Tellurite Glass Optical Fiber Doped With Pbte Quantum Dots

We produced a PbTe quantum dot core doped optical fiber with tellurite glasses intended to be used in highly nonlinear ultrafast optical devices capable to operate at the optical communication window at 1300 and 1500 nm wavelength region. Attenuation peaks of the optical fiber depends on the heat treatment time as expected for dots growth and covered the whole mid infrared region near 1500 nm. The optical fiber preform was made with the rod-in-tube method and the fiber was produced with a 4 m high Heatway drawing tower. The optical fiber core can be heavily doped because tellurite glasses solubility for PbTe quantum dots is order of magnitude higher than borosilicate and phosphate glasses, for example. In order to match all the requirements for core-clad optical fibers we studied undoped and doped tellurite glasses optical and thermophysical properties as a function of the glass composition. We also followed the growth kinetics of the quantum dots by High Resolution Transmission Electron Microscopy in the bulk glass matrix and the optical fiber.5734124129Borrelli, N.F., Aitken, B.G., Newhouse, M.A., (1995) J. Non-cryst.Sol., p. 185Wise, F.W., (2000) Acc. Chem. Res., 33, p. 773Borrelli, N.F., Smith, D.W., (1994) J. Non-cryst. Sol., 180, p. 25Lipovskii, A., Kolobkova, E.A., Petrikov, V., Kang, I., Olkhovets, A., Krauus, T., Thomas, M., Kycia, S., (1997) Appl. Phys. Lett., 71, p. 3406Reynoso, V.C.S., De Paula, A.M., Cuevas, R.F., Neto, J.A.M., Alves, O.L., Cesar, C.L., Barbosa, L.C., (1995) Elect. Lett., 31 (12), pp. 1013-1014Rodriguez, E., Jimenez, E., Jacob, G.J., Neves, A., Cesar, C.L., Barbosa, L.C., Photonics West 2005, , poster 5734-22Jacob, G.J., Cesar, C.L., Barbosa, L.C., (2002) Physics and Chemistry of Glass, 43 C, pp. 250-253Tudury, G.E., Marquezini, M.V., Ferreira, L.G., Barbosa, L.C., Cesar, C.L., (2000) Phys. Rev. B, 62 (11), p. 7357Cho, S.J., Paek, U.C., Han, W.T., Heo, J., (2001) OFC2001, , ThC4-1 paperJu, S., Kim, Y.H., Han, W.T., (2004) ECOC2004, , Stockholm, Sweden, September 5-9, Th2.3.3 pape

One-dimensional Photonic Crystal For The 1.3-1.5 μm Region

Multilayer of PbTe quantum dots embedded in SiO2 were fabricated by alternatively use of Plasma Enhanced Chemical Vapor Deposition and Laser Ablation techniques. The optimal growing parameters for both the SiO2 films and the PbTe quantum dots were obtained. The refractive index and optical absorption of the sample were studied. Multilayer X-ray diffraction patterns were used to estimate the nanoparticles diameter. Morphological properties of the nanostructured material were studied using Transmission Electron Microscopy. Both absorption spectra and X-ray diffraction patterns reveled the nanoparticles are 6-8 nm in diameter, consequently appropriate for developing optical devices in the infra red region. Finally the multilayer was grown inside a Fabry Perot cavity. The transmittance of the one-dimensional photonic crystal was measured.6129Tsunetomo, K., Shunsuke, S., Koyama, T., Tanaka, S., Sasaki, F., Kobayashi, S., Ultrafast nonlinear optical response of CdTe microcrystallite-doped glasses fabricated by laser evaporation (1995) Molecular Crystals and Liquid Crystals Science and Technology Section B, Nonlinear Optics, 13 (1-3), pp. 109-126Gleiter, H., (1989) Prog. Mater. Sci., 33, p. 223Tudury, G.E., Marquezini, M.V., Ferreira, L.G., Barbosa, L.C., Cesar, C.L., Effect of band anisotropy on electronic structure of PbS, PbSe, and PbTe quantum dots (2000) Phys. Rev. B, 62 (11), pp. 7357-7364Rodriguez, E., Jimenez, E., Padilha, L.A., Neves, A.A.R., Jacob, G.J., Cesar, C.L., Barbosa, L.C., SiO2/PbTe quantum dots multilayer production and characterization (2005) Appl. Phys. Lett., 86, pp. 113117-113120Rodriguez, E., Jimenez, E., Cesar, C.L., Barbosa, L.C., 1D photonic band gap silica doped PbTe quantum dot optical device (2005) Glass Technology, 46 (2), pp. 47-49Rodriguez, E., Jimenez, E., Neves, A.A.R., Jacob, G.J., Cesar, C.L., Barbosa, L.C., Fabrication and characterization of PbTe quantum dot multilayers for Photonic Fabry-Perot Devices (2005) Physica E, 26, pp. 361-36

Ultra Large Amplification Bandwidth Of Er3+ And Tm3+ At S And L Band From Teo2-wo3-na2o-nb 2o5 Glass Doped Optical Fibers

Tellurite glasses optical fibers became promising for optical amplifiers due to its high rare earth ions solubility and very large amplification bandwidth. Among several tellurite glasses the TeO2-WO 3-Na2O-Nb2O5 system show one of the largest bandwidth. Our previous characterization of lifetime using the Ω2, Ω4, Ω6, Judd-Ofelt parameters indicate a quantum efficiency maximum for 7500ppm Er3+ concentration. Therefore we decided to produce jointed Er3+ and Tm3+ single mode optical fibers with this glass system keeping the 7500ppm Er3+ concentration and varying the Tm3+ concentration from 2500ppm to 15000ppm. This single mode fiber was pumped by 120mW of the semiconductor laser at 790nm and we observed a flat ASE bandwidth from 1400 to 1570nm for the 5000ppm Tm3+ concentration.5723243247Jeong, H., Oh, K., Han, S.R., Morse, T.F., Broadband amplified spontaneous emission from an Er3+-Tm 3+ - Codoped silica fibar (2003) Opt. Lett., 28, pp. 161-163Reisfeld, R., Jorgensen, C.K., (1987) Handbook on the Physics and Chemistry of Rare Earths, 9, pp. 1-90. , K. A. Gschneidner, Jr. and L. Eyring (Eds.), Elsevier ScienceChen, C.Y., Petrin, R.R., Yeh, D.C., Sibley, W.A., Concentration-dependent energy-transfer processes in Er3+-and Tm3+ -doped heavy-metal fluoride (1989) Opt. Lett., 14, pp. 432-434Miniscalco, W.J., Quimby, R.S., General procedure for the analysis of Er3+ cross sections (1991) Opt. Lett, 16, pp. 258-26

Pbte Quantum Dots - Sio2 Multilayers For Optical Devices Produced By Laser Ablation

Thin films of glass doped with PbTe quantum dots were successfully fabricated. The semiconducting quantum dots were grown by laser ablation of a PbTe target (99.99%) using the second harmonic of a Q-Switched Quantel Nd:YAG laser under high purity argon atmosphere. The glass matrix was fabricated by a plasma chemical vapor deposition method using vapor of tetramethoxysilane (TMOS) as precursor. The QD's and the glass matrix were alternately deposited onto a Si (100) wafer for 60 cycles. Cross-section TEM image clearly showed QD's layer well separated from each other with glass matrix layers. The influence of the ablation time on the size distribution of the quantum dots is studied. HRTEM revealed anisotropy in the size of the QD's: they were about 9nm in the high and 3-5 in diameter. Furthermore HRTEM studies revealed that the QD's basically growth in the (200) and (220) directions. The thickness of the glass matrix layer was about 20 nm. Absorption, photo luminescence and relaxation time of the multilayer were also measured.5734116123Alivisatos, A.P., (1996) Sci., 271, p. 933Warnock, J., Awschalom, D.D., (1985) Phys. Rev. B, 32, p. 5529Borrelli, N.F., May, D.W., Holland, H.J., Smith, D.W., (1987) J. Appl. Phys., 61, p. 399Potter, B.G., Simmons, J.H., (1988) Phys. Rev. B, 37, p. 10838Gleiter, H., (1989) Prog. Mater. Sci., 33, p. 223Tsunetomo, K., Shunsuke, S., Koyama, T., Tanaka, S., Sasaki, F., Kobayashi, S., (1995) Nonlinear Opt., 13, p. 109Reynoso, V.C.S., De Paula, A.M., Cuevas, R.F., Neto, J.A.M., Alves, O.L., Cesar, C.L., Barbosa, L.C., (1995) Electr. Lett., 31 (12), pp. 1013-1015Jacob, G.J., Cesar, C.L., Barbosa, L.C., (2002) Chem. Phys. Glass, 43 C, pp. 250-252Singh, R.K., Narayan, J., (1990) Phys. Rev. B, 41, p. 8843Barnes, J.P., (2002) Nanotechnology, 13, p. 465Tudury, G.E., Marquezini, M.V., Ferreira, L.G., Barbosa, L.C., Cesar, C.L., (2000) Phys. Rev. B, 62 (11), pp. 7357-7364Cesar, C.L., Jacob, G.J., Tudury, G.E., Marquezini, M.V., Barbosa, L.C., (2004) Atti della Fondazione G. Ronchi Journal, (4), pp. 519-528. , Anno LI

Carbon Nanotube Doped Tellurite Glasses

In the past it was observed that buck ball doped glasses showed enhanced optical nonlinearities. However, carbon nanotubes are much more stable than buck ball and should be a better choice for that purpose. Therefore we decided to investigate the possibility to produce carbon nanotubes doped tellurite glasses and measured their optical nonlinearities. Tellurite glasses already have a larger nonlinearity compared to silica, and other, glasses. We produced TeO 2-ZnO tellurite family glasses doped with multi wall Carbon Nanotube (CNT). The CNTs acquired from Carbolex were vigorously mechanically mixed with the tellurite glass precursors and melted in platinum crucible around 650°C in a controlled atmosphere inside an electrical induction furnace. We used the lowest temperature possible and controlled atmosphere to avoid the CNT oxidation. The glass melt was cast in a stainless steel and thermally treated at 300°C for 5 hours to relieve internal stresses. The samples were than cutted and polished to perform the optical characterization. We measured refractive index and thermo physical properties, such as vitreous transition Tg, crystallization onset Tx and melting Tf temperatures. Raman spectroscopy showed the possible presence of CNTs.6890Iijima, S., (1991) Nature, 354, p. 56http://www.ati.surrey.ac.uk/news/n, onlinearDiMaio, J., Rhyne, S., Yang, Z., Fu, K., Czerw, R., Xu, J., Webster, S., Ballato, J., (2003) Information Sciences, 149, p. 69Aoki, Y., Okubo, S., Kataura, H., Nagasawa, H., Achiba, Y., (2005) Chem. Lett, 34 (4), p. 562Misra, S.K., Watts, P.C.P., Valappil, S.P., Silva, S.R.P., Roy, I., Boccaccini, A.R., (2007) Nanotechnology, 18, p. 07570

Photothermal Spectroscopic Characterization In Teliurite Glasses Codoped With Rare-earth Ions

Thermal Lens (TL) and spectroscopic characterizations were performed in 70TeO2-19WO3-7Na2O-4Nb2O 5 (mol%) tellurite glasses. TL measurements were accomplished in Er3+/Tm3+ co-doped tellurite glasses in function of the Tm2O3 concentration (0.4 -1.6 ×1020 ions/cm3). Fluorescence spectra at 488 nm showed that Er 3+/Tm3+co-doped tellurite glasses present several emission bands between (500-1800) nm. However, the more iniense emission bands correspond to the Er3+ and Tm3+ transitions ( 4I13/2 → 4I15/2 and 3F4 → 3H6), respectively. The absolute nonradiative quantum efficiency (φ) was determined by TL method. Higher values of φ were obtained with the increase of Tm2O 3 concentration inside of the Er3+/Tm3+ co-doped tellurite glasses. These results are corroborated by the Judd-Ofelt calculations.6116Ryba-Romanowski, W., Effect of Temperature and activator concentration on luminescence decay of erbium-doped tellurite glass (1990) J. Lumin., 46, pp. 163-172Tanabe, S., Hirao, K., Soga, N., Upconversion fluorescences of TeO2 and Ga2O 3. based oxide glasses containing Er3+ (1990) J. Non-cryst. Solids, 122, pp. 79-82Inoue, S., Nukui, A., Yamamoto, K., Yano, T., Shibata, S., Yamane, M., Refractive index patterning of tellurite glass surfaces by ultra short pulse laser spot heating (2002) J. Mater. Sci., 37, pp. 3459-3465Huang, L., Jha, A., Shen, S., Chung, W.J., Visible emissions at 592 and 613 nm in Er3+-Eu3+ -codoped tellurite fibers (2004) Opt. Commun., 239, pp. 403-408Chillece, E.F., Rodriguez, E., Neves, A.A.R., Moreira, W.C., César, C.L., Barbosa, L.C., Er3+-Tm3+ co-doped tellurite fibers for broadband optical fiber amplifier around 1550 nm band (2005) Opt. Fiber Tech.Tanabe, S., Suzuki, K., Soga, N., Hanada, T., Mechanisms and concentration dependence of Tm3+ blue and Er3+ green up-con version in codoped glasses by red-laser pumping (1995) J. Lumin., 65, pp. 247-255Dai, S.X., Yang, J.H., Liu, Z.P., Wen, L., Hu, L.L., Jiang, Z.H., The luminescence of Er3+, Yb3+, Tm 3+-codoped tellurite glass pumped at 970 nm (2003) Acta Physica Sinica, 52, pp. 729-735Shen, S.X., Jha, A., Huang, L.H., Joshi, P., 980-nm diode-pumped Tm3+/Yb3+-codoped tellurite fiber for S-band amplification (2005) Optics Letters, 30, pp. 1437-1439Shen, X., Nie, Q., Xu, T., Peng, T., Gao, Y., Green and red upconversion emission and energy-transfer between Er 3+ and Tm3+ions in tellurite glasses (2004) Phys. Lett. A, 332, pp. 101-106Daf, S., Yang, J., Xu, S., Dai, N., Hu, L., Jiang, Z., The spectroscopic properties of Er3+, Yb3+, Tm 3+ -codoped tellurite glass (2003) Proc. SPIE, 4990, pp. 150-156. , Rare-Earth-Doped Materials and Devices Vil, S. Jiang, J. Lucas (Eds.)Lima, S.M., Sampaio, J.A., Catuncla, T., Bento, A.C., Miranda, L.C.M., Baesso, M.L., Mode-mismatched thermal lens spcctrometry for thermo-optical properties measurement in optical glasses: A review (2000) J. Non-cryst. Solids, 273, pp. 215-227Sampaio, J.A., Catunda, T., Gama, S., Baesso, M.L., Thermo-optical properties of OH-free erbium-doped low silica calcium aluminosilicate glasses measured by thermal lens technique (2001) J. Non-cryst. Solids, 284, pp. 210-216Lima, S.M., De Camargo, A.S.S., Nunes, L.A.O., Catunda, T., Fluorescence quantum efficiency measurements of excitation and nonradiative deexcitation processes of rare earth 4f-states in chalcogenide glasses (2002) Appl. Phys. Lett., 81, pp. 589-591Oliveira, S.L., Lima, S.M., Catunda, T., Nunes, L.A.O., Rohling, J.H., Bento, A.C., Baesso, M.L., High fluorescence quantum efficiency of 1.8 μm emission in Tm-dopcd low silica calcium aluminate glass determined by thermal lens spectroscopy (2004) Appl. Phys. Lett., 84, pp. 359-361Jacinto, C., Oliveira, S.L., Nunes, L.A.O., Catunda, T., Bell, M.J.V., Thermal lens study of the OH influence on the fluorescence efficiency of Yb3+ -doped phosphate glasses (2005) Appl. Phys. Lett., 86Sampaio, J.A., Gama, S., Baesso, M.L., Catunda, T., Fluorescence quantum efficiency of Er3+ in low silica calcium aluminate glasses determined by mode-mismatched thermal lens spectromctry (2005) J. Non-cryst. Solids, 351, pp. 1594-1602Pilla, V., Lima, S.M., Catunda, T., Medina, A., Baesso, M.L., Jenssen, H.P., Cassanho, A., Thermal quenching of the fluorescence quantum efficiency in colquiriite crystals measured by thermal lens spcctrometry (2004) J. Opt. Soc. Am. B., 21, pp. 1784-1791Pilla, V., Catunda, T., Balogh, D.T., Faria, R.M., Zilio, S.C., Thermal lensing in Polyvinyl alcoholVpolyaniline blends (2002) J. Polym. Sc., Part B Polym. Physics, 40, pp. 1949-1956Lima, S.M., Catunda, T., Lebullenger, R., Hernandes, A.C., Baesso, M.L., Bento, A.C., Miranda, L.C.M., Temperature dependence of thermo-optical properties of fluoride glasses determined by thermal lens spectrometry (1999) Phys. Rev. B, 60, pp. 15173-15178Lima, S.M., Sampaio, J.A., Catunda, T., De Camargo, A.S.S., Nunes, L.A.O., Baesso, M.L., Hewak, D.W., Spectroscopy, thermal and optical properties of Nd3+ -doped chalcogenide glasses (2001) J. Non-cryst. Solids, 284, pp. 274-281Zou, X., Izumitani, T., Spectroscopic properties and mechanisms of excited state absorption and energy transfer upconversion for Er3+ -doped glasses (1993) J. Non-cryst. Solids, 162, pp. 68-8

Quantum Confinement Effects On The Phonons Of Pbte Quantum Dots In Tellurite Glasses

We present Raman-scattering results for PbTe quantum dots (QDs) in doped telluride glasses which clearly show the confinement effects on the phonon spectra as a function of the quantum-dot size..6892Kraus and F. Wise;Phys. Rev. Lett. 79 (25), 5102-05 (1997)Thoen, E.R., (1998) Appl, Phys. Lett, 73 (15), p. 2149Wise, F., (2000) Ace. Chem. Res, 33, pp. 773-780Tsuda, S., Cruz, C.H.B., (1991) Opt. Lett, 16, p. 1596Nakamura, A., Tokizaki, T., Akiyama, H., Kataoka, T., (1992) J. Lumin, 53, p. 105Ohtsuka, S., Koyama, T., Tsunetomo, K., Nagata, H., Tanaka, S., (1992) Appl. Phys. Lett, 61, p. 2953Tsunetomo, K., Ohtsuka, S., Koyama, T., Tanaka, S., Sasaki, F., Kobayashi, S., (1995) Nonlin. Opt, 13, p. 109Colvin, V.L., Schlamp, M.C., Alivisatos, A.P., (1995) Nature ∼London, 370, p. 354Dabbousi, M., Bawendi, G., Onitsuka, O., Rubner, M.F., (1995) Appl. Phys. Lett, 66, p. 1316Guerreiro, T., Ten, S., Borrelli, N.F., Butty, J., Jabbour, G.E., Peyghambarian, N., (1997) Appl. Phys. Lett, 71, p. 1595Murray, C.B., Kagan, C.R., Bawendi, M.G., (1995) Science, 270, p. 1335Kang, I., Wise, F.W., (1997) J. Opt. Soc. Am. B, 14, p. 1632Reynoso, V.C.S., de Paula, A.M., Cuevas, R.F., Medeiros Neto, J.A., Alves, O.L., Cesar, C.L., Barbosa, L.C., (1995) Electron. Lett, 31, p. 1013G.J.Jacob, C.L.Cesar,L.C.Barbosa, Chem.Phys.Glass 43C (2002)250-252Esch, V., Fluegel, B., Khitrova, G., Gibbs, H.M., Jiajin, X., Kang, K., Koch, S.W., Peyghambarian, N., (1990) Phys. Rev, B42, p. 7450Sercel, P.C., Valhala, K.J., (1990) Phys. Rev, B42, p. 3690Schoenlein, R.W., Mittleman, D.M., Shiang, J.J., Alivisatos, A.P., Shank, C.V., (1993) Phys. Rev. Lett, 70, p. 1014Ekimov, A.I., Hache, F., Schanne-Klein, M.C., Ricard, D., Flytzanis, C., Kudryavtsev, I.A., Yazeva, T.V., Efros, A.L., (1993) J. Opt. Soc. Am, B10, p. 100Norris, D.J., Sacra, A., Bawendi, C.B.M.M.G., (1994) Phys. Rev. Lett, 72, p. 2612de Oliveira, C.R.M., de Paula, A.M., Filho, F.O.P., Neto, J.A.M., Barbosa, L.C., Alves, O.L., Menezes, E.A., Cesar, C.L., (1995) Appl. Phys. Lett, 66, p. 439R. Ruppin and R. Englman, Rep. Prog. Phys. 33, 149 (1970)R. Ruppin, J. Phys. C: 8, 1969 (1975)Thoen, E.R., Steinmeyer, G., Langlois, P., Ippen, E.P., Tudury, G.E., Brito Cruz, C.H., Barbosa, L.C., Cesar, C.L., (1998) Appl. Phys. Lett, 73Krauss, T.D., Wise, F.W., Coherent and Acoustical Phonon in a Semiconductor Quantum DotsPhis (1997) Rev. Lett, 79, pp. 5102-510

Optical Tweezers 3d Photonic Force Spectroscopy

Since optical tweezers trapped microspheres can be used as an ultrasensitive force measurements technique, the knowledge of its theoretical description is of utmost importance. However, even the description of the incident electromagnetic fields under very tight focusing, typical of the optical trap, is not yet a closed problem. Therefore it is important to experimentally obtain whole accurate curves of the force as a function of wavelength, polarization and incident beam 3D position with respect to the center of the microsphere. Theoretical models for optical forces such as the Generalized Lorenz-Mie theory, can then be applied to the precisely evaluated experimental results. Using a dual trap in an upright standard optical microscope, one to keep the particle at the equilibrium position and the other to disturb it we have been able to obtain these force curves as a function of x, y and z position, incident beam polarization and also wavelength. Further investigation of optical forces was conducted for wavelengths in and out Mie resonances of the dielectric microspherical cavities for both TM and TE modes.6131Ashkin, A., Dziedzic, J.M., Bjorkholm, J.E., Chu, S., Observation of a single-beam gradient force trap for dielectric particles (1986) Opt. Lett., 11, pp. 288-290Ashkin, A., Dziedzic, J.M., Optical trapping and manipulation of viruses and bacteria (1987) Science, 235, pp. 1517-1520Grier, D.G., A revolution in optical manipulation (2003) Nature, 424, pp. 810-816Neuman, K.C., Block, S., Optical trapping (2004) Rev. Sci. Instrum., 75, pp. 2787-2809Lock, J.A., Calculation of the radiation trapping force for laser tweezers by use of generalized Lorenz-Mie theory. I. Localized model description of an on-axis tightly focused laser beam with spherical aberration (2004) Appl. Opt., 43, pp. 2532-2544Lock, J.A., Calculation of the radiation trapping force for laser tweezers by use of generalized Lorenz-Mie theory. II. On-axis trapping force (2004) Appl. Opt., 43, pp. 2545-2554Mazolli, A., Neto, P.A.M., Nussenzveig, H.M., Theory of trapping forces in optical tweezers (2003) Proc. Royal Soc. London Ser. A Math. Phys. Eng. Sci., 459, pp. 3021-3041Fontes, A., Neves, A.A.R., Moreira, W.L., De Thomaz, A.A., Barbosa, L.C., De Paula, A.M., Cesar, C.L., Double optical tweezers for ultrasensitive force spectroscopy in microsphere Mie scattering (2005) Appl. Phys. Lett., 87. , Art. No. 221109Ren, K.F., Gouesbet, G., Gréhan, G., Integral localized approximation in generalized Lorenz-Mie theory (1998) Appl. Opt., 37, pp. 4218-4225Lock, J.A., Excitation efficiency of a morphology-dependent resonance by a focused Gaussian beam (1998) J. Opt. Soc. Am. A, 15, pp. 2986-2994Davis, L.W., Theory of electromagnetic beams (1979) Phys. Rev. A, 19, pp. 1177-1779Ren, K.F., Gréhan, G., Gouesbet, G., Radiation pressure forces exerted on a particle arbitrarily located in a gaussian beam by using the generalized Lorenz-Mie theory and associated resonance effects (1994) Opt. Commun., 108, pp. 343-354Ren, K.F., Gréhan, G., Gouesbet, G., Symmetry relations in generalized Lorenz-Mie theory (1994) J. Opt. Soc. Am. A, 11, pp. 1812-181

Micro-structured Er 3+-tm 3+ Co-doped Tellurite Fiber For Broadband Optical Amplifier Around 1550nm

Micro-structured Er 3+-Tm 3+ co-doped tellurite fiber with three rings of holes was fabricated using a soft glass drawing tower by a stack-and-draw technique. Amplified spontaneous emission (ASE) around 1550nm band were observed when pumped with both, 980nm and 790nm, lasers.6314Russell, P., Photonic crystal fibers (2003) Science, 299, pp. 358-362Knight, J.C., Photonic crystal fibers (2003) Nature, 424, pp. 847-851Kumar, V.V.R.K., George, A.K., Reeves, W.H., Knight, J.C., Russell, P.St.J., Omenetto, F.G., Taylor, A.J., Extruded soft glass photonic crystal fiber for ultrabroad supercontinuum generation (2002) Opt. Exp, 10 (25), pp. 1520-1525Chillcce, E.F., Cordeiro, C.M.B., Barbosa, L.C., Cruz, C.H.B., Er 3+-Tm 3+ co-doped tellurite fibers for broadband optical fiber amplifier around 1550nm band (2006) Opt. Fiber Technol., 12, pp. 185-195Chillcce, E.F., Rodriguez, E., Neves, A.A.R., Moreira, W.C., Cesar, C.L., Barbosa, L.C., Cruz, C.H.B., Tellurite photonic crystal fiber by a stack-and-draw technique (2006) J. Non-cryst. Solids, , accepted to publicationWhite, T.P., McPhedran, R.C., De Sterke, C.M., Botten, L.C., Steel, M.J., Confinement losses in microstructured optical fibers (2001) Opt. Lett, 26 (21), pp. 1660-1663Barbosa, L.C., Cruz, C.H.B., Cesar, C.L., Cordeiro, C.M.B., Chillcce, E.F., Production process of tellurite glass tubes, capillaries and rods Brazilian pending Patent No 018050002734Chillcce, E.F., Cordeiro, C.M.B., Rodriguez, E., Cruz, C.H.B., Cesar, C.L., Barbosa, L.C., Tellurite photonic crystal fiber with Er 3+-Tm 3+ for broadband optical amplifier in 1550nm (2006) Proc. of SPIE, 6116, p. 61160

Chemotaxis Study Using Optical Tweezers To Observe The Strength And Directionality Of Forces Of Leishmania Amazonensis

The displacements of a dielectric microspheres trapped by an optical tweezers (OT) can be used as a force transducer for mechanical measurements in life sciences. This system can measure forces on the 50 femto Newtons to 200 pico Newtons range, of the same order of magnitude of a typical forces induced by flagellar motion. The process in which living microorganisms search for food and run away from poison chemicals is known is chemotaxy. Optical tweezers can be used to obtain a better understanding of chemotaxy by observing the force response of the microorganism when placed in a gradient of attractors and or repelling chemicals. This report shows such observations for the protozoa Leishmania amazomenzis, responsible for the leishmaniasis, a serious tropical disease. We used a quadrant detector to monitor the movement of the protozoa for different chemicals gradient. This way we have been able to observe both the force strength and its directionality. The characterization of the chemotaxis of these parasites can help to understand the infection mechanics and improve the diagnosis and the treatments employed for this disease.6326Law, A.M.J., Aitken, M.D., Continuous-flow capillary assay for measuring bacterial chemotaxi (2005) Applied and Environmental Microbiology, 71 (6), pp. 3137-3143Khan, S., Jain, S., Reid, G.P., Trentham, D.R., The fast tumble signal in bacterial chemotaxis (2004) Biophysical Journal, 86 (6), pp. 4049-4058Neuman, K.C., Chadd, E.H., Liou, G.F., Bergman, K., Block, S.M., Characterization of photodamage to Escherichia coli in optical traps (1999) Biophysical Journal, 77 (5), pp. 2856-2863Who, World Health Organization, 2001Gontijo, B., Carvalho, M.L.R., Leishmaniose tegumentar Americana (2003) Revista da Sociedade Brasileira de Medicina Tropical, 36 (1), pp. 71-80Handman, E., Cell biology of Leishmania (2000) Advances in Parasitology, 44, pp. 1-39Rice, S.E., Purcell, T.J., Spudich, J.A., Building and using optical traps to study properties of molecular motors (2003) Biophotonics, PT B, 361, pp. 112-133Rohrbach, A., Stelzer, E.H.K., Three-dimensional position detection of optically trapped dielectric particles (2002) Journal of Applied Physics, 91 (8), pp. 5474-5488Gittes, F., Schmidt, C.F., Interference model for back-focal-plane displacement detection in optical tweezers (1998) Optics Letters, 23 (1), pp. 7-9Allersma, M.W., Gittes, F., DeCastro, M.J., Stewart, R.J., Schmidt, C.F., Two-dimensional tracking of ncd motiliry by back focal plane interferometry (1998) Biophysical Journal, 74 (2), pp. 1074-108