, B.; Nickles, P. V.; Orava, R.; Pancheri, G.; Penin, A.; Potylitsyn, A.; Poulose, P.; Quast, T.; Raimondi, P.; Redlin, H.; Richard, F.; Rindani, S. D.; Rizzo, T.; Saldin, E.; Sandner, W.; Schönnagel, H.; Schneidmiller, E.; Schreiber, H. J.; Schreiber, S.; Schüler, K. P.; Serbo, V.; Seryi, A.; Shanidze, R.; da Silva, W.; Söldner-Rembold, S.; Spira, M.; Stasto, A. M.; Sultansoy, S.; Takahashi, T.; Telnov, V.; Tkabladze, A.; Trines, D.; Undrus, A.; Wagner, A.; Walker, N.; Watanabe, I.; Wengler, T.; Will, I.; Wipf, S.; Yavaş, Ö.; Yokoya, K.; Yurkov, M.; Zarnecki, A. F.; Zerwas, P.; Zomer, F.

    High energy photon colliders (γγ,γe) are based on e-e- linear colliders where high energy photons are produced using Compton scattering of laser light on high energy electrons just before the interaction point. This paper is a part of the Technical Design Report of the linear collider TESLA.1 Physics program, possible parameters and some technical aspects of the photon collider at TESLA are discussed.

  5. Topological Order in Silicon Photonics

    Science.gov (United States)

    2017-02-07

    AFRL-AFOSR-VA-TR-2017-0037 Topological orders in Silicon photonics Mohammad Hafezi MARYLAND UNIV COLLEGE PARK 3112 LEE BLDG COLLEGE PARK, MD 20742...15 SEP 2016 4. TITLE AND SUBTITLE Topological Order in Silicon Photonics 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA-9550-14-1-0267 5c. PROGRAM...matter to ultra cold gases. Recently, photonic systems have been under investigation to explore various types of topological orders and to potentially

  6. CERN manufactured hybrid photon detectors

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    These hybrid photon detectors (HPDs) produce an electric signal from a single photon. An electron is liberated from a photocathode and accelerated to a silicon pixel array allowing the location of the photon on the cathode to be recorded. The electronics and optics for these devices have been developed in close collaboration with industry. HPDs have potential for further use in astrophysics and medical imaging.

  7. Silicon photonic heater-modulator

    Science.gov (United States)

    Zortman, William A.; Trotter, Douglas Chandler; Watts, Michael R.

    2015-07-14

    Photonic modulators, methods of forming photonic modulators and methods of modulating an input optical signal are provided. A photonic modulator includes a disk resonator having a central axis extending along a thickness direction of the disk resonator. The disk resonator includes a modulator portion and a heater portion. The modulator portion extends in an arc around the central axis. A PN junction of the modulator portion is substantially normal to the central axis.

  8. Silicon photonic integration in telecommunications

    Directory of Open Access Journals (Sweden)

    Christopher Richard Doerr

    2015-08-01

    Full Text Available Silicon photonics is the guiding of light in a planar arrangement of silicon-based materials to perform various functions. We focus here on the use of silicon photonics to create transmitters and receivers for fiber-optic telecommunications. As the need to squeeze more transmission into a given bandwidth, a given footprint, and a given cost increases, silicon photonics makes more and more economic sense.

  9. Photonic based marine radar demonstrator

    OpenAIRE

    Laghezza, Francesco; Scotti, Filippo; Ghelfi, Paolo; Bogoni, Antonella; Banchi, Luca; Malaspina, Vincenzo; Serafino, Giovanni

    2015-01-01

    This paper presents the results obtained during the field trial experiments of the first photonic-based radar system demonstrator, in a real maritime environment. The developed demonstrator exploits photonic technologies for both the generation and the detection of radar RF signals, allowing increased performance even in term of system flexibility. The photonic radar performance have been compared with a state of the art commercial system for maritime applications provide...

  10. Nanodiamond Emitters of Single Photons

    Directory of Open Access Journals (Sweden)

    Vlasov I.I.

    2015-01-01

    Full Text Available Luminescence properties of single color centers were studied in nanodiamonds of different origin. It was found that single photon emitters could be realized even in molecularsized diamond (less than 2 nm capable of housing stable luminescent center “silicon-vacancy.” First results on incorporation of single-photon emitters based on luminescent nanodiamonds in plasmonic nanoantennas to enhance the photon count rate and directionality, diminish the fluorescence decay time, and provide polarization selectivity are presented.

  11. Silicon applications in photonics

    Science.gov (United States)

    Jelenski, A. M.; Gawlik, G.; Wesolowski, M.

    2005-09-01

    Silicon technology enabled the miniaturization of computers and other electronic system for information storage, transmission and transformation allowing the development of the Knowledge Based Information Society. Despite the fact that silicon roadmap indicates possibilities for further improvement, already now the speed of electrons and the bandwidth of electronic circuits are not sufficient and photons are commonly utilized for signal transmission through optical fibers and purely photonic circuits promise further improvements. However materials used for these purposes II/V semiconductor compounds, glasses make integration of optoelectronic circuits with silicon complex an expensive. Therefore research on light generation, transformation and transmission in silicon is very active and recently, due to nanotechnology some spectacular results were achieved despite the fact that mechanisms of light generation are still discussed. Three topics will be discussed. Porous silicon was actively investigated due to its relatively efficient electroluminescence enabling its use in light sources. Its index of refraction, differs considerably from the index of silicon, and this allows its utilization for Bragg mirrors, wave guides and photonic crystals. The enormous surface enables several applications on medicine and biotechnology and in particular due to the effective chemo-modulation of its refracting index the design of optical chemosensors. An effective luminescence of doped and undoped nanocrystalline silicon opened another way for the construction of silicon light sources. Optical amplification was already discovered opening perspectives for the construction of nanosilicon lasers. Luminescences was observed at red, green and blue wavelengths. The used technology of silica and ion implantation are compatible with commonly used CMOS technology. Finally the recently developed and proved idea of optically pumped silicon Raman lasers, using nonlinearity and vibrations in the

  12. Fully reflective photon sieve

    Science.gov (United States)

    Sun, Wenbo; Hu, Yongxiang; MacDonnell, David G.; Kim, Hyun Jung; Weimer, Carl; Baize, Rosemary R.

    2018-02-01

    Photon sieves (PS) have many applications and various designs in focusing light. However, a traditional PS only has a light transmissivity up to ∼25% and a focusing efficiency up to ∼7%, which hinder the application of them in many fields, especially for satellite remote sensing. To overcome these inherent drawbacks of traditional PSs, a concept of reflective photon sieve is developed in this work. This reflective photon sieve is based on a transparent membrane backed by a mirror. The transparent membrane is optimally a fully transparent material sheet with given refractive index and designed geometric thickness which has an optical thickness of a quarter incident wavelength (i.e. an anti-reflective coating). The PS-patterned pinholes are made on the transparent membrane. The design makes the light reflected from pinholes and that from zones of membrane material have 180° phase difference. Thus, light incident on this optical device is reflected and focused on its focal point. This device can have a reflectivity of ∼100% and a focusing efficiency of ∼50% based on numerical simulation. This device functions similar to a concave focusing mirror but can preserve the phase feature of light (such as that for the light with orbital angular momentum). It also has excellent wavelength-dependent property, which can exclude most of the undesired light from the focal point. A thin sheet of this component can perform the joint function of lenses and gratings/etalons in the optical path of a remote sensing system, thus is suitable for controling/filtering light in compact instruments such as satellite sensors. This concept is validated by the finite-difference time domain (FDTD) modeling and a lab prototype in this study.

  13. Higgs-photon resonances

    Energy Technology Data Exchange (ETDEWEB)

    Dobrescu, Bogdan A.; Fox, Patrick J.; Kearney, John [Fermilab, Theoretical Physics Department, Batavia, IL (United States)

    2017-10-15

    We study models that produce a Higgs boson plus photon (h{sup 0}γ) resonance at the LHC. When the resonance is a Z{sup '} boson, decays to h{sup 0}γ occur at one loop. If the Z{sup '} boson couples at tree level to quarks, then the h{sup 0}γ branching fraction is typically of order 10{sup -5} or smaller. Nevertheless, there are models that would allow the observation of Z{sup '} → h{sup 0}γ at √(s) = 13 TeV with a cross section times branching fraction larger than 1 fb for a Z{sup '} mass in the 200-450 GeV range, and larger than 0.1 fb for a mass up to 800 GeV. The one-loop decay of the Z{sup '} into lepton pairs competes with h{sup 0}γ, even if the Z{sup '} couplings to leptons vanish at tree level. We also present a model in which a Z{sup '} boson decays into a Higgs boson and a pair of collimated photons, mimicking an h{sup 0}γ resonance. In this model, the h{sup 0}γ resonance search would be the discovery mode for a Z{sup '} as heavy as 2 TeV. When the resonance is a scalar, although decay to h{sup 0}γ is forbidden by angular momentum conservation, the h{sup 0} plus collimated photons channel is allowed. We comment on prospects of observing an h{sup 0}γ resonance through different Higgs decays, on constraints from related searches, and on models where h{sup 0} is replaced by a nonstandard Higgs boson. (orig.)

  14. Multichannel strobed photon counter

    International Nuclear Information System (INIS)

    Ganichev, V.A.; Elkin, O.K.; Zajdel', I.N.; Kozlov, V.A.; Lyapunov, G.M.; Malinovskij, A.L.; Ryabov, E.A.; Sil'kis, Eh.G.

    1987-01-01

    A multichannel strobed photon counter operating in the visible spectrum range is developed on the basis of luminescence amplifier with a microchannel plate and LI-706 supervidicon. The pulses overvoltaged supply mode of a microchannel plate has brought about amplification necessary for input into plateau of the counting characteristics and photoacceptor strobing in the nanosecond (140 ns) range. Device noises are practically completely determined by noises in luminescence amplifier photocathode. the above multichannel counter has a durable stability of parameters, electronic system simplicity and small dimensions of the photoacceptor

  15. Spaceborne Photonics Institute

    Science.gov (United States)

    Venable, D. D.; Farrukh, U. O.; Han, K. S.; Hwang, I. H.; Jalufka, N. W.; Lowe, C. W.; Tabibi, B. M.; Lee, C. J.; Lyons, D.; Maclin, A.

    1994-01-01

    This report describes in chronological detail the development of the Spaceborne Photonics Institute as a sustained research effort at Hampton University in the area of optical physics. This provided the research expertise to initiate a PhD program in Physics. Research was carried out in the areas of: (1) modelling of spaceborne solid state laser systems; (2) amplified spontaneous emission in solar pumped iodine lasers; (3) closely simulated AM0 CW solar pumped iodine laser and repeatedly short pulsed iodine laser oscillator; (4) a materials spectroscopy and growth program; and (5) laser induced fluorescence and atomic and molecular spectroscopy.

  16. Photonic crystal optofluidic biolaser

    Science.gov (United States)

    Mozaffari, Mohammad Hazhir; Ebnali-Heidari, Majid; Abaeiani, Gholamreza; Moravvej-Farshi, Mohammad Kazem

    2017-09-01

    Optofluidic biolasers are recently being considered in bioanalytical applications due to their advantages over the conventional biosensing methods Exploiting a photonic crystal slab with selectively dye-infiltrated air holes, we propose a new optofluidic heterostructure biolaser, with a power conversion efficiency of 25% and the spectral linewidth of 0.24 nm. Simulations show that in addition to these satisfactory lasing characteristics, the proposed lab-on-a-chip biolaser is highly sensitive to the minute biological changes that may occur in its cavity and can detect a single virus with a radius as small as 13 nm.

  17. Recent photon results from ATLAS

    CERN Document Server

    Glasman, Claudia; The ATLAS collaboration

    2017-01-01

    The production of prompt isolated photons at hadron colliders provides a stringent test of perturbative QCD and can be used to probe the gluon density function of the proton. The ATLAS collaboration has performed precise measurements of the inclusive production o f isolated prompt photons at a center-of-mass energy of 13 TeV, differential in both rap idity and the photon transverse momentum. In addition, the integrated and differential c ross sections for isolated photon pair production 8 TeV have been measured. The results are compared with state-of-the-art theory predictions at NLO in QCD and with predictions of several MC generators.

  18. Characteristics of the quarry as shielding for 241AmBe neutrons and monoenergetic photons

    International Nuclear Information System (INIS)

    Vega C, H. R.; Hernandez D, V. M.; Letechipia de L, C.; Salas L, M. A.; Rodriguez R, J. A.; Juarez A, C. A.

    2016-09-01

    Shielding is an important element in radiation protection since allows the management of radiation sources. Currently there are different materials of natural or anthropogenic origin that are used as shielding for both photons and neutrons. The quarry is a material of natural origin and abundant in our country, which is used in construction or for the manufacture of sculptures, however its characteristics as shielding have not been reported. In this paper we report some of the properties of the quarry as shielding for monoenergetic photons and for neutrons produced by an isotopic neutron source of 241 AmBe. A quarry piece was used to determine its density and its chemical composition, with the XCOM code the elemental composition was determined and the mass interaction and total attenuation coefficients of the quarry were determined with photons of 10 -3 to 10 -5 MeV; the interaction coefficients included coherent dispersion, photoelectric absorption, Compton dispersion and the production of pairs in the nuclear and electronic field. Using the MCNP5 code, a narrow geometry attenuation experiment was modeled and the photon fluence was estimated that reaches a point detector at a distance of 42 cm from a point source, isotropic and monoenergetic photon when the source and the point detector were added quarry pieces of different thicknesses. The reduction of the number of photons as a function of the thickness of the quarry was used to determine the coefficient of linear attenuation of the quarry before photons of 0.03, 0.07, 0.1, 0.3, 1, 2 and 3 MeV that were the same as those calculated with the XCOM code. With the MCNP, the K a and H(10) transmission curves were also calculated. This same model was used to determined the variation of the 241 AmBe neutron spectrum as a function of quarry thickness, as well as the E ROT and H(10) transmission curves. (Author)

  19. Deterministically swapping frequency-bin entanglement from photon-photon to atom-photon hybrid systems

    Science.gov (United States)

    Ou, Bao-Quan; Liu, Chang; Sun, Yuan; Chen, Ping-Xing

    2018-02-01

    Inspired by the recent developments of the research on the atom-photon quantum interface and energy-time entanglement between single-photon pulses, we are motivated to study the deterministic protocol for the frequency-bin entanglement of the atom-photon hybrid system, which is analogous to the frequency-bin entanglement between single-photon pulses. We show that such entanglement arises naturally in considering the interaction between a frequency-bin entangled single-photon pulse pair and a single atom coupled to an optical cavity, via straightforward atom-photon phase gate operations. Its anticipated properties and preliminary examples of its potential application in quantum networking are also demonstrated. Moreover, we construct a specific quantum entanglement witness tool to detect such extended frequency-bin entanglement from a reasonably general set of separable states, and prove its capability theoretically. We focus on the energy-time considerations throughout the analysis.

  20. Direct Writing of Photonic Structures by Two-Photon Polymerization

    Directory of Open Access Journals (Sweden)

    Li Yan

    2013-11-01

    Full Text Available Single-mode dielectric-loaded surface plasmon-polariton nanowaveguides with strong mode confinement at excitation wavelength of 830 nm and high-Q polymer whispering gallery mode microcavities with surface roughness less than 12 nm have been directly written by two-photon polymerization, which pave the way to fabricate 3D plasmonic photonic structures by direct laser writing.

  1. Photon and di-photon production at ATLAS

    CERN Document Server

    INSPIRE-00213273

    2013-01-01

    The latest ATLAS measurements of the cross section for the inclusive production of isolated prompt photons in $pp$ collisions at a centre-of-mass energy $\\sqrt{s}$ = 7 TeV at the LHC are presented, as well as the measurement of the di-photon production cross section.

  2. Sidewall roughness measurement of photonic wires and photonic crystals

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Frandsen, Lars Hagedorn; Garnæs, Jørgen

    2007-01-01

    The performance of nanophotonic building blocks such as photonic wires and photonic crystals are rapidly improving, with very low propagation loss and very high cavity Q-factors being reported. In order to facilitate further improvements in performance the ability to quantitatively measure...

  3. Photonic band gap engineering in 2D photonic crystals

    Indian Academy of Sciences (India)

    -dimensional photonic crystals with square lattices composed of air holes in dielectric and vice versa i.e., dielectric rods in air, using the plane-wave expansion method are investigated. We then study, how the photonic band gap size is ...

  4. Quantum photonics with quantum dots in photonic wires

    DEFF Research Database (Denmark)

    Munsch, Mathieu; Kuhlmann, Andreas; Cadeddu, Davide

    2016-01-01

    We present results from the spectroscopy of a single quantum dot in a photonic wire. The device presents a high photon extraction efficiency, and strong hybrid coupling to mechanical modes. We use resonance fluorescence to probe the emitter’s properties with the highest sensitivity. Weperform...

  5. Non-Poissonian photon statistics from macroscopic photon cutting materials

    NARCIS (Netherlands)

    De Jong, Mathijs; Meijerink, A; Rabouw, Freddy T.

    2017-01-01

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and

  6. Monitoring moisture movements in building materials using x-ray attenuation

    DEFF Research Database (Denmark)

    Pease, Bradley Justin; Scheffler, Gregor A.; Janssen, Hans

    2012-01-01

    X-ray attenuation measurements are commonly used as a non-destructive method to monitor internal concentration changes of moisture (i.e., moisture content) and other chemical compounds in porous building materials. The technique provides direct measurements of moisture content changes through...... analysis with a composite model consisting of a dry porous material and a thickness of water equivalent to the moisture content of the material. The current formulation of this composite model relies on certain assumptions, including a monochromatic x-ray photon beam source (i.e., x-ray photons of a single...

  7. Photon counting systems

    International Nuclear Information System (INIS)

    Cuby, J.G.

    1988-01-01

    This paper is a review of the various photon counting systems, used in astronomy, at optical wavelengths. Technological differences between available devices are introduced according to the processes applied to these photoelectrons (multiplication and/or acceleration), and their impact targets (phosphors, photodetectors, resistive or conductive anodes...). Two detection processes are involved: threshold discrimination above noise for most types of devices, and analog measurement for systems using resistive and wedge-and-strip anodes. Devices currently used for astronomical observations are presented, and their performance characteristics. These devices are: photomultipliers, which are monopixel detectors, using multiplication with dynodes; images intensifiers cameras, most frequently read with CCDs; analog devices with resistive or wedge-and-strip anodes, behind microchannel plates (MCP); Digicons, using direct electronic bombardment; the MAMA detector, with coincidence anodes behind MCP; and then the PAPA detector using masks encoding readout. Dead time effects, which define the dynamic range are presented with some details. Finally, because of the improvement of low level readout noise devices (CCDs), the field of application of the photon counting techniques confines to the blue and the UV part of the spectrum, at low signal to noise ratios [fr

  8. Amplified Photon Upconversion by Photonic Shell of Cholesteric Liquid Crystals.

    Science.gov (United States)

    Kang, Ji-Hwan; Kim, Shin-Hyun; Fernandez-Nieves, Alberto; Reichmanis, Elsa

    2017-04-26

    As an effective platform to exploit triplet-triplet-annihilation-based photon upconversion (TTA-UC), microcapsules composed of a fluidic UC core and photonic shell are microfluidically prepared using a triple emulsion as the template. The photonic shell consists of cholesteric liquid crystals (CLCs) with a periodic helical structure, exhibiting a photonic band gap. Combined with planar anchoring at the boundaries, the shell serves as a resonance cavity for TTA-UC emission and enables spectral tuning of the UC under low-power-density excitation. The CLC shell can be stabilized by introducing a polymerizable mesogen in the LC host. Because of the microcapsule spherical symmetry, spontaneous emission of the delayed fluorescence is omnidirectionally amplified at the edge of the stop band. These results demonstrate the range of opportunities provided by TTA-UC systems for the future design of low-threshold photonic devices.

  9. Photonic integration and photonics-electronics convergence on silicon platform

    CERN Document Server

    Liu, Jifeng; Baba, Toshihiko; Vivien, Laurent; Xu, Dan-Xia

    2015-01-01

    Silicon photonics technology, which has the DNA of silicon electronics technology, promises to provide a compact photonic integration platform with high integration density, mass-producibility, and excellent cost performance. This technology has been used to develop and to integrate various photonic functions on silicon substrate. Moreover, photonics-electronics convergence based on silicon substrate is now being pursued. Thanks to these features, silicon photonics will have the potential to be a superior technology used in the construction of energy-efficient cost-effective apparatuses for various applications, such as communications, information processing, and sensing. Considering the material characteristics of silicon and difficulties in microfabrication technology, however, silicon by itself is not necessarily an ideal material. For example, silicon is not suitable for light emitting devices because it is an indirect transition material. The resolution and dynamic range of silicon-based interference de...

  10. Robust Adaptive Photon Tracing using Photon Path Visibility

    DEFF Research Database (Denmark)

    Hachisuka, Toshiya; Jensen, Henrik Wann

    2011-01-01

    algorithm is the use of visibility of photon path as the importance function which ensures that our sampling algorithm focuses on paths that are visible from the given viewpoint. Our sampling algorithm builds on two recent developments in Markov chain Monte Carlo methods: adaptive Markov chain sampling...... and replica exchange. Using these techniques, each photon path is adaptively mutated and it explores the sampling space efficiently without being stuck at a local peak of the importance function. We have implemented this sampling approach in the progressive photon mapping algorithm which provides visibility...... information in a natural way when a photon path contributes to a measurement point. We demonstrate that the final algorithm is strikingly simple, yet effective at sampling photons under lighting conditions that would be difficult for existing Monte Carlo ray tracing-based methods....

  11. A comparison study for mass attenuation coefficients of some amino acids using MCNP code

    Energy Technology Data Exchange (ETDEWEB)

    Vahabi, Seyed Milad; Bahreynipour, Mostean; Shamsaie-Zafarghandi, Mojtaba [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Dept. of Energy Engineering and Physics

    2017-07-15

    In this study, a novel model of MCNP4C code reported recently was used to determine the photon mass attenuation coefficients of some amino acids at energies, 123, 360, 511, 662, 1170, 1280 and 1330 keV. The simulation results were compared with the XCOM data. It was indicated that the results were highly close to the calculated XCOM values. Obtained results were used to calculate the molar extinction coefficient. All the results showed the convenience and usefulness of the model in calculation of mass attenuation coefficients of amino acids.

  12. High-dimensional quantum key distribution based on multicore fiber using silicon photonic integrated circuits

    DEFF Research Database (Denmark)

    Ding, Yunhong; Bacco, Davide; Dalgaard, Kjeld

    2017-01-01

    is intrinsically limited to 1 bit/photon. Here we propose and experimentally demonstrate, for the first time, a high-dimensional quantum key distribution protocol based on space division multiplexing in multicore fiber using silicon photonic integrated lightwave circuits. We successfully realized three mutually......-dimensional quantum states, and enables breaking the information efficiency limit of traditional quantum key distribution protocols. In addition, the silicon photonic circuits used in our work integrate variable optical attenuators, highly efficient multicore fiber couplers, and Mach-Zehnder interferometers, enabling...... manipulating high-dimensional quantum states in a compact and stable manner. Our demonstration paves the way to utilize state-of-the-art multicore fibers for noise tolerance high-dimensional quantum key distribution, and boost silicon photonics for high information efficiency quantum communications....

  13. Exploring the Temporal and Spatial Dynamics of UV Attenuation and CDOM in the Surface Ocean Using New Algorithms

    Science.gov (United States)

    2007-09-30

    in situ scalar irradiance. • Developed a CO photoproduction climatology and submitted manuscript to GBC . RESULTS SeaUV was applied to...SeaUV does an admirable job of estimating UV attenuation once photons are in the ocean, the correction for clouds (which spectrally alters both the

  14. The STAR Photon Multiplicity Detector

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, M.M.; Badyal, S.K.; Bhaskar, P.; Bhatia, V.S.; Chattopadhyay, S. E-mail: sub@veccal.ernet.in; Das, S.; Datta, R.; Dubey, A.K.; Dutta Majumdar, M.R.; Ganti, M.S.; Ghosh, P.; Gupta, A.; Gupta, M.; Gupta, R.; Kaur, I.; Kumar, A.; Mahajan, S.; Mahapatra, D.P.; Mangotra, L.K.; Mishra, D.; Mohanty, B.; Nayak, S.K.; Nayak, T.K.; Pal, S.K.; Phatak, S.C.; Potukuchi, B.V.K.S.; Raniwala, R.; Raniwala, S.; Sahoo, R.; Sharma, A.; Singaraju, R.N.; Sood, G.; Trivedi, M.D.; Varma, R.; Viyogi, Y.P

    2003-03-01

    Details concerning the design, fabrication and performance of STAR Photon Multiplicity Detector (PMD) are presented. The PMD will cover the forward region, within the pseudorapidity range 2.3-3.5, behind the forward time projection chamber. It will measure the spatial distribution of photons in order to study collective flow, fluctuation and chiral symmetry restoration.

  15. Photonic nanowires for quantum optics

    DEFF Research Database (Denmark)

    Munsch, M.; Claudon, J.; Bleuse, J.

    Photonic nanowires (PWs) are simple dielectric structures for which a very efficient and broadband spontaneous emission (SE) control has been predicted [1]. Recently, a single photon source featuring a record high efficiency was demonstrated using this geometry [2]. Using time-resolved micro-phot...

  16. Advances on integrated microwave photonics

    DEFF Research Database (Denmark)

    Dong, Jianji; Liao, Shasha; Yan, Siqi

    2017-01-01

    Integrated microwave photonics has attracted a lot of attentions and makes significant improvement in last 10 years. We have proposed and demonstrated several schemes about microwave photonics including waveform generation, signal processing and energy-efficient micro-heaters. Our schemes are all...

  17. Nanodiamond particles forming photonic structures

    International Nuclear Information System (INIS)

    Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga

    2008-01-01

    Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds

  18. Nanodiamond particles forming photonic structures

    Energy Technology Data Exchange (ETDEWEB)

    Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga [International Technology Center, 8100 Brownleigh Drive, Suite 120, Raleigh, NC 27617 (United States)], E-mail: oshenderova@itc-inc.org

    2008-06-04

    Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds.

  19. Photon Production Within Storage Capsules

    CERN Document Server

    Rittmann, P D

    2003-01-01

    This report provides tables and electronic worksheets that list the photon production rate within SrF2 and CsC1 storage capsules, particularly the continuous spectrum of bremsstrahlung photons from the slowing down of the emitted electrons (BREMCALC).

  20. Silicon photonics fundamentals and devices

    CERN Document Server

    Deen, M Jamal

    2012-01-01

    The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

  1. Two-dimensional topological photonics

    Science.gov (United States)

    Khanikaev, Alexander B.; Shvets, Gennady

    2017-12-01

    Originating from the studies of two-dimensional condensed-matter states, the concept of topological order has recently been expanded to other fields of physics and engineering, particularly optics and photonics. Topological photonic structures have already overturned some of the traditional views on wave propagation and manipulation. The application of topological concepts to guided wave propagation has enabled novel photonic devices, such as reflection-free sharply bent waveguides, robust delay lines, spin-polarized switches and non-reciprocal devices. Discrete degrees of freedom, widely used in condensed-matter physics, such as spin and valley, are now entering the realm of photonics. In this Review, we summarize the latest advances in this highly dynamic field, with special emphasis on the experimental work on two-dimensional photonic topological structures.

  2. Photonic quantum information: science and technology.

    Science.gov (United States)

    Takeuchi, Shigeki

    2016-01-01

    Recent technological progress in the generation, manipulation and detection of individual single photons has opened a new scientific field of photonic quantum information. This progress includes the realization of single photon switches, photonic quantum circuits with specific functions, and the application of novel photonic states to novel optical metrology beyond the limits of standard optics. In this review article, the recent developments and current status of photonic quantum information technology are overviewed based on the author's past and recent works.

  3. Photonics a short course

    CERN Document Server

    Degiorgio, Vittorio

    2016-01-01

    This extended and revised edition will serve as a concise, self-contained, up-to-date introduction to Photonics for undergraduate students. It can also be used as a primer by researchers and professionals who start working in the field. Blending theory with technical descriptions, the book covers a wide range of topics, including the general mechanism of laser action, continuous and pulsed laser operation, optical propagation in isotropic and anisotropic media, operating principles and structure of passive optical components, electro-optic and acousto-optic modulation, solid-state lasers, semiconductor lasers and LEDs, nonlinear optical phenomena, and optical fiber components and devices. The book concludes with an overview of applications, including optical communications, telemetry and sensing, industrial and biomedical applications, solid-state lighting, displays, and photovoltaics. This second edition includes a set of problems at the end of all but the last chapter. These problems deal with numerical c...

  4. Progress on photonic crystals

    CERN Document Server

    Lecoq, P; Gundacker, S; Hillemanns, H; Jarron, P; Knapitsch, A; Leclercq, J L; Letartre, X; Meyer, T; Pauwels, K; Powolny, F; Seassal, C

    2010-01-01

    The renewal of interest for Time of Flight Positron Emission Tomography (TOF PET) has highlighted the need for increasing the light output of scintillating crystals and in particular for improving the light extraction from materials with a high index of refraction. One possible solution to overcome the problem of total internal reflection and light losses resulting from multiple bouncing within the crystal is to improve the light extraction efficiency at the crystal/photodetector interface by means of photonic crystals, i.e. media with a periodic modulation of the dielectric constant at the wavelength scale. After a short reminder of the underlying principles this contribution proposes to present the very encouraging results we have recently obtained on LYSO pixels and the perspectives on other crystals such as BGO, LuYAP and LuAG. These results confirm the impressive predictions from our previously published Monte Carlo simulations. A detailed description of the sample preparation procedure is given as well ...

  5. Ordered photonic microstructures

    Science.gov (United States)

    Chen, Kevin Ming

    2001-09-01

    This thesis examines novel photonic materials systems possessing order in the atomic, microscopic, and macroscopic dimensional regimes. In the atomic order regime, a structure-property investigation is done for Er2O3 in which the first report of room temperature photoluminescence (PL) is provided. Thin films of the rare earth oxide were deposited via reactive sputtering of Er metal in an Ar/O2 ambient, and subsequently annealed to promote grain growth. Heat treatment consisting of a 650°C followed by 1000°C anneal produces maximum crystallinity as measured by glancing angle x-ray diffraction. These films show characteristic PL at λ = 1.54 μm. In the microscopic order regime, omnidirectional reflectors and thin film microcavities are demonstrated using sol-gel and solid-state materials. A first demonstration of omnidirectional reflectivity in sol-gel structures was accomplished using a dielectric stack consisting of 12 spin-on SiO 2/TiO2 quarterwave sol-gel films. Similarly, solid-state dielectric stacks consisting of 6 Si/SiO2 sputtered films were used to demonstrate the same principle. Microcavities were formed using solgel structures, producing a low quality factor Q = 35 due to limitations in film thickness control and lossy interfaces from stress-induced cracks. The high index contrast Si/SiO2 microcavities enabled Q ~ 1000 using 17 total layers following hydrogenation of dangling bonds within the amorphous Si films. Combining fabrication processes for the solid-state microcavity and Er2O3 films, a device was fabricated to demonstrate photoluminescence enhancement of an Er2O3 film embedded in a microcavity. The structure consisted of 3-bilayer mirrors on either side of an SiO2/Er2O3/SiO2 cavity. The Q ~ 300 was near the theoretical value for such a structure. At room temperature, PL of Er2O3 was enhanced by a factor of 1000 in the microcavity compared to a single thin film. In the macroscopic order regime, self-assembly of micron- sized SiO 2 and

  6. The advanced photon source

    International Nuclear Information System (INIS)

    Galayda, J.N.

    1995-01-01

    The Advanced Photon Source (APS) is a 7-GeV third-generation synchrotron radiation storage ring and full-energy positron injector. Construction project funding began in 1989, and ground breaking took place on 5 May 1990. Construction of all accelerator facilities was completed in January 1995 and storage ring commissioning is underway. First observation of x-rays from a bending magnet source took place on 26 March 1995. Nearly all performance specifications of the injector have been reached, and first observations indicate that the reliability, dynamic aperture, emittance, and orbit stability in the storage ring are satisfactory. Observation of radiation from the first of 20 insertion device beamlines is scheduled for October 1995. Start of regular operations is expected to take place well before the APS Project target date of December 1996

  7. Photonics a short course

    CERN Document Server

    Degiorgio, Vittorio

    2014-01-01

    This book will serve as a concise, self-contained, up-to-date introduction to Photonics, to be used as a textbook for undergraduate students or as a reference book for researchers and professionals. Blending theory with technical descriptions, the book covers a wide range of topics, including the general mechanism of laser action, continuous and pulsed laser operation, optical propagation in isotropic and anisotropic media, operating principles and structure of passive optical components, electro-optical and acousto-optical modulation, solid-state lasers, semiconductor lasers and LEDs, nonlinear optics, and optical fiber components and devices.. The book concludes with an overview of applications, including optical communications, telemetry and sensing, industrial and biomedical applications, solid-state lighting, displays, and photovoltaics.

  8. Attenuation in Superconducting Circular Waveguides

    Directory of Open Access Journals (Sweden)

    K. H. Yeap

    2016-09-01

    Full Text Available We present an analysis on wave propagation in superconducting circular waveguides. In order to account for the presence of quasiparticles in the intragap states of a superconductor, we employ the characteristic equation derived from the extended Mattis-Bardeen theory to compute the values of the complex conductivity. To calculate the attenuation in a circular waveguide, the tangential fields at the boundary of the wall are first matched with the electrical properties (which includes the complex conductivity of the wall material. The matching of fields with the electrical properties results in a set of transcendental equations which is able to accurately describe the propagation constant of the fields. Our results show that although the attenuation in the superconducting waveguide above cutoff (but below the gap frequency is finite, it is considerably lower than that in a normal waveguide. Above the gap frequency, however, the attenuation in the superconducting waveguide increases sharply. The attenuation eventually surpasses that in a normal waveguide. As frequency increases above the gap frequency, Cooper pairs break into quasiparticles. Hence, we attribute the sharp rise in attenuation to the increase in random collision of the quasiparticles with the lattice structure.

  9. Nonlocal hyperconcentration on entangled photons using photonic module system

    International Nuclear Information System (INIS)

    Cao, Cong; Wang, Tie-Jun; Mi, Si-Chen; Zhang, Ru; Wang, Chuan

    2016-01-01

    Entanglement distribution will inevitably be affected by the channel and environment noise. Thus distillation of maximal entanglement nonlocally becomes a crucial goal in quantum information. Here we illustrate that maximal hyperentanglement on nonlocal photons could be distilled using the photonic module and cavity quantum electrodynamics, where the photons are simultaneously entangled in polarization and spatial-mode degrees of freedom. The construction of the photonic module in a photonic band-gap structure is presented, and the operation of the module is utilized to implement the photonic nondestructive parity checks on the two degrees of freedom. We first propose a hyperconcentration protocol using two identical partially hyperentangled initial states with unknown coefficients to distill a maximally hyperentangled state probabilistically, and further propose a protocol by the assistance of an ancillary single photon prepared according to the known coefficients of the initial state. In the two protocols, the total success probability can be improved greatly by introducing the iteration mechanism, and only one of the remote parties is required to perform the parity checks in each round of iteration. Estimates on the system requirements and recent experimental results indicate that our proposal is realizable with existing or near-further technologies.

  10. Photon technology. Laser processing technology; Photon technology. Laser process gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Survey has been conducted to develop laser processing technology utilizing the interaction between substance and photon. This is a part of the leading research on photon technology development. The photon technology development is aimed at novel technology development highly utilizing the quantum nature of photons. In the field of laser processing, high quality photons are used as tools, special functions of atoms and molecules will be discovered, and processing for functional fabrication (photon machining) will be established. A role of laser processing in industries has become significant, which is currently spreading not only into cutting and welding of materials and scalpels but also into such a special field as ultrafine processing of materials. The spreading is sometimes obstructed due to the difficulty of procurement of suitable machines and materials, and the increase of cost. The purpose of this study is to develop the optimal laser technology, to elucidate the interaction between substance and photon, and to develop the laser system and the transmission and regulation systems which realize the optimal conditions. 387 refs., 115 figs., 25 tabs.

  11. Photonic crystals, amorphous materials, and quasicrystals.

    Science.gov (United States)

    Edagawa, Keiichi

    2014-06-01

    Photonic crystals consist of artificial periodic structures of dielectrics, which have attracted much attention because of their wide range of potential applications in the field of optics. We may also fabricate artificial amorphous or quasicrystalline structures of dielectrics, i.e. photonic amorphous materials or photonic quasicrystals. So far, both theoretical and experimental studies have been conducted to reveal the characteristic features of their optical properties, as compared with those of conventional photonic crystals. In this article, we review these studies and discuss various aspects of photonic amorphous materials and photonic quasicrystals, including photonic band gap formation, light propagation properties, and characteristic photonic states.

  12. Holographic Two-Photon Induced Photopolymerization

    Data.gov (United States)

    Federal Laboratory Consortium — Holographic two-photon-induced photopolymerization (HTPIP) offers distinct advantages over conventional one-photon-induced photopolymerization and current techniques...

  13. Multi-Photon Entanglement and Quantum Teleportation

    National Research Council Canada - National Science Library

    Shih, Yanhua

    1999-01-01

    The project 'Multi-Photon Entanglement and Quantum Teleportation' concerns a series of experimental and theoretical investigations on multi-photon entangled states and the applications, for example...

  14. Heavy-quark correlations in direct photon-photon collisions

    CERN Document Server

    Krämer, M; Kramer, Michael; Laenen, Eric

    1996-01-01

    In two-photon collisions at LEP2 and a future e^+e^- linear collider heavy quarks (mainly charm) will be pair-produced rather copiously. The production via direct and resolved photons can be distinguished experimentally via a remnant-jet tag. We study correlations of the heavy quarks at next-to-leading order in QCD in the direct channel, which is free from phenomenological parton densities in the photon. These correlations are therefore directly calculable in perturbative QCD and provide a stringent test of the production mechanism.

  15. Higher-order photon correlations in pulsed photonic crystal nanolasers

    International Nuclear Information System (INIS)

    Elvira, D.; Hachair, X.; Braive, R.; Beaudoin, G.; Robert-Philip, I.; Sagnes, I.; Abram, I.; Beveratos, A.; Verma, V. B.; Baek, B.; Nam, S. W.; Stevens, M. J.; Dauler, E. A.

    2011-01-01

    We report on the higher-order photon correlations of a high-β nanolaser under pulsed excitation at room temperature. Using a multiplexed four-element superconducting single-photon detector we measured g (n) (0-vector) with n=2,3,4. All orders of correlation display partially chaotic statistics, even at four times the threshold excitation power. We show that this departure from coherence and Poisson statistics is due to the quantum fluctuations associated with the small number of photons at the lasing threshold.

  16. Photonic Paint Developed with Metallic Three-Dimensional Photonic Crystals

    Science.gov (United States)

    Sun, Po; Williams, John D.

    2012-01-01

    This work details the design and simulation of an inconspicuous photonic paint that can be applied onto an object for anticounterfeit and tag, track, and locate (TTL) applications. The paint consists of three-dimensional metallic tilted woodpile photonic crystals embedded into a visible and infrared transparent polymer film, which can be applied to almost any surface. The tilted woodpile photonic crystals are designed with a specific pass band detectable at nearly all incident angles of light. When painted onto a surface, these crystals provide a unique reflective infra-red optical signature that can be easily observed and recorded to verify the location or contents of a package.

  17. Analysis of photonic band gap in novel piezoelectric photonic crystal

    Science.gov (United States)

    Malar Kodi, A.; Doni Pon, V.; Joseph Wilson, K. S.

    2018-03-01

    The transmission properties of one-dimensional novel photonic crystal having silver-doped novel piezoelectric superlattice and air as the two constituent layers have been investigated by means of transfer matrix method. By changing the appropriate thickness of the layers and filling factor of nanocomposite system, the variation in the photonic band gap can be studied. It is found that the photonic band gap increases with the filling factor of the metal nanocomposite and with the thickness of the layer. These structures possess unique characteristics enabling one to operate as optical waveguides, selective filters, optical switches, integrated piezoelectric microactuators, etc.

  18. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc biased...... at different points in the current-voltage characteristic. Both numerical calculations based on the Tien-Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the ''open'' state. The performance of a fully...... integrated submillimeter receiver circuit which comprises a flux-flow oscillator (FFO) as local oscillator, a superconducting variable attenuator, and a microwave SIS detector with tuned-out capacitance is also reported....

  19. Transport of Photonic Bloch Wave in Arrayed Two-Level Atoms.

    Science.gov (United States)

    Chang, Chih-Chun; Lin, Lee; Chen, Guang-Yin

    2018-01-24

    In a quantum system of arrayed two-level atoms interacting with light, the interacted (dressed) photon is propagating in a periodic medium and its eigenstate ought to be of Bloch type with lattice symmetry. As the energy of photon is around the spacing between the two atomic energy levels, the photon will be absorbed and is not in the propagating mode but the attenuated mode. Therefore an energy gap exists in the dispersion relation of the photonic Bloch wave of dressed photon in addition to the nonlinear behaviors due to atom-light interactions. There follows several interesting results which are distinct from those obtained through a linear dispersion relation of free photon. For example, slow light can exist, the density of state of dressed photon is non-Lorentzian and is very large around the energy gap; the Rabi oscillations become monotonically decreasing in some cases; and besides the superradiance occurs at long wavelengths, the spontaneous emission is also very strong near the energy gap because of the high density of state.

  20. The LCLS Gas Attenuator Revisited

    International Nuclear Information System (INIS)

    Ryutov, D

    2005-01-01

    In the report ''X-ray attenuation cell'' [1] a preliminary analysis of the gas attenuator for the Linac Coherent Light Source (LCLS) was presented. This analysis was carried out for extremely stringent set of specifications. In particular, a very large diameter for the unobstructed beam was set (1 cm) to accommodate the spontaneous radiation; the attenuator was supposed to cover the whole range of energies of the coherent radiation, from 800 eV to 8000 eV; the maximum attenuation was set at the level of 10 4 ; the use of solid attenuators was not allowed, as well as the use of rotating shutters. The need to reach a sufficient absorption at the high-energy end of the spectrum predetermined the choice of Xe as the working gas (in order to have a reasonable absorption at a not-too-high pressure). A sophisticated differential pumping system that included a Penning-type ion pump was suggested in order to minimize the gas leak into the undulator/accelerator part of the facility. A high cost of xenon meant also that an efficient (and expensive) gas-recovery system would have to be installed. The main parameter that determined the high cost and the complexity of the system was a large radius of the orifice. The present viewpoint allows for much smaller size of the orifice, r 0 = 1.5 mm. (1) The use of solid attenuators is also allowed (R.M. Bionta, private communication). It is, therefore, worthwhile to reconsider various parameters of the gas attenuator for these much less stringent conditions. This brief study should be considered as a physics input for the engineering design. As a working gas we consider now the argon, which, on the one hand, provides a reasonable absorption lengths and, on the other hand, is inexpensive enough to be exhausted into the atmosphere (no recovery). The absorption properties of argon are illustrated by Fig.1 where the attenuation factor A is shown for various beam energies, based on Ref. [2]. The other relevant parameters for argon are

  1. ITMO Photonics: center of excellence

    Science.gov (United States)

    Voznesenskaya, Anna; Bougrov, Vladislav; Kozlov, Sergey; Vasilev, Vladimir

    2016-09-01

    ITMO University, the leading Russian center in photonics research and education, has the mission to train highlyqualified competitive professionals able to act in conditions of fast-changing world. This paradigm is implemented through creation of a strategic academic unit ITMO Photonics, the center of excellence concentrating organizational, scientific, educational, financial, laboratory and human resources. This Center has the following features: dissemination of breakthrough scientific results in photonics such as advanced photonic materials, ultrafast optical and quantum information, laser physics, engineering and technologies, into undergraduate and graduate educational programs through including special modules into the curricula and considerable student's research and internships; transformation of the educational process in accordance with the best international educational practices, presence in the global education market in the form of joint educational programs with leading universities, i.e. those being included in the network programs of international scientific cooperation, and international accreditation of educational programs; development of mechanisms for the commercialization of innovative products - results of scientific research; securing financial sustainability of research in the field of photonics of informationcommunication systems via funding increase and the diversification of funding sources. Along with focusing on the research promotion, the Center is involved in science popularization through such projects as career guidance for high school students; interaction between student's chapters of international optical societies; invited lectures of World-famous experts in photonics; short educational programs in optics, photonics and light engineering for international students; contests, Olympics and grants for talented young researchers; social events; interactive demonstrations.

  2. Single photon imaging. New instrumentation and techniques

    International Nuclear Information System (INIS)

    Muehllehner, G.; Colsher, J.

    1981-01-01

    The performance of Anger scintillation cameras continues to be enhanced through a series of small improvements which result in significantly better imaging characteristics. The most recent changes in camera design consist of: (1) the introduction of photomultipliers with better photocathode and electron collection efficiencies, (2) the use of thinner (3/8 or 1/4 in) crystals giving slightly better intrinsic resolution for low gamma-ray energies, (3) inclusion of a spatially varying energy window to compensate for variations of light collection efficiency, (4) event-by-event, real-time distortion removal for uniformity correction, and (5) introduction of new methods to improve the count-rate capability. Whereas some of these improvements are due to better understanding of the fundamentals of camera design, others are the result of technological advances in electronic components such as analogue-to-digital converters, microprocessors and high-density digital memories. The development of single photon tomography has developed along two parallel paths. Multipinhole and rotating slant-hole collimator attachments provide some degree of longitudinal tomography, and are currently being applied to cardiac imaging. At the same time rotating camera systems capable of transverse as well as longitudinal imaging are being refined technically and evaluated clinically. Longitudinal tomography is of limited use in quantitative studies and is likely to be an interim solution to three-dimensional imaging. Rotating camera systems, on the other hand, not only provide equal resolution in all three dimensions but are also capable of providing quantitative accuracy. This is the result of progress in attenuation correction and the design of special collimators. Single photon tomography provides a small but noticeable improvement in diagnostic accuracy which is likely to result in widespread use of rotating camera systems in the future

  3. SU-E-J-69: Iterative Deconvolution of the Initial Photon Fluence for EPID Dosimetry: A Monte Carlo Based Study

    Energy Technology Data Exchange (ETDEWEB)

    Czarnecki, D; Voigts-Rhetz, P von; Shishechian, D Uchimura [Technische Hochschule Mittelhessen - University of Applied Sciences, Giessen (Germany); Zink, K [Technische Hochschule Mittelhessen - University of Applied Sciences, Giessen (Germany); Germany and Department of Radiotherapy and Radiooncology, University Medical Center Giessen-Marburg, Marburg (Germany)

    2015-06-15

    Purpose: Developing a fast and accurate calculation model to reconstruct the applied photon fluence from an external photon radiation therapy treatment based on an image recorded by an electronic portal image device (EPID). Methods: To reconstruct the initial photon fluence the 2D EPID image was corrected for scatter from the patient/phantom and EPID to generate the transmitted primary photon fluence. This was done by an iterative deconvolution using precalculated point spread functions (PSF). The transmitted primary photon fluence was then backprojected through the patient/phantom geometry considering linear attenuation to receive the initial photon fluence applied for the treatment.The calculation model was verified using Monte Carlo simulations performed with the EGSnrc code system. EPID images were produced by calculating the dose deposition in the EPID from a 6 MV photon beam irradiating a water phantom with air and bone inhomogeneities and the ICRP anthropomorphic voxel phantom. Results: The initial photon fluence was reconstructed using a single PSF and position dependent PSFs which depend on the radiological thickness of the irradiated object. Appling position dependent point spread functions the mean uncertainty of the reconstructed initial photon fluence could be reduced from 1.13 % to 0.13 %. Conclusion: This study presents a calculation model for fluence reconstruction from EPID images. The{sup Result} show a clear advantage when position dependent PSF are used for the iterative reconstruction. The basic work of a reconstruction method was established and further evaluations must be made in an experimental study.

  4. Photonic band gap engineering in 2D photonic crystals

    Indian Academy of Sciences (India)

    -dimensional photonic crystals with square lattices composed of air holes in ... TIFAC-Center of Relevance & Excellence in Fiber Optics & Optical Communication, Department of Applied Physics, Delhi College of Engineering, Faculty of ...

  5. Evaluation of attenuation and scatter correction requirements in small animal PET and SPECT imaging

    Science.gov (United States)

    Konik, Arda Bekir

    Positron emission tomography (PET) and single photon emission tomography (SPECT) are two nuclear emission-imaging modalities that rely on the detection of high-energy photons emitted from radiotracers administered to the subject. The majority of these photons are attenuated (absorbed or scattered) in the body, resulting in count losses or deviations from true detection, which in turn degrades the accuracy of images. In clinical emission tomography, sophisticated correction methods are often required employing additional x-ray CT or radionuclide transmission scans. Having proven their potential in both clinical and research areas, both PET and SPECT are being adapted for small animal imaging. However, despite the growing interest in small animal emission tomography, little scientific information exists about the accuracy of these correction methods on smaller size objects, and what level of correction is required. The purpose of this work is to determine the role of attenuation and scatter corrections as a function of object size through simulations. The simulations were performed using Interactive Data Language (IDL) and a Monte Carlo based package, Geant4 application for emission tomography (GATE). In IDL simulations, PET and SPECT data acquisition were modeled in the presence of attenuation. A mathematical emission and attenuation phantom approximating a thorax slice and slices from real PET/CT data were scaled to 5 different sizes (i.e., human, dog, rabbit, rat and mouse). The simulated emission data collected from these objects were reconstructed. The reconstructed images, with and without attenuation correction, were compared to the ideal (i.e., non-attenuated) reconstruction. Next, using GATE, scatter fraction values (the ratio of the scatter counts to the total counts) of PET and SPECT scanners were measured for various sizes of NEMA (cylindrical phantoms representing small animals and human), MOBY (realistic mouse/rat model) and XCAT (realistic human model

  6. Gain attenuation of gated framing camera

    International Nuclear Information System (INIS)

    Xiao Shali; Liu Shenye; Cao Zhurong; Li Hang; Zhang Haiying; Yuan Zheng; Wang Liwei

    2009-01-01

    The theoretic model of framing camera's gain attenuation is analyzed. The exponential attenuation curve of the gain along the pulse propagation time is simulated. An experiment to measure the coefficient of gain attenuation based on the gain attenuation theory is designed. Experiment result shows that the gain follows an exponential attenuation rule with a quotient of 0.0249 nm -1 , the attenuation coefficient of the pulse is 0.00356 mm -1 . The loss of the pulse propagation along the MCP stripline is the leading reason of gain attenuation. But in the figure of a single stripline, the gain dose not follow the rule of exponential attenuation completely, instead, there is a gain increase at the stripline bottom. That is caused by the reflection of the pulse. The reflectance is about 24.2%. Combining the experiment and theory, which design of the stripline MCP can improved the gain attenuation. (authors)

  7. Photonics activities at DTU Fotonik

    DEFF Research Database (Denmark)

    Jeppesen, Palle; Jepsen, Peter Uhd; Lodahl, Peter

    2010-01-01

    DTU Fotonik, Department of Photonics Engineering at the Technical University of Denmark has about 200 employees including 60 PhD students. The ambition is to be among the world’s leading University departments within photonics research, education and innovation. To fulfil this ambition, DTU Fotonik...... tries to attract excellent researchers and students from all over the world and to collaborate with world leading research institutes and companies. The activities span from quantum photonics, nanotechnology and metamaterials over nonlinear fiber optics, optical sensors and diode lasers & LED systems...

  8. Photon-counting image sensors

    CERN Document Server

    Teranishi, Nobukazu; Theuwissen, Albert; Stoppa, David; Charbon, Edoardo

    2017-01-01

    The field of photon-counting image sensors is advancing rapidly with the development of various solid-state image sensor technologies including single photon avalanche detectors (SPADs) and deep-sub-electron read noise CMOS image sensor pixels. This foundational platform technology will enable opportunities for new imaging modalities and instrumentation for science and industry, as well as new consumer applications. Papers discussing various photon-counting image sensor technologies and selected new applications are presented in this all-invited Special Issue.

  9. Spin-photon entangling diode

    DEFF Research Database (Denmark)

    Flindt, Christian; Sørensen, A. S.; Lukin, M. D.

    2007-01-01

    We propose a semiconductor device that can electrically generate entangled electron spin-photon states, providing a building block for entanglement of distant spins. The device consists of a p-i-n diode structure that incorporates a coupled double quantum dot. We show that electronic control...... of the diode bias and local gating allow for the generation of single photons that are entangled with a robust quantum memory based on the electron spins. Practical performance of this approach to controlled spin-photon entanglement is analyzed....

  10. Summary of Lepton Photon 2011

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, Michael E.; /SLAC

    2012-03-14

    In this lecture, I summarize developments presented at the Lepton Photon 2011 conference and give my perspective on the current situation in high-energy physics. I am grateful to the organizers of Lepton Photon 2011 for providing us a very pleasant and simulating week in Mumbai. This year's Lepton Photon conference has covered the full range of subjects that fall within the scope of high-energy physics, including connections to cosmology, nuclear physics, and atomic physics. The experiments that were discussed detect particles ranging in energy from radio frequencies to EeV.

  11. gPhoton: THE GALEX PHOTON DATA ARCHIVE

    Energy Technology Data Exchange (ETDEWEB)

    Million, Chase [Million Concepts LLC, P.O. Box 119, 141 Mary Street, Lemont, PA 16851 (United States); Fleming, Scott W.; Shiao, Bernie; Smith, Myron; Thompson, Randy; White, Richard L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seibert, Mark [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Loyd, Parke [Laboratory for Atmospheric and Space Physics, Boulder, Colorado, 80309 (United States); Tucker, Michael [Dept. of Physics and Astronomy, Appalachian State University, Boone, NC 28608 (United States)

    2016-12-20

    gPhoton is a new database product and software package that enables analysis of GALEX ultraviolet data at the photon level. The project’s stand-alone, pure-Python calibration pipeline reproduces the functionality of the original mission pipeline to reduce raw spacecraft data to lists of time-tagged, sky-projected photons, which are then hosted in a publicly available database by the Mikulski Archive at Space Telescope. This database contains approximately 130 terabytes of data describing approximately 1.1 trillion sky-projected events with a timestamp resolution of five milliseconds. A handful of Python and command-line modules serve as a front end to interact with the database and to generate calibrated light curves and images from the photon-level data at user-defined temporal and spatial scales. The gPhoton software and source code are in active development and publicly available under a permissive license. We describe the motivation, design, and implementation of the calibration pipeline, database, and tools, with emphasis on divergence from prior work, as well as challenges created by the large data volume. We summarize the astrometric and photometric performance of gPhoton relative to the original mission pipeline. For a brief example of short time-domain science capabilities enabled by gPhoton, we show new flares from the known M-dwarf flare star CR Draconis. The gPhoton software has permanent object identifiers with the ASCL (ascl:1603.004) and DOI (doi:10.17909/T9CC7G). This paper describes the software as of version v1.27.2.

  12. The photonic nanowire: A highly efficient single-photon source

    DEFF Research Database (Denmark)

    Gregersen, Niels

    2014-01-01

    The photonic nanowire represents an attractive platform for a quantum light emitter. However, careful optical engineering using the modal method, which elegantly allows access to all relevant physical parameters, is crucial to ensure high efficiency.......The photonic nanowire represents an attractive platform for a quantum light emitter. However, careful optical engineering using the modal method, which elegantly allows access to all relevant physical parameters, is crucial to ensure high efficiency....

  13. gPhoton: THE GALEX PHOTON DATA ARCHIVE

    International Nuclear Information System (INIS)

    Million, Chase; Fleming, Scott W.; Shiao, Bernie; Smith, Myron; Thompson, Randy; White, Richard L.; Seibert, Mark; Loyd, Parke; Tucker, Michael

    2016-01-01

    gPhoton is a new database product and software package that enables analysis of GALEX ultraviolet data at the photon level. The project’s stand-alone, pure-Python calibration pipeline reproduces the functionality of the original mission pipeline to reduce raw spacecraft data to lists of time-tagged, sky-projected photons, which are then hosted in a publicly available database by the Mikulski Archive at Space Telescope. This database contains approximately 130 terabytes of data describing approximately 1.1 trillion sky-projected events with a timestamp resolution of five milliseconds. A handful of Python and command-line modules serve as a front end to interact with the database and to generate calibrated light curves and images from the photon-level data at user-defined temporal and spatial scales. The gPhoton software and source code are in active development and publicly available under a permissive license. We describe the motivation, design, and implementation of the calibration pipeline, database, and tools, with emphasis on divergence from prior work, as well as challenges created by the large data volume. We summarize the astrometric and photometric performance of gPhoton relative to the original mission pipeline. For a brief example of short time-domain science capabilities enabled by gPhoton, we show new flares from the known M-dwarf flare star CR Draconis. The gPhoton software has permanent object identifiers with the ASCL (ascl:1603.004) and DOI (doi:10.17909/T9CC7G). This paper describes the software as of version v1.27.2.

  14. Direct Reconstruction of CT-based Attenuation Correction Images for PET with Cluster-Based Penalties

    Science.gov (United States)

    Kim, Soo Mee; Alessio, Adam M.; De Man, Bruno; Asma, Evren; Kinahan, Paul E.

    2015-01-01

    Extremely low-dose CT acquisitions for the purpose of PET attenuation correction will have a high level of noise and biasing artifacts due to factors such as photon starvation. This work explores a priori knowledge appropriate for CT iterative image reconstruction for PET attenuation correction. We investigate the maximum a posteriori (MAP) framework with cluster-based, multinomial priors for the direct reconstruction of the PET attenuation map. The objective function for direct iterative attenuation map reconstruction was modeled as a Poisson log-likelihood with prior terms consisting of quadratic (Q) and mixture (M) distributions. The attenuation map is assumed to have values in 4 clusters: air+background, lung, soft tissue, and bone. Under this assumption, the MP was a mixture probability density function consisting of one exponential and three Gaussian distributions. The relative proportion of each cluster was jointly estimated during each voxel update of direct iterative coordinate decent (dICD) method. Noise-free data were generated from NCAT phantom and Poisson noise was added. Reconstruction with FBP (ramp filter) was performed on the noise-free (ground truth) and noisy data. For the noisy data, dICD reconstruction was performed with the combination of different prior strength parameters (β and γ) of Q- and M-penalties. The combined quadratic and mixture penalties reduces the RMSE by 18.7% compared to post-smoothed iterative reconstruction and only 0.7% compared to quadratic alone. For direct PET attenuation map reconstruction from ultra-low dose CT acquisitions, the combination of quadratic and mixture priors offers regularization of both variance and bias and is a potential method to derive attenuation maps with negligible patient dose. However, the small improvement in quantitative accuracy relative to the substantial increase in algorithm complexity does not currently justify the use of mixture-based PET attenuation priors for reconstruction of CT

  15. Engineering Photon-Photon Interactions within Rubidium-Filled Waveguides

    Science.gov (United States)

    Perrella, C.; Light, P. S.; Vahid, S. Afshar; Benabid, F.; Luiten, A. N.

    2018-04-01

    Strong photon-photon interactions are a required ingredient for deterministic two-photon optical quantum logic gates. Multiphoton transitions in dense atomic vapors have been shown to be a promising avenue for producing such interactions. The strength of a multiphoton interaction can be enhanced by conducting the interaction in highly confined geometries such as small-cross-section optical waveguides. We demonstrate, both experimentally and theoretically, that the strength of such interactions scale only with the optical mode diameter, d , not d2 as might be initially expected. This weakening of the interaction arises from atomic motion inside the waveguides. We create an interaction between two optical signals, at 780 and 776 nm, using the 5 S1 /2→5 D5 /2 two-photon transition in rubidium vapor within a range of hollow-core fibers with different core sizes. The interaction strength is characterized by observing the absorption and phase shift induced on the 780-nm beam, which is in close agreement with theoretical modeling that accounts for the atomic motion inside the fibers. These observations demonstrate that transit-time effects upon multiphoton transitions are of key importance when engineering photon-photon interactions within small-cross-section waveguides that might otherwise be thought to lead to enhanced optical nonlinearity through increased intensities.

  16. PHOTON PBL: problem-based learning in photonics technology education

    Science.gov (United States)

    Massa, Nicholas; Audet, Richard; Donnelly, Judith; Hanes, Fenna; Kehrhahn, Marijke

    2007-06-01

    Problem-based learning (PBL) is an educational approach whereby students learn course content by actively and collaboratively solving real-world problems presented in a context similar to that in which the learning is to be applied. Research shows that PBL improves student learning and retention, critical thinking and problem-solving skills, and the ability to skillfully apply knowledge to new situations - skills deemed critical to lifelong learning. Used extensively in medical education since the 1970's, and widely adopted in other fields including business, law, and education, PBL is emerging as an alternative to traditional lecture-based courses in engineering and technology education. In today's ever-changing global economy where photonics technicians are required to work productively in teams to solve complex problems across disciplines as well as cultures, PBL represents an exciting alternative to traditional lecture-based photonics education. In this paper we present the PHOTON PBL project, a National Science Foundation Advanced Technology Education (NSF-ATE) project aimed at creating, in partnership with the photonics industry and university research labs from across the US, a comprehensive series of multimedia-based PBL instructional resource materials and offering faculty professional development in the use of PBL in photonics technology education. Quantitative and qualitative research will be conducted on the effectiveness of PBL in photonics technician education.

  17. EDITORIAL: Photonic terahertz technology

    Science.gov (United States)

    Lisauskas, Alvydas; Löffler, Torsten; Roskos, Hartmut G.

    2005-07-01

    In recent years, when reading newspapers and journals or watching TV, one has been able to find feature presentations dealing with the prospects of terahertz (THz) technology and its potential impact on market applications. THz technology aims to fill the THz gap in the electro-magnetic spectrum in order to make the THz frequency regime, which spans the two orders of magnitude from 100 GHz to 10 THz, accessible for applications. From the lower-frequency side, electronics keeps pushing upwards, while photonic approaches gradually improve our technological options at higher frequencies. The popular interest reflects the considerable advances in research in the THz field, and it is mainly advances in the photonic branch, with the highlight being the development of the THz quantum cascade laser, which in recent years have caught the imagination of the public, and of potential users and investors. This special issue of Semiconductor Science and Technology provides an overview of key scientific developments which currently represent the cutting edge of THz photonic technology. In order to be clear about the implications, we should define exactly what we mean by 'THz photonic technology', or synonymously 'THz photonics'. It is characterized by the way in which THz radiation (or a guided THz wave) is generated, namely by the use of lasers. This may be done in one of two fundamentally different schemes: (i) by laser action in the terahertz frequency range itself (THz lasers), or (ii) by down-conversion processes (photomixing) involving the radiation of lasers which operate in the visible, near-infrared or infrared spectral ranges, either in pulsed or continuous-wave mode. The field of THz photonics has grown so considerably that it is out of the question to cover all its aspects in a single special issue of a journal. We have elected, instead, to focus our attention on two types of development with a potentially strong impact on the THz field: first, on significant advances

  18. Attenuation corrections through energy spectra analysis of whole body and partial body measurements applying gamma spectroscopy

    International Nuclear Information System (INIS)

    Schelper, L.F.; Lassmann, M.; Haenscheid, H.; Reiners, C.

    1997-01-01

    The study was carried out within the framework of activities for testing means of direct determination of radioactivity levels in the human body due to incorporated, inhomogenously distributed radionuclides. A major task was to derive the average depth of activity distributions, particularly from photon radiation at energies below 500 keV, for the purpose of making suitable attenuation corrections. The paper presents two applicable methods which yield information on the mean depths of activity distributions, obtained through additional analyses of the energy spectra. The analyses are based on measuring the dependence of intensity of the Compton radiation on the length of pathways of the photons penetrating the soft tissue, or on measuring the energy-dependent absorption effects with photons. (orig./CB) [de

  19. Ultrasonic attenuation in cuprate superconductors

    Indian Academy of Sciences (India)

    Ultrasonic attenuation in cuprate superconductors. T GUPTA1,∗ and D M GAITONDE1,2. 1Harish-Chandra Research Institute, Allahabad 211 019, India. 2High Pressure Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. ∗. Email: gupta@mri.ernet.in. Abstract. We calculate the longitudinal ...

  20. A Generalized Correction for Attenuation.

    Science.gov (United States)

    Petersen, Anne C.; Bock, R. Darrell

    Use of the usual bivariate correction for attenuation with more than two variables presents two statistical problems. This pairwise method may produce a covariance matrix which is not at least positive semi-definite, and the bivariate procedure does not consider the possible influences of correlated errors among the variables. The method described…

  1. Attenuation of Vrancea events revisited

    International Nuclear Information System (INIS)

    Radulian, M.; Popa, M.; Grecu, B.; Panza, G.F.

    2003-11-01

    New aspects of the frequency-dependent attenuation of the seismic waves traveling from Vrancea subcrustal sources toward NW (Transylvanian Basin) and SE (Romanian Plain) are evidenced by the recent experimental data made available by the CALIXTO'99 tomography experiment. The observations validate the previous theoretical computations performed for the assessment, by means of a deterministic approach, of the seismic hazard in Romania. They reveal an essential aspect of the seismic ground motion attenuation, that has important implications on the probabilistic assessment of seismic hazard from Vrancea intermediate-depth earthquakes. The attenuation toward NW is shown to be a much stronger frequency-dependent effect than the attenuation toward SE and the seismic hazard computed by the deterministic approach fits satisfactorily well the observed ground motion distribution in the low-frequency band (< 1 Hz). The apparent contradiction with the historically-based intensity maps arises mainly from a systematic difference in the vulnerability (buildings eigenperiod) of the buildings in the intra- and extra-Carpathians regions. (author)

  2. Compact plasmonic variable optical attenuator

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Pétur Gordon

    2008-01-01

    We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization...

  3. Photon interactions with nuclei

    International Nuclear Information System (INIS)

    Thornton, S.T.; Sealock, R.M.

    1989-01-01

    This document is a progress report for DOE Grant No. FG05-89ER40501, A000. The grant began March, 1989. Our primary research effort has been expended at the LEGS project at Brookhaven National Laboratory. This report will summarize our present research effort at LEGS as well as data analysis and publications from previous experiments performed at SLAC. In addition the principal investigators are heavily involved in the CLAS collaboration in Hall B at CEBAF. We have submitted several letters of intent and proposals and have made commitments to construct experimental equipment for CEBAF. We expect our primary experimental effort to continue at LEGS until CEBAF becomes operational. This report will be divided into separate sections describing our progress at LEGS, SLAC, and CEBAF. We will also discuss our significant efforts in the education and training of both undergraduate and graduate students. Photon detectors are described as well as experiments on delta deformation in nuclei of quasielastic scattering and excitation of the delta by 4 He(e,e')

  4. Patterned Colloidal Photonic Crystals.

    Science.gov (United States)

    Hou, Jue; Li, Mingzhu; Song, Yanlin

    2018-03-01

    Colloidal photonic crystals (PCs) have been well developed because they are easy to prepare, cost-effective, and versatile with regards to modification and functionalization. Patterned colloidal PCs contribute a novel approach to constructing high-performance PC devices with unique structures and specific functions. In this review, an overview of the strategies for fabricating patterned colloidal PCs, including patterned substrate-induced assembly, inkjet printing, and selective immobilization and modification, is presented. The advantages of patterned PC devices are also discussed in detail, for example, improved detection sensitivity and response speed of the sensors, control over the flow direction and wicking rate of microfluidic channels, recognition of cross-reactive molecules through an array-patterned microchip, fabrication of display devices with tunable patterns, well-arranged RGB units, and wide viewing-angles, and the ability to construct anti-counterfeiting devices with different security strategies. Finally, the perspective of future developments and challenges is presented. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Photonic MEMS switch applications

    Science.gov (United States)

    Husain, Anis

    2001-07-01

    As carriers and service providers continue their quest for profitable network solutions, they have shifted their focus from raw bandwidth to rapid provisioning, delivery and management of revenue generating services. Inherently transparent to data rate the transmission wavelength and data format, MEMS add scalability, reliability, low power and compact size providing flexible solutions to the management and/or fiber channels in long haul, metro, and access networks. MEMS based photonic switches have gone from the lab to commercial availability and are now currently in carrier trials and volume production. 2D MEMS switches offer low up-front deployment costs while remaining scalable to large arrays. They allow for transparent, native protocol transmission. 2D switches enable rapid service turn-up and management for many existing and emerging revenue rich services such as storage connectivity, optical Ethernet, wavelength leasing and optical VPN. As the network services evolve, the larger 3D MEMS switches, which provide greater scalability and flexibility, will become economically viable to serve the ever-increasing needs.

  6. Scatter and attenuation correction in Technetium-99m brain SPECT

    International Nuclear Information System (INIS)

    Hashimoto, Jun

    1997-01-01

    The imaging in the nuclear medicine is inferior to other modalities in the spatial resolution, but it can quantitatively evaluate the biological function. The attempt to measure the absolute or the relative values of local functions quantitatively based on the SPECT of the brain or the heart, has become popular recently. It is not only necessary to introduce an appropriate analytical model for each radioisotope tracer for the correct quantification, but also to be equipped with the photographing system to measure correctly the accumulation of the tracer. The main cause to decrease the precision of the photographing system is the scatter and the absorption (attenuation) of photon. In the present study we attempted to enhance the quantification of the brain SPECT by the usable and practical correction method for the scatter and the attenuation in the daily clinical business. We used the triple-energy-window (TEW) method as the scatter correction and the attenuation calculation map obtained from the transmission scanning (TCT) by the external source as the attenuation correction. We examined the brain SPECT in combination with these two correction methods. We could not measure correctly the amount of the tracer accumulation by only one correction method, and obtain the excellent quantitative SPECT images in combination with both correction methods. We could get excellently stable data by collecting the emission and the transmission data simultaneously as well as separately, and the excellent images by the arithmetical treatment of data between the scatter beam and the detector correction when we used 99m Tc as the source which is economically cheap, and adopted the combination of the tracers labeled by the same kind of radioisotopes. Altogether we expect that our method is very practical and will contribute to enhance the accuracy in quantitative analysis of clinical brain SPECT imaging. (K.H.)

  7. Parity-Time Symmetric Photonics

    KAUST Repository

    Zhao, Han

    2018-01-17

    The establishment of non-Hermitian quantum mechanics (such as parity-time (PT) symmetry) stimulates a paradigmatic shift for studying symmetries of complex potentials. Owing to the convenient manipulation of optical gain and loss in analogy to the complex quantum potentials, photonics provides an ideal platform for visualization of many conceptually striking predictions from the non-Hermitian quantum theory. A rapidly developing field has emerged, namely, PT symmetric photonics, demonstrating intriguing optical phenomena including eigenstate coalescence and spontaneous PT symmetry breaking. The advance of quantum physics, as the feedback, provides photonics with brand-new paradigms to explore the entire complex permittivity plane for novel optical functionalities. Here, we review recent exciting breakthroughs in PT symmetric photonics while systematically presenting their underlying principles guided by non-Hermitian symmetries. The potential device applications for optical communication and computing, bio-chemical sensing, and healthcare are also discussed.

  8. Photon management in solar cells

    CERN Document Server

    Rau, Uwe; Gombert, Andreas

    2015-01-01

    Written by renowned experts in the field of photon management in solar cells, this one-stop reference gives an introduction to the physics of light management in solar cells, and discusses the different concepts and methods of applying photon management. The authors cover the physics, principles, concepts, technologies, and methods used, explaining how to increase the efficiency of solar cells by splitting or modifying the solar spectrum before they absorb the sunlight. In so doing, they present novel concepts and materials allowing for the cheaper, more flexible manufacture of solar cells and systems. For educational purposes, the authors have split the reasons for photon management into spatial and spectral light management. Bridging the gap between the photonics and the photovoltaics communities, this is an invaluable reference for materials scientists, physicists in industry, experimental physicists, lecturers in physics, Ph.D. students in physics and material sciences, engineers in power technology, appl...

  9. Modelling of photonic crystal fibres

    DEFF Research Database (Denmark)

    Knudsen, Erik

    2003-01-01

    , as well as a honeycomb bandgap fibre and the first analysis of semi-periodic layered air-hole fibres. Using the modelling framework established as a basis, we provide an analysis of microbend loss, by regarding displacement of a fibre core as a stationary stochastic process, inducing mismatch between......In the presenta ph.d. work a theoretical study of aspects of modelling photonic crystal fibres was carried out. Photonic crystal fibres form a class of optical waveguides where guidance is no longer provided by a difference in refractive index between core and cladding. Instead, guidance...... is provided by an arrangement of air-holes running along the length of the fibre. Depending on the geometry of the fibre, the guiding mechanism may be either arising from the formation of a photonic bandgap in the cladding structure (photonic bandgap fibre), or by an effect resembling total internal...

  10. Photon states in anisotropic media

    Indian Academy of Sciences (India)

    Abstract. Quantum aspects of optical polarization are discussed for waves traveling in anisotropic dielectric media with a view to relate the dynamics of polarization with that of photon spin and its manipulation by classical polarizers.

  11. Manipulating continuous variable photonic entanglement

    International Nuclear Information System (INIS)

    Plenio, M.B.

    2005-01-01

    I will review our work on photonic entanglement in the continuous variable regime including both Gaussian and non-Gaussian states. The feasibility and efficiency of various entanglement purification protocols are discussed this context. (author)

  12. Improving the quantitative accuracy of optical-emission computed tomography by incorporating an attenuation correction: application to HIF1 imaging

    Science.gov (United States)

    Kim, E.; Bowsher, J.; Thomas, A. S.; Sakhalkar, H.; Dewhirst, M.; Oldham, M.

    2008-10-01

    Optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT) are new techniques for imaging the 3D structure and function (including gene expression) of whole unsectioned tissue samples. This work presents a method of improving the quantitative accuracy of optical-ECT by correcting for the 'self'-attenuation of photons emitted within the sample. The correction is analogous to a method commonly applied in single-photon-emission computed tomography reconstruction. The performance of the correction method was investigated by application to a transparent cylindrical gelatin phantom, containing a known distribution of attenuation (a central ink-doped gelatine core) and a known distribution of fluorescing fibres. Attenuation corrected and uncorrected optical-ECT images were reconstructed on the phantom to enable an evaluation of the effectiveness of the correction. Significant attenuation artefacts were observed in the uncorrected images where the central fibre appeared ~24% less intense due to greater attenuation from the surrounding ink-doped gelatin. This artefact was almost completely removed in the attenuation-corrected image, where the central fibre was within ~4% of the others. The successful phantom test enabled application of attenuation correction to optical-ECT images of an unsectioned human breast xenograft tumour grown subcutaneously on the hind leg of a nude mouse. This tumour cell line had been genetically labelled (pre-implantation) with fluorescent reporter genes such that all viable tumour cells expressed constitutive red fluorescent protein and hypoxia-inducible factor 1 transcription-produced green fluorescent protein. In addition to the fluorescent reporter labelling of gene expression, the tumour microvasculature was labelled by a light-absorbing vasculature contrast agent delivered in vivo by tail-vein injection. Optical-CT transmission images yielded high-resolution 3D images of the absorbing contrast agent, and

  13. Coupling the photon kinetics of soft photons with high energy photons

    Science.gov (United States)

    Silva, L. O.; Bingham, R.

    2017-10-01

    The description of electromagnetic fields based on the generalized photon kinetic theory, which takes advantage of the Wigner-Moyal description for the corresponding classical field theory, is capable of capturing collective plasma dynamics in the relativistic regime driven by broadband incoherent or partially coherent sources. We explore the possibility to extend this description to include the dynamics of hard photons in the plasma, whose interaction is dominated by single scattering processes. Examples of the modification of classical plasma instabilities due to the presence of hard photons is discussed. Work supported by the European Research Council (ERC-AdG-2015 InPairs Grant No. 695088).

  14. National Photonics Skills Standard for Technicians.

    Science.gov (United States)

    Center for Occupational Research and Development, Inc., Waco, TX.

    This document defines "photonics" as the generation, manipulation, transport, detection, and use of light information and energy whose quantum unit is the photon. The range of applications of photonics extends from energy generation to detection to communication and information processing. Photonics is at the heart of today's…

  15. Photon final states at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Campanelli, Mario; /University Coll. London

    2008-04-01

    The authors present here several recent measurements involving associate production of photons and jets at the Tevatron. In particular, inclusive photon + met from D0, and photon + b-jets and photon + b-jet + leptons + MET from CDF are described in some detail. These measurements offer a good test of QCD predictions in rather complex final states.

  16. Photon factory activity report, 1992

    International Nuclear Information System (INIS)

    1993-01-01

    This issue is the annual report of the Photon Factory, National laboratory of High Energy Physics. First, the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, the Tristan synchrotron radiation facility at the accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.) (435 refs.)

  17. Modeling of photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Barkou, Stig Eigil

    1999-01-01

    Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated.......Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated....

  18. Topology Optimized Photonic Wire Splitters

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Borel, Peter Ingo; Jensen, Jakob Søndergaard

    2006-01-01

    Photonic wire splitters have been designed using topology optimization. The splitters have been fabricated in silicon-on-insulator material and display broadband low-loss 3dB splitting in a bandwidth larger than 100 nm.......Photonic wire splitters have been designed using topology optimization. The splitters have been fabricated in silicon-on-insulator material and display broadband low-loss 3dB splitting in a bandwidth larger than 100 nm....

  19. Photon factory activity report, 1993

    International Nuclear Information System (INIS)

    1994-01-01

    This issue is the annual report of the Photon Factory, National Laboratory of High Energy Physics. First the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, synchrotron radiation facility at the Tristan accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.)

  20. Experimental search for muonic photons

    CERN Document Server

    Vilain, P; Beyer, R; Flegel, Wilfried; Mouthuy, T; Øverås, H; Panman, J; Rozanov, A N; Winter, Klaus; Zacek, G; Zacek, V; Büsser, F W; Foos, C; Gerland, L; Layda, T; Niebergall, F; Rädel, G; Stähelin, P; Voss, T; Favart, D; Grégoire, G; Knoops, E; Lemaître, V; Gorbunov, P; Grigoriev, E A; Ilyin, V A; Khovanskii, V D; Maslennikov, A M; Okun, Lev Borisovich; Lippich, W; Nathaniel, A; Staude, A; Vogt, J; Cocco, A G; Ereditato, A; Fiorillo, G; Marchetti-Stasi, F; Palladino, Vittorio; Strolin, P; Capone, A; De Pedis, D; Dore, U; Frenkel-Rambaldi, A; Loverre, P F; Macina, Daniela; Piredda, G; Santacesaria, R; Di Capua, E; Ricciardi, S; Saitta, B; Akkus, B; Arik, E; Serin-Zeyrek, M; Sever, R; Tolun, P; Hiller, K; Nahnhauer, R; Roloff, H

    1998-01-01

    We report new limits on the production of muonic photons in the CERN neutrino beam. The results are based on the analysis of neutrino production of dimuons in the CHARM II detector. A $90\\%$ CL limit on the coupling constant of muonic photons, $\\alpha_{\\mu} / \\alpha < (1.5 \\div 3.2) \\times10^{-6}$ is derived for a muon neutrino mass in the range $m_{\

  1. Attenuation of the gamma rays in tissues; Atenuacion de los rayos gamma en tejidos

    Energy Technology Data Exchange (ETDEWEB)

    Arcos P, A.; Rodriguez N, S.; Pinedo S, A.; Amador V, P.; Chacon R, A.; Vega C, H.R. [Unidad Academica de Estudios Nucleares, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2005-07-01

    The mass and lineal attenuation coefficient and of hepatic tissue, muscular, osseous and of brain before gamma rays of 10{sup -3} to 10{sup 5} MeV were calculated. For the case of the osseous tissue the calculation was made for the cartilage, the cortical tissue and the bone marrow. During the calculations the elementary composition of the tissues of human origin was used. The calculations include by separate the Photoelectric effect, the Compton scattering and the Pair production, as well as the total. For to establish a comparison with the attenuation capacities, the coefficients of the water, the aluminum and the lead also were calculated. The study was complemented measuring the attenuation coefficient of hepatic tissue of bovine before gamma rays of 0.662 MeV of a source of {sup 137} Cs. The measurement was made through of an experiment of photons transmission through samples frozen of hepatic tissue and with a Geiger-Mueller detector. (Author)

  2. Topological Photonics for Continuous Media

    Science.gov (United States)

    Silveirinha, Mario

    Photonic crystals have revolutionized light-based technologies during the last three decades. Notably, it was recently discovered that the light propagation in photonic crystals may depend on some topological characteristics determined by the manner how the light states are mutually entangled. The usual topological classification of photonic crystals explores the fact that these structures are periodic. The periodicity is essential to ensure that the underlying wave vector space is a closed surface with no boundary. In this talk, we prove that it is possible calculate Chern invariants for a wide class of continuous bianisotropic electromagnetic media with no intrinsic periodicity. The nontrivial topology of the relevant continuous materials is linked with the emergence of edge states. Moreover, we will demonstrate that continuous photonic media with the time-reversal symmetry can be topologically characterized by a Z2 integer. This novel classification extends for the first time the theory of electronic topological insulators to a wide range of photonic platforms, and is expected to have an impact in the design of novel photonic systems that enable a topologically protected transport of optical energy. This work is supported in part by Fundacao para a Ciencia e a Tecnologia Grant Number PTDC/EEI-TEL/4543/2014.

  3. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  4. Computational Modeling of Photonic Crystal Microcavity Single-Photon Emitters

    Science.gov (United States)

    Saulnier, Nicole A.

    Conventional cryptography is based on algorithms that are mathematically complex and difficult to solve, such as factoring large numbers. The advent of a quantum computer would render these schemes useless. As scientists work to develop a quantum computer, cryptographers are developing new schemes for unconditionally secure cryptography. Quantum key distribution has emerged as one of the potential replacements of classical cryptography. It relics on the fact that measurement of a quantum bit changes the state of the bit and undetected eavesdropping is impossible. Single polarized photons can be used as the quantum bits, such that a quantum system would in some ways mirror the classical communication scheme. The quantum key distribution system would include components that create, transmit and detect single polarized photons. The focus of this work is on the development of an efficient single-photon source. This source is comprised of a single quantum dot inside of a photonic crystal microcavity. To better understand the physics behind the device, a computational model is developed. The model uses Finite-Difference Time-Domain methods to analyze the electromagnetic field distribution in photonic crystal microcavities. It uses an 8-band k · p perturbation theory to compute the energy band structure of the epitaxially grown quantum dots. We discuss a method that combines the results of these two calculations for determining the spontaneous emission lifetime of a quantum dot in bulk material or in a microcavity. The computational models developed in this thesis are used to identify and characterize microcavities for potential use in a single-photon source. The computational tools developed are also used to investigate novel photonic crystal microcavities that incorporate 1D distributed Bragg reflectors for vertical confinement. It is found that the spontaneous emission enhancement in the quasi-3D cavities can be significantly greater than in traditional suspended slab

  5. Prospects for Photon-Photon and Photon-Proton Measurements with Forward Proton Taggers in ATLAS

    CERN Document Server

    Trzebinski, Maciej; The ATLAS collaboration

    2017-01-01

    Talk for Photon2017 conference. Topics covered: ALFA and AFP detectors. Physics: elastic scattering, diffractive bremsstrahlung, exclusive pion pair production, anomalous gauge couplings, new physics (e.g. magnetic monopoles).

  6. What is a photon?

    Science.gov (United States)

    Kracklauer, A. F.

    2015-09-01

    The linguistic and epistemological constraints on finding and expressing an answer to the title question are reviewed. First, it is recalled that "fields" are defined in terms of their effect on "test charges" and not in terms of any, even idealistically considered, primary, native innate qualities of their own. Thus, before fields can be discussed, the theorist has to have already available a defined "test particle" and field source. Clearly, neither the test nor the engendering particles can be defined as elements of the considered field without redefining the term "field." Further, the development of a theory as a logical structure (i.e., an internally self consistent conceptual complex) entails that the subject(s) of the theory (the primitive elements) and the rules governing their interrelationships (axioms) cannot be deduced by any logical procedure. They are always hypothesized on the basis of intuition supported by empirical experience. Given hypothesized primitive elements and axioms it is possible, in principle, to test for the 'completion' of the axiom set (i.e., any addition introduces redundancy) and for self consistency. Thus, theory building is limited to establishing the self consistency of a theory's mathematical expression and comparing that with the external, ontic world. Finally, a classical model with an event-by-event simulation of an EPR-B experiment to test a Bell Inequality is described. This model leads to a violation of Bell's limit without any quantum input (no nonlocal interaction nor entanglement), thus substantiating previous critical analysis of the derivation of Bell inequalities. On the basis of this result, it can be concluded that the electromagnetic interaction possesses no preternatural aspects, and that the usual models in terms of waves, fields and photons are all just imaginary constructs with questionable relation to a presumed reality.

  7. Analysis of the factors that affect photon counts in Compton scattering.

    Science.gov (United States)

    Luo, Guang; Xiao, Guangyu

    2014-10-30

    Compton scattering has been applied in a variety of fields. The factors that affect Compton scattering have been studied extensively in the literature. However, the factors that affect the measured photon counts in Compton scattering are rarely considered. In this paper, we make a detailed discussion on those factors. First, Compton scattering experiments of some alloy series and powder mixture series are explored. Second, the electron density is researched in terms of atom and lattice constants. Third, the factor of attenuation coefficient is discussed. And then, the active degree of electrons is discussed based on the DFT theory. Lastly, the conclusions are made, that the factors affecting Compton scattering photon counts include mainly electron number density, attenuation coefficient and active degree of electrons. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. single photon emission tomography and positron emission tomography - Part 1 (October 2012), Part 2 (October 2010)

    International Nuclear Information System (INIS)

    Buvat, Irene

    2010-10-01

    The objective of this lecture is to present the single photon emission computed tomography (SPECT) and the positron emission tomography (PET) imaging techniques. Part 1 Content: 1 - Introduction: anatomic, functional and molecular imaging; 2 - Radiotracers: chemical and physical constraints, gamma photon emitters, positon emitters, radioisotopes production, emitters type and imaging techniques; 3 - Gamma cameras; 4 - Quantification in emission tomography: attenuation, scattering, un-stationary spatial resolution; 5 - Synthesis and conclusion. Part 2 content: 1 - Positon emitters; 2 - Positons detection: Coincidence detection (electronic collimation, PET detectors with gamma cameras, dedicated PET detectors, spectrometry); PET detectors type; time-of-flight PET; 2D PET; 3D PET; 3 - Quantification in emission tomography: detected events, attenuation, scattering, fortuitous coincidences, standardisation; 4 - Common SPECT and PET problems: partial volume effect, movement, tomographic reconstruction, calibration, dead time; 5 - Synthesis and conclusion

  9. Formation of η' mesons in photon-photon collisions

    International Nuclear Information System (INIS)

    Uitert, B.K. van.

    1986-01-01

    This thesis describes an experiment performed at the positron electron storage ring PEP at the Stanford Linear Accelerator Center on the formation of the η' resonance which is observed in its decay mode ρ 0 γ, where the ρ decays into a π + π - pair. Some general features of the relatively new subject of photon-photon physics are introduced. The η' and the coupling of photons to the η' are discussed in the context of the quark model. It is shown how the mixing angle in the nonet of pseudoscalar mesons can be derived from ratios of γγ widths. The kinematics of the two-photon exchange process, the formation of the η' resonance by the two virtual photons and its subsequent electromagnetic decay into ρ 0 γ are discussed. The selected sample of events is used to determine the γγ width of the η' under the conventional assignment J P = 0 - for the η' and J P = 1 - for the ρ. The result is combined with measurements by other experiments to a world average, which is used to determine the mixing angle for the pseudoscalar nonet under various assumptions. The decay angular and energy distributions are investigated in detail. (Auth.)

  10. PHOTON09. Proceedings of the international conference on the structure and interactions of the photon including the 18th international workshop on photon-photon collisions and the international workshop on high energy photon linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Olaf; Diehl, Markus; Schoerner-Sadenius, Thomas; Steinbrueck, Georg (eds.)

    2010-01-15

    The following topics were dealt with: Electroweak and new physics, photon-collider technology, low-energy photon experiments, prompt photons, photon structure, jets and heavy flavours, vacuum polarization and light-by-light scattering, small-x processes, diffraction, total cross sections, exclusive channels and resonances, photons in astroparticle physics. (HSI)

  11. PHOTON09. Proceedings of the international conference on the structure and interactions of the photon including the 18th international workshop on photon-photon collisions and the international workshop on high energy photon linear colliders

    International Nuclear Information System (INIS)

    Behnke, Olaf; Diehl, Markus; Schoerner-Sadenius, Thomas; Steinbrueck, Georg

    2010-01-01

    The following topics were dealt with: Electroweak and new physics, photon-collider technology, low-energy photon experiments, prompt photons, photon structure, jets and heavy flavours, vacuum polarization and light-by-light scattering, small-x processes, diffraction, total cross sections, exclusive channels and resonances, photons in astroparticle physics. (HSI)

  12. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  13. Silicon photonics: some remaining challenges

    Science.gov (United States)

    Reed, G. T.; Topley, R.; Khokhar, A. Z.; Thompson, D. J.; Stanković, S.; Reynolds, S.; Chen, X.; Soper, N.; Mitchell, C. J.; Hu, Y.; Shen, L.; Martinez-Jimenez, G.; Healy, N.; Mailis, S.; Peacock, A. C.; Nedeljkovic, M.; Gardes, F. Y.; Soler Penades, J.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Cheben, P.; Mashanovich, G. Z.

    2016-03-01

    This paper discusses some of the remaining challenges for silicon photonics, and how we at Southampton University have approached some of them. Despite phenomenal advances in the field of Silicon Photonics, there are a number of areas that still require development. For short to medium reach applications, there is a need to improve the power consumption of photonic circuits such that inter-chip, and perhaps intra-chip applications are viable. This means that yet smaller devices are required as well as thermally stable devices, and multiple wavelength channels. In turn this demands smaller, more efficient modulators, athermal circuits, and improved wavelength division multiplexers. The debate continues as to whether on-chip lasers are necessary for all applications, but an efficient low cost laser would benefit many applications. Multi-layer photonics offers the possibility of increasing the complexity and effectiveness of a given area of chip real estate, but it is a demanding challenge. Low cost packaging (in particular, passive alignment of fibre to waveguide), and effective wafer scale testing strategies, are also essential for mass market applications. Whilst solutions to these challenges would enhance most applications, a derivative technology is emerging, that of Mid Infra-Red (MIR) silicon photonics. This field will build on existing developments, but will require key enhancements to facilitate functionality at longer wavelengths. In common with mainstream silicon photonics, significant developments have been made, but there is still much left to do. Here we summarise some of our recent work towards wafer scale testing, passive alignment, multiplexing, and MIR silicon photonics technology.

  14. Macroseismic intensity attenuation in Iran

    Science.gov (United States)

    Yaghmaei-Sabegh, Saman

    2018-01-01

    Macroseismic intensity data plays an important role in the process of seismic hazard analysis as well in developing of reliable earthquake loss models. This paper presents a physical-based model to predict macroseismic intensity attenuation based on 560 intensity data obtained in Iran in the time period 1975-2013. The geometric spreading and energy absorption of seismic waves have been considered in the proposed model. The proposed easy to implement relation describes the intensity simply as a function of moment magnitude, source to site distance and focal depth. The prediction capability of the proposed model is assessed by means of residuals analysis. Prediction results have been compared with those of other intensity prediction models for Italy, Turkey, Iran and central Asia. The results indicate the higher attenuation rate for the study area in distances less than 70km.

  15. Long period gratings written in large-mode area photonic crystal fiber

    DEFF Research Database (Denmark)

    Nodop, D.; Linke, S.; Jansen, F.

    2008-01-01

    We report for the first time, to the best of our knowledge, on the fabrication and characterization of CO2-laser written long-period gratings in a large-mode area photonic crystal fiber with a core diameter of 25 mu m. The gratings have low insertion losses (<1 dB) and high attenuation (> 10 dB) ......B) at the resonant wavelengths, making them particularly interesting for high power applications....

  16. Characteristics of liver tissue for attenuate the gamma radiation; Caracteristicas del tejido hepatico para atenuar la radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Arcos P, A.; Rodriguez N, S.; Pinedo S, A.; Amador V, P.; Chacon R, A.; Vega C, H.R. [Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2005-07-01

    It was determined the lineal attenuation coefficient of hepatic tissue before gamma radiation of a source of {sup 137} Cs. When exposing organic material before X or gamma radiation fields, part of the energy of the photons is absorbed by the material, while another part crosses it without producing any effect. The quantity of energy that is absorbed is a measure of the dose that receives the material. The three main mechanisms by means of which the gamma rays interacting with the matter are: The Photoelectric Effect, the Compton dispersion and the Even production; the sum of these three processes is translated in the attenuation coefficient of the radiation. In this work we have used hepatic tissue of bovine, as substitute of the human hepatic tissue, and we have measured the lineal attenuation coefficient for photons of 0.662 MeV. Through a series of calculations we have determined the lineal attenuation coefficient for photons from 10{sup -3} to 10{sup -5} MeV and the measured coefficient was compared with the one calculated. (Author)

  17. Study of photon-photon collision reactions on DCI

    International Nuclear Information System (INIS)

    Falvard, Alain.

    1978-01-01

    One first shows interesting aspects specific of photon-photon collisions (γγ → X; leptonic or hadronic system C=+1, any Jsup(p) (a priori)). Then, one justifies the introduction, in experimental conditions at DCI, of a double Williams-Weiszacker approximation to compute ee → eeX reactions cross sections. This is made after a calculation developped in the frame of an 0(2,1) group's formalism. After, one presents to the important points of two photons experiments: essentially, necessity tagg electrons diffused at zero degree. The tagging system on DCI is then described: drift chambers of good spatial accuracy (0.2 mm), proximity of the beam are its main characteristics. One then estimates the background in detectors and the waited counting rates for ee→ee+(2γ) e + e - ,μ + μ - , π + π - [fr

  18. Photonics Research and Development

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, Elizabeth [UNLV Research Foundation, Las Vegas, NV (United States)

    2010-01-15

    During the period August 2005 through October 2009, the UNLV Research Foundation (UNLVRF), a non-profit affiliate of the University of Nevada, Las Vegas (UNLV), in collaboration with UNLV's Colleges of Science and Engineering; Boston University (BU); Oak Ridge National Laboratory (ORNL); and Sunlight Direct, LLC, has managed and conducted a diverse and comprehensive research and development program focused on light-emitting diode (LED) technologies that provide significantly improved characteristics for lighting and display applications. This final technical report provides detailed information on the nature of the tasks, the results of the research, and the deliverables. It is estimated that about five percent of the energy used in the nation is for lighting homes, buildings and streets, accounting for some 25 percent of the average home's electric bill. However, the figure is significantly higher for the commercial sector. About 60 percent of the electricity for businesses is for lighting. Thus replacement of current lighting with solid-state lighting technology has the potential to significantly reduce this nation's energy consumption by some estimates, possibly as high as 20%. The primary objective of this multi-year R&D project has been to develop and advance lighting technologies to improve national energy conversion efficiencies; reduce heat load; and significantly lower the cost of conventional lighting technologies. The UNLVRF and its partners have specifically focused these talents on (1) improving LED technologies; (2) optimizing hybrid solar lighting, a technology which potentially offers the benefits of blending natural with artificial lighting systems, thus improving energy efficiency; and (3) building a comprehensive academic infrastructure within UNLV which concentrates on photonics R&D. Task researchers have reported impressive progress in (1) the development of quantum dot laser emitting diodes (QDLEDs) which will ultimately improve

  19. Entangled photons and quantum communication

    International Nuclear Information System (INIS)

    Yuan Zhensheng; Bao Xiaohui; Lu Chaoyang; Zhang Jun; Peng Chengzhi; Pan Jianwei

    2010-01-01

    This article reviews the progress of quantum communication that utilizes photonic entanglement. We start with a survey of various methods for generating entangled photons, followed by an introduction of the theoretical principles and the experimental implementations of quantum key distribution. We then move on to a discussion of more involved quantum communication protocols including quantum dense coding, teleportation and quantum communication complexity. After that, we review the progress in free-space quantum communication, decoherence-free subspace, and quantum repeater protocols which are essential ingredients for long-distance quantum communication. Practical realizations of quantum repeaters, which require an interface between photons and quantum memories, are discussed briefly. Finally, we draw concluding remarks considering the technical challenges, and put forward an outlook on further developments of this field.

  20. Photon Factory activity report, 1991

    International Nuclear Information System (INIS)

    1992-01-01

    The Photon Factory is a national synchrotron radiation research facility affiliated with the National Laboratory for High Energy Physics located in Tsukuba Science City. The Photon Factory consists of a 2.5 GeV electron/positron linear accelerator, a 2.5 GeV electron/positron storage ring, beam lines and experimental stations. All the facilities for synchrotron radiation research are open to scientists. A part of the accumulation ring of the TRISTAN main ring has been used as a synchrotron radiation source in the energy range from 5.8 to 6.5 GeV. The Photon Factory is composed of three divisions of Injector Linac, Light Source and Instrumentation. The researches of each divisions are reviewed, and the users' short reports are collected. The list of published papers with author index is also included in the publication. (K.I.) 233 refs

  1. Photonic quantum technologies (Presentation Recording)

    Science.gov (United States)

    O'Brien, Jeremy L.

    2015-09-01

    The impact of quantum technology will be profound and far-reaching: secure communication networks for consumers, corporations and government; precision sensors for biomedical technology and environmental monitoring; quantum simulators for the design of new materials, pharmaceuticals and clean energy devices; and ultra-powerful quantum computers for addressing otherwise impossibly large datasets for machine learning and artificial intelligence applications. However, engineering quantum systems and controlling them is an immense technological challenge: they are inherently fragile; and information extracted from a quantum system necessarily disturbs the system itself. Of the various approaches to quantum technologies, photons are particularly appealing for their low-noise properties and ease of manipulation at the single qubit level. We have developed an integrated waveguide approach to photonic quantum circuits for high performance, miniaturization and scalability. We will described our latest progress in generating, manipulating and interacting single photons in waveguide circuits on silicon chips.

  2. Quantum photonics hybrid integration platform

    Energy Technology Data Exchange (ETDEWEB)

    Murray, E.; Floether, F. F. [Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Ellis, D. J. P.; Meany, T.; Bennett, A. J., E-mail: anthony.bennet@crl.toshiba.co.uk; Shields, A. J. [Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Lee, J. P. [Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge CB4 0GZ (United Kingdom); Engineering Department, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Griffiths, J. P.; Jones, G. A. C.; Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2015-10-26

    Fundamental to integrated photonic quantum computing is an on-chip method for routing and modulating quantum light emission. We demonstrate a hybrid integration platform consisting of arbitrarily designed waveguide circuits and single-photon sources. InAs quantum dots (QD) embedded in GaAs are bonded to a SiON waveguide chip such that the QD emission is coupled to the waveguide mode. The waveguides are SiON core embedded in a SiO{sub 2} cladding. A tuneable Mach Zehnder interferometer (MZI) modulates the emission between two output ports and can act as a path-encoded qubit preparation device. The single-photon nature of the emission was verified using the on-chip MZI as a beamsplitter in a Hanbury Brown and Twiss measurement.

  3. Optical properties of photonic crystals

    CERN Document Server

    Sakoda, Kazuaki

    2001-01-01

    The interaction between the radiation field and matter is the most fundamen­ tal source of dynamics in nature. It brings about the absorption and emission of photons, elastic and inelastic light scattering, the radiative lifetime of elec­ tronic excited states, and so on. The huge amount of energy carried from the sun by photons is the source of all activities of creatures on the earth. The absorption of photons by chlorophylls and the successive electronic excita­ tion initiate a series of chemical reactions that are known as photosynthesis, which support all life on the earth. Radiative energy is also the main source of all meteorological phenomena. The fundamentals of the radiation field and its interaction with matter were clarified by classical electromagnetism and quantum electrodynamics. These theories, we believe, explain all electromagnetic phenomena. They not only provide a firm basis for contemporary physics but also generate a vast range of technological applications. These include television, ...

  4. Stochastic stabilization of cosmological photons

    International Nuclear Information System (INIS)

    Dettmann, C P; Keating, J P; Prado, S D

    2004-01-01

    The stability of photon trajectories in models of the universe that have constant spatial curvature is determined by the sign of the curvature: they are exponentially unstable if the curvature is negative and stable if it is positive or zero. We demonstrate that random fluctuations in the curvature provide an additional stabilizing mechanism. This mechanism is analogous to the one responsible for stabilizing the stochastic Kapitsa pendulum. When the mean curvature is negative it is capable of stabilizing the photon trajectories; when the mean curvature is zero or positive it determines the characteristic frequency with which neighbouring trajectories oscillate about each other. In constant negative curvature models of the universe that have compact topology, exponential instability implies chaos (e.g. mixing) in the photon dynamics. We discuss some consequences of stochastic stabilization in this context. (letter to the editor)

  5. Silicon photonic physical unclonable function.

    Science.gov (United States)

    Grubel, Brian C; Bosworth, Bryan T; Kossey, Michael R; Sun, Hongcheng; Cooper, A Brinton; Foster, Mark A; Foster, Amy C

    2017-05-29

    Physical unclonable functions (PUFs) serve as a hardware source of private information that cannot be duplicated and have applications in hardware integrity and information security. Here we demonstrate a photonic PUF based on ultrafast nonlinear optical interactions in a chaotic silicon micro-cavity. The device is probed with a spectrally-encoded ultrashort optical pulse, which nonlinearly interacts with the micro-cavity. This interaction produces a highly complex and unpredictable, yet deterministic, ultrafast response that can serve as a unique "fingerprint" of the cavity and as a source of private information for the device's holder. Experimentally, we extract 17.1-kbit binary keys from six different photonic PUF designs and demonstrate the uniqueness and reproducibility of these keys. Furthermore, we experimentally test exact copies of the six photonic PUFs and demonstrate their unclonability due to unavoidable fabrication variations.

  6. Clinical two-photon microendoscopy.

    Science.gov (United States)

    König, K; Ehlers, A; Riemann, I; Schenkl, S; Bückle, R; Kaatz, M

    2007-05-01

    Two-photon medical imaging has found its way into dermatology as an excellent method for noninvasive skin cancer detection without need of contrast agents as well as for in situ drug screening of topically-applied cosmetical and pharmaceutical components. There is an increasing demand to apply the multiphoton technology also for deep-tissue skin imaging as well as for intracorporal imaging. We report on the first clinical use of multiphoton endoscopes, in particular of a miniaturized rigid two-photon GRIN lens endoscope. The microendoscope was attached to the multiphoton tomograph DermaInspect and employed to detect the extracellular matrix proteins collagen and elastin in the human dermis of volunteers and patients with ulcera by in vivo second harmonic generation and in vivo two-photon autofluorescence. Copyright 2007 Wiley-Liss, Inc.

  7. Apparatus for photon activation positron annihilation analysis

    Science.gov (United States)

    Akers, Douglas W [Idaho Falls, ID

    2007-06-12

    Non-destructive testing apparatus according to one embodiment of the invention comprises a photon source. The photon source produces photons having predetermined energies and directs the photons toward a specimen being tested. The photons from the photon source result in the creation of positrons within the specimen being tested. A detector positioned adjacent the specimen being tested detects gamma rays produced by annihilation of positrons with electrons. A data processing system operatively associated with the detector produces output data indicative of a lattice characteristic of the specimen being tested.

  8. Effective atomic numbers, electron densities and kinetic energy released in matter of vitamins for photon interaction

    Science.gov (United States)

    Shantappa, A.; Hanagodimath, S. M.

    2014-01-01

    Effective atomic numbers, electron densities of some vitamins (Retinol, Riboflavin, Niacin, Biotin, Folic acid, Cobalamin, Phylloquinone and Flavonoids) composed of C, H, O, N, Co, P and S have been calculated for total and partial photon interactions by the direct method for energy range 1 keV-100 GeV by using WinXCOM and kinetic energy released in matter (Kerma) relative to air is calculated in energy range of 1 keV-20 MeV. Change in effective atomic number and electron density with energy is calculated for all photon interactions. Variation of photon mass attenuation coefficients with energy are shown graphically only for total photon interaction. It is observed that change in mass attenuation coefficient with composition of different chemicals is very large below 100 keV and moderate between 100 keV and 10 MeV and negligible above 10 MeV. Behaviour of vitamins is almost indistinguishable except biotin and cobalamin because of large range of atomic numbers from 1(H) to 16 (S) and 1(H) to 27(Co) respectively. K a value shows a peak due to the photoelectric effect around K-absorption edge of high- Z constituent of compound for biotin and cobalamin.

  9. Modeling gamma-ray burst observations by Fermi and MAGIC including attenuation due to diffuse background light

    OpenAIRE

    Gilmore, Rudy C.; Prada, Francisco; Primack, Joel R.

    2009-01-01

    Gamma rays from extragalactic sources are attenuated by pair-production interactions with diffuse photons of the extragalactic background light (EBL). Gamma-ray bursts (GRBs) are a source of high-redshift photons above 10 GeV, and could be therefore useful as a probe of the evolving UV background radiation. In this paper, we develop a simple phenomenological model for the number and redshift distribution of gamma-ray bursts that can be seen at GeV energies with the Fermi satellite and MAGIC a...

  10. Research summer camp in photonics

    Science.gov (United States)

    Buyanovskaya, Elizaveta; Melnik, Maksim; Egorov, Vladimir; Gleim, Artur; Lukishova, Svetlana; Kozlov, Sergei; Zhang, Xi-Cheng

    2017-08-01

    ITMO University and the University of Rochester became close partners several years ago. One of the first outcomes of this mutually beneficial partnership was the creation of International Institute of Photonics and Optical Information Technologies led by Prof. Sergei Kozlov and Prof. Xi-Cheng Zhang. Universities have created a double Masters-degree program in optics in 2014, and several ITMO students have been awarded degrees from Rochester. At the same time ITMO University organizes Summer Research camp in Photonics for University of Rochester students. Students spent two weeks in the Northern Capital of Russia learning about the emerging practical applications of femtosecond optics, terahertz biomedicine and quantum information technologies.

  11. Polymers for electronic & photonic application

    CERN Document Server

    Wong, C P

    2013-01-01

    The most recent advances in the use of polymeric materials by the electronic industry can be found in Polymers for Electronic and Photonic Applications. This bookprovides in-depth coverage of photoresis for micro-lithography, microelectronic encapsulants and packaging, insulators, dielectrics for multichip packaging,electronic and photonic applications of polymeric materials, among many other topics. Intended for engineers and scientists who design, process, and manufacturemicroelectronic components, this book will also prove useful for hybrid and systems packaging managers who want to be info

  12. Fast pulse discriminator for photon counting at high photon densities

    International Nuclear Information System (INIS)

    Benoit, R.; Pedrini, A.

    1977-03-01

    A fast tunnel diode discriminator for photon counting up to 200MHz count frequency is described. The tunnel diode is operated on its apparent I.V. characteristics displayed when the diode is driven into its oscillating region. The pulse shaper-discriminator is completely D.C. coupled in order to avoid base-line shift at high pulse rates

  13. Photonic wires and trumpets for ultrabright single photon sources

    DEFF Research Database (Denmark)

    Gérard, Jean-Michel; Claudon, Julien; Bleuse, Joël

    2013-01-01

    as to tailor their radiation diagram in the far-field. We highlight the novel “photonic trumpet” geometry, which provides a clean Gaussian beam, and is much less sensitive to fabrication imperfections than the more common needle-like taper geometry. S4Ps based on a single QD in a PW with integrated bottom...

  14. Photon management with luminescent materials and photonic structures

    Science.gov (United States)

    Goldschmidt, J. C.; Fischer, S.; Fröhlich, Benjamin; Gutmann, J.; Herter, B.; Hofmann, C.; Löffler, J.; van Veggel, Frank C. J. M.; Wolf, S.

    2014-05-01

    Upconversion of sub-band-gap photons is a promising approach to increase the efficiency of solar cells. In this paper, we review the recent progress in upconverter material development and realization of efficient upconverter silicon solar cell devices. Current published record values for the increase in the short-circuit current density due to upconversion are 13.1 mA/cm2 at a solar concentration of 210 suns determined in a sun simulator measurement. This increase is equivalent to a relative efficiency enhancement of 0.19% for the silicon solar cell. Although this is a considerable enhancement by more than one order of magnitude from values published only a few years ago, further enhancement of the upconversion performance is necessary. To this end, we investigate theoretically the application of resonant cavity and grating photonic structures. Our simulation based analysis considers irradiance enhancement and modified density of photon states due to the photonic structures and their impact on the upconversion dynamics in β-NaYF4: 20%Er3+. It shows that an optimized grating can increase upconversion luminescence by a factor of 3 averaged over the whole structure in comparison to an unstructured reference with the same amount of upconverter material.

  15. Gamma irradiation of minimal latency Hollow-Core Photonic Bandgap Fibres

    CERN Document Server

    Olanterae, L; Richardson, D J; Vasey, F; Wooler, J P; Petrovich, M N; Wheeler, N V; Poletti, F; Troska, J

    2013-01-01

    Hollow-Core Photonic-Bandgap Fibres (HC-PBGFs) offer several distinct advantages over conventional fibres, such as low latency and radiation hardness; properties that make HC-PBGFs interesting for the high energy physics community. This contribution presents the results from a gamma irradiation test carried out using a new type of HC-PBGF that combines sufficiently low attenuation over distances that are compatible with high energy physics applications together with a transmission bandwidth that covers the 1550 nm region. The radiation induced attenuation of the HC-PBGF was two orders of magnitude lower than that of a conventional fibre during a 67.5 h exposure to gamma-rays, resulting in a radiation-induced attenuation of only 2.1 dB/km at an accumulated dose of 940 kGy.

  16. Dose attenuation by a carbon fiber linac couch and modeling with a treatment planning system

    International Nuclear Information System (INIS)

    Sanchez Galiano, P.; Garcia Sancho, J.M.; Crelgo, D.; Pamos, M.; Fernandez, J.; Vivanco, J.

    2010-01-01

    The purpose of this work is to investigate the attenuation caused by a carbon fiber linac treatment couch and the ability of a commercial radiotherapy treatment planning system to simulate it. The attenuation caused by an Exact treatment couch in a Varian Clinac 2100 C/D was characterized in detail. Both 6 MV and 18 MV photon beams were studied. The treatment couch was modeled and incorporated to Elekta XiO treatment planning system. Measured and computed attenuation values were compared. As a result we found that the attenuation caused by this complex treatment couch is strongly dependent on the incidence angle of the beam. The measured attenuation values reach 16% for 6 MV and 10% for 18 MV. The model incorporated to the treatment planning software allows reducing the differences between measured and calculated data below 2.5% and 2.0% for 6 MV and 18 MV respectively. In conclusion, it is strongly recommended accounting for the perturbation caused by this carbon fiber treatment couch when the beam intersects it. The treatment planning system studied can simulate this treatment couch accurately. Clinical implementation of the described method requires a reliable procedure to reproduce the same patient geometry in the treatment delivery and planning. (Author).

  17. Beam hardening: Analytical considerations of the effective attenuation coefficient of x-ray tomography

    International Nuclear Information System (INIS)

    Alles, J.; Mudde, R. F.

    2007-01-01

    Polychromatic x-ray beams traveling though material are prone to beam hardening, i.e., the high energy part of the incident spectrum gets over represented when traveling farther into the material. This study discusses the concept of a mean attenuation coefficient in a formal way. The total energy fluence is one-to-one related to the traveled distance in case of a polychromatic beam moving through a given, inhomogeneous material. On the basis of this one-to-one relation, it is useful to define a mean attenuation coefficient and study its decrease with depth. Our results are based on a novel parametrization of the energy dependence of the attenuation coefficient that allows for closed form evaluation of certain spectral integrals. This approach underpins the ad hoc semianalytical expressions given in the literature. An analytical model for the average attenuation coefficient is proposed that uses a simple fit of the attenuation coefficient as a function of the photon energy as input. It is shown that a simple extension of this model gives a rather good description of beam hardening for x-rays traveling through water

  18. Bremsstrahlung versus Monoenergetic Photon Dose and Photonuclear Stimulation Comparisons At Long Standoff Distances

    Energy Technology Data Exchange (ETDEWEB)

    J. L. Jones; J.W. Sterbentz; W.Y. Yoon

    2009-06-01

    Energetic photon sources with energies greater than 6 MeV continue to be recognized as viable source for various types of inspection applications, especially those related to nuclear and/or explosive material detection. These energetic photons can be produced as a continuum of energies (i.e., bremsstrahlung distribution) or as a set of one or more discrete photon energies (i.e., monoenergetic distribution). This paper will provide a follow-on extension of the photon dose comparison presented at the 9th International Conference on Applications of Nuclear Techniques (June 2008). The latter paper showed the comparative advantages and disadvantages of the photon doses provided by these two energetic interrogation sources and highlighted the higher energy advantage of the bremsstrahlung source, especially at long standoff distances (i.e., distance from source to the inspected object). Specifically, this paper will pursue this higher energy photon inspection advantage (up to 100 MeV) by providing dose and stimulated photonuclear interaction predictions for air and an infinitely dilute interrogated material (used for comparative interaction rate assessments since it excludes material self-shielding) as the interrogation object positioned forward on the inspection beam axis at increasing standoff distances. In addition to the direct energetic photon-induced stimulation, the predictions will identify the importance of any secondary downscattered/attenuated source-term effects arising from the photon transport in the intervening atmosphere. *Supported in part by the Defense Threat Reduction Agency and Department of Energy (DOE) Idaho Operations Office under Contract Number DE-AC07-05ID14517.

  19. Gamma-ray attenuation studies of PbO-BaO-B2O3 glass system

    International Nuclear Information System (INIS)

    Singh, Narveer; Singh, Kanwar Jit; Singh, Kulwant; Singh, Harvinder

    2006-01-01

    PbO-BaO-B 2 O 3 glass system has been investigated in terms of molar mass, mass attenuation coefficient and half value layer parameters by using gamma-ray at 511,662 and 1274keV photon energies. Gamma-ray attenuation coefficients of the prepared glass samples have been compared with tabulations based upon the results of XCOM. Good agreement has been observed between experimental and theoretical tabulations. Our results have uncertainty less than 3%. Radiation shielding properties of the glass system have been compared with some standard radiation shielding concretes

  20. Frequency Dependent Attenuation in Rocks

    Science.gov (United States)

    1990-01-20

    WORK UNIT ELEMENT NO NO NO ACCESSION NO 62714E 7A10 DA DA 1𔃻 T. ,E (Incude Security Clasification ) Frequency Dependent Attenuation in Rocks Ŗ 0E;SO’.A_...P., and L. Peselnick, Investigation of internal friction in fused quartz, steel , plexiglass, and Westerly granite from 0.01 to 1.00 Hertz at 10- to 10...P., and L. Peselnick, Investigation of internal friction in fused quartz, steel , plexiglas, and Westerly granite from 0.01 to 1.00 Hertz at 10-8 to 10

  1. Vision 20/20: Magnetic resonance imaging-guided attenuation correction in PET/MRI: Challenges, solutions, and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Mehranian, Abolfazl; Arabi, Hossein [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Geneva Neuroscience Centre, University of Geneva, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen 9700 RB (Netherlands)

    2016-03-15

    Attenuation correction is an essential component of the long chain of data correction techniques required to achieve the full potential of quantitative positron emission tomography (PET) imaging. The development of combined PET/magnetic resonance imaging (MRI) systems mandated the widespread interest in developing novel strategies for deriving accurate attenuation maps with the aim to improve the quantitative accuracy of these emerging hybrid imaging systems. The attenuation map in PET/MRI should ideally be derived from anatomical MR images; however, MRI intensities reflect proton density and relaxation time properties of biological tissues rather than their electron density and photon attenuation properties. Therefore, in contrast to PET/computed tomography, there is a lack of standardized global mapping between the intensities of MRI signal and linear attenuation coefficients at 511 keV. Moreover, in standard MRI sequences, bones and lung tissues do not produce measurable signals owing to their low proton density and short transverse relaxation times. MR images are also inevitably subject to artifacts that degrade their quality, thus compromising their applicability for the task of attenuation correction in PET/MRI. MRI-guided attenuation correction strategies can be classified in three broad categories: (i) segmentation-based approaches, (ii) atlas-registration and machine learning methods, and (iii) emission/transmission-based approaches. This paper summarizes past and current state-of-the-art developments and latest advances in PET/MRI attenuation correction. The advantages and drawbacks of each approach for addressing the challenges of MR-based attenuation correction are comprehensively described. The opportunities brought by both MRI and PET imaging modalities for deriving accurate attenuation maps and improving PET quantification will be elaborated. Future prospects and potential clinical applications of these techniques and their integration in commercial

  2. Nuclear Resonance Fluorescence Using Different Photon Sources

    International Nuclear Information System (INIS)

    Warren, Glen A.; Caggiano, Joseph A.; Ahmed, Mohammad; Bertozzi, William; Hunt, Alan W.; Johnson, James; Jones, James L.; Korbly, Steve; Reedy, Edward; Seipel, Heather; Stave, Sean; Watson, Scott; Weller, Henry

    2008-01-01

    Nuclear resonance fluorescence (NRF) is a photon-based active interrogation approach that provides isotope-specific signatures that can be used to detect and characterize samples. As NRF systems are designed to address specific applications, an obvious first question to address is the type of photon source to be employed for the application. Our collaboration has conducted a series of NRF measurements using different photon sources to begin to examine this issue. The measurements were designed to be as similar as possible to facilitate a straightforward comparison of the different sources. Measurements were conducted with a high-duty factor electron accelerator using bremsstrahlung photons, with a pulsed linear accelerator using bremsstrahlung photons, and with a narrow bandwidth photon source using Compton backscattered photons. We present our observations on the advantages and disadvantages of each photon source type. Issues such as signal rate, the signal-to-noise ratio, and absorbed dose are discussed

  3. Photonic analogies of gravitational attractors

    KAUST Repository

    San-Román-Alerigi, Damián P.

    2013-01-01

    In our work we demonstrate a Gaussian-like refractive index mapping to realize light trapping. Our study shows that this centro-symmetrical photonic structure is able to mime the light geodesics described by celestial mechanics. Possible applications are discussed. © 2013 IEEE.

  4. Distinguishing Isolated Photons from Jets

    CERN Document Server

    Pieri, Marco; Branson, James G

    2006-01-01

    We have developed isolation and shower-shape variables that are optimized for reducing the jet background for a high transverse-energy photon signal. To help understand the relative importance of each variable, we have computed the background rejection power as a function of signal efficiency for these variables as well as for some simple combinations of variables. We find that a combination of tracker plus ECAL information can give very significant background rejection power. By adding information from the HCAL, the rejection power can be improved. In addition we find that a very significant reduction in background can be achieved by adding photon shower shape information from the ECAL to the Neural Net inputs. About 1 in 200 jets contains a high E_T electromagnetic shower that is reconstructed by the CMS software and is therefore a potential background for photon detection. An additional jet rejection factor of 100 with 80% photon efficiency (or 400 with 50% efficiency) can be achieved by using the isolatio...

  5. Photonic-crystal waveguide biosensor

    DEFF Research Database (Denmark)

    Skivesen, Nina; Têtu, Amélie; Kristensen, Martin

    2007-01-01

    A photonic-crystal waveguide sensor is presented for biosensing. The sensor is applied for refractive index measurements and detection of protein-concentrations. Concentrations around 10 μg/ml (0.15μMolar) are measured with excellent signal to noise ratio, and a broad, dynamic refractive index...

  6. The Story of the Photon

    Indian Academy of Sciences (India)

    ton Lewis in 1926, is a child of the 20th century. It is the. 'particle of light' - or 'light quantum' - first ... the photon is rich in history, development of ideas, experi- ment and personalities. In this account an attempt will ..... Einstein had realised the importance of the volume depen- dence of thermodynamic quantities, in particular ...

  7. The Story of the Photon

    Indian Academy of Sciences (India)

    The story of the photon is rich in history, development of ideas, experi- ment and personalities. In this account an attempt will be made to convey something of each of these aspects; the fun- damental ..... during his student days at the Eidgenossische Technische .... Einstein then took a 'phenomenological' attitude to the radi-.

  8. Photonic effects in natural nanostructures

    Science.gov (United States)

    Rey GonzáLez, Rafael Ramón; Barrera Patiã+/-O, Claudia Patricia

    Nature exhibits a great variety of structures and nanostructures. In particular the interaction light-matter has a strong dependence with the shape of the nanostructures. In some cases, in the so called structural color, ordered arrays of nanostructures play a very critical role. One of the most interesting color effects is the iridescence, the angular dependence of the observed color in some species of butterflies, insects, plants, beetles, fishes, birds and even in minerals. In the last years, iridescence has been related with photonic properties. In the present work, we present a theoretical study of the photonic properties for different patterns that exist in natural nanostructures present in wings of butterflies that exhibit iridescence. The nanostructures observed in these cases present spatial variations of the dielectric constant that are possible to model them as 1D and 2D photonic crystal. Partial photonic gaps are found as function of lattice constant, dielectric contrast and geometrical configuration. Also, disordered effects are considered. Authors would like to thank the División de Investigación Sede Bogotá for their financial support at Universidad Nacional de Colombia.

  9. One-dimensional photonic crystals

    NARCIS (Netherlands)

    Shen, Huaizhong; Wang, Zhanhua; Wu, Yuxin; Yang, Bai

    2016-01-01

    A one-dimensional photonic crystal (1DPC), which is a periodic nanostructure with a refractive index distribution along one direction, has been widely studied by scientists. In this review, materials and methods for 1DPC fabrication are summarized. Applications are listed, with a special emphasis

  10. Photonics of 2D materials

    Science.gov (United States)

    Zhang, Han; Wang, Junzhuan; Hasan, Tawfique; Bao, Qiaoliang

    2018-01-01

    The emergence of graphene and graphene-like two dimensional (2D) materials has attracted a strong interest from the photonics community in recent decade. Apart from zero-gap graphene, insulating hexagonal boron nitride and semiconducting transition metal dichalcogenides and phosphorene/black phosphorus are being intensively investigated because of their fascinating photonic and optoelectronic properties. Compared to traditional bulk photonic materials such as Gallium Arsenide (GaAs) and Silicon (Si), 2D materials exhibit many unique properties important for device applications in nanophotonics. Firstly, quantum confinement in the direction perpendicular to 2D plane leads to novel electronic and optical features that are distinctively different from their bulk counterparts. Secondly, their surfaces are naturally passivated without any dangling bonds making them readily compatible for integration with photonic structures such as waveguides and cavities. It is also possible to construct vertical hetero-structures by using different 2D materials, without considering lattice mismatch issues that are common in bulk semiconductors. This is because the 2D layers with different lattice constants in heterostructures are only weakly bounded by van der Waals force. Thirdly, despite being atomically thin, many 2D materials interact very strongly with light.

  11. Photon Physics of Revised Electromagnetics

    Directory of Open Access Journals (Sweden)

    Lehnert B.

    2006-04-01

    Full Text Available Conventional theory, as based on Maxwell’s equations and associated quantum electrodynamical concepts in the vacuum, includes the condition of zero electric field divergence. In applications to models of the individual photon and to dense light beams such a theory exhibits several discrepancies from experimental evidence. These include the absence of angular momentum (spin, and the lack of spatially limited geometry in the directions transverse to that of the propagation. The present revised theory includes on the other hand a nonzero electric field divergence, and this changes the field equations substantially. It results in an extended quantum electrodynamical approach, leading to nonzero spin and spatially limited geometry for photon models and light beams. The photon models thereby behave as an entirety, having both particle and wave properties and possessing wave-packet solutions which are reconcilable with the photoelectric effect, and with the dot-shaped marks and interference patterns on a screen by individual photons in a two-slit experiment.

  12. Single photon searches at PEP

    Energy Technology Data Exchange (ETDEWEB)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented.

  13. Single photon searches at PEP

    International Nuclear Information System (INIS)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented

  14. The Story of the Photon

    Indian Academy of Sciences (India)

    N Mllkunda. An account of the story of the light quantum or pho- ton is given, from its inception in 1905 to its final acceptance in 1924. Necessary background informa- tion on radiation theory and historical details are included. Introduction. The photon, so named by the physical chemist Gilbert Nor- ton Lewis in 1926, is a ...

  15. Silicon Photonics Cloud (SiCloud)

    DEFF Research Database (Denmark)

    DeVore, P. T. S.; Jiang, Y.; Lynch, M.

    2015-01-01

    Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

  16. Biomedical photonics handbook therapeutics and advanced biophotonics

    CERN Document Server

    Vo-Dinh, Tuan

    2014-01-01

    Shaped by Quantum Theory, Technology, and the Genomics RevolutionThe integration of photonics, electronics, biomaterials, and nanotechnology holds great promise for the future of medicine. This topic has recently experienced an explosive growth due to the noninvasive or minimally invasive nature and the cost-effectiveness of photonic modalities in medical diagnostics and therapy. The second edition of the Biomedical Photonics Handbook presents recent fundamental developments as well as important applications of biomedical photonics of interest to scientists, engineers, manufacturers, teachers,

  17. Integrated Microwave Photonics for Wideband Signal Processing

    Directory of Open Access Journals (Sweden)

    Xiaoke Yi

    2017-11-01

    Full Text Available We describe recent progress in integrated microwave photonics in wideband signal processing applications with a focus on the key signal processing building blocks, the realization of monolithic integration, and cascaded photonic signal processing for analog radio frequency (RF photonic links. New developments in integration-based microwave photonic techniques, that have high potentialities to be used in a variety of sensing applications for enhanced resolution and speed are also presented.

  18. Liquid crystal tunable photonic crystal dye laser

    DEFF Research Database (Denmark)

    Buss, Thomas; Christiansen, Mads Brøkner; Smith, Cameron

    2010-01-01

    We present a dye-doped liquid crystal laser using a photonic crystal cavity. An applied electric field to the liquid crystal provides wavelength tunability. The photonic crystal enhances resonant interaction with the gain medium.......We present a dye-doped liquid crystal laser using a photonic crystal cavity. An applied electric field to the liquid crystal provides wavelength tunability. The photonic crystal enhances resonant interaction with the gain medium....

  19. Testing PVLAS axions with resonant photon splitting

    CERN Document Server

    Gabrielli, E; Gabrielli, Emidio; Giovannini, Massimo

    2007-01-01

    The photon splitting gamma -> gamma gamma in a time-independent and inhomogeneous magnetized background is considered when neutral and ultralight spin-0 particles are coupled to two-photons. Depending on the inhomogeneity scale of the external field, resonant photon splitting can occur. If an optical laser crosses a magnetic field of few Tesla with typical inhomogeneity scale of the order of the meter, a potentially observable rate of photon splittings is expected for the PVLAS range of couplings and masses.

  20. Energy calibration of the photon tagging system

    International Nuclear Information System (INIS)

    Endo, Satoru; Niki, Kazuaki; Suzuki, Akira

    1989-07-01

    There is a photon tagging system at the 1.3 GeV Electron Synchrotron (ES), and the system is designed to produce a monochromatic photon beam with an energy resolution of ±5 MeV. To calibrate the energies of tagged photons produced by this system, electron beams of various energies from ES are injected directly into this system. As the result of this calibration, we conclude that the photon tagging system has the performance of designed values. (author)

  1. Attenuation correction for the large non-human primate brain imaging using microPET

    Science.gov (United States)

    Naidoo-Variawa, S.; Lehnert, W.; Kassiou, M.; Banati, R.; Meikle, S. R.

    2010-04-01

    Assessment of the biodistribution and pharmacokinetics of radiopharmaceuticals in vivo is often performed on animal models of human disease prior to their use in humans. The baboon brain is physiologically and neuro-anatomically similar to the human brain and is therefore a suitable model for evaluating novel CNS radioligands. We previously demonstrated the feasibility of performing baboon brain imaging on a dedicated small animal PET scanner provided that the data are accurately corrected for degrading physical effects such as photon attenuation in the body. In this study, we investigated factors affecting the accuracy and reliability of alternative attenuation correction strategies when imaging the brain of a large non-human primate (papio hamadryas) using the microPET Focus 220 animal scanner. For measured attenuation correction, the best bias versus noise performance was achieved using a 57Co transmission point source with a 4% energy window. The optimal energy window for a 68Ge transmission source operating in singles acquisition mode was 20%, independent of the source strength, providing bias-noise performance almost as good as for 57Co. For both transmission sources, doubling the acquisition time had minimal impact on the bias-noise trade-off for corrected emission images, despite observable improvements in reconstructed attenuation values. In a [18F]FDG brain scan of a female baboon, both measured attenuation correction strategies achieved good results and similar SNR, while segmented attenuation correction (based on uncorrected emission images) resulted in appreciable regional bias in deep grey matter structures and the skull. We conclude that measured attenuation correction using a single pass 57Co (4% energy window) or 68Ge (20% window) transmission scan achieves an excellent trade-off between bias and propagation of noise when imaging the large non-human primate brain with a microPET scanner.

  2. Attenuation correction for the large non-human primate brain imaging using microPET

    International Nuclear Information System (INIS)

    Naidoo-Variawa, S; Lehnert, W; Kassiou, M; Banati, R; Meikle, S R

    2010-01-01

    Assessment of the biodistribution and pharmacokinetics of radiopharmaceuticals in vivo is often performed on animal models of human disease prior to their use in humans. The baboon brain is physiologically and neuro-anatomically similar to the human brain and is therefore a suitable model for evaluating novel CNS radioligands. We previously demonstrated the feasibility of performing baboon brain imaging on a dedicated small animal PET scanner provided that the data are accurately corrected for degrading physical effects such as photon attenuation in the body. In this study, we investigated factors affecting the accuracy and reliability of alternative attenuation correction strategies when imaging the brain of a large non-human primate (papio hamadryas) using the microPET Focus 220 animal scanner. For measured attenuation correction, the best bias versus noise performance was achieved using a 57 Co transmission point source with a 4% energy window. The optimal energy window for a 68 Ge transmission source operating in singles acquisition mode was 20%, independent of the source strength, providing bias-noise performance almost as good as for 57 Co. For both transmission sources, doubling the acquisition time had minimal impact on the bias-noise trade-off for corrected emission images, despite observable improvements in reconstructed attenuation values. In a [ 18 F]FDG brain scan of a female baboon, both measured attenuation correction strategies achieved good results and similar SNR, while segmented attenuation correction (based on uncorrected emission images) resulted in appreciable regional bias in deep grey matter structures and the skull. We conclude that measured attenuation correction using a single pass 57 Co (4% energy window) or 68 Ge (20% window) transmission scan achieves an excellent trade-off between bias and propagation of noise when imaging the large non-human primate brain with a microPET scanner.

  3. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  4. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; Ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. A High-Efficiency Photonic Nanowire Single-Photon Source Featuring An Inverted Conical Taper

    DEFF Research Database (Denmark)

    Gregersen, Niels; Nielsen, Torben Roland; Mørk, Jesper

    2011-01-01

    A photonic nanowire single-photon source design incorporating an inverted conical tapering is proposed. The inverted taper allows for easy electrical contacting and a high photon extraction efficiency of 89 %. Unlike cavity-based approaches, the photonic nanowire features broadband spontaneous...... emission control and an improved tolerance towards fabrication imperfections....

  6. Exact Reconstruction From Uniformly Attenuated Helical Cone-Beam Projections in SPECT

    International Nuclear Information System (INIS)

    Gullberg, Grant T.; Huang, Qiu; You, Jiangsheng; Zeng, Gengsheng L.

    2008-01-01

    In recent years the development of cone-beam reconstruction algorithms has been an active research area in x-ray computed tomography (CT), and significant progress has been made in the advancement of algorithms. Theoretically exact and computationally efficient analytical algorithms can be found in the literature. However, in single photon emission computed tomography (SPECT), published cone-beam reconstruction algorithms are either approximate or involve iterative methods. The SPECT reconstruction problem is more complicated due to degradations in the imaging detection process, one of which is the effect of attenuation of gamma ray photons. Attenuation should be compensated for to obtain quantitative results. In this paper, an analytical reconstruction algorithm for uniformly attenuated cone-beam projection data is presented for SPECT imaging. The algorithm adopts the DBH method, a procedure consisting of differentiation and backprojection followed by a finite inverse cosh-weighted Hilbert transform. The significance of the proposed approach is that a selected region of interest can be reconstructed even with a detector with a reduced field of view. The algorithm is designed for a general trajectory. However, to validate the algorithm, a numerical study was performed using a helical trajectory. The implementation is efficient and the simulation result is promising

  7. Time relative single-photon (photoelectron) method

    International Nuclear Information System (INIS)

    Luo Binqiao

    1988-01-01

    A single-photon (photoelectron) measuring system is designed. It researches various problems in single-photon (photoelectron) method. The electronic resolving time is less than 25 ps. The resolving time of single-photon (photoelectron) measuring system is 25 to 65 ps

  8. Photonics for MS study in radiocommunications

    Science.gov (United States)

    Volner, Rudolf; Klima, Milos; Ticha, Dasa

    2002-05-01

    The paper is devoted to an education of Photonics at the Dept. of Telecommunications, Faculty of Electrical Engineering, at the University of Zilina. Originated from the university historical development the photonic subjects are implemented in two basic areas: Telecommunication Technology and Radiocommunication Technology. From the school year 1994/95 the new subject Photonics has been taught and it has attracted numerous students. The subject is focused on both physical principles and system application. The relevant parts can be listed as: interaction photon - matter, photonic receivers and transmitters, modulation and demodulation in Photonics, photonic networks - narrowband and wideband, photonic switches, image sensors and displays. The education of Photonics has been supported by research activities in the field of applied photonic system for signal (data) transmission and selected results have been implemented into the subject structure. The paper listed a detailed content of the subject in two fields: lectures and experimental laboratory exercises. As an integral part of the course we plan to implement selected experiments from the area of 2D photonic (image) processing and to expand the imaging photonic part.

  9. Photon Differential Splatting for Rendering Caustics

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Schjøth, Lars; Erleben, Kenny

    2014-01-01

    on heuristics rather than knowledge of the local flux density. We use photon differentials to determine the size and shape of the splats such that we achieve adaptive anisotropic flux density estimation in photon splatting. As compared to previous work that uses photon differentials, we present the first method...

  10. NanoData Landscape Compilation. Photonics

    NARCIS (Netherlands)

    Allan, J.E.M.; Buist, H.E.; Chapman, A.; Flament, G.; Hartmann, C.; Jawad, I.; Kuijpers, L.T.; Kuittinen, H.; Noyons, E.; Giessen, A.M. van der; Yegros, A.

    2017-01-01

    Photonics emerged in the 1960s and 1970s from work on semiconductor light emitters, lasers and optical fibres. Nanoscale effects impact on photonics, e.g. in the surface quality of waveguides and optical fibres. The focus here remains as closely as possible on photonics as it relates to

  11. ePIXfab - The silicon photonics platform

    NARCIS (Netherlands)

    Khanna, A.; Drissi, Y.; Dumon, P.; Baets, R.; Absil, P.; Pozo Torres, J.M.; Lo Cascio, D.M.R.; Fournier, M.; Fedeli, J.M.; Fulbert, L.; Zimmermann, L.; Tillack, B.; Aalto, T.; O'Brien, P.; Deptuck, D.; Xu, J.; Gale, D.

    2013-01-01

    ePIXfab-The European Silicon Photonics Support Center continues to provide state-of-the-art silicon photonics solutions to academia and industry for prototyping and research. ePIXfab is a consortium of EU research centers providing diverse expertise in the silicon photonics food chain, from training

  12. Photonic hybrid assembly through flexible waveguides

    NARCIS (Netherlands)

    Wörhoff, Kerstin; Prak, Albert; postma, F; Leinse, A; Wu, K.; Peters, T.J.; Tichem, M.; Amaning-Appiah, B.; Renukappa, V.; Vollrath, G.; Balcells-Ventura, J.; Uhlig, P.; Seyfried, M.; Rose, D.; Santos, Raquel; Leijtens, XJM; Flintham, B.; Wale, M.; Robbins, D.; Vivien, Laurent; Pavesi, Lorenzo; Pelli, Stefano

    2016-01-01

    Fully automated, high precision, cost-effective assembly technology for photonic packages remains one of the main challenges in photonic component manufacturing. Next to the cost aspect the most demanding assembly task for multiport photonic integrated circuits (PICs) is the high-precision (±0.1

  13. Single-photon manipulation in Nanophotonic Circuits

    DEFF Research Database (Denmark)

    Hansen, Sofie Lindskov

    on a gallium arsenide platform. This platform offers near-unity coupling between embedded single-photon emitters and a photonic mode, as well as the ability to suppress decoherence mechanisms, making it highly suited for quantum information applications. In this thesis we show how a single-photon router can...

  14. Single-Photon Technologies Based on Quantum-Dots in Photonic Crystals

    DEFF Research Database (Denmark)

    Lehmann, Tau Bernstorff

    In this thesis, the application of semiconductor quantum-dots in photonic crystals is explored as aresource for single-photon technology.Two platforms based on photonic crystals, a cavity and a waveguide, are examined as platformssingle-photon sources. Both platforms demonstrate strong single-photon...... purity under quasi-resonantexcitation. Furthermore the waveguide based platform demonstrates indistinguishable single-photonsat timescales up to 13 ns.A setup for active demultiplexing of single-photons to a three-fold single-photon state is proposed.Using a fast electro-optical modulator, single-photons...... from a quantum-dot are routed on timescalesof the exciton lifetime. Using active demultiplexing a three-fold single-photon state is generated at anextracted rate of 2:03 ±0:49 Hz.An on-chip power divider integrated with a quantum-dot is investigated. Correlation measurementof the photon statistic...

  15. Estimating Rain Attenuation In Satellite Communication Links

    Science.gov (United States)

    Manning, R. M.

    1991-01-01

    Attenuation computed with help of statistical model and meteorological data. NASA Lewis Research Center Satellite Link Attenuation Model (SLAM) program QuickBASIC computer program evaluating static and dynamic statistical assessment of impact of rain attenuation on communication link established between Earth terminal and geosynchronous satellite. Application in specification, design, and assessment of satellite communication links for any terminal location in continental United States. Written in Microsoft QuickBASIC.

  16. Noiseless attenuation using an optical parametric amplifier

    Science.gov (United States)

    Brewster, R. A.; Nodurft, I. C.; Pittman, T. B.; Franson, J. D.

    2017-10-01

    The process of heralded noiseless amplification, and the inverse process of heralded noiseless attenuation, have potential applications in the context of quantum communications. Although several different physical implementations of heralded noiseless amplifiers have now been demonstrated, the research on heralded noiseless attenuators has been largely confined to a beam-splitter based approach. Here we show that an optical parametric amplifier (OPA), combined with appropriate heralding, can also serve as a heralded noiseless attenuator. The counterintuitive use of an optical amplifier as an attenuator is only possible due to the probabilistic nature of the device.

  17. Attenuation corrected SPECT using transmission measurements

    International Nuclear Information System (INIS)

    Ziegler, S.I.; Ficaro, E.P.; Boening, G.; Schwaiger, M.

    1996-01-01

    Modern SPECT instrumentation allows attenuation correction in cardiac scans by using transmission measurements. Simultaneous transmission and emission measurements are feasible with different geometries in multihead SPECT systems and are already commercially available. The selection of the transmission nuclide affects the quality of data, depending on the emission nuclide used. Iterative reconstruction methods have to be implemented to get accurate results in the case of heterogeneous attenuation distributions. Methodological aspects concerning simultaneous scatter and attenuation correction have to be studied in future. The clinical significance of routine attenuation correction measurements for myocardial perfusion has to be shown in a large patient population. (orig.) [de

  18. Photon management assisted by surface waves on photonic crystals

    CERN Document Server

    Angelini, Angelo

    2017-01-01

    This book illustrates original pathways to manipulate light at the nanoscale by means of surface electromagnetic waves (here, Bloch surface waves, BSWs) on planar dielectric multilayers, also known as one-dimensional photonic crystals. This approach is particularly valuable as it represents an effective alternative to the widely exploited surface plasmon paradigm. After a brief overview on the fundamentals of BSWs, several significant applications of BSW-sustaining structures are described. Particular consideration is given to the propagation, guiding, and diffraction of BSW-coupled radiation. Further, the interaction of organic emitters with BSWs on planar and corrugated multilayers is investigated, including fluorescence beaming in free space. To provide greater insight into sensing applications, an illustrative example of fluorescent microarray-based detection is presented. The book is intended for scientists and researchers working on photon management opportunities in fields such as biosensing, optical c...

  19. Nuclear photon science with inverse compton photon beam

    International Nuclear Information System (INIS)

    Fujiwara, Mamoru

    2007-01-01

    Recent developments of the synchrotron radiation facilities and intense lasers are now guiding us to a new research frontier with probes of a high energy GeV photon beam and an intense and short pulse MeV γ-ray beam. New directions of the science developments with photo-nuclear reactions are discussed. The inverse Compton γ-ray has two good advantages for searching for a microscopic quantum world; they are 1) good emittance and 2) high linear and circular polarizations. With these advantages, photon beams in the energy range from MeV to GeV are used for studying hadron structure, nuclear structure, astrophysics, materials science, as well as for applying medical science. (author)

  20. High-Energy QCD Asymptotics of Photon--Photon Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.

    2002-07-26

    The high-energy behavior of the total cross section for highly virtual photons, as predicted by the BFKL equation at next-to-leading order (NLO) in QCD, is discussed. The NLO BFKL predictions, improved by the BLM optimal scale setting, are in good agreement with recent OPAL and L3 data at CERN LEP2. NLO BFKL predictions for future linear colliders are presented.

  1. Photonic band gap engineering in 2D photonic crystals

    Indian Academy of Sciences (India)

    (i) PhC composed of square lattice of elliptical air holes in silicon (Si) (n = 3.42) as shown in figure 1a. (ii) PhC ... consist of silicon and air as they provide adequate dielectric contrast for obtaining photonic band gaps. ... periodic with lattice vectors R. The relative permeability µ is taken as 1 and the relative permittivity is ...

  2. Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons.

    Science.gov (United States)

    Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J; Treutlein, Philipp

    2017-08-11

    Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δf=0.66  GHz, the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure η_{e2e}^{50  ns}=3.4(3)% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency η_{int}=17(3)%. Straightforward technological improvements can boost the end-to-end-efficiency to η_{e2e}≈35%; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9×10^{-3} photons is dominated by atomic fluorescence, and for input pulses containing on average μ_{1}=0.27(4) photons, the signal to noise level would be unity.

  3. Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons

    Science.gov (United States)

    Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J.; Treutlein, Philipp

    2017-08-01

    Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δ f =0.66 GHz , the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure ηe2 e 50 ns=3.4 (3 )% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency ηint=17 (3 )%. Straightforward technological improvements can boost the end-to-end-efficiency to ηe 2 e≈35 %; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9 ×10-3 photons is dominated by atomic fluorescence, and for input pulses containing on average μ1=0.27 (4 ) photons, the signal to noise level would be unity.

  4. Photonic Crystals Physics and Practical Modeling

    CERN Document Server

    Sukhoivanov, Igor A

    2009-01-01

    The great interest in photonic crystals and their applications in the past decade requires a thorough training of students and professionals who can practically apply the knowledge of physics of photonic crystals together with skills of independent calculation of basic characteristics of photonic crystals and modelling of various photonic crystal elements for application in all-optical communication systems. This book combines basic backgrounds in fiber and integrated optics with detailed analysis of mathematical models for 1D, 2D and 3D photonic crystals and microstructured fibers, as well as with descriptions of real algorithms and codes for practical realization of the models.

  5. Helioscope bounds on hidden sector photons

    International Nuclear Information System (INIS)

    Redondo, J.

    2008-01-01

    The flux of hypothetical ''hidden photons'' from the Sun is computed under the assumption that they interact with normal matter only through kinetic mixing with the ordinary standard model photon. Requiring that the exotic luminosity is smaller than the standard photon luminosity provides limits for the mixing parameter down to χ -14 , depending on the hidden photon mass. Furthermore, it is pointed point out that helioscopes looking for solar axions are also sensitive to hidden photons. The recent results of the CAST collaboration are used to further constrain the mixing parameter χ at low masses (m γ' <1 eV) where the luminosity bound is weaker. In this regime the solar hidden photon ux has a sizable contribution of longitudinally polarized hidden photons of low energy which are invisible for current helioscopes. (orig.)

  6. FDTD simulation for plasma photonic crystals

    International Nuclear Information System (INIS)

    Liu Shaobin; Zhu Chuanxi; Yuan Naichang

    2005-01-01

    Plasma photonic crystals are artificially periodic structures, which are composed of plasmas and dielectric structures (or vacuum). In this paper, the piecewise linear current density recursive convolution (PLCDRC) finite-difference time-domain (FDTD) method is applied to study the plasma photonic crystals and those containing defects. In time-domain, the electromagnetic (EM) propagation process and reflection/transmission electric field of Gauss pulses passing through the plasma photonic crystals are investigated. In frequency-domain, the reflection and transmission coefficients of the pulses through the two kinds of crystals are computed. The results illustrate that the plasma photonic crystals mostly reflect for the EM wave of frequencies less than the plasma frequency, and mostly transmit for EM wave of frequencies higher than the plasma frequency. In high frequency domain, the plasma photonic crystals have photonic band gaps, which is analogous to the conventional photonic crystals. (authors)

  7. Designing Photonic Crystal Devices for Accelerators

    CERN Document Server

    Werner, Gregory

    2005-01-01

    Photonic crystals (periodic dielectric structures with a lattice constant on the order of the wavelength of light) can have a wide range of properties. For instance, photonic crystals can be designed to be completely reflective within a certain bandwidth, thereby becoming a replacement for metal in accelerator structures such as waveguides and cavities. To see whether photonic crystals might find application in accelerators, and to design potential accelerator structures, we will need reliable computer simulations to predict fields and frequencies and other properties of photonic crystal structures. We propose to build photonic crystal structures in the microwave regime and test the validity of computer simulation against experiment. We can then explore more complex issues such as coupling to photonic crystal structures, higher-order mode rejection, and tunable photonic crystals.

  8. Shielding data for 100-250 MeV proton accelerators double differential neutron distributions and attenuation in concrete

    CERN Document Server

    Agosteo, S; Mereghetti, A; Silari, M; Zajacova, Z

    2007-01-01

    Double differential distributions of neutrons produced by 100, 150, 200 and 250 MeV protons stopped in a thick iron target were simulated with the FLUKA Monte Carlo code at four emission angles: forward, 45°, transverse and 135° backwards. The attenuation in ordinary concrete of the dose equivalent due to secondary neutrons, protons, photons and electrons was calculated. Some of the resulting attenuation curves are best fitted by a double-exponential function rather than a single-exponential. The effect of various approximations introduced in the simulations is thoroughly discussed. The contribution to the total ambient dose equivalent from photons and protons is usually limited to a few percent, except in the backward direction where photons contribute more than 10% and up to 35% to the total dose for a shield thickness of 1 – 2 m. Source terms and attenuation lengths are given as a function of energy and emission angle, along with fit to the Monte Carlo data. An extensive comparison is made of values ob...

  9. Optical Properties of Photonic Crystals

    CERN Document Server

    Sakoda, Kazuaki

    2005-01-01

    This is the first comprehensive textbook on the optical properties of photonic crystals. It deals not only with the properties of the radiation modes inside the crystals but also with their peculiar optical response to external fields. A general theory of linear and nonlinear optical response is developed in a clear and detailed fashion using the Green's function method. The symmetry of the eigenmodes is treated systematically using group theory to show how it affects the optical properties of photonic crystals. Important recent developments such as the enhancement of stimulated emission, second harmonic generation, quadrature-phase squeezing, and low-threshold lasing are also treated in detail and made understandable. Numerical methods are also emphasized. Thus this book provides both an introduction for graduate and undergraduate students and also key information for researchers in this field. This second edition has been updated and includes a new chapter on superfluorescence.

  10. The Advanced LIGO photon calibrators.

    Science.gov (United States)

    Karki, S; Tuyenbayev, D; Kandhasamy, S; Abbott, B P; Abbott, T D; Anders, E H; Berliner, J; Betzwieser, J; Cahillane, C; Canete, L; Conley, C; Daveloza, H P; De Lillo, N; Gleason, J R; Goetz, E; Izumi, K; Kissel, J S; Mendell, G; Quetschke, V; Rodruck, M; Sachdev, S; Sadecki, T; Schwinberg, P B; Sottile, A; Wade, M; Weinstein, A J; West, M; Savage, R L

    2016-11-01

    The two interferometers of the Laser Interferometry Gravitational-wave Observatory (LIGO) recently detected gravitational waves from the mergers of binary black hole systems. Accurate calibration of the output of these detectors was crucial for the observation of these events and the extraction of parameters of the sources. The principal tools used to calibrate the responses of the second-generation (Advanced) LIGO detectors to gravitational waves are systems based on radiation pressure and referred to as photon calibrators. These systems, which were completely redesigned for Advanced LIGO, include several significant upgrades that enable them to meet the calibration requirements of second-generation gravitational wave detectors in the new era of gravitational-wave astronomy. We report on the design, implementation, and operation of these Advanced LIGO photon calibrators that are currently providing fiducial displacements on the order of 10 -18 m/Hz with accuracy and precision of better than 1%.

  11. The Advanced LIGO photon calibrators

    Science.gov (United States)

    Karki, S.; Tuyenbayev, D.; Kandhasamy, S.; Abbott, B. P.; Abbott, T. D.; Anders, E. H.; Berliner, J.; Betzwieser, J.; Cahillane, C.; Canete, L.; Conley, C.; Daveloza, H. P.; De Lillo, N.; Gleason, J. R.; Goetz, E.; Izumi, K.; Kissel, J. S.; Mendell, G.; Quetschke, V.; Rodruck, M.; Sachdev, S.; Sadecki, T.; Schwinberg, P. B.; Sottile, A.; Wade, M.; Weinstein, A. J.; West, M.; Savage, R. L.

    2016-11-01

    The two interferometers of the Laser Interferometry Gravitational-wave Observatory (LIGO) recently detected gravitational waves from the mergers of binary black hole systems. Accurate calibration of the output of these detectors was crucial for the observation of these events and the extraction of parameters of the sources. The principal tools used to calibrate the responses of the second-generation (Advanced) LIGO detectors to gravitational waves are systems based on radiation pressure and referred to as photon calibrators. These systems, which were completely redesigned for Advanced LIGO, include several significant upgrades that enable them to meet the calibration requirements of second-generation gravitational wave detectors in the new era of gravitational-wave astronomy. We report on the design, implementation, and operation of these Advanced LIGO photon calibrators that are currently providing fiducial displacements on the order of 1 0-18m /√{Hz } with accuracy and precision of better than 1%.

  12. Photon corpuscule in Riemann space

    International Nuclear Information System (INIS)

    Paillere, P.

    1984-05-01

    The aim of this paper is to collect some results about the corpuscle photon considered in the domain of the classical general relativity. Starting from a formal analogy with the mechanics of the ponderous relativistic particles in any riemannian metric with signature -+++, we are led by the use of intermediary and in some way artificial notions of proper time and proper mass, to write the Boltzmann equation of photons transport and the equations of radiative transfer. In the course of the development, some secondary results appear, particularly, the formula of the Doppler effect and of the Compton effect in a metric where the crossed space-time terms are different from zero, such as, for instance, the Kerr metrics [fr

  13. Recent trends in computational photonics

    CERN Document Server

    Benson, Trevor; Rue, Richard; Wurtz, Gregory

    2017-01-01

    This book brings together the recent cutting-edge work on computational methods in photonics and their applications. The latest advances in techniques such as the Discontinuous Galerkin Time Domain method, Finite Element Time Domain method, Finite Difference Time Domain method as well as their applications are presented. Key aspects such as modelling of non-linear effects (Second Harmonic Generation, lasing in fibers, including gain nonlinearity in metamaterials), the acousto-optic effect, and the hydrodynamic model to explain electron response in nanoplasmonic structures are included. The application areas covered include plasmonics, metamaterials, photonic crystals, dielectric waveguides, fiber lasers. The chapters give a representative survey of the corresponding area. .

  14. Photonic band gap structure simulator

    Science.gov (United States)

    Chen, Chiping; Shapiro, Michael A.; Smirnova, Evgenya I.; Temkin, Richard J.; Sirigiri, Jagadishwar R.

    2006-10-03

    A system and method for designing photonic band gap structures. The system and method provide a user with the capability to produce a model of a two-dimensional array of conductors corresponding to a unit cell. The model involves a linear equation. Boundary conditions representative of conditions at the boundary of the unit cell are applied to a solution of the Helmholtz equation defined for the unit cell. The linear equation can be approximated by a Hermitian matrix. An eigenvalue of the Helmholtz equation is calculated. One computation approach involves calculating finite differences. The model can include a symmetry element, such as a center of inversion, a rotation axis, and a mirror plane. A graphical user interface is provided for the user's convenience. A display is provided to display to a user the calculated eigenvalue, corresponding to a photonic energy level in the Brilloin zone of the unit cell.

  15. Neuro-photonics using GPC

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    stimulating light at single neuronal processes, neurons or groups of neurons. The underlying laser technique combines our patented Generalized Phase Contrast (GPC) with socalled temporal focusing to shape two-photon excitation for this purpose. The laser excitation patterns are generated automatically from......I will be presenting a powerful approach for controlling light-gated ion channels and pumps that makes it possible to probe intact neural circuits by manipulating the activity of groups of genetically similar neurons. It is experimentally demonstrated how it is now possible to precisely aiming...... fluorescence images of neurons and shaped to cover the cell body or dendrites, or distributed groups of cells. The temporal focusing GPC two-photon excitation patterns can generate large photocurrents in Channelrhodopsin-2–expressing cultured cells and neurons and in mouse acute cortical slices. The amplitudes...

  16. Optical Magnetometer Incorporating Photonic Crystals

    Science.gov (United States)

    Kulikov, Igor; Florescu, Lucia

    2007-01-01

    According to a proposal, photonic crystals would be used to greatly increase the sensitivities of optical magnetometers that are already regarded as ultrasensitive. The proposal applies, more specifically, to a state-of-the-art type of quantum coherent magnetometer that exploits the electromagnetically-induced-transparency (EIT) method for determining a small change in a magnetic field indirectly via measurement of the shift, induced by that change, in the hyperfine levels of resonant atoms exposed to the field.

  17. Somatic risks by photon irradiation

    International Nuclear Information System (INIS)

    Barrote, W.G.

    1983-01-01

    A methodology of energy deposited calculation in organs and tissues of human body for external photon beams is proposed. Physical parameters of X-ray, used to diagnostic in human beings, were chosen to estimate dose in 121 units of Rio de Janeiro. Absorbed dose distributions in ovaries, testicles, thyroid, uterus, lungs, active bone marrow and whole body in 7 kinds of more frequent exams were obtained. (M.A.C.) [pt

  18. Quantum Photonics Beyond Conventional Computing

    Science.gov (United States)

    2015-07-10

    Ref [15] to directly configure our device by choosing each of the experimental parameters from a set of probability density functions . The averages... functions (pdfs) corresponding to the elements in b). c) A histogram of statistical fidelities for 100 boson sampling experiments for three photons, two...well defined energies. The ability to implement and reconfigure FIG. 11. Simulation of localised phonons in a ring of atoms. a) relative volume of

  19. Relativistic gravitational deflection of photons

    CERN Document Server

    Saca, J M

    2002-01-01

    A relativistic analysis of the deflection of a light ray due to a massive attractive centre is here developed by solving a differential equation of the orbit of photons. Results are compared with a widely known approximate formula for the deflection obtained by Einstein in 1916. Finally, it is concluded that the results here obtained, although very close to Einstein's values, could stand out as a conclusive reference for comparison with future direct measurements of the deflection.

  20. Gamma-ray attenuation to measure water contents and/or bulk densities of porous materials

    International Nuclear Information System (INIS)

    Ferraz, E.S.B.

    1983-01-01

    Attenuation of gamma radiation during transmission through soil and porous materials has been used for approximately three decades as a method for determining volumetric water content, theta, and bulk density, rho. This method is particularly suited for laboratory determinations of theta and rho in soil columns but it also has been used with success under field conditions. Measurements of attentuation of a collimated beam of monoernergetic gamma-rays has been used successfully by many investigators to provide rapid, non-destructive determinations for small volumes of soil. For stable soils, i.e. soils which do not swell upon wetting or shrink upon drying, rho may be assumed to remain constant during water flow through the soil, and thus changes in intensity or transmitted radiation may be attributed to changes in water content, theta. However, for unstable soils, the dry bulk density is subject to change with time during water flow through the soil and cannot be assumed to be a constant. Several investigators have utilized either a single beam of dual-energy gamma photons or two separate monoenergetic photon beams with greatly different energies to simultaneously determine theta and rho in these soils. A general review of gamma-ray attenuation methods for determining theta and rho in laboratory soil cores and in field soil profiles is reported in this paper. Theoretical equations for transmission and attenuation of gamma radiation in soils are presented for both single and double beams of gamma photons. Sensitivity, precision, accuracy, and experimental errors for the method are evaluated and discussed with respect to the theory. (author)

  1. Enhancement of Photon Absorption on BaxSr1-xTiO3 Thin-Film Semiconductor Using Photonic Crystal

    Directory of Open Access Journals (Sweden)

    Abd. Wahidin Nuayi

    2014-01-01

    Full Text Available Enhancement of photon absorption on barium strontium titanate (BaxSr1-xTiO3 thin-film semiconductor for mole fraction x=0.25, 0.35, 0.45, and 0.55 using one-dimensional photonic crystal with defect was investigated experimentally. The thin film was grown on transparent conductive oxide (TCO substrate using chemical solution deposition method and annealed at 500°C for 15 hours with increasing rate of 1.6°C/min. From optical characterization in visible spectrum it was found that the average absorption percentages are 92.04%, 83.55%, 91.16%, and 80.12%, respectively. The BST thin film with embedded photonic crystal exhibited a relatively significant enhancement on photon absorption, with increasing value of 3.96%, 7.07%, 3.04%, and 13.33% for the respective mole fraction and demonstrating absorbance characteristic with flat feature. In addition, we also discuss the thin-film properties of attenuation constant and electrical conductivity.

  2. Lattice topology dictates photon statistics.

    Science.gov (United States)

    Kondakci, H Esat; Abouraddy, Ayman F; Saleh, Bahaa E A

    2017-08-21

    Propagation of coherent light through a disordered network is accompanied by randomization and possible conversion into thermal light. Here, we show that network topology plays a decisive role in determining the statistics of the emerging field if the underlying lattice is endowed with chiral symmetry. In such lattices, eigenmode pairs come in skew-symmetric pairs with oppositely signed eigenvalues. By examining one-dimensional arrays of randomly coupled waveguides arranged on linear and ring topologies, we are led to a remarkable prediction: the field circularity and the photon statistics in ring lattices are dictated by its parity while the same quantities are insensitive to the parity of a linear lattice. For a ring lattice, adding or subtracting a single lattice site can switch the photon statistics from super-thermal to sub-thermal, or vice versa. This behavior is understood by examining the real and imaginary fields on a lattice exhibiting chiral symmetry, which form two strands that interleave along the lattice sites. These strands can be fully braided around an even-sited ring lattice thereby producing super-thermal photon statistics, while an odd-sited lattice is incommensurate with such an arrangement and the statistics become sub-thermal.

  3. Photonic Bandgap (PBG) Shielding Technology

    Science.gov (United States)

    Bastin, Gary L.

    2007-01-01

    Photonic Bandgap (PBG) shielding technology is a new approach to designing electromagnetic shielding materials for mitigating Electromagnetic Interference (EM!) with small, light-weight shielding materials. It focuses on ground planes of printed wiring boards (PWBs), rather than on components. Modem PSG materials also are emerging based on planar materials, in place of earlier, bulkier, 3-dimensional PBG structures. Planar PBG designs especially show great promise in mitigating and suppressing EMI and crosstalk for aerospace designs, such as needed for NASA's Constellation Program, for returning humans to the moon and for use by our first human visitors traveling to and from Mars. Photonic Bandgap (PBG) materials are also known as artificial dielectrics, meta-materials, and photonic crystals. General PBG materials are fundamentally periodic slow-wave structures in I, 2, or 3 dimensions. By adjusting the choice of structure periodicities in terms of size and recurring structure spacings, multiple scatterings of surface waves can be created that act as a forbidden energy gap (i.e., a range of frequencies) over which nominally-conductive metallic conductors cease to be a conductor and become dielectrics. Equivalently, PBG materials can be regarded as giving rise to forbidden energy gaps in metals without chemical doping, analogous to electron bandgap properties that previously gave rise to the modem semiconductor industry 60 years ago. Electromagnetic waves cannot propagate over bandgap regions that are created with PBG materials, that is, over frequencies for which a bandgap is artificially created through introducing periodic defects

  4. Photon Factory activity report, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The Photon Factory at the National Laboratory for High Energy Physics is a national facility for scientific research utilizing synchrotron radiation. Although the Photon Factory operator the linear injector, two light sources including the 2.5 GeV storage ring and the 6.5 GeV TRISTAN accumulation Ring as well as a major fraction of their beamlines and experimental station. This report is covered the period from October 1994 to September 1995. The total number of proposals by this PAC was 399 in 1995. Facility development projects currently in progress include the following, TRISTAN Super Light Facility (TSLF) project, VUV-FEL project, KEKB project and Slow-positron Source. This report contents outline of the Photon Factory, introduction, scientific disciplines, electronic properties of condensed matters, atomic and molecular science, X-ray imaging, radiobiology using synchrotron radiation, structural properties of condensed matters, structural properties of solid surfaces and adsorbates, structure and function of proteins, theoretical researches, experimental facilities, beamlines, new instrumentation, AR Upgrade, collaborations, projects, user`s short reports, list of published papers 1994/95. (S.Y.)

  5. Nanomanipulation using near field photonics.

    Science.gov (United States)

    Erickson, David; Serey, Xavier; Chen, Yih-Fan; Mandal, Sudeep

    2011-03-21

    In this article we review the use of near-field photonics for trapping, transport and handling of nanomaterials. While the advantages of traditional optical tweezing are well known at the microscale, direct application of these techniques to the handling of nanoscale materials has proven difficult due to unfavourable scaling of the fundamental physics. Recently a number of research groups have demonstrated how the evanescent fields surrounding photonic structures like photonic waveguides, optical resonators, and plasmonic nanoparticles can be used to greatly enhance optical forces. Here, we introduce some of the most common implementations of these techniques, focusing on those which have relevance to microfluidic or optofluidic applications. Since the field is still relatively nascent, we spend much of the article laying out the fundamental and practical advantages that near field optical manipulation offers over both traditional optical tweezing and other particle handling techniques. In addition we highlight three application areas where these techniques namely could be of interest to the lab-on-a-chip community, namely: single molecule analysis, nanoassembly, and optical chromatography. This journal is © The Royal Society of Chemistry 2011

  6. Introduction to photonics and holography

    International Nuclear Information System (INIS)

    Grosmann, M.

    1982-01-01

    These new terms cover a group of advanced technologies based on the specific properties of the ineraction between light and matter that have been discovered since the development of lasers. Electronics uses electricity to process information: photonics performs the same functions, but uses light instead of electricity. Photonics can be said to cover all the methods, processes or systems which serve of study, measure and transform or transmit by means of light. The photon devices which have resulted from fundamental and applied research in this field over the last ten years or so cover a comparable range of application areas to that of electronics - mechanical engineering, medicine, avionics, telecommunications, biology, metrology, quality control, hydraulics, computers, botanical science, textiles, remote sensing, pneumatics, aerospace, etc. The list is too long to give in its entirety, but for our present purposes there are four types of significant products: lasers and their accessories, optical fibres and their accessories, data acquisition, processing and display systems and photovoltaic and solar systems. (orig.)

  7. Photon Factory activity report, 1995

    International Nuclear Information System (INIS)

    1996-01-01

    The Photon Factory at the National Laboratory for High Energy Physics is a national facility for scientific research utilizing synchrotron radiation. Although the Photon Factory operator the linear injector, two light sources including the 2.5 GeV storage ring and the 6.5 GeV TRISTAN accumulation Ring as well as a major fraction of their beamlines and experimental station. This report is covered the period from October 1994 to September 1995. The total number of proposals by this PAC was 399 in 1995. Facility development projects currently in progress include the following, TRISTAN Super Light Facility (TSLF) project, VUV-FEL project, KEKB project and Slow-positron Source. This report contents outline of the Photon Factory, introduction, scientific disciplines, electronic properties of condensed matters, atomic and molecular science, X-ray imaging, radiobiology using synchrotron radiation, structural properties of condensed matters, structural properties of solid surfaces and adsorbates, structure and function of proteins, theoretical researches, experimental facilities, beamlines, new instrumentation, AR Upgrade, collaborations, projects, user's short reports, list of published papers 1994/95. (S.Y.)

  8. Photon Factory activity report, 1990

    International Nuclear Information System (INIS)

    1991-01-01

    The Photon Factory has grown at a considerable rate, and 600 experiments are carried out in 1991, while the number of users is now 2300 including about 500 from industrial sectors. The use of synchrotron radiation increased from fundamental research to industrial development. The development at the Photon Factory is supported by the capability of the accelerators. At present, the 2.5 GeV PF ring is operated with positrons at the initial beam current of 350 mA. The total operation time was 3500 hours in the fiscal year 1990. The development of an avalanche mode photodiode, the observation of quantum beat in the experiment of nuclear Bragg scattering, the measurement of photo-electron and photo-ion spectroscopy were carried out. The conversion of TRISTAN main ring to an ultrahigh brilliance and high coherence source is planned for the future. The annual PF Symposium was held, and Professor H. Winick gave the lecture 'Ultrahigh brightness and coherent radiation from large storage rings'. In this report, the outline of the Photon Factory and the activities in Divisions of Injector Linac, Light Source and Instrumentation are described. (K.I.)

  9. High index contrast photonics platform

    Science.gov (United States)

    Chu, Sai T.; Little, Brent E.; Hryniewicz, John V.; Johnson, Fred G.; King, Oliver; Gill, Dave; Chen, Wenlu; Chen, Wei

    2005-10-01

    A new low-loss high-index-contrast photonics platform has been developed for integrated optics and microwave photonics. The platform consists of a material system that has an index contrast that is adjustable from 0 to 25% and which is processed using conventional CMOS tools. The platform allows one to four orders of magnitude reduction in the size of optical components compared with conventional planar technologies. As an example, meter long path lengths occupy coils that are millimeters in diameter. Microwave photonic building blocks that are enabled include large bit count programmable delay lines for beam steering and shaping that fit in less than a square centimeter and which have delays controllable from 5 fsec to 10 nsec. Also enabled are arrays of high order tunable filters, a hundred micrometers in size, having linewidths ranging from tens of MHz to tens of GHz. These filters can be tuned over several hundred GHz, and when placed in Vernier architectures can be tuned across the C band (5 THz). An optical chip typically consists of dozens of optical elements. Each element is placed in its own micro-control loop that consists of a thin film heater for thermo-optic control and a thermistor for electronic feedback. The micro-control loops impart intelligence to the optical chip.

  10. Single photon detector design features

    Science.gov (United States)

    Zaitsev, Sergey V.; Kurochkin, Vladimir L.; Kurochkin, Yury V.

    2016-12-01

    In the report are discussed the laboratory test results of SPAD detectors with InGaAs / InP avalanche photodiodes, operating in Geiger mode. Device operating in synchronous mode with the dead timer setting for proper working conditions of photodiodes. The report materials will showing the functional block diagram of the detector, real operating signals in the receiver path and clock circuits and main results of measurements. The input signal of the synchronous detector is the clock, which determines the time positions of expected photons arrival. Increasing the clock speed 1-300 MHz or getting more time positions of the time grid, we provide increased capacity for time position code of signals, when QKD information transmitted over the nets. At the same time, the maximum attainable speed of photon reception is limited by diode dead time. Diode quantum noise are minimized by inclusion of a special time interval - dead time 0.1-10 usec, after each received and registered a photon. The lowest attainable value of the dead time is determined as a compromise between transients in electrical circuits, passive avalanche «quenching» circuit and thermal transients cooling crystal diode, after each avalanche pass though photodiode. Achievable time and speed parameters are discussed with specific examples of detectors.

  11. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...

  12. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    mary production and diffuse attenuation coeffi- cient (Austin 1981; Sathyendranath et al 2000). The Indian IRS-P3 ... oceanic and coastal production of phytoplank- ton (Tyler 1975; Pennock and Sharp 1986). As a result basic ... cient to the plant pigment content. The term dif- fuse attenuation coefficient, most commonly used.

  13. Single photon imaging and timing array sensor apparatus and method

    Science.gov (United States)

    Smith, R. Clayton

    2003-06-24

    An apparatus and method are disclosed for generating a three-dimension image of an object or target. The apparatus is comprised of a photon source for emitting a photon at a target. The emitted photons are received by a photon receiver for receiving the photon when reflected from the target. The photon receiver determines a reflection time of the photon and further determines an arrival position of the photon on the photon receiver. An analyzer is communicatively coupled to the photon receiver, wherein the analyzer generates a three-dimensional image of the object based upon the reflection time and the arrival position.

  14. Providing reference standards and metrology for the few photon-photon counting community

    Science.gov (United States)

    Beaumont, Andrew R.; Cheung, Jessica Y.; Chunnilall, Christopher J.; Ireland, Jane; White, Malcolm G.

    2009-10-01

    The main drivers for developing few-photon metrological techniques are the rapidly progressing field of quantum information processing, which requires the development of high-efficiency photon-counting detectors, and the wider use of photon-counting technology in biology, medical physics and nuclear physics. This paper will focus on the provision of standards for the few photon community and the development of techniques for the characterisation of photon-counting detectors. At the high-power end, microwatts, we are developing a low-power absolute radiometer as a primary standard that will be used to provide traceability over a much broader spectral range. At the few photon-photon-counting level we are developing a conventional calibration technique, which is traceable to the primary standard through a reference trap detector. This method can be used in both analogue and photon-counting modes and provides a convenient route for providing customer calibration at few-photon levels across the optical spectrum. At the photon-counting/single-photon level we are developing a technique based on correlated photons. These are produced via parametric downconversion and can be used to measure directly the detection efficiency of photon-counting detectors. A cross-validation of the correlated photon and conventional technique is reported. Finally we discuss this work in the context of an EU project, that is aimed at establishing the route towards the re-definition of the candela, the SI unit for optical radiation.

  15. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    of the rectangles and sums all contributions to arrive at the spatial impulse response for the aperture and field point. This approach makes it possible to model all transducer apertures, and the program can readily calculate the emitted, pulse-echo and continuous wave field. Attenuation is included by splitting...... it into a frequency dependent part and frequency independent part. The latter results in an attenuation factor that is multiplied onto the responses from the individual elements, and the frequency dependent part is handled by attenuating the basic one-dimensional pulse. The influence on ultrasound fields from......Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...

  16. Monte carlo simulation of innovative neutron and photon shielding material composing of high density concrete, waste rubber, lead and boron carbide

    Science.gov (United States)

    Aim-O, P.; Wongsawaeng, D.; Phruksarojanakun, P.; Tancharakorn, S.

    2017-06-01

    High-density concrete exhibits high strength and can perform an important role of gamma ray attenuation. In order to upgrade this material’s radiation-shielding performance, hydrogen-rich material can be incorporated. Waste rubber from vehicles has high hydrogen content which is the prominent characteristic to attenuate neutron. The objective of this work was to evaluate the radiation-shielding properties of this composite material against neutron and photon radiations. Monte Carlo transport simulation was conducted to simulate radiation through the composite material. Am-241/Be was utilized for neutron source and Co-60 for photon source. Parameters of the study included volume percentages of waste rubber, lead and boron carbide and thickness of the shielding material. These designs were also fabricated and the radiation shielding properties were experimentally evaluated. The best neutron and gamma ray shielding material was determined to be high-density concrete mixed with 5 vol% crumb rubber and 5 vol% lead powder. This shielding material increased the neutron attenuation by 64% and photon attenuation by 68% compared to ordinary concrete. Also, increasing the waste rubber content to greater than 5% resulted in a decrease in the radiation attenuation. This innovative composite radiation shielding material not only benefits nuclear science and engineering applications, but also helps solve the environmental issue of waste rubber.

  17. Photon Factory Activity Report, 1994

    International Nuclear Information System (INIS)

    1995-01-01

    Photon Factory Activity Report no.12 deals with our activities in the period from October 1993 through September 1994. We operate two light sources at the Photon Factory; the 2.5-GeV Photon Factory storage ring, which is a dedicated light source, and the 6.5-GeV TRISTAN Accumulation Ring, which is parasitically used as a light source. We keep more than seventy experimental stations at two facilities, and accept experiments primarily according to approval by the Program Advisory Committee. The number of proposals to the Photon Factory has been still growing. Three-hundred eighty two proposals were approved by the PAC in FY1994, which is an increase by thirteen percent compared to the previous year. Remarkable was growth in biology proposals, particularly proposals in protein crystallography. In FY 1994, we accepted approximately 20,000 man-days as general users, and almost ten percent of them were from abroad. We always open the facility to users, not only domestic but also international. Recently we have been concentrating our effort to upgrading of the light sources and reconstruction of the experimental stations to keep the Photon Factory an attractive research facility in the forthcoming years. We have already started a program of reducing the emittance of the 2.5-GeV storage ring, which now operates with an emittance of 110 nm-rad, to 27 nm-rad by modifying the lattice, with the goal of operation at the reduced emittance in the fall of 1997. We also have conceived of a conversion of the TRISTAN Accumulation Ring to a dedicated light source of high energies. The on-going TRISTAN project will terminate by the end of 1995, and the TRISTAN Main Ring will be converted to a new B-Factory. At this moment, the TRISTAN Accumulation Ring will be disused as the injector to the Main Ring, and conversion of the AR to a dedicated light source becomes possible. (J.P.N.)

  18. Photon Factory Activity Report, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    Photon Factory Activity Report no.12 deals with our activities in the period from October 1993 through September 1994. We operate two light sources at the Photon Factory; the 2.5-GeV Photon Factory storage ring, which is a dedicated light source, and the 6.5-GeV TRISTAN Accumulation Ring, which is parasitically used as a light source. We keep more than seventy experimental stations at two facilities, and accept experiments primarily according to approval by the Program Advisory Committee. The number of proposals to the Photon Factory has been still growing. Three-hundred eighty two proposals were approved by the PAC in FY1994, which is an increase by thirteen percent compared to the previous year. Remarkable was growth in biology proposals, particularly proposals in protein crystallography. In FY 1994, we accepted approximately 20,000 man-days as general users, and almost ten percent of them were from abroad. We always open the facility to users, not only domestic but also international. Recently we have been concentrating our effort to upgrading of the light sources and reconstruction of the experimental stations to keep the Photon Factory an attractive research facility in the forthcoming years. We have already started a program of reducing the emittance of the 2.5-GeV storage ring, which now operates with an emittance of 110 nm-rad, to 27 nm-rad by modifying the lattice, with the goal of operation at the reduced emittance in the fall of 1997. We also have conceived of a conversion of the TRISTAN Accumulation Ring to a dedicated light source of high energies. The on-going TRISTAN project will terminate by the end of 1995, and the TRISTAN Main Ring will be converted to a new B-Factory. At this moment, the TRISTAN Accumulation Ring will be disused as the injector to the Main Ring, and conversion of the AR to a dedicated light source becomes possible. (J.P.N.)

  19. Review and history of photon cross section calculations

    International Nuclear Information System (INIS)

    Hubbell, J H

    2006-01-01

    Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, μ/ρ, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's μ/ρ compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Oeverboe, these names being representative of the vast legions of other researchers whose work fed into these

  20. Colloidal photonic crystals: from lasing to microfluidics

    Science.gov (United States)

    Clays, Koen; Zhong, Kuo; Song, Kai

    2017-08-01

    Colloidal photonic crystals are photonic crystals made by bottom-up physical chemistry strategies from monodisperse colloidal particles. The self-assembly process is automatically leading to inherently three-dimensional structures with their optical properties determined by the periodicity, induced by this ordering process, in the dielectric properties of the colloidal material. The best-known optical effect is the photonic band gap, the range of energies, or wavelengths, that is forbidden for photons to exist in the structure. This photonic band gap is similar to the electronic band gap of electronic semiconductor crystals. We have previously shown how with the proper photonic band gap engineering, we can insert allowed pass band defect modes and use the suppressing band gap in combination with the transmitting pass band to induce spectral narrowing of emission. We show now how with a high-quality narrow pass band in a broad stop band, it is possible to achieve photonic crystal lasing in self-assembled colloidal photonic crystals with a planar defect. In addition, with proper surface treatment in combination with patterning, we prepare for addressable integrated photonics. Finally, by incorporating a water in- and outlet, we can create optomicrofluidic structures on a photonic crystal allowing the optical probing of microreactors or micro-stopped-flow in the lab-on-an-optical-chip.

  1. Study of prompt photon and neutral pion production in photon-photon scattering with the OPAL experiment

    CERN Document Server

    Lillich, Joachim

    2003-01-01

    For the first time at LEP the production of prompt photons is studied in the collisions of quasi-real photons using the OPAL data taken at e+e- centre-of mass energies between 183 GeV and 209 GeV. The total inclusive production cross-section for isolated prompt photons in the kinematic range of transverse momentum > 3.0 GeV and the absolut value of pseudorapidity <1 is determined to be (0.32 +- 0.04 (stat) +- 0.04 (sys)) pb. Differential cross-sections are compared to the predictions of a next-to-leading-order (NLO) calculation. In the second part of this thesis inclusive differential neutral pion cross-sections in photon photon collisons are measured. This measurement is an important test of QCD. In addition this process is the main background for prompt photons.

  2. Evaluation of transmission methodology and attenuation correction for the microPET Focus 220 animal scanner

    International Nuclear Information System (INIS)

    Lehnert, Wencke; Meikle, Steven R; Siegel, Stefan; Newport, Danny; Banati, Richard B; Rosenfeld, Anatoly B

    2006-01-01

    An accurate, low noise estimate of photon attenuation in the subject is required for quantitative microPET studies of molecular tracer distributions in vivo. In this work, several transmission-based measurement techniques were compared, including coincidence mode with and without rod windowing, singles mode with two different energy sources ( 68 Ge and 57 Co), and postinjection transmission scanning. In addition, the effectiveness of transmission segmentation and the propagation of transmission bias and noise into the emission images were examined. The 57 Co singles measurements provided the most accurate attenuation coefficients and superior signal-to-noise ratio, while 68 Ge singles measurements were degraded due to scattering from the object. Scatter correction of 68 Ge transmission data improved the accuracy for a 10 cm phantom but over-corrected for a mouse phantom. 57 Co scanning also resulted in low bias and noise in postinjection transmission scans for emission activities up to 20 MBq. Segmentation worked most reliably for transmission data acquired with 57 Co but the minor improvement in accuracy of attenuation coefficients and signal-to-noise may not justify its use, particularly for small subjects. We conclude that 57 Co singles transmission scanning is the most suitable method for measured attenuation correction on the microPET Focus 220 animal scanner

  3. 137Cs transmission imaging and segmented attenuation corrections in a small animal PET scanner.

    Science.gov (United States)

    Nai, Ying-Hwey; Ose, Takayuki; Shidahara, Miho; Watabe, Hiroshi

    2017-09-01

    Attenuation correction (AC) is required for accurate quantitative evaluation of small animal PET data. Our objective was to compare three AC methods in the small animal Clairvivo-PET scanner. The three AC methods involve applying attenuation coefficient maps generated by simulating a cylindrical map (SAC), segmenting the emission data (ESAC), and segmenting the transmission data (TSAC), imaged using a 137 Cs single-photon source. Investigation was carried out using a 65 mm uniform cylinder and an NEMA NU4 2008 mouse phantom, filled with water or tungsten liquid, to mimic bone. Evaluation was carried out using the difference of the segmented map volume from the known cylindrical phantom volume, the recovery of the radioactivity concentration, and the line profiles. The optimal transmission scan time for achieving accurate AC using TSAC was determined using 5, 10, 15, 20, and 25 min transmission scan time. The effects of scatter correction and reconstruction algorithms on ESAC were investigated. SAC showed the best performance but was unable to correct for different tissues and the scanner bed, and faced difficulty with correct positioning of the attenuation coefficient map. ESAC was affected by scatter correction and reconstruction algorithm, and may result in poor boundary delineation, and hence was unreliable. TSAC showed reasonable performance but required further optimization of the default segmentation setting. A minimum transmission scan time of 20 min is recommended for Clairvivo-PET using 137 Cs source to ensure that sufficient transmission counts are obtained to generate accurate attenuation coefficient map.

  4. Squeezing, photon bunching, photon antibunching and nonclassical photon statistics in degenerate hyper Raman processes

    International Nuclear Information System (INIS)

    Sen, Biswajit; Mandal, Swapan

    2007-01-01

    An initially prepared coherent state coupled to a second-order nonlinear medium is responsible for stimulated and spontaneous hyper Raman processes. By using an intuitive approach based on perturbation theory, the Hamiltonian corresponding to the hyper Raman processes is analytically solved to obtain the temporal development of the field operators. It is true that these analytical solutions are valid for small coupling constants. However, the interesting part is that these solutions are valid for reasonably large time. Hence, the present analytical solutions are quite general and are fresh compared to those solutions under short-time approximations. By exploiting the analytical solutions of field operators for various modes, we investigate the squeezing, photon antibunching and nonclassical photon statistics for pure modes of the input coherent light responsible for hyper Raman processes. At least in one instance (stimulated hyper Raman processes for vibration phonon mode), we report the simultaneous appearance of classical (photon bunching) and nonclassical (squeezing) effects of the radiation field responsible for hyper Raman processes

  5. Determination of scatter factor parameters and electron disequilibrium for monoenergetic photon beams.

    Science.gov (United States)

    McDonough, J; Bloch, P; Bjärngard, B E

    1999-02-01

    The tissue-phantom-ratio (TPR) is expressed as the product of the phantom scatter factor (SF), an electron disequilibrium factor, and an attenuation factor, equal to the zero-area TPR. The scatter factor, as a function of depth d and field size s, has been described by two parameters a and w, SF(d,s) = 1 + asd/(ws + d). We have determined the parameters a and w for 20 monoenergetic photon beams between 1 and 20 MeV. Pencil-beam energy-deposition kernels were obtained using Monte Carlo simulations. The kernels were used to calculate broad-beam depth-dose data, which were converted to TPR and fitted to the equation above using an iterative search over a-w space. The parameter a is nearly equal to the attenuation coefficient for all energies while the parameter w increases with energy. The resulting a and w compare favorably to values determined for clinical photon beams, as a function of the measured attenuation coefficient. With the scatter factor determined, we isolated the electron disequilibrium factor for each monoenergetic beam. It can be characterized as a quadratic function of the depth. The coefficients of the quadratic function can be related to the range of the most energetic secondary electron produced.

  6. Image reconstruction in single photon emission computed tomography for radioactive waste testing

    International Nuclear Information System (INIS)

    Pouletaut, P.

    1993-02-01

    The aim of this study is to reconstruct by tomography the spatial distribution of the activity of an object which emits photons. First, an analysis of the imaging qualities of a tomograph in terms of physical parameters related to the measurement process is proposed. Then, an algorithm which evaluates, the self-attenuation of the emitted photons and corrects for the collimator aperture angle is developed; this computation corresponds to a subdivision of the object into voxels and to a parallel geometry of the projections. Two algebraic reconstruction methods have been studied; one using a regularized least-squares technique, the other using a bayesian approach. We show by computer simulations the dependence of the reconstruction on the condition number of the self-attenuation matrix and on the estimation errors of this matrix. Then, the reconstruction is tested on experimental data; the images we reconstruct on a square grid of ten by ten voxels from one hundred twenty measurements show an accurate location of the sources; their activities are efficiently estimated when the collimator aperture angle is well taken into account in the self-attenuation matrix

  7. Transport and attenuation of radiations

    CERN Document Server

    Nimal, J C

    2003-01-01

    This article treats of the calculation methods used for the dimensioning of the protections against radiations. The method consists in determining for a given point the flux of particles coming from a source at a given time. A strong attenuation (of about some few mu Sv.h sup - sup 1) is in general expected between the source and the areas accessible to the personnel or the public. The calculation has to take into account a huge number of radiation-matter interactions and to solve the integral-differential transport equation which links the particles flux to the source. Several methods exist from the simplified physical model with numerical developments to the more or less precise resolution of the transport equation. These methods allows also the calculation of the uncertainties of equivalent dose rates, heat sources, structure damages using the data covariances (efficient cross-sections, modeling, etc..): 1 - transport equation; 2 - Monte-Carlo method; 3 - semi-numerical methods S sub N; 4 - methods based o...

  8. Beta attenuation transmission system (BATS)

    International Nuclear Information System (INIS)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm 2 , of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A 90 Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (μP) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined

  9. Theory of fluorescence in photonic crystals

    International Nuclear Information System (INIS)

    Vats, Nipun; John, Sajeev; Busch, Kurt

    2002-01-01

    We present a formalism for the description of fluorescence from optically active materials embedded in a photonic crystal structure possessing a photonic band gap or pseudogap. An electromagnetic field expansion in terms of Bloch modes of the crystal is used to develop the equations for fluorescence in terms of the local density of photon modes available to the emitting atoms in either the high or low dielectric regions of the crystal. We then obtain expressions for fluorescence spectra and emission dynamics for luminescent materials in photonic crystals. The validity of our formalism is demonstrated through the calculation of relevant quantities for model photon densities of states. The connection of our calculations to the description of realistic systems is discussed. We also describe the consequences of these analyses on the accurate description of the interaction between radiative systems and the electromagnetic reservoir within photonic crystals

  10. Hybrid colloidal plasmonic-photonic crystals.

    Science.gov (United States)

    Romanov, Sergei G; Korovin, Alexander V; Regensburger, Alois; Peschel, Ulf

    2011-06-17

    We review the recently emerged class of hybrid metal-dielectric colloidal photonic crystals. The hybrid approach is understood as the combination of a dielectric photonic crystal with a continuous metal film. It allows to achieve a strong modification of the optical properties of photonic crystals by involving the light scattering at electronic excitations in the metal component into moulding of the light flow in series to the diffraction resonances occurring in the body of the photonic crystal. We consider different realizations of hybrid plasmonic-photonic crystals based on two- and three-dimensional colloidal photonic crystals in association with flat and corrugated metal films. In agreement with model calculations, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tuneable functionality of these crystals. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Photonics Applications and Web Engineering: WILGA 2017

    Science.gov (United States)

    Romaniuk, Ryszard S.

    2017-08-01

    XLth Wilga Summer 2017 Symposium on Photonics Applications and Web Engineering was held on 28 May-4 June 2017. The Symposium gathered over 350 participants, mainly young researchers active in optics, optoelectronics, photonics, modern optics, mechatronics, applied physics, electronics technologies and applications. There were presented around 300 oral and poster papers in a few main topical tracks, which are traditional for Wilga, including: bio-photonics, optical sensory networks, photonics-electronics-mechatronics co-design and integration, large functional system design and maintenance, Internet of Things, measurement systems for astronomy, high energy physics experiments, and other. The paper is a traditional introduction to the 2017 WILGA Summer Symposium Proceedings, and digests some of the Symposium chosen key presentations. This year Symposium was divided to the following topical sessions/conferences: Optics, Optoelectronics and Photonics, Computational and Artificial Intelligence, Biomedical Applications, Astronomical and High Energy Physics Experiments Applications, Material Research and Engineering, and Advanced Photonics and Electronics Applications in Research and Industry.

  12. Quantum-dot based photonic quantum networks

    Science.gov (United States)

    Lodahl, Peter

    2018-01-01

    Quantum dots (QDs) embedded in photonic nanostructures have in recent years proven to be a very powerful solid-state platform for quantum optics experiments. The combination of near-unity radiative coupling of a single QD to a photonic mode and the ability to eliminate decoherence processes imply that an unprecedent light-matter interface can be obtained. As a result, high-cooperativity photon-emitter quantum interfaces can be constructed opening a path-way to deterministic photonic quantum gates for quantum-information processing applications. In the present manuscript, I review current state-of-the-art on QD devices and their applications for quantum technology. The overarching long-term goal of the research field is to construct photonic quantum networks where remote entanglement can be distributed over long distances by photons.

  13. Engineering photonic density of states using metamaterials

    DEFF Research Database (Denmark)

    Jacob, Z.; Kim, J.Y.; Naik, G.V.

    2010-01-01

    The photonic density of states (PDOS), like its electronic counterpart, is one of the key physical quantities governing a variety of phenomena and hence PDOS manipulation is the route to new photonic devices. The PDOS is conventionally altered by exploiting the resonance within a device such as a......The photonic density of states (PDOS), like its electronic counterpart, is one of the key physical quantities governing a variety of phenomena and hence PDOS manipulation is the route to new photonic devices. The PDOS is conventionally altered by exploiting the resonance within a device...... such as a microcavity or a bandgap structure like a photonic crystal. Here we show that nanostructured metamaterials with hyperbolic dispersion can dramatically enhance the photonic density of states paving the way for metamaterial-based PDOS engineering....

  14. Quantum delocalization in photon-pair generation

    Science.gov (United States)

    Forbes, Kayn A.; Ford, Jack S.; Jones, Garth A.; Andrews, David L.

    2017-08-01

    The generation of correlated photon pairs is a key to the production of entangled quantum states, which have a variety of applications within the area of quantum information. In spontaneous parametric down-conversion—the primary method of generating correlated photon pairs—the associated photon annihilation and creation events are generally thought of as being colocated: The correlated pair of photons is localized with regards to the pump photon and its positional origin. A detailed quantum electrodynamical analysis highlights a mechanism exhibiting the possibility of a delocalized origin for paired output photons: The spatial extent of the region from which the pair is generated can be much larger than previously thought. The theory of both localized and nonlocalized degenerate down-conversion is presented, followed by a quantitative analysis using discrete-volume computational methods. The results may have significant implications for quantum information and imaging applications, and the design of nonlinear optical metamaterials.

  15. Massive hidden photons as lukewarm dark matter

    International Nuclear Information System (INIS)

    Redondo, Javier; Postma, Marieke

    2008-11-01

    We study the possibility that a keV-MeV mass hidden photon (HP), i.e. a hidden sector U(1) gauge boson, accounts for the observed amount of dark matter. We focus on the case where the HP interacts with the standard model sector only through kinetic mixing with the photon. The relic abundance is computed including all relevant plasma effects into the photon's self-energy, which leads to a resonant yield almost independent of the HP mass. The HP can decay into three photons. Moreover, if light enough it can be copiously produced in stars. Including bounds from cosmic photon backgrounds and stellar evolution, we find that the hidden photon can only give a subdominant contribution to the dark matter. This negative conclusion may be avoided if another production mechanism besides kinetic mixing is operative. (orig.)

  16. Spectroscopy by frequency entangled photon pairs

    OpenAIRE

    Yabushita, Atsushi; Kobayashi, Takayoshi

    2003-01-01

    Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler photon detector, and the frequency of signal photons was resolved by a diffraction grating. The absorption spectrum of the sample was measured by counting the coincidences, and the result is in agreement with the one measured by a conventional spectrophotometer with a classical light source.

  17. Generating single microwave photons in a circuit.

    Science.gov (United States)

    Houck, A A; Schuster, D I; Gambetta, J M; Schreier, J A; Johnson, B R; Chow, J M; Frunzio, L; Majer, J; Devoret, M H; Girvin, S M; Schoelkopf, R J

    2007-09-20

    Microwaves have widespread use in classical communication technologies, from long-distance broadcasts to short-distance signals within a computer chip. Like all forms of light, microwaves, even those guided by the wires of an integrated circuit, consist of discrete photons. To enable quantum communication between distant parts of a quantum computer, the signals must also be quantum, consisting of single photons, for example. However, conventional sources can generate only classical light, not single photons. One way to realize a single-photon source is to collect the fluorescence of a single atom. Early experiments measured the quantum nature of continuous radiation, and further advances allowed triggered sources of photons on demand. To allow efficient photon collection, emitters are typically placed inside optical or microwave cavities, but these sources are difficult to employ for quantum communication on wires within an integrated circuit. Here we demonstrate an on-chip, on-demand single-photon source, where the microwave photons are injected into a wire with high efficiency and spectral purity. This is accomplished in a circuit quantum electrodynamics architecture, with a microwave transmission line cavity that enhances the spontaneous emission of a single superconducting qubit. When the qubit spontaneously emits, the generated photon acts as a flying qubit, transmitting the quantum information across a chip. We perform tomography of both the qubit and the emitted photons, clearly showing that both the quantum phase and amplitude are transferred during the emission. Both the average power and voltage of the photon source are characterized to verify performance of the system. This single-photon source is an important addition to a rapidly growing toolbox for quantum optics on a chip.

  18. Photon Dispersion in a Supernova Core

    OpenAIRE

    Kopf, A.; Raffelt, G.

    1997-01-01

    While the photon forward-scattering amplitude on free magnetic dipoles (e.g. free neutrons) vanishes, the nucleon magnetic moments still contribute significantly to the photon dispersion relation in a supernova (SN) core where the nucleon spins are not free due to their interaction. We study the frequency dependence of the relevant spin susceptibility in a toy model with only neutrons which interact by one-pion exchange. Our approach amounts to calculating the photon absorption rate from the ...

  19. REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS

    Science.gov (United States)

    2017-09-01

    AFRL-RY-WP-TR-2017-0156 REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components...TITLE AND SUBTITLE REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER N/A...number 88ABW-2017-4071, Clearance Date 23 August 2017. Report contains color. 14. ABSTRACT Radio Frequency (RF) photonics can be used for multiple

  20. Review of Radio Frequency Photonics Basics

    Science.gov (United States)

    2017-09-06

    AFRL-RY-WP-TR-2017-0157 REVIEW OF RADIO FREQUENCY PHOTONICS BASICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components & Subsystems...Final March 1, 2007 – July 31, 2017 4. TITLE AND SUBTITLE REVIEW OF RADIO FREQUENCY PHOTONICS BASICS 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER...display or disclose the work. PAO case number 88ABW-2017-4067, Clearance Date 23 August 2017. Report contains color. 14. ABSTRACT Photonics can operate

  1. Exclusive hadron production in two photon reactions

    International Nuclear Information System (INIS)

    Poppe, M.

    1986-02-01

    This paper summarises experimental results on exclusive hadron production in two photon collisions at electron positron storage rings and attempts some interpretation. Experimental know how is described and new suggestions are made for future analyses. New model calculations on resonance form factors and pair production amplitudes are presented. The two photon vertex is decomposed such that experiments can be parameterised with the minimal number of free parameters. Selection rules for off shell photon collisions are given in addition to Yang's theorems. (orig.)

  2. Architectural Considerations for Photonic Switching Networks

    OpenAIRE

    Hinton, Harvard S.

    1988-01-01

    Photonic technologies are reviewed that could become important components of future telecommunication systems. Photonic devices and systems are divided into two classes according to the function they perform. The first class, relational, refers to devices, that map the input channels to the output channels under external control. The second class, logic, perform some type or combination of Boolean logic functions. Some of the strengths and weaknesses of operating in the photonic domain are pr...

  3. Photon Linear Collider Gamma-Gamma Summary

    International Nuclear Information System (INIS)

    Gronberg, J.

    2012-01-01

    High energy photon - photon collisions can be achieved by adding high average power short-pulse lasers to the Linear Collider, enabling an expanded physics program for the facility. The technology required to realize a photon linear collider continues to mature. Compton back-scattering technology is being developed around the world for low energy light source applications and high average power lasers are being developed for Inertial Confinement Fusion.

  4. Number Albedo of Low-Energy Photons

    International Nuclear Information System (INIS)

    Ljubenov, V.; Simovic, R.; Markovic, S.

    2007-01-01

    Number albedo of water, aluminum and iron for incident photons in energy range from 20 keV to 100 keV is presented in this paper. Results are obtained through the Monte Carlo simulations of photon reflection by using the MCNP, FOTELP and PENELOPE computer codes. Calculated values are compared with the classical data published by B. P. Bulatov and his collaborators. Influence of the fluorescence yield to the photon number albedo of iron target is analyzed in detail. (author)

  5. Laser and photonic systems design and integration

    CERN Document Server

    Nof, Shimon Y; Cheng, Gary J

    2014-01-01

    New, significant scientific discoveries in laser and photonic technologies, systems perspectives, and integrated design approaches can improve even further the impact in critical areas of challenge. Yet this knowledge is dispersed across several disciplines and research arenas. Laser and Photonic Systems: Design and Integration brings together a multidisciplinary group of experts to increase understanding of the ways in which systems perspectives may influence laser and photonic innovations and application integration.By bringing together chapters from leading scientists and technologists, ind

  6. Photonics

    Science.gov (United States)

    1991-01-01

    Optoelectronic materials and devices are examined. Optoelectronic devices, which generate, detect, modulate, or switch electromagnetic radiation are being developed for a variety of space applications. The program includes spatial light modulators, solid state lasers, optoelectronic integrated circuits, nonlinear optical materials and devices, fiber optics, and optical networking photovoltaic technology and optical processing.

  7. Jaynes-Cummings photonic superlattices.

    Science.gov (United States)

    Longhi, Stefano

    2011-09-01

    A classical realization of the Jaynes-Cummings (JC) model, describing the interaction of a two-level atom with a quantized cavity mode, is proposed based on light transport in engineered waveguide superlattices. The optical setting enables us to visualize in Fock space dynamical regimes not yet accessible in quantum systems, providing new physical insights into the deep strong coupling regime of the JC model. In particular, bouncing of photon number wave packets in Hilbert space and revivals of populations are explained as generalized Bloch oscillations in an inhomogeneous tight-binding lattice.

  8. Jaynes--Cummings photonic superlattices

    Science.gov (United States)

    Longhi, Stefano

    2011-09-01

    A classical realization of the Jaynes--Cummings (JC) model, describing the interaction of a two-level atom with a quantized cavity mode, is proposed based on light transport in engineered waveguide superlattices. The optical setting enables us to visualize in Fock space dynamical regimes not yet accessible in quantum systems, providing new physical insights into the deep strong coupling regime of the JC model. In particular, bouncing of photon number wave packets in Hilbert space and revivals of populations are explained as generalized Bloch oscillations in an inhomogeneous tight-binding lattice.

  9. Photonics for safety and security

    CERN Document Server

    Mignani, Anna Grazia; Tajani, Antonella

    2014-01-01

    This volume aims to illustrate the state-of-the-art as well as the newest and latest applications of photonics in safety and security. The contributions from renowned and experienced Italian and international scientists, both from the academic and industrial community, present a multidisciplinary and comprehensive overview of this popular topic. The volume is self-contained and offers a broad survey of the various emerging technologies, as well as their applications in the real world. It spans from applications in cultural heritage, to environment, space, monitoring of coasts, quantum cryptogr

  10. A PHOTONIC BAND GAP FIBRE

    DEFF Research Database (Denmark)

    1999-01-01

    An optical fibre having a periodicidal cladding structure provididing a photonic band gap structure with superior qualities. The periodical structure being one wherein high index areas are defined and wherein these are separated using a number of methods. One such method is the introduction...... of additional low index elements, another method is providing elongated elements deformed in relation to a circular cross section. Also described is a cladding structure comprising elongated elements of a material having an index of refraction higher than that of the material adjacent thereto. Using...

  11. Introduction to THz wave photonics

    CERN Document Server

    Zhang, X-C

    2009-01-01

    Introduction to THz Wave Photonics examines the science and technology related to terahertz wave technologies, taking a dual approach between presenting the field 's history while simultaneously providing an overview of existing technology. The latest research in developing THz areas such as electromagnetic waves are presented, along with an introduction to continuous wave THz technology. Authors X.-C. Zhang and Jingzhou Xu place particular emphasis on pulsed THz technology, among many other facets of THz technology including: Complete coverage of THz wave spectroscopy and imagingA discussion

  12. Gasdynamic lasers and photon machines.

    Science.gov (United States)

    Christiansen, W. H.; Hertzberg, A.

    1973-01-01

    The basic operational highlights of CO2-N2 gasdynamic lasers (GDL's) are described. Features common to powerful gas lasers are indicated. A simplified model of the vibrational kinetics of the system is presented, and the importance of rapid expansion nozzles is shown from analytic solutions of the equations. A high-power pulsed GDL is described, along with estimations of power extraction. A closed-cycle laser is suggested, leading to a description of a photon generator/engine. Thermodynamic analysis of the closed-cycle laser illustrates in principle the possibility of direct conversion of laser energy to work.

  13. Organic Thin Films for Photonics Applications

    National Research Council Canada - National Science Library

    Thorner, John

    1999-01-01

    The Organic Thin Films for Photonics Applications Topical Meeting provided an interdisciplinary forum for the presentation and discussion of new and previously unpublished results on advanced organic...

  14. Progress in photon science basics and applications

    CERN Document Server

    2017-01-01

    This book features chapters based on lectures presented by world-leading researchers of photon science from Russia and Japan at the first “STEPS Symposium on Photon Science” held in Tokyo in March 2015. It describes recent progress in the field of photon science, covering a wide range of interest to experts in the field, including laser-plasma interaction, filamentation and its applications, laser assisted electron scattering, exotic properties of light, ultrafast imaging, molecules and clusters in intense laser fields, photochemistry and spectroscopy of novel materials, laser-assisted material synthesis, and photon technology.

  15. Entangled-photon compressive ghost imaging

    International Nuclear Information System (INIS)

    Zerom, Petros; Chan, Kam Wai Clifford; Howell, John C.; Boyd, Robert W.

    2011-01-01

    We have experimentally demonstrated high-resolution compressive ghost imaging at the single-photon level using entangled photons produced by a spontaneous parametric down-conversion source and using single-pixel detectors. For a given mean-squared error, the number of photons needed to reconstruct a two-dimensional image is found to be much smaller than that in quantum ghost imaging experiments employing a raster scan. This procedure not only shortens the data acquisition time, but also suggests a more economical use of photons for low-light-level and quantum image formation.

  16. Hybrid Integrated Platforms for Silicon Photonics

    Science.gov (United States)

    Liang, Di; Roelkens, Gunther; Baets, Roel; Bowers, John E.

    2010-01-01

    A review of recent progress in hybrid integrated platforms for silicon photonics is presented. Integration of III-V semiconductors onto silicon-on-insulator substrates based on two different bonding techniques is compared, one comprising only inorganic materials, the other technique using an organic bonding agent. Issues such as bonding process and mechanism, bonding strength, uniformity, wafer surface requirement, and stress distribution are studied in detail. The application in silicon photonics to realize high-performance active and passive photonic devices on low-cost silicon wafers is discussed. Hybrid integration is believed to be a promising technology in a variety of applications of silicon photonics.

  17. Nonlinear Photonics and Novel Optical Phenomena

    CERN Document Server

    Morandotti, Roberto

    2012-01-01

    Nonlinear Photonics and Novel Optical Phenomena contains contributed chapters from leading experts in nonlinear optics and photonics, and provides a comprehensive survey of fundamental concepts as well as hot topics in current research on nonlinear optical waves and related novel phenomena. The book covers self-accelerating airy beams, integrated photonics based on high index doped-silica glass, linear and nonlinear spatial beam dynamics in photonic lattices and waveguide arrays, polariton solitons and localized structures in semiconductor microcavities, terahertz waves, and other novel phenomena in different nanophotonic and optical systems.

  18. Search for chameleon particles via photon regeneration

    International Nuclear Information System (INIS)

    Chou, Aaron S.; CCPP, New York U.

    2008-01-01

    We report the first results from the GammeV search for chameleon particles, which may be created via photon-photon interactions within a strong magnetic field. The chameleons are assumed to have matter effects sufficiently strong that they reflect from all solid surfaces of the apparatus, thus evading detection in our previous search for weakly-interacting axion-like particles. We implement a novel technique to create and trap the reflective particles within a jar and to detect them later via their afterglow as they slowly convert back into photons. These measurements provide the first experimental constraints on the couplings of chameleons to photons

  19. Changing optical band structure with single photons

    Science.gov (United States)

    Albrecht, Andreas; Caneva, Tommaso; Chang, Darrick E.

    2017-11-01

    Achieving strong interactions between individual photons enables a wide variety of exciting possibilities in quantum information science and many-body physics. Cold atoms interfaced with nanophotonic structures have emerged as a platform to realize novel forms of nonlinear interactions. In particular, when atoms are coupled to a photonic crystal waveguide, long-range atomic interactions can arise that are mediated by localized atom-photon bound states. We theoretically show that in such a system, the absorption of a single photon can change the band structure for a subsequent photon. This occurs because the first photon affects the atoms in the chain in an alternating fashion, thus leading to an effective period doubling of the system and a new optical band structure for the composite atom-nanophotonic system. We demonstrate how this mechanism can be engineered to realize a single-photon switch, where the first incoming photon switches the system from being highly transmissive to highly reflective, and analyze how signatures can be observed via non-classical correlations of the outgoing photon field.

  20. Oblique photon expansion of QED structure functions

    International Nuclear Information System (INIS)

    Chahine, C.

    1986-01-01

    In the oblique photon expansion, the collinear part of photon emission is summed up to all orders in perturbation theory. The number of oblique or non-collinear photons is the expansion order. Unlike in perturbation theory, every term of the expansion is both infrared finite and gauge invariant. The zero oblique photon contribution to the electromagnetic structure tensor in QED is computed in detail. The behaviors of the structure functions F1 and F2 are discussed in the soft and ultra-soft limits

  1. Photonics Technology Development for Optical Fuzing

    National Research Council Canada - National Science Library

    VON DER Lippe, Christian M; Keeler, G. A; Serkland, D. K; Geib, K. M; Peake, G. M; Mar, A; Jiang Liu, J

    2004-01-01

    This paper describes the photonic component development, which exploits pioneering work and unique expertise at Sandia National Laboratories, ARDEC and the Army Research Laboratory by combining key...

  2. Silicon photonics III systems and applications

    CERN Document Server

    Lockwood, David

    2016-01-01

    This book is volume III of a series of books on silicon photonics. It reports on the development of fully integrated systems where many different photonics component are integrated together to build complex circuits. This is the demonstration of the fully potentiality of silicon photonics. It contains a number of chapters written by engineers and scientists of the main companies, research centers and universities active in the field. It can be of use for all those persons interested to know the potentialities and the recent applications of silicon photonics both in microelectronics, telecommunication and consumer electronics market.

  3. Optical trapping apparatus, methods and applications using photonic crystal resonators

    Science.gov (United States)

    Erickson, David; Chen, Yih-Fan

    2015-06-16

    A plurality of photonic crystal resonator optical trapping apparatuses and a plurality optical trapping methods using the plurality of photonic crystal resonator optical trapping apparatuses include located and formed over a substrate a photonic waveguide that is coupled (i.e., either separately coupled or integrally coupled) with a photonic crystal resonator. In a particular embodiment, the photonic waveguide and the photonic crystal resonator comprise a monocrystalline silicon (or other) photonic material absent any chemical functionalization. In another particular embodiment, the photonic waveguide and the photonic crystal resonator comprise a silicon nitride material which when actuating the photonic crystal resonator optical trapping apparatus with a 1064 nanometer resonant photonic radiation wavelength (or other resonant photonic radiation wavelength in a range from about 700 to about 1200 nanometers) provides no appreciable heating of an aqueous sample fluid that is analyzed by the photonic crystal resonator optical trapping apparatus.

  4. Energy dependence of effective atomic numbers for photon energy absorption and photon interaction: Studies of some biological molecules in the energy range 1 keV-20 MeV

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2008-01-01

    Effective atomic numbers for photon energy absorption, Z(PEA,eff), and for photon interaction, Z(PI,eff), have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for biological molecules, such as fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic...... dependence of the mass attenuation coefficient, Z(PEA, eff), and the mass energy-absorption coefficient, Z(PI, eff), is shown graphically and in tabular form. Significant differences of 17%-38% between Z(PI, eff) and Z(PEA, eff) occur in the energy region 5-100 keV. The reasons for these differences...

  5. Limits on the photon mass; Limites sur la masse du photon

    Energy Technology Data Exchange (ETDEWEB)

    Vasseur, G.

    1996-03-01

    Is the photon mass strictly null as it is told in quantum electrodynamics. In fact, a coherent theory can be build with a massive photon. Experiences have been regularly led to try to make obvious an eventual non null photon mass. Superior limits more and more strict have been found. Here is given a general survey of the consequences of a non null photon mass, different methods to measure it and the achieved limits. (author). 30 refs., 1 fig.

  6. Attenuation caused by infrequently updated covariates in survival analysis

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Liestøl, Knut

    2003-01-01

    Attenuation; Cox regression model; Measurement errors; Survival analysis; Time-dependent covariates......Attenuation; Cox regression model; Measurement errors; Survival analysis; Time-dependent covariates...

  7. Modelling and design of complete photonic band gaps in two ...

    Indian Academy of Sciences (India)

    Photonic crystal; complete photonic band gap; plane-wave expansion method. PACS Nos 71.20; 42.70.Q. 1. Introduction. Photonic band gap structures/photonic crystals, especially two-dimensional (2D) photonic crystals, which are dielectric structures periodic on length scale, have recently achieved much attention, as they ...

  8. Integrating optical emitters into silicon photonic waveguides

    Science.gov (United States)

    Milgram, Joel

    This thesis reports work targeting the integration of Si light emitters with optical waveguides. Such integrated devices would find utility in a number of applications including telecommunications, optical interconnects, and biological and chemical sensors. Much research has been directed by others on how to improve the emission efficiency and achieve lasing in VLSI (very large scale integration) compatible sources. Here, the focus is on how such devices can be integrated with planar waveguides. Two enhancement techniques were selected for potential integration; defect engineering (DE), and Si nanocrystals (Si-nc) embedded in SOI2. Defect engineered light emitting diodes (LEDs) made on silicon-on-insulator (SOI) and emitting at 1.1 mum were successfully demonstrated. In addition, surface photoluminescence from SOI was analyzed to account for interference from the SOI cavity. However, it was determined that the emission efficiency of defect engineered LEDs studied during the course of this work is below that which was reported previously, and that the fabrication procedure thus suffers from irreproducibility. Barring an enormous advancement in the DE technique, it is concluded that the emission efficiency is too small to make use of its integration potential. A more successful approach was obtained from the Si-nc system fabricated using electron-cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD). Optically pumped edge emitting devices were designed, fabricated and characterized. The devices are comprised of Si-ncs emitting at 800 nm, integrated with slab silicon nitride waveguides. This work is the first report of edge emission from Si-ncs integrated with silicon nitride waveguides. Edge emission and waveguide properties were characterized in the ˜850 nm emission band of the Si-ncs, The edge emission was well described as a propagating mode, attenuated primarily by the Si-nc film. Propagation losses of a typical air/Si-nc/SiNx/SiO2 waveguide

  9. Single-photon detector operating under extremely high background photon flux conditions

    International Nuclear Information System (INIS)

    Prochazka, Ivan; Sopko, Bruno; Blazej, Josef

    2009-01-01

    We are reporting our results in research and development in the field of avalanche semiconductor single-photon detectors and their application. Our goal was a development of a solid-state photon-counting detector capable of high-precision photon arrival time tagging in extremely harsh operating conditions. The background photon flux exceeding 10 9 photons per second hitting the detector active area should not avoid the useful signal detection and recognition on the signal level of units of photons per second. This is background photon flux about two orders of magnitude higher than what the conventional solid-state photon counters accept. The detection timing resolution should be better than 100 ps and the delay stability should be on picosecond level. We have developed and tested the active quenched and gated avalanche structure on silicon providing the required features in connection with the K14 detection chips. The detector is capable of gated operation under the conditions of background photon flux of 5x10 9 photons per second. The operational detector tolerates long term exposures to the input photon flux exceeding 10 15 photons (>1 mW) per second without damage.

  10. Photon statistics in the three-photon hyper-Raman process

    OpenAIRE

    Sainz de los Terreros, L.; Santos, M.; González-Díaz, Pedro F.

    1985-01-01

    An exact solution of the master equation for the three-photon hyper-Raman process is obtained by a matrix method. Several cases of the photon statistics are considered and the appearance of photon-antibunching effect and the violation of the classical Cauchy inequality are discussed. © 1985 The American Physical Society.

  11. Photonic compressive sensing with a micro-ring-resonator-based microwave photonic filter

    DEFF Research Database (Denmark)

    Chen, Ying; Ding, Yunhong; Zhu, Zhijing

    2015-01-01

    A novel approach to realize photonic compressive sensing (CS) with a multi-tap microwave photonic filter is proposed and demonstrated. The system takes both advantages of CS and photonics to capture wideband sparse signals with sub-Nyquist sampling rate. The low-pass filtering function required...

  12. A high-efficiency electrically-pumped single-photon source based on a photonics nanowire

    DEFF Research Database (Denmark)

    Gregersen, Niels; Nielsen, Torben Roland; Mørk, Jesper

    An electrically-pumped single-photon source design with a predicted efficiency of 89% is proposed. The design is based on a quantum dot embedded in a photonic nanowire with tailored ends and optimized contact electrodes. Unlike cavity-based approaches, the photonic nanowire features broadband...

  13. Large field enhancement obtained by combining Fabry-Perot resonance and Rayleigh anomaly in photonic crystal slabs

    Science.gov (United States)

    Dossou, Kokou B.

    2017-04-01

    By applying the properties of Fabry-Perot resonance and Rayleigh anomaly, we have shown that a photonic crystal slab can scatter the light from an incident plane wave into a diffracted light with a very large reflection or transmission coefficient. The enhanced field is either a propagating diffracted wave (with a grazing angle of diffraction) or a weakly evanescent diffracted wave, so it can be particularly useful for applications requiring an enhanced propagating field (or an enhanced field with a low attenuation). An efficient effective medium technique is developed for the design of the resonant photonic crystal slabs. Numerical simulations have shown that photonic crystal slabs with low index contrast, such as the ones found in the cell wall of diatoms, can enhance the intensity of the incident light by four orders of magnitude.

  14. arXiv Photon detector system performance in the DUNE 35-ton prototype liquid argon time projection chamber

    CERN Document Server

    Adams, D.L.; Anderson, J.T.; Bagby, L.; Baird, M.; Barr, G.; Barros, N.; Biery, K.; Blake, A.; Blaufuss, E.; Boone, T.; Booth, A.; Brailsford, D.; Buchanan, N.; Chatterjee, A.; Convery, M.; Davies, J.; Dealtry, T.; DeLurgio, P.; Deuerling, G.; Dharmapalan, R.; Djurcic, Z.; Drake, G.; Eberly, B.; Freeman, J.; Glavin, S.; Gomes, R.A.; Goodman, M.C.; Graham, M.; Hahn, A.; Haigh, J.T.; Hartnell, J.; Higuera, A.; Himmel, A.; Insler, J.; Jacobsen, J.; Junk, T.; Kirby, B.; Klein, J.; Kudryavtsev, V.A.; Kutter, T.; Li, Y.; Li, X.; Lin, S.; Martin-Albo, J.; McConkey, N.; Moura, C.A.; Mufson, S.; Nicholls, T.C.; Nowak, J.; Oberling, M.; Paley, J.; Qian, X.; Raaf, J.L.; Rivera, D.; Santucci, G.; Sinev, G.; Spooner, N.J. C.; Stancari, M.; Stancu, I.; Stefan, D.; Stewart, J.; Stock, J.; Strauss, T.; Sulej, R.; Sun, Y.; Thiesse, M.; Thompson, L.F.; Tsai, Y.T.; Wallbank, M.; Warburton, T.K.; Warner, D.; Whittington, D.; Wilson, R.J.; Worcester, M.; Worcester, E.; Yang, T.; Zhang, C.

    The 35-ton prototype for the Deep Underground Neutrino Experiment far detector was a single-phase liquid argon time projection chamber with an integrated photon detector system, all situated inside a membrane cryostat. The detector took cosmic-ray data for six weeks during the period of February 1, 2016 to March 12, 2016. The performance of the photon detection system was checked with these data. An installed photon detector was demonstrated to measure the arrival times of cosmic-ray muons with a resolution better than 32 ns, limited by the timing of the trigger system. A measurement of the timing resolution using closely-spaced calibration pulses yielded a resolution of 15 ns for pulses at a level of 6 photo-electrons. Scintillation light from cosmic-ray muons was observed to be attenuated with increasing distance with a characteristic length of $155 \\pm 28$ cm.

  15. Photon Factory activity report, 1988

    International Nuclear Information System (INIS)

    1989-01-01

    Since the foundation of Photon Factory a decade age, it has played an important role as a unique synchrotron X-ray radiation source in Japan. Installation of various insertion devices, storage of intense positron beam and reduction of beam emittance were the substantial achievements in the last several years. The exploitation of the TRISTAN Accumulation Ring as a synchrotron radiation source has paved the way for a new potential of development. All these activities have brought about the increase of beamlines and the expansion of scientific fronts. Third International Conference on Synchrotron Radiation Instrumentation held in Tsukuba was one of the most highlighted events for the facility. In coming years, it is intended to open new research fields using the promising single bunch beam and circularly polarized wiggler radiation. The TRISTAN Main Ring also will be applied to synchrotron radiation research. The Photon Factory in a national synchrotron radiation research facility affiliated to the National Laboratory for High Energy Physics, and it consists of a 2.5 GeV electron linac, a 2.5 GeV storage ring as a synchrotron light source, beam lines and experimental stations. The operation, improvement and development in respective departments are reported. (Kako, I.)

  16. Focus issue introduction: nonlinear photonics.

    Science.gov (United States)

    Akhmediev, Nail; Rottwitt, Karsten

    2012-11-19

    It is now 23 years since the first Topical Meeting "Nonlinear Guided Wave Phenomena" (Houston, TX, February 2-4, 1989) has been organised by George Stegeman and Allan Boardman with support of the Optical Society of America. These series of the OSA conferences known as NLGW, continued under the name "Nonlinear Photonics" starting from 2007. The latest one, in Colorado Springs in June 17-21, 2012 has been a great success despite the fierce fires advancing around the city at the time of the conference. This Focus issue is a collection of several papers presented at the conference with extended content submitted to Optics Express. Although this collection is small in comparison to the total number of papers presented at the conference, it gives a flavor of the topics considered at the meeting. It is also worthy to mention here that the next meeting "Nonlinear Photonics" is planned to be held in Barcelona - one of the main European centers on this subject.

  17. Photonic Crystals: Physics and Technology

    CERN Document Server

    Sibilia, Concita; Marciniak, Marian; Szoplik, Tomasz

    2008-01-01

    The aim of the work is give an overview of the activity in the field of Photonic Crystal developed in the frame of COST P11 action . The main objective of the COST P11 action was to unify and coordinate national efforts aimed at studying linear and nonlinear optical interactions with Photonic Crystals (PCs), without neglecting an important aspect related to the material research as idea and methods of realizations of 3D PC, together with the development and implementation of measurement techniques for the experimental evaluation of their potential applications in different area, as for example telecommunication with novel optical fibers, lasers, nonlinear multi-functionality, display devices , opto-electronics, sensors. The book contain contributions from authors who gave their lecture at the Cost P11 Training School. Training School was held at the Warsaw University (2007) and National Institute of Telecommunications (May 23), Warsaw. It was attended by 23 students. The focus of the School was on the work of...

  18. Photon and graviton mass limits

    Science.gov (United States)

    Goldhaber, Alfred Scharff; Nieto, Michael Martin

    2010-01-01

    Efforts to place limits on deviations from canonical formulations of electromagnetism and gravity have probed length scales increasing dramatically over time. Historically, these studies have passed through three stages: (1) testing the power in the inverse-square laws of Newton and Coulomb, (2) seeking a nonzero value for the rest mass of photon or graviton, and (3) considering more degrees of freedom, allowing mass while preserving explicit gauge or general-coordinate invariance. Since the previous review the lower limit on the photon Compton wavelength has improved by four orders of magnitude, to about one astronomical unit, and rapid current progress in astronomy makes further advance likely. For gravity there have been vigorous debates about even the concept of graviton rest mass. Meanwhile there are striking observations of astronomical motions that do not fit Einstein gravity with visible sources. “Cold dark matter” (slow, invisible classical particles) fits well at large scales. “Modified Newtonian dynamics” provides the best phenomenology at galactic scales. Satisfying this phenomenology is a requirement if dark matter, perhaps as invisible classical fields, could be correct here too. “Dark energy” might be explained by a graviton-mass-like effect, with associated Compton wavelength comparable to the radius of the visible universe. Significant mass limits are summarized in a table.

  19. Photon and graviton mass limits

    International Nuclear Information System (INIS)

    Goldhaber, Alfred Scharff; Nieto, Michael Martin

    2010-01-01

    Efforts to place limits on deviations from canonical formulations of electromagnetism and gravity have probed length scales increasing dramatically over time. Historically, these studies have passed through three stages: (1) testing the power in the inverse-square laws of Newton and Coulomb, (2) seeking a nonzero value for the rest mass of photon or graviton, and (3) considering more degrees of freedom, allowing mass while preserving explicit gauge or general-coordinate invariance. Since the previous review the lower limit on the photon Compton wavelength has improved by four orders of magnitude, to about one astronomical unit, and rapid current progress in astronomy makes further advance likely. For gravity there have been vigorous debates about even the concept of graviton rest mass. Meanwhile there are striking observations of astronomical motions that do not fit Einstein gravity with visible sources. ''Cold dark matter'' (slow, invisible classical particles) fits well at large scales. ''Modified Newtonian dynamics'' provides the best phenomenology at galactic scales. Satisfying this phenomenology is a requirement if dark matter, perhaps as invisible classical fields, could be correct here too. ''Dark energy''might be explained by a graviton-mass-like effect, with associated Compton wavelength comparable to the radius of the visible universe. Significant mass limits are summarized in a table.

  20. Photon and graviton mass limits

    Energy Technology Data Exchange (ETDEWEB)

    Nieto, Michael [Los Alamos National Laboratory; Goldhaber Scharff, Alfred [SUNY

    2008-01-01

    We review past and current studies of possible long-distance, low-frequency deviations from Maxwell electrodynamics and Einstein gravity. Both have passed through three phases: (1) Testing the inverse-square laws of Newton and Coulomb, (2) Seeking a nonzero value for the rest mass of photon or graviton, and (3) Considering more degrees of freedom, allowing mass while preserving gauge or general-coordinate invariance. For electrodynamics there continues to be no sign of any deviation. Since our previous review the lower limit on the photon Compton wavelength (associated with weakening of electromagnetic fields in vacuum over large distance scale) has improved by four orders of magnitude, to about one astronomical unit. Rapid current progress in astronomical observations makes it likely that there will be further advances. These ultimately could yield a bound exceeding galactic dimensions, as has long been contemplated. Meanwhile, for gravity there have been strong arguments about even the concept of a graviton rest mass. At the same time there are striking observations, commonly labeled 'dark matter' and 'dark energy' that some argue imply modified gravity. This makes the questions for gravity much more interesting. For dark matter, which involves increased attraction at large distances, any explanation by modified gravity would be qualitatively different from graviton mass. Because dark energy is associated with reduced attraction at large distances, it might be explained by a graviton-mass-like effect.