1,721,001 research outputs found
High Precision Measurement And Generation Of Optical And Microwave Frequencies Using Narrow-band And Short-pulse Lasers
No full textSince the advent of the laser, more than forty years ago, the development of narrow-band single-frequency and high-spectral-purity sources has been quite separated from the efforts in the generation of short pulse, high-bandwidth mode-locked lasers. Today we have continuous-wave, single-frequency lasers with linewidths smaller than one Hertz, along with mode-locked lasers emitting pulses of only a few femtoseconds and whose spectra can cover an entire octave. These two classes of lasers have met recently in the field of metrology and nonlinear optics. It has been realized that the active control techniques traditionally used to reduce FM noise in single-frequency lasers, thus reducing their linewidths, could be used to stabilize the frequency comb which constitutes a mode-locked laser. By stabilization of both the repetition rate and the carrier-to-envelope offset of a femtosecond laser, a direct phase-coherent link between microwave and optical frequencies is possible, allowing for example the direct measurement of optical frequencies. A dramatic development from this has been the advent of optical atomic clocks. With stabilities and accuracies order of magnitude higher than the conventional microwave clocks, they are opening a new era in precision measurements and will have great impact, for example, in navigation and telecommunications. Another close potential application is the development of optical frequency synthesizers, which can generate high-spectral-purity optical and microwave frequencies in a phase-coherent way. In this talk, an overview of these developments will be given, along with the present status of our work towards frequency measurement and synthesis and the development of an optical atomic clock based on cold Calcium atoms.279281noteAudoin, C., Viennet, J., Lesage, P., Hydrogen maser - Active and Passive (1981) J. Physique, 42 (NC8), pp. 159-170(1995) Proc. 5th Symposium on Frequency Standards and Metrology, , Woods Hole, MA, Oct. (World Scientific)Schnatz, H., Lipphardt, B., Helmcke, J., Riehle, F., Zinner, G., First phase-coherent frequency measurement of visible radiation (1996) Phys. Rev. Lett., 76 (1), pp. 18-21Young, B.C., Cruz, F.C., Bergquist, J.C., Itano, W.M., Lasers with subhertz linewidths (1999) Phys. Rev. Lett., 82 (19), pp. 3799-3802Eil, R., Morgner, U., Kartner, F.X., Fujimoto, J.G., Ippen, E.P., Scheuer, V., Angelow, G., Luther-Davies, B., Generation of 5-fs pulses and octave-spanning spectra directly from a Ti: Sapphire laser (2001) Opt. Lett., 26 (6), pp. 373-375Morgner, U., Ell, R., Metzler, G., Schibli, T.R., Kartner, F.X., Fujimoto, J.G., Haus, H.A., Ippen, E.P., Nonlinear optics with phase-controlled pulses in the sub-two-cycle regime (2001) Phys. Rev. Lett., 86 (24), pp. 5462-5465Zhu, M., Hall, J.L., Frequency Stabilization of Tunable Lasers (1996) Experimental Methods in the Physical Sciences, 29 C. , Atomic, Molecular and Optical Physics: Eletromagetic Radiation, F.B.Dunning and R.G.Hulet, Eds., Academic, San DiegoFox, R.W., Oates, C.W., Hollberg, L.W., Stabilizing diode lasers to high-finesse cavities (2002) Experimental Methods in the Physical Sciences, 40. , Chap. 1Quinn, T.J., Mise en Pratique of the definition of the Metre(1992) (1993) Metrologia, 30, pp. 523-541Verdeyen, J.T., (1995) Laser Electronics, 3rd Ed., , Prentice-Hall, CambridgeReichert, J., Niering, M., Holzwarth, R., Weitz, M., Udem, Th., Hänsen, T.W., Phase coherent vaccum-ultraviolet to radio frequency comparison with a mode-locked laser (1999) Phys. Rev. Lett., 84, pp. 3232-3335Jones, D.J., Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis (2000) Science, 288, pp. 635-639Ranka, J.K., Windeler, R.S., Stentz, A., Visible continuum generation in air-silica microstructure optical fibers with anomalous dispersion at 800 nm (2000) Opt. Lett., 25, pp. 25-27Diddams, S.A., Udem, Th., Bergquist, J.C., Curtis, E.A., Drullinger, R.E., Hollberg, L., Itano, W.M., Wineland, D.J., An optical clock based on a single trapped Hg-199(+) ion (2001) Science, 293, pp. 825-828Gill, P., Atomic clocks - Raising the standards (2001) Science, 294 (5547), pp. 1666-1668(2001) Proceedings of the 6th Symposium on Frequency Standards and Metrology, , Scotland, September, 09-14, World ScientificUdem, Th., Holzwarth, R., Hänsch, T.W., (2002) Nature, 416, pp. 233-237Conroy, R.S., Frequency standards, metrology and fundamental constants (2003) Contemporary Physics, 44 (2), pp. 99-135Bize, S., Diddams, S.A., Tanaka, U., Tanner, C.E., Oskay, W.H., Drullinger, R.E., Parker, T.E., Bergquist, J.C., Testing the stability of fundamental constants with the Hg-199(+) single-ion optical clock (2003) Phys. Rev. Lett., 90 (15), p. 150802Diddams, S., (2003) International Comb Workshop, , BIPM, Sèvres, France, March 13Zeng, Z.N., Li, R.X., Yu, W., Xu, Z.Z., Effect of the carrier-envelope phase of the driving laser field on the high-order harmonic attosecond pulse (2003) Phys. Rev. A, 67, p. 1Paul, A., Bartels, R.A., Tobey, R., Green, H., Weiman, S., Christov, I.P., Murnane, M.M., Backus, S., Quasi-phase-matched generation of coherent extreme-ultraviolet light (2003) Nature, 421 (6918), pp. 51-54Cavasso-Filho, R.L., Magno, W.C., Manoel, D.A., Scalabrin, A., Pereira, D., Cruz, F.C., Deceleration, Trapping and Two-Photon Cooling of Calcium Atoms (2003) J. Opt. Soc. Am. B - Special Feature on Laser Cooling of Matter, 20, p. 5Onisto, H.J., Cavasso-Filho, R.L., Scalabrin, A., Pereira, D., Cruz, F.C., Frequency doubled and stabilized all-solid-state Ti:sapphire lasers (2002) Opt. Engineering, 41 (5), p. 1122Manoel, D.A., Cavasso-Filho, R.L., Scalabrin, A., Pereira, D., Cruz, F.C., Frequency doubled diode laser in alternative extended cavity (2002) Opt. Communications, 201, pp. 157-163Manoel, D.A., Figueira, D.L.S., Pereira, D., Cruz, F.C., Single-frequency blue light source based on optically injected diode laser (2003) Opt. Communications, , submitte
Broadband 2 Ghz Femtosecond Ti:sapphire Laser
No full textWe report a 2.12 GHz prismless femtosecond Ti:sapphire ring laser with a broadband spectrum, extending from 635 to 1060 nm at -20 dB below its maximum at 680 nm, and with an average power of 0.93 W for 8 W of pump power. ©OSA.(2005) Femtosecond Optical Frequency Comb Technology, , J. Ye and S. T. Cundiff, eds, SpringerUdem, T., Reichert, J., Holzwarth, R., Hänsch, T.W., (1999) Opt. Lett, 24, p. 881Diddams, S.A., Udem, T., Bergquist, J.C., Curtis, E.A., Drullinger, R.E., Hollberg, L., Itano, W.M., Wineland, D.J., (2001) Science, 293, p. 825Morgner, U., Ell, R., Metzler, G., Schibli, T.R., Kärtner, F.X., Fujimoto, J.G., Haus, H.A., Ippen, E.P., (2001) Phys. Rev. Lett, 86, p. 5462Nogueira, G.T., Cruz, F.C., (2006) Opt. Lett, 31, p. 2069also at Virtual Journal of Ultrafast Science, 5 (8), (2006) MayBartels, A., Kurz, H., (2002) Opt.Lett, 27, p. 183
Broadband 2 Ghz Femtosecond Ti: Sapphire Laser
No full textWe report a 2.12 GHz prismless femtosecond Ti:sapphire ring laser with a broadband spectrum, extending from 635 to 1060 nm at -20 dB below its maximum at 680 nm, and with an average power of 0.93 W for 8 W of pump power. © 2007 OSA.Ye, J., Cundiff, S.T., Femtosecond Optical Frequency Comb Technology (2005), SpringerUdem, T., Reichert, J., Holzwarth, R., Hänsch, T.W., (1999) Opt. Lett., 24, p. 881Diddams, S.A., Udem, T., Bergquist, J.C., Curtis, E.A., Drullinger, R.E., Hollberg, L., Itano, W.M., Wineland, D.J., (2001) Science, 293, p. 825Morgner, U., Ell, R., Metzler, G., Schibli, T.R., Kärtner, F.X., Fujimoto, J.G., Haus, H.A., Ippen, E.P., (2001) Phys. Rev. Lett., 86, p. 5462Nogueira, G.T., Cruz, F.C., (2006) Opt. Lett., 31, p. 2069. , also at Virtual Journal of Ultrafast Science, 5 (8), (2006) MayBartels, A., Kurz, H., (2002) Opt.Lett., 27, p. 183
Terahertz Laser Generation By Optically Pumped Polar Molecules
No full textIn this work we report 12 new optically pumped far-infrared (FIR) laser lines from CH3OH and 19 from 13CH3OH. A 13CO2 laser of wide tunability (110 MHz) was used as pump source, and a Fabry-Perot open cavity was used as a FIR laser resonator. © 2007 Optical Society of America.Costa, L.F.L., Viscovini, R.C., Moraes, J.C.S., Cruz, F.C., Pereira, D., CH3OH Optically pumped by a 13CO2 laser: New laser lines and assignments (2006) Appl. Phys. B, , acceptedCosta, L.F.L., Viscovini, R.C., Moraes, J.C.S., Cruz, F.C., Pereira, D., Infrared and Far-Infrared Spectroscopy of 13CH3OH: Terahertz Laser Lines and Assignments (2006), submitted, NovemberGregory, I.S., Baker, C., Tribe, W.R., Bradley, I.V., Evans, M.J., Linfield, E.H., Davies, A.G., Missous, M., Optimization of Photomixers and Antennas for Continuous-Wave Terahertz Emission (2005) IEEE J. Quantum Electron, 41, pp. 717-728Kemp, M.C., Taday, P.F., Cole, B.E., Cluff, J.A., Fitzgerald, A.J., Tribe, W.R., Security applications of terahertz technology (2003) Proc SPIE, 5070, pp. 44-52Arnone, D.D., Ciesla, C.M., Pepper, M., Terahertz imaging comes into view (2000) Phys. World, 13, pp. 35-40Carelli, G., Ioli, N., Moretti, A., Pereira, D., Strumia, F., New large offset far-infrared laser lines CD3OH (1987) Appl. Phys. B., 44, pp. 111-117Inguscio, M., Moretti, A., Strumia, F., IR-FIR Tranferred Lamb-Dip Spectroscopy in Optically Pumped Molecular Lasers (1979) Opt. Commun., 30, pp. 355-35
Optical Frequency Comb For High-resolution And Precision Metrology
No full textIn this work we describe two optical frequency comb systems based on homemade high-repetition rate mode- locked femtosecond Ti:sapphire lasers. One of them uses a laser that has the spectrum broadened with a microstructure fiber to cover a whole optical octave. Its repetition rate can be easily adjusted form 750 MHz to 1 GHz. The other system is based in a ultra-broadband femtosecond high repetition rate Ti:sapphire laser whose spectrum covers a range from 585 nm to 1200 nm (at 20 dB below the maximum) without the use of the microstructure fibers. We have increased the repetition rate from 1 GHz to 2.12 GHz without observing any significant change in the width of the spectrum. The repetition rate of both lasers has been phase- locked to stable microwave oscillators, and could also be frequency tuned in a range of 30 kHz with respect to the reference oscillator. We are going to use these systems in a direct optical frequency measurement technique and in an optical atomic clock based on the Calcium intercombination transition at 457 THz. © 2007 IEEE.644647Udem, T., Holzwarth, R., Hansch, T.W., Optical frequency metrology (2002) Nature, 416 (14), pp. 233-237. , MarchCundiff*, S.T., Ye, J., Colloquium: Femtosecond optical frequency combs (2003) Rev. Mod. Phys, 75 (1), pp. 325-342. , JanuaryHollberg, L., WOates, C., Wilpers, G., Hoyt, C.W., Barber, Z.W., Diddams, S.A., Oskay, W.H., Bergquist, J.C., Optical frequency/wavelength references (2005) J. Phys. B: At. Mol. Opt. Phys, 38, pp. S469-S495Bauch, A., Telle, H.R., Frequency standards and frequency measurement (2002) Rep. Frog. Phys, 65, pp. 789-843. , AprilNogueira, G.T., Cruz, F.C., Efficient 1 GHz Ti:sapphire laser with improved broadband continuum in the infrared (2006) Opt. Lett, 31 (13), pp. 2069-2071. , Julyalso at Virtual Journal of Ultrafast Science, 5, no. 8, May 2006Bartels, A., Kurz, H., Generation of a broadband continuum by a Ti:sapphire femtosecond oscillator with a 1-GHz repetition rate (2002) Opt.Lett, 27 (20), pp. 1839-1841. , Octobe
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Broadband 2.12 Ghz Ti:sapphire Laser Compressed To 5.9 Femtoseconds Using Miips
No full textWe report a self-starting prismless femtosecond Ti:sapphire ring laser whose repetition rate has been gradually increased from 1 to 2.12 GHz. A broadband spectrum extending from 650 to 1040 nm, in which 17% of the intracavity power is generated in a single-pass through the crystal, is preserved in spite of the reduction in peak power. An average power of 0.95 W was obtained for 7.5 W of pump power, with very stable operation verified over 22 hours. Pulses from this laser have been fully characterized in spectral phase, and then compressed to 5.9 femtoseconds using multiphoton intrapulse interference phase scan (MIIPS). © 2008 Optical Society of America.16141003310038Bartels, A., Kurz, H., Generation of a broadband continuum by a Ti:sapphire femtosecond oscillator with a 1-GHz repetition rate (2002) Opt. Lett, 27, pp. 1839-1841Bartels, A., Gebs, R., Kirchnerm, M.S., Diddams, S.A., Spectrally resolved optical frequency comb from a self-referenced 5 GHz femtosecond laser (2006) Opt. Lett, 32, pp. 2553-2555Cundiff, S.T., Ye, J., Colloquium: Femtosecond optical frequency combs (2003) Rev. Mod. Phys, 75, pp. 325-342Ell, R., Morgner, U., Kärtner, F.X., Fujimoto, J.G., Ippen, E.P., Scheuerm, V., Angelow, G., Luther-Davies, B., Generation of 5-fs pulses and octave-spanning spectra directly from a Tiisapphire laser (2001) Opt. Lett, 26, pp. 373-375Fortier, T.M., Bartels, A., Diddams, S.A., Octave-spanning Ti:sapphire laser with a repetition rate >1 GHz for optical frequency measurements and comparisons (2006) Opt. Lett, 31, pp. 1011-1013Nogueira, G.T., Cruz, F.C., Efficient 1 GHz Ti:sapphire laser with improved broadband continuum in the infrared (2006) Opt. Lett, 31, pp. 2069-2071Diddams, S.A., Hollberg, L., Mbele, V., Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb (2007) Nature, 445, pp. 627-630Thorpe, M.J., Moll, K.D., Jones, R.J., Safdi, B., Ye, J., Broadband Cavity Ringdown Spectroscopy for Sensitive and Molecular Detection (2006) Science, 311, pp. 1595-1599Paul, P.M., Toma, E.S., Breger, P., Mullot, G., Augé, F., Balcou, P., Muller, H.G., Agostini, P., Observation, of a Train of Attosecond Pulses from High Harmonic Generation (2001) Science, 292, pp. 1689-1692Dudovich, N., Oron, D., Silberberg, Y., Single-pulse coherently controlled nonlinear Raman spectroscopy and microscopy (2002) Nature, 418, pp. 512-514Li, H., Harris, D.A., Xu, B., Wrzesinski, P.J., Lozovoy, V.V., Dantus, M., Coherent, mode-selective Raman excitation towards standoff detection (2008) Opt. Express, 16, pp. 5499-5504Stowe, M.C., Cruz, F.C., Marian, A., Ye, J., Coherent population, transfer dynamics controlled by pulse accumulation and spectral phase manipulation (2006) Phys. Rev. Lett, 96, p. 153001Coello, Y., Lozovoy, V.V.V., Gunaratne, T.C., Xu, B., Borukhovich, I., Tseng, C., Weinacht, T., Dantus, M., Interference without an interferometer: A different approach to measuring, compressing, and shaping ultrashort laser pulses (2008) J. Opt. Soc. Am. B, 25, pp. 140-150Fortier, T.M., Jones, D.J., Cundiff, S.T., Phase stabilization, of an octave-spanning Ti:sapphire laser (2003) Opt. Lett, 28, pp. 2198-2200Fuji, T., Unterhuber, A., Yakolev, V.S., Tempea, G., Stingl, A., Krausz, F., Drexler, W., Generation of smooth, ultra-broadband spectra directly from a prism-less Ti:sapphire laser (2003) Appl. Phys. B, 77, pp. 125-128Brabec, T., Spielmann, C., Krausz, F., Limits of pulse shortening in solitary lasers (1992) Opt. Lett, 17, pp. 748-750Bartels, A., Dekorsy, T., Kurz, H., Femtosecond Ti:sapphire ring laser with a 2-GHz repetition rate and its application in time-resolved spectroscopy (1999) Opt. Lett, 24, pp. 996-998Xu, B., Coello, Y., Lozovoy, V.V., Harris, D.A., Dantus, M., Pulse shaping of octave spanning femtosecond laser pulses (2006) Opt. Express, 14, pp. 10939-10944Xu, B., Coello, Y., Nogueira, G.T., Cruz, F.C., Dantus, M., paper in preparatio
Deep Optical Trap For Cold Calcium Atoms
No full textWe describe a setup for a deep optical dipole trap or lattice which should be capable of trapping atoms at temperatures of a few milliKelvin. This apparatus will be used to trap and cool calcium atoms below the Doppler temperature and also to produce a ID optical lattice. We intend to perform resolved sideband cooling on the trapped atoms, using for example the calcium intercombination transition at 657 nm, in addition to investigate the use of evaporative cooling by lowering the trap potential. © 2008 American Institute of Physics.992431434Metcalf, H., van der Straten, P., (1999) Laser Cooling and Trapping, , Springer-Verlag, New YorkDunn, J.W., Thomsen, J.W., Greene, C.H., Cruz, F.C., Coherent quantum engineering of free-space laser cooling (2007) Phys. Rev. A, 76, pp. 011401RGrimm, R., Weidemuller, M., Ovchinnikov, Y.B., Optical dipole trap for neutral atoms (2000) Advances in Atomic, Molecular and Optical Physics, 42, p. 95Jessen, P.S., Salomon, C., Niu, Q., Optical lattices (1996) Advances in Atomic, Molecular and Optical Physics, 37, p. 95Drever, R.W.P., Hall, J.L., Kowalski, F.V., Hough, J., Ford, G.M., Munley, A.J., Ward, H., Laser phase and frequency stabilization using an optical resonator (1993) Appl. Phys. B, 31, p. 97Leibfried, D., Blatt, R., Monroe, C., Wineland, D., Quantum dynamics of single trapped ions (2003) Rev. Mod. Phys, 75, p. 28
Frequency Stabilized And Doubled Nd:ylf Laser: An Allsolid-state Local Oscillator For A Calcium Optical Atomic Clock
No full textWe describe a frequency-doubled, stabilized, diode-pumped solid-state Nd:YLF laser at 657 nm, proposed as a candidate for a local oscillator in optical atomic clocks based on neutral calcium atoms. © 2009 Optical Society of America.Ludlow, D., Zelevinsky, T., Campbell, G.K., Blatt, S., Boyd, M.M., de Miranda, M.H.G., Martin, M.J., Oates, C.W., Sr Lattice Clock at 1 x 10-16 Fractional Uncertainty by Remote Optical Evaluation with a Ca Clock (2008) Science, 319, pp. 1805-1808Young, B.C., Cruz, F.C., Itano, W.M., Bergquist, J.C., Visible lasers with subhertz linewidth (1999) Phys. Rev. Lett., 82, pp. 3799-3802Webster, S.A., Oxborrowa, M., Gill, P., Subhertz-linewidth Nd: YAG laser (2004) Opt.Lett., 29, pp. 1497-1499Oates, C.W., Curtis, E.A., Hollberg, L., Improved short-term stability of optical frequency standards: approaching 1 Hz in 1s with the Ca standard at 657 nm (2000) Opt. Lett., 25, pp. 1603-1609Stoehr, H., Mensing, F., Helmcke, J., Sterr, U., Diode laser with 1 Hz linewidth (2006) Opt. Lett., 31, pp. 736-738Ludlow, A.D., Huang, X., Notcutt, M., Zanon-Willette, T., Foreman, S.M., Boyd, M.M., Blatt, S., Ye, J., Compact, thermal-noise-limited optical cavity for diode laser stabilization at 1x10-15 (2007) Opt. Lett., 32, pp. 641-643Sousa, S.V., Badr, T., Xu, G., Zondy, J.J., Watt-level single frequency tunable Nd: YLF/ periodically poled KTiOPO4 red laser (2007) Opt. Lett., 32, pp. 2732-2734Drever, R.W.P., Hall, J.L., Kowalski, F.V., Hough, J., Ford, G.M., Mundey, A.J., Ward, H., Laser phase and frequency stabilization using an optical resonator (1983) Appl. Phys., B31, p. 9
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