201
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Zelevinsky T, Blatt S, Boyd MM, Campbell GK, Ludlow AD, Ye J. Highly coherent spectroscopy of ultracold atoms and molecules in optical lattices. Chemphyschem 2008; 9:375-82. [PMID: 18275047 DOI: 10.1002/cphc.200700713] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cooling and trapping of neutral atoms using laser techniques has enabled extensive progress in precise, coherent spectroscopy. In particular, trapping ultracold atoms in optical lattices in a tight confinement regime allows us to perform high-resolution spectroscopy unaffected by atomic motion. We report on the recent developments of optical lattice atomic clocks that have led to optical spectroscopy coherent at the one second timescale. The lattice clock techniques also open a promising pathway toward trapped ultracold molecules and the possible precision measurement opportunities such molecules offer.
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Affiliation(s)
- Tanya Zelevinsky
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, CO 80309-0440, USA.
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202
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203
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Yokoyama H, Tsubokawa H, Guo H, Shikata JI, Sato KI, Takashima K, Kashiwagi K, Saito N, Taniguchi H, Ito H. Two-photon bioimaging utilizing supercontinuum light generated by a high-peak-power picosecond semiconductor laser source. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:054019. [PMID: 17994907 DOI: 10.1117/1.2800393] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We developed a novel scheme for two-photon fluorescence bioimaging. We generated supercontinuum (SC) light at wavelengths of 600 to 1200 nm with 774-nm light pulses from a compact turn-key semiconductor laser picosecond light pulse source that we developed. The supercontinuum light was sliced at around 1030- and 920-nm wavelengths and was amplified to kW-peak-power level using laboratory-made low-nonlinear-effects optical fiber amplifiers. We successfully demonstrated two-photon fluorescence bioimaging of mouse brain neurons containing green fluorescent protein (GFP).
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Affiliation(s)
- Hiroyuki Yokoyama
- Tohoku University, New Industry Creation Hatchery Center (NICHe), 6-6-10 Aramaki-Aoba, Aoba-ku, Sendai 980-8579, Japan.
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204
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Abstract
Optical frequency combs from mode-locked femtosecond lasers have revolutionized the art of counting the frequency of light. They can link optical and microwave frequencies in a single step, and they provide the long missing clockwork for optical atomic clocks. By extending the limits of time and frequency metrology, they enable new tests of fundamental physics laws. Precise comparisons of optical resonance frequencies of atomic hydrogen and other atoms with the microwave frequency of a cesium atomic clock are establishing sensitive limits for possible slow variations of fundamental constants. Optical high harmonic generation is extending frequency comb techniques into the extreme ultraviolet, opening a new spectral territory to precision laser spectroscopy. Frequency comb techniques are also providing a key to attosecond science by offering control of the electric field of ultrafast laser pulses. In our laboratories at Stanford and Garching, the development of new instruments and techniques for precision laser spectroscopy has long been motivated by the goal of ever higher resolution and measurement accuracy in optical spectroscopy of the simple hydrogen atom which permits unique confrontations between experiment and fundamental theory. This lecture recounts these adventures and the evolution of laser frequency comb techniques from my personal perspective.
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Affiliation(s)
- Theodor W Hänsch
- Max-Planck Institute of Quantum Optics, Garching, and Department of Physics, Ludwig-Maximilians University Munich, Germany.
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205
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Abstract
Femtosecond stimulated Raman spectroscopy (FSRS) is a new ultrafast spectroscopic technique that provides vibrational structural information with high temporal (50-fs) and spectral (10-cm(1)) resolution. As a result of these unique capabilities, FSRS studies of chemical and biochemical reaction dynamics are expected to grow rapidly, giving previously unattainable insight into the structural dynamics of reactively evolving systems with atomic spatial and femtosecond temporal resolution. This review discusses the experimental and theoretical concepts behind FSRS, with an emphasis on the origins of its unique temporal and spectral capabilities. We illustrate these capabilities with vibrational studies of ultrafast electronic dynamics, as well as the direct structural observation of nonstationary vibrational wave-packet motion in small molecules and in complex biochemical reaction dynamics.
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Affiliation(s)
- Philipp Kukura
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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206
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Ivanov EN, McFerran JJ, Diddams SA, Hollberg L. Noise properties of microwave signals synthesized with femtosecond lasers. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2007; 54:736-45. [PMID: 17441583 DOI: 10.1109/tuffc.2007.307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We discuss various aspects of high resolution measurements of phase fluctuations at microwave frequencies. This includes methods to achieve thermal noise limited sensitivity, along with the improved immunity to oscillator amplitude noise. A few prototype measurement systems were developed to measure phase fluctuations of microwave signals extracted from the optical pulse trains generated by femtosecond lasers. This enabled first reliable measurements of the excess phase noise associated with optical-to-microwave frequency division. The spectral density of the excess phase noise was found to be -140 dBc/Hz at 100 Hz offset from the 10 GHz carrier which was almost 40 dB better than that of a high quality microwave synthesizer.
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Affiliation(s)
- Eugene N Ivanov
- School of Physics, University of Western Australia, Crawley.
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207
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Kalashnikov VL, Sorokin E, Sorokina IT. Raman effects in the infrared supercontinuum generation in soft-glass PCFs. APPLIED PHYSICS. B, LASERS AND OPTICS 2007; 87:37-44. [PMID: 20975981 PMCID: PMC2958656 DOI: 10.1007/s00340-006-2545-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Measurements of the Raman gain spectra in the SF6 and SF57 highly-nonlinear-glasses demonstrated twice as high Raman shift in comparison with the fused silica. Numerical simulation predicted that a large Raman shift in combination with high nonlinearity can significantly reduce the required input pulse intensity for supercontinuum in these glasses, retaining the necessary degree of coherence. We found, that the degradation of the SC coherence due to Raman soliton jitter can be effectively controlled by a correct choice of input intensity and fiber length. Also it was found, that high degree of coherence correlates with the spectrum shape in the vicinity of the Raman threshold, providing an convenient experimental observable.
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Affiliation(s)
- V L Kalashnikov
- Institut für Photonik, TU Wien, Gusshausstr. 27/387, A-1040 Vienna, Austria
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208
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Foreman SM, Holman KW, Hudson DD, Jones DJ, Ye J. Remote transfer of ultrastable frequency references via fiber networks. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:021101. [PMID: 17578096 DOI: 10.1063/1.2437069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Three distinct techniques exist for distributing an ultrastable frequency reference over optical fibers. For the distribution of a microwave frequency reference, an amplitude-modulated continuous wave (cw) laser can be used. Over kilometer-scale lengths this approach provides an instability at 1 s of approximately 3 x 10(-14) without stabilization of the fiber-induced noise and approximately 1 x 10(-14) with active noise cancellation. An optical frequency reference can be transferred by directly transmitting a stabilized cw laser over fiber and then disseminated to other optical and microwave regions using an optical frequency comb. This provides an instability at 1 s of 2 x 10(-14) without active noise cancellation and 3 x 10(-15) with active noise cancellation [Recent results reduce the instability at 1 s to 6 x 10(-18).] Finally, microwave and optical frequency references can be simultaneously transmitted using an optical frequency comb, and we expect the optical transfer to be similar in performance to the cw optical frequency transfer. The instability at 1 s for transfer of a microwave frequency reference with the comb is approximately 3 x 10(-14) without active noise cancellation and <7 x 10(-15) with active stabilization. The comb can also distribute a microwave frequency reference with root-mean-square timing jitter below 16 fs integrated over the Nyquist bandwidth of the pulse train (approximately 50 MHz) when high-bandwidth active noise cancellation is employed, which is important for remote synchronization applications.
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Affiliation(s)
- Seth M Foreman
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA.
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209
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Park SE, Kim EB, Park YH, Yee DS, Kwon TY, Park CY, Moon HS, Yoon TH. Sweep optical frequency synthesizer with a distributed-Bragg-reflector laser injection locked by a single component of an optical frequency comb. OPTICS LETTERS 2006; 31:3594-6. [PMID: 17130914 DOI: 10.1364/ol.31.003594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A sweep optical frequency synthesizer is demonstrated by using a frequency-stabilized optical frequency comb and injection-locked distributed-Bragg-reflector (DBR) laser diode. The injection-locked DBR laser acts as a single-frequency filter and, simultaneously, a high-gain amplifier of the optical frequency comb. The frequency instability of the heterodyne beat signal between two independently injection-locked DBR lasers is measured to be 2.3 x 10(-16) at 1 s averaging time. The output frequency of the sweep optical frequency synthesizer can be precisely tuned over 1 GHz, and a saturated absorption spectrum of the Cs D2 line at 852 nm is recorded by the injected DBR laser.
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Affiliation(s)
- S E Park
- Korea Research Institute of Standards and Science, Yuseong-Gu, Daejeon, Korea.
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210
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Hommelhoff P, Kealhofer C, Kasevich MA. Ultrafast electron pulses from a tungsten tip triggered by low-power femtosecond laser pulses. PHYSICAL REVIEW LETTERS 2006; 97:247402. [PMID: 17280322 DOI: 10.1103/physrevlett.97.247402] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Indexed: 05/13/2023]
Abstract
We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8-fs low-power laser pulses. This process is nonlinear in the laser electric field, and the nonlinearity can be tuned via the dc voltage applied to the tip. Numerical simulations of this system show that electron emission takes place within less than one optical period of the exciting laser pulse, so that an 8 fs 800 nm laser pulse is capable of producing a single electron pulse of less than 1 fs duration. Furthermore, we find that the carrier-envelope phase dependence of the emission process is smaller than 0.1% for an 8 fs pulse but is steeply increasing with decreasing laser pulse duration.
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Affiliation(s)
- Peter Hommelhoff
- Physics Department, Stanford University, Stanford, California 94305, USA
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211
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Beugin V, Bigot L, Niay P, Lancry M, Quiquempois Y, Douay M, Mélin G, Fleureau A, Lempereur S, Gasca L. Efficient Bragg gratings in phosphosilicate and germanosilicate photonic crystal fiber. APPLIED OPTICS 2006; 45:8186-93. [PMID: 17068560 DOI: 10.1364/ao.45.008186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We present ArF laser-induced dynamics of Bragg grating (BG) growths in phosphosilicate-doped or germanosilicate-doped core photonic crystal fibers (PCFs). To this end, we have adapted the technique of H2 loading, usually used in conventional fiber, to the case of microstructured fiber, allowing both the concentration of hydrogen in the PCFs to be kept nearly constant for the time of the exposure and the BG spectra to be easily recorded. We compared the characteristics of BG growths in the two types of PCF to those in conventional step-index fibers. We then conducted a study of the thermal stability of the BGs in PCFs through 30 min of isochronal annealing. At the same time we discuss the role played by the microstructuration and the doping with regard to the grating contrast and the Bragg wavelength stability.
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Affiliation(s)
- V Beugin
- Laboratoire de Physique des Lasers, Atomes et Molécules, Universités des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
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212
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Schuhler N, Salvadé Y, Lévêque S, Dändliker R, Holzwarth R. Frequency-comb-referenced two-wavelength source for absolute distance measurement. OPTICS LETTERS 2006; 31:3101-3. [PMID: 17041648 DOI: 10.1364/ol.31.003101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We propose a new tunable laser source concept for multiple-wavelength interferometry, offering an unprecedented large choice of synthetic wavelengths with a relative uncertainty better than 10(-11) in vacuum. Two lasers are frequency stabilized over a wide range of frequency intervals defined by the frequency comb generated by a mode-locked fiber laser. In addition, we present experimental results demonstrating the generation of a 90 mum synthetic wavelength calibrated with an accuracy better than 0.2 parts in 10(6). With this synthetic wavelength we can resolve one optical wavelength, which opens the way to absolute distance measurement with nanometer accuracy.
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Affiliation(s)
- Nicolas Schuhler
- Laboratoire des Systèmes Photoniques, Boulevard Sébastien Brant, BP 10413, 67400 Illkirch, France
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213
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Gorbach AV, Skryabin DV, Stone JM, Knight JC. Four-wave mixing of solitons with radiation and quasi-nondispersive wave packets at the short-wavelength edge of a supercontinuum. OPTICS EXPRESS 2006; 14:9854-9863. [PMID: 19529378 DOI: 10.1364/oe.14.009854] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We apply the recently developed theory of frequency generation by mixing of solitons and dispersive waves [Phys. Rev. E 72, 016619 (2005)] to explain the observed formation, quasi-trapping and frequency shift of the spectral peaks at the blue edge of supercontinua generated in silica-core photonic crystal fibers.
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214
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Le Targat R, Baillard X, Fouché M, Brusch A, Tcherbakoff O, Rovera GD, Lemonde P. Accurate optical lattice clock with 87Sr atoms. PHYSICAL REVIEW LETTERS 2006; 97:130801. [PMID: 17026019 DOI: 10.1103/physrevlett.97.130801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Indexed: 05/12/2023]
Abstract
We report a frequency measurement of the 1S0-3P0 transition of 87Sr atoms in an optical lattice clock. The frequency is determined to be 429 228 004 229 879(5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall. The two previous measurements of this transition were found to disagree by about 2 x 10(-13), i.e., almost 4 times the combined error bar and 4 to 5 orders of magnitude larger than the claimed ultimate accuracy of this new type of clocks. Our measurement is in agreement with one of these two values and essentially resolves this discrepancy.
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Affiliation(s)
- Rodolphe Le Targat
- LNE-SYRTE, Observatoire de Paris 61, Avenue de l'Observatoire, 75014 Paris, France
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215
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Fedotov AB, Serebryannikov EE, Ivanov AA, Zheltikov AM. Spectral transformation of femtosecond Cr:forsterite laser pulses in a flint-glass photonic-crystal fiber. APPLIED OPTICS 2006; 45:6823-30. [PMID: 16926918 DOI: 10.1364/ao.45.006823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nonlinear-optical performance of photonic-crystal fibers (PCFs) made of highly nonlinear TF10 glass is studied and compared with the general tendencies of nonlinear-optical interactions in fused-silica PCFs. The loss of TF10 glass PCFs prevents the generation of supercontinuum emission with a broad and flat spectrum, which typically requires propagation lengths comparable with or exceeding the attenuation length of the fiber. However, dispersive-wave emission of solitons, induced by high-order dispersion, phase-matched four-wave-mixing processes, and self-phase-modulation-induced spectral broadening are substantially enhanced in TF10 glass PCFs due to the high material nonlinearity, providing a high efficiency of frequency conversion of Cr:forsterite laser pulses.
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Affiliation(s)
- A B Fedotov
- Department of Physics, International Laser Center, M. V. Lomonosov Moscow University, Vorob'evy gory, Moscow, Russia
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216
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Ishii N, Teisset CY, Köhler S, Serebryannikov EE, Fuji T, Metzger T, Krausz F, Baltuska A, Zheltikov AM. Widely tunable soliton frequency shifting of few-cycle laser pulses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:036617. [PMID: 17025774 DOI: 10.1103/physreve.74.036617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Indexed: 05/12/2023]
Abstract
Photonic-crystal fibers are employed to demonstrate widely tunable frequency down-conversion of unamplified 6-fs Ti:sapphire laser pulses through the soliton self-frequency shift induced by the Raman effect. Wavelength shifts as large as 500 nm are achieved for input few-cycle pulses with broadband spectra centered at approximately 820 nm. The central wavelength of the redshifted output of a photonic-crystal fiber is smoothly tuned from the low-frequency edge in the spectrum of the 6-fs Ti:sapphire laser pulse up to 1.35 microm by varying the input energy in the fundamental mode of the fiber.
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Affiliation(s)
- N Ishii
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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217
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Mills JD, Chaipiboonwong T, Brocklesby WS, Charlton MDB, Zoorob ME, Netti C, Baumberg JJ. Observation of the developing optical continuum along a nonlinear waveguide. OPTICS LETTERS 2006; 31:2459-61. [PMID: 16880855 DOI: 10.1364/ol.31.002459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We describe what is to our knowledge the first nondestructive measurement of the evolution of an optical continuum as a function of distance along a nonlinear waveguide. Spectral mapping is achieved on a subwavelength scale by utilizing near-field microscopy to probe the waveguide's evanescent field. The measured continuum broadening along the waveguide agrees in general form with predictions of broadening from theoretical calculations, but differs in some important details. Subwavelength resolution measurements are made both along and across the waveguide to reveal spectral variations not seen before by other techniques.
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Affiliation(s)
- John D Mills
- Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.
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218
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Inaba H, Ikegami T, Hong FL, Bitou Y, Onae A, Schibli TR, Minoshima K, Matsumoto H. Doppler-free spectroscopy using a continuous-wave optical frequency synthesizer. APPLIED OPTICS 2006; 45:4910-5. [PMID: 16807599 DOI: 10.1364/ao.45.004910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
A continuous-wave (cw) optical frequency synthesizer is demonstrated by using a monolithic-type cw optical parametric oscillator (cw-OPO) and an optical frequency comb. The cw-OPO is phase locked to an optical frequency comb that is phase locked to an atomic clock. The output frequency of the cw-OPO is frequency shifted with an electro-optic modulator, which makes it possible to tune the frequency continuously over 10 GHz. Furthermore, Doppler-free spectroscopy is performed using the optical frequency synthesizer for a cesium D1 line at 895 nm. The observed linewidth of 5 MHz is the natural linewidth of cesium. The center frequency of the line is consistent with a previous report.
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Affiliation(s)
- Hajime Inaba
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
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219
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Serebryannikov EE, Zheltikov AM, Köhler S, Ishii N, Teisset CY, Fuji T, Krausz F, Baltuska A. Diffraction-arrested soliton self-frequency shift of few-cycle laser pulses in a photonic-crystal fiber. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:066617. [PMID: 16907007 DOI: 10.1103/physreve.73.066617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Indexed: 05/11/2023]
Abstract
The balance between diffraction and index-step guiding in photonic-crystal fibers is controlled by modifying the fiber structure, leading to different wavelength dependences of the effective mode area and providing a mechanism to control nonlinear-optical phenomena. In optical fibers with a steep profile, the guided mode of the light field tends to become much less compact with an increase in radiation wavelength, slowing down the Raman-induced soliton self-frequency shift of an ultrashort laser pulse. A reduction of the soliton self-frequency shift is demonstrated for input laser pulses.
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Affiliation(s)
- E E Serebryannikov
- Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, Vorob'evy gory, Moscow 119992, Russia
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220
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221
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Zheltikov AM. Let there be white light: supercontinuum generation by ultrashort laser pulses. ACTA ACUST UNITED AC 2006. [DOI: 10.3367/ufnr.0176.200606d.0623] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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222
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Hänsch TW, Alnis J, Fendel P, Fischer M, Gohle C, Herrmann M, Holzwarth R, Kolachevsky N, Udem T, Zimmermann M. Precision spectroscopy of hydrogen and femtosecond laser frequency combs. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2005; 363:2155-63. [PMID: 16147503 DOI: 10.1098/rsta.2005.1639] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Precision spectroscopy of the simple hydrogen atom has inspired dramatic advances in optical frequency metrology: femtosecond laser optical frequency comb synthesizers have revolutionized the precise measurement of optical frequencies, and they provide a reliable clock mechanism for optical atomic clocks. Precision spectroscopy of the hydrogen 1S-2S two-photon resonance has reached an accuracy of 1.4 parts in 10(14), and considerable future improvements are envisioned. Such laboratory experiments are setting new limits for possible slow variations of the fine structure constant alpha and the magnetic moment of the caesium nucleus mu(Cs) in units of the Bohr magneton mu(B).
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Affiliation(s)
- T W Hänsch
- Department of Physics, Ludwig-Maximilians-Universität, München, Germany.
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223
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224
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Konorov SO, Akimov DA, Zheltikov AM, Ivanov AA, Alfimov MV, Scalora M. Tuning the frequency of ultrashort laser pulses by a cross-phase-modulation-induced shift in a photonic crystal fiber. OPTICS LETTERS 2005; 30:1548-50. [PMID: 16007803 DOI: 10.1364/ol.30.001548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Femtosecond pulses of fundamental Cr:forsterite laser radiation are used as a pump field to tune the frequency of copropagating second-harmonic pulses of the same laser through cross-phase modulation in a photonic crystal fiber. Sub-100-kW femtosecond pump pulses coupled into a photonic crystal fiber with an appropriate dispersion profile can shift the central frequency of the probe field by more than 100 nm, suggesting a convenient way to control propagation and spectral transformations of ultrashort laser pulses.
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Affiliation(s)
- S O Konorov
- Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, Vorob'evy gory, Moscow 119899, Russia
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225
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Konorov S, Akimov D, Ivanov A, Alfimov M, Yakimanskii A, Zheltikov A. Probing resonant nonlinearities in organic materials using photonic-crystal fiber frequency converters. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.01.127] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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226
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Liu TM, Kärtner FX, Fujimoto JG, Sun CK. Multiplying the repetition rate of passive mode-locked femtosecond lasers by an intracavity flat surface with low reflectivity. OPTICS LETTERS 2005; 30:439-441. [PMID: 15762454 DOI: 10.1364/ol.30.000439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
By inserting a low-reflectivity flat surface inside the oscillator cavity, we demonstrate a flexible and phase-insensitive method for multiplying the repetition rate of a femtosecond passive mode-locked solid-state laser. Without mode matching and feedback control, we successfully multiplied the repetition rate of a passively mode-locked Cr:forsterite laser from 124 MHz to 1.24 GHz. High-repetition-rate femtosecond optical pulses with average power of >100 mW can be obtained with the demonstrated method.
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Affiliation(s)
- Tzu-Ming Liu
- Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei 10617, Taiwan
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227
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Fuji T, Rauschenberger J, Apolonski A, Yakovlev VS, Tempea G, Udem T, Gohle C, Hänsch TW, Lehnert W, Scherer M, Krausz F. Monolithic carrier-envelope phase-stabilization scheme. OPTICS LETTERS 2005; 30:332-334. [PMID: 15751902 DOI: 10.1364/ol.30.000332] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A new scheme for stabilizing the carrier-envelope (CE) phase of a few-cycle laser pulse train is demonstrated. Self-phase modulation and difference-frequency generation in a single periodically poled lithium niobate crystal that transmits the main laser beam allows CE phase locking directly in the usable output. The monolithic scheme obviates the need for splitting off a fraction of the laser output for CE phase control, coupling into microstructured fiber, and separation and recombination of spectral components. As a consequence, the output yields 6-fs, 800-nm pulses with an unprecedented degree of short- and long-term reproducibility of the electric field waveform.
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Affiliation(s)
- Takao Fuji
- Photonics Institute, Vienna University of Technology, Gusshausstrasse 27/387, A-1040 Vienna, Austria.
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228
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Witte S, Zinkstok RT, Ubachs W, Hogervorst W, Eikema KSE. Deep-Ultraviolet Quantum Interference Metrology with Ultrashort Laser Pulses. Science 2005; 307:400-3. [PMID: 15662007 DOI: 10.1126/science.1106612] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Precision spectroscopy at ultraviolet and shorter wavelengths has been hindered by the poor access of narrow-band lasers to that spectral region. We demonstrate high-accuracy quantum interference metrology on atomic transitions with the use of an amplified train of phase-controlled pulses from a femtosecond frequency comb laser. The peak power of these pulses allows for efficient harmonic upconversion, paving the way for extension of frequency comb metrology in atoms and ions to the extreme ultraviolet and soft x-ray spectral regions. A proof-of-principle experiment was performed on a deep-ultraviolet (2 x 212.55 nanometers) two-photon transition in krypton; relative to measurement with single nanosecond laser pulses, the accuracy of the absolute transition frequency and isotope shifts was improved by more than an order of magnitude.
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Affiliation(s)
- Stefan Witte
- Laser Centre, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, Netherlands
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229
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Zinkstok RT, Witte S, Hogervorst W, Eikema KSE. High-power parametric amplification of 11.8-fs laser pulses with carrier-envelope phase control. OPTICS LETTERS 2005; 30:78-80. [PMID: 15648644 DOI: 10.1364/ol.30.000078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Phase-stable parametric chirped-pulse amplification of ultrashort pulses from a carrier-envelope phase-stabilized mode-locked Ti:sapphire oscillator (11.0 fs) to 0.25 mJ/pulse at 1 kHz is demonstrated. Compression with a grating compressor and a LCD shaper yields near-Fourier-limited 11.8-fs pulses with an energy of 0.12 mJ. The amplifier is pumped by 532-nm pulses from a synchronized mode-locked laser, Nd:YAG amplifier system. This approach is shown to be promising for the next generation of ultrafast amplifiers aimed at producing terawatt-level phase-controlled few-cycle laser pulses.
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Affiliation(s)
- R Th Zinkstok
- Atomic, Molecular, and Laser Physics Group, Laser Centre Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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230
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Beverini N, Carelli G, De Michele A, Maccioni E, Nyushkov B, Sorrentino F, Moretti A. Coherent multiwave heterodyne frequency measurement of a far-infared laser by means of a femtosecond laser comb. OPTICS LETTERS 2005; 30:32-34. [PMID: 15648628 DOI: 10.1364/ol.30.000032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We demonstrate the possibility of using a femtosecond laser to measure with high accuracy the frequency of a far-infrared (FIR) monochromatic source, such as an optically pumped molecular laser, by generating in a suitable mixer a signal in the radio-frequency region at the frequency difference between n steps of a femtosecond comb and the FIR source. All the couples of modes lying a distance of n steps from one another contribute coherently to the heterodyne signal. The technique has been tested up to 670 GHz.
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Affiliation(s)
- N Beverini
- Dipartimento di Fisica Enrico Fermi dell'Università di Pisa and Istituto Nazionale per la Fisica della Materia, Via F. Buonarroti 2, 56127 Pisa, Italy
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231
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Xu S, Reitze D, Windeler R. Controlling nonlinear processes in microstructured fibers using shaped pulses. OPTICS EXPRESS 2004; 12:4731-4741. [PMID: 19484025 DOI: 10.1364/opex.12.004731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
It is possible to modify pulse propagation and nonlinear interactions in microstructured fibers using phase-tailored ultrashort laser pulses. We experimentally investigate how pre-shaping of the input laser pulse can be used to alter its evolution and subsequent output characteristics. We also demonstrate how adaptive pulse shaping can be used to control the output properties of the pulse spectrum. Numerical simulations based on the nonlinear Schrodinger equation predict the output spectral profiles of the propagated pulse in good agreement with experimental results, and elucidate the relevant processes producing the optimal output.
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232
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Kim J, Kärtner FX, Perrott MH. Femtosecond synchronization of radio frequency signals with optical pulse trains. OPTICS LETTERS 2004; 29:2076-2078. [PMID: 15455785 DOI: 10.1364/ol.29.002076] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A synchronization scheme for extraction of low-jitter rf signals from optical pulse trains, which is robust against photodetector nonlinearities, is described. The scheme is based on a transfer of timing information into an intensity imbalance of the two output beams from a Sagnac loop. Sub-100-fs timing jitter between the extracted 2-GHz rf signal and the 100-MHz optical pulse train from a mode-locked Ti:sapphire laser is demonstrated.
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Affiliation(s)
- J Kim
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.
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233
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Genty G, Lehtonen M, Ludvigsen H, Kaivola M. Enhanced bandwidth of supercontinuum generated in microstructured fibers. OPTICS EXPRESS 2004; 12:3471-3480. [PMID: 19483874 DOI: 10.1364/opex.12.003471] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Enhancement of the bandwidth of supercontinuum generated in microstructured fibers with a tailored dispersion profile is demonstrated experimentally. The fibers are designed to have two zero-dispersion wavelengths separated by more than 700 nm, which results in an amplification of two dispersive waves at visible and infrared wavelengths. The underlying physics behind the broad continuum formation is discussed and analyzed in detail. The experimental observations are confirmed through numerical simulations.
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234
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Matos L, Kleppner D, Kuzucu O, Schibli TR, Kim J, Ippen EP, Kaertner FX. Direct frequency comb generation from an octave-spanning, prismless Ti:sapphire laser. OPTICS LETTERS 2004; 29:1683-1685. [PMID: 15309859 DOI: 10.1364/ol.29.001683] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We describe a self-referenced optical frequency comb generator based on an octave-spanning, prismless Ti:sapphire laser. Dispersion compensation is provided by novel double-chirped mirror pairs and BaF2 wedges. Current versions operate at 80 and 150 MHz. The compact prismless design allows system scaling to a gigahertz repetition rate. Its carrier-envelope beat note is intrinsically stable with a signal-to-noise ratio of 30 dB in a 100-kHz bandwidth. The octave is reached at 25 dB below the average power level. The in-loop accumulated phase error is 1.4 rad (20 mHz to 1 MHz). The technique has the advantages of simplicity and stability compared with previous designs.
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Affiliation(s)
- L Matos
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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235
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Konorov SO, Serebryannikov EE, Zheltikov AM, Zhou P, Tarasevitch AP, von der Linde D. Generation of femtosecond anti-stokes pulses through phase-matched parametric four-wave mixing in a photonic crystal fiber. OPTICS LETTERS 2004; 29:1545-1547. [PMID: 15259741 DOI: 10.1364/ol.29.001545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Phase-matched parametric four-wave mixing in higher-order guided modes of a photonic crystal fiber is shown to result in an efficient decay of 40-fs 800-nm Ti:sapphire laser pump pulses into an anti-Stokes signal with a central wavelength around 590-600 nm and a Stokes signal centered at 1.25 microm. The photonic crystal fiber is designed in such a way as to minimize the group-velocity dispersion at the pump wavelength, phase match the parametric four-wave-mixing process, and reduce the group delay between the pump and the anti-Stokes pulses. The duration of the anti-Stokes pulse under these conditions, as shown by cross-correlation frequency-resolved optical gating measurements, is less than 200 fs.
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Affiliation(s)
- S O Konorov
- Department of Physics, International Laser Center, M. V. Lomonosov Moscow State University, 119899 Moscow, Russia
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236
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Ma LS, Bi Z, Bartels A, Robertsson L, Zucco M, Windeler RS, Wilpers G, Oates C, Hollberg L, Diddams SA. Optical frequency synthesis and comparison with uncertainty at the 10(-19) level. Science 2004; 303:1843-5. [PMID: 15031498 DOI: 10.1126/science.1095092] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A femtosecond laser-based optical frequency synthesizer is referenced to an optical standard, and we use it to demonstrate the generation and control of the frequency of electromagnetic fields over 100 terahertz of bandwidth with fractional uncertainties approaching 1 part in 10(19). The reproducibility of this performance is verified by comparison of different types of femtosecond laser-based frequency synthesizers from three laboratories.
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Affiliation(s)
- Long-Sheng Ma
- Bureau International des Poids et Mesures (BIPM), Pavillon de Breteuil, 92312 Sèvres, France.
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237
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Fuji T, Apolonski A, Krausz F. Self-stabilization of carrier-envelope offset phase by use of difference-frequency generation. OPTICS LETTERS 2004; 29:632-634. [PMID: 15035494 DOI: 10.1364/ol.29.000632] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Self-stabilized carrier-envelope offset phase is achieved by use of difference-frequency (DF) generation. The spectrum from a Ti:sapphire oscillator is broadened in a photonic crystal fiber, and a DF (900 nm) between the blue component (490 nm) and the infrared component (1080 nm) is generated. The beat signal between the fundamental and the DF signal is clearly observed. The wavelength of the DF signal can be tuned down to 780 nm, and hence the signal can be used for injection seeding of a Ti:sapphire oscillator.
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Affiliation(s)
- Takao Fuji
- Photonics Institute, Vienna University of Technology, Gusshausstrasse 27/387 A-1040, Vienna, Austria.
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238
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Ma LS, Robertsson L, Picard S, Zucco M, Bi Z, Wu S, Windeler RS. First international comparison of femtosecond laser combs at the International Bureau of Weights and Measures. OPTICS LETTERS 2004; 29:641-643. [PMID: 15035497 DOI: 10.1364/ol.29.000641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The first international comparison of femtosecond laser combs has been carried out at the International Bureau of Weights and Measures (BIPM). Three comb systems were involved: BIPM-C1 and BIPM-C2 from the BIPM and ECNU-C1 from the East China Normal University (ECNU). The agreement among the three combs was found to be on the subhertz level in the vicinity of 563 THz. A frequency difference measurement scheme was demonstrated that is suitable for general comb comparisons.
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Affiliation(s)
- Long-Sheng Ma
- Bureau International des Poids et Mesures, Pavilion de Breteuil, F-92312, Sèvres Cedex, France.
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239
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Apolonski A, Dombi P, Paulus GG, Kakehata M, Holzwarth R, Udem T, Lemell C, Torizuka K, Burgdörfer J, Hänsch TW, Krausz F. Observation of light-phase-sensitive photoemission from a metal. PHYSICAL REVIEW LETTERS 2004; 92:073902. [PMID: 14995852 DOI: 10.1103/physrevlett.92.073902] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2003] [Indexed: 05/24/2023]
Abstract
We demonstrate that multiphoton-induced photoelectron emission from a gold surface caused by low-energy (unamplified) 4-fs, 750-nm laser pulses is sensitive to the timing of electric field oscillations with respect to the pulse peak. This observation confirms recent theoretical predictions and opens the door to measuring the absolute value of the carrier-envelope phase difference of few-cycle light pulses with a solid-state detector.
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Affiliation(s)
- A Apolonski
- Institut für Photonik, Technische Universität Wien, Gusshausstrasse 27, A-1040 Vienna, Austria
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240
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Zimmermann M, Gohle C, Holzwarth R, Udem T, Hänsch TW. Optical clockwork with an offset-free difference-frequency comb: accuracy of sum- and difference-frequency generation. OPTICS LETTERS 2004; 29:310-312. [PMID: 14759061 DOI: 10.1364/ol.29.000310] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We demonstrate a simple optical clockwork mechanism based on the broadened frequency comb of a femtosecond laser and on difference-frequency generation (DFG) in a nonlinear crystal. The DFG comb possesses a vanishing carrier envelope offset frequency that permits the construction of a simple and thus potentially more stable optical clockwork. In addition it offers the possibility of extending the frequency comb into the infrared spectral region. The overall accuracy and stability of the DFG comb relative to the initial frequency comb were measured to be 6.6 x 10(-21) and 10(-18) tau(-1), respectively, where tau is the averaging time in seconds. Assuming that sum- and difference-frequency generation are independent processes, our measurements suggest a <10(-20) accuracy for them.
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Affiliation(s)
- Marcus Zimmermann
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany.
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241
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242
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243
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Precision Spectroscopy of Atomic Hydrogen and Variations of Fundamental Constants. ASTROPHYSICS, CLOCKS AND FUNDAMENTAL CONSTANTS 2004. [DOI: 10.1007/978-3-540-40991-5_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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244
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Kano H, Hamaguchi HO. Characterization of a supercontinuum generated from a photonic crystal fiber and its application to coherent Raman spectroscopy. OPTICS LETTERS 2003; 28:2360-2362. [PMID: 14680182 DOI: 10.1364/ol.28.002360] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The temporal and spectral profiles of supercontinuum radiation generated from a photonic crystal fiber are evaluated with a polarization-gate frequency-resolved optical gating technique. The supercontinuum is then applied to coherent inverse Raman spectroscopy. A stimulated Raman signal of cyclohexane is observed as an induced absorption signal with an instantaneous response. The Raman signal has a peak at a slight negative delay time, which is explained by perturbed Raman-induced coherence.
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Affiliation(s)
- Hideaki Kano
- Department of Chemistry, School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan.
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245
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Akimov DA, Serebryannikov EE, Zheltikov AM, Schmitt M, Maksimenka R, Kiefer W, Dukel'skii KV, Shevandin VS, Kondrat'ev YN. Efficient anti-Stokes generation through phase-matched four-wave mixing in higher-order modes of a microstructure fiber. OPTICS LETTERS 2003; 28:1948-1950. [PMID: 14587785 DOI: 10.1364/ol.28.001948] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Phase-matched four-wave mixing in higher-order modes of microstructure fibers allows unprecedentedly high efficiencies of anti-Stokes frequency conversion to be achieved for subnanojoule femtosecond laser pulses. 70-fs pulses of 790-nm radiation were used to generate an anti-Stokes component at 520-530 nm in a higher-order mode of a microstructure fiber with a 4.8-microm core. The maximum ratio of the anti-Stokes signal energy to the energy of the pump component in the output spectrum is estimated as 1.7.
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Affiliation(s)
- D A Akimov
- Physics Department, International Laser Center, M. V. Lomonosov Moscow State University, 119899 Moscow, Russia
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246
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Abstract
Ultrafast lasers, which generate optical pulses in the picosecond and femtosecond range, have progressed over the past decade from complicated and specialized laboratory systems to compact, reliable instruments. Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution (much smaller than 10 fs), extremely high peak optical intensities (greater than 10 TW/cm2) and extremely fast pulse repetition rates (greater than 100 GHz).
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Affiliation(s)
- Ursula Keller
- Physics Department, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland.
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247
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Reeves WH, Skryabin DV, Biancalana F, Knight JC, Russell PSJ, Omenetto FG, Efimov A, Taylor AJ. Transformation and control of ultra-short pulses in dispersion-engineered photonic crystal fibres. Nature 2003; 424:511-5. [PMID: 12891348 DOI: 10.1038/nature01798] [Citation(s) in RCA: 317] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2003] [Accepted: 06/04/2003] [Indexed: 11/09/2022]
Abstract
Photonic crystal fibres (PCFs) offer greatly enhanced design freedom compared to standard optical fibres. For example, they allow precise control of the chromatic dispersion (CD) profile--the frequency dependence of propagation speed--over a broad wavelength range. This permits studies of nonlinear pulse propagation in previously inaccessible parameter regimes. Here we report on spectral broadening of 100-fs pulses in PCFs with anomalously flat CD profiles. Maps of the spectral and spatio-temporal behaviour as a function of power show that dramatic conversion (to both longer and shorter wavelengths) can occur in remarkably short lengths of fibre, depending on the magnitude and shape of the CD profile. Because the PCFs used are single-mode at all wavelengths, the light always emerges in a fundamental guided mode. Excellent agreement is obtained between the experimental results and numerical solutions of the nonlinear wave equation, indicating that the underlying processes can be reliably modelled. These results show how, through appropriate choice of CD, nonlinearities can be efficiently harnessed to generate laser light at new wavelengths.
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Affiliation(s)
- W H Reeves
- Optoelectronics Group, Department of Physics, University of Bath, Bath BA2 7AY, UK
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248
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Jacquey M, Bonhommeau S, Bouchene MA. Experimental demonstration of phase control of dispersion effects for an ultrashort pulse train propagating in a resonant medium. OPTICS LETTERS 2003; 28:1272-1274. [PMID: 12885044 DOI: 10.1364/ol.28.001272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present an experiment in which an ultrashort pulse train propagates resonantly through anoptically dense vapor of atomic rubidium. The sequence obtained from a Fabry-Perot interferometer comprises nearly 10 regularly time-delayed and mode-locked pulses. We show that a sequence with phase shift phi = 0[2pi] between two successive pulses propagates with important temporal distortion, whereas a sequence with phi = pi[2pi] experiences few propagation effects, thus leading for the first time to our knowledge to the possibility of phase control of dispersion effects for an ultrashort pulse train.
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Affiliation(s)
- M Jacquey
- Laboratoire de Collisions Agrégats Réactivité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5589, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex 4, France
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249
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Bast R, Schwerdtfeger P. Parity-violation effects in the C-F stretching mode of heavy-atom methyl fluorides. PHYSICAL REVIEW LETTERS 2003; 91:023001. [PMID: 12906477 DOI: 10.1103/physrevlett.91.023001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2003] [Indexed: 05/24/2023]
Abstract
Relativistic four-component electronic structure calculations including parity-odd electroweak interactions give unprecedented large energy differences of 158 mHz for PH3AuCHFCl and 219 mHz for ClHgCHFCl for the C-F stretching mode of the corresponding enantiomeric compounds. This signifies a considerable improvement over previous predictions for chiral methyl compounds of the form CHXYZ (X, Y, Z=F, Cl, Br, or I). These organometallic compounds are therefore ideal for future high resolution spectroscopy experiments.
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Affiliation(s)
- Radovan Bast
- Department of Chemistry, University of Auckland, Private Bag 92019, Auckland, New Zealand
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250
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Bize S, Diddams SA, Tanaka U, Tanner CE, Oskay WH, Drullinger RE, Parker TE, Heavner TP, Jefferts SR, Hollberg L, Itano WM, Bergquist JC. Testing the stability of fundamental constants with the 199Hg+ single-ion optical clock. PHYSICAL REVIEW LETTERS 2003; 90:150802. [PMID: 12732024 DOI: 10.1103/physrevlett.90.150802] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2002] [Revised: 02/27/2003] [Indexed: 05/24/2023]
Abstract
Over a two-year duration, we have compared the frequency of the 199Hg+ 5d(10)6s (2)S(1/2)(F=0)<-->5d(9)6s(2) (2)D(5/2)(F=2) electric-quadrupole transition at 282 nm with the frequency of the ground-state hyperfine splitting in neutral 133Cs. These measurements show that any fractional time variation of the ratio nu(Cs)/nu(Hg) between the two frequencies is smaller than +/-7 x 10(-15) yr(-1) (1sigma uncertainty). According to recent atomic structure calculations, this sets an upper limit to a possible fractional time variation of g(Cs)(m(e)/m(p))alpha(6.0) at the same level.
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Affiliation(s)
- S Bize
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.
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