Academic literature on the topic 'Stimulated Raman transition'
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Journal articles on the topic "Stimulated Raman transition"
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Fainberg, B. D., and B. Levinsky. "Stimulated Raman Adiabatic Passage in a Dense Medium." Advances in Physical Chemistry 2010 (December 22, 2010): 1–8. http://dx.doi.org/10.1155/2010/798419.
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We have considered a coherent population transfer to a higher excited singlet state (S2) of molecules with anomalous fluorescence in molecular assemblies (e.g., a dense medium). A direct excitation to S2 requires light in the UV region. Because of this, the transition is conveniently realized by a two-step (two-photon) process: S0→S1→S2, where transitions S0→S1 and S1→S2 correspond to the optical region. We have shown that efficient stimulated Raman adiabatic passage (STIRAP) in the ladder configuration can be realized in this case, using suitably chirped pulses, to compensate a change of the two-photon transition frequency in time, induced by the pulses themselves, due to near dipole-dipole interactions. We have provided a reduced state formulation of the optical control process. Chirping the “pump” pulse that excites transition S0→S1 is nonequivalent to chirping the “Stokes” pulse that excites transition S1→S2, with respect to the population of the intermediate state (S1) in the pulse nonadiabatic regime. We have also shown that with suitably chirped pulses, efficient STIRAP still persists even for a rather large decay of the intermediate state.
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He Huiyong, 贺慧勇, and 黄春佳 Huang Chunjia. "Squeezed Atom Laser Oringinating From Stimulated Raman Transition." Acta Optica Sinica 29, no. 12 (2009): 3531–35. http://dx.doi.org/10.3788/aos20092912.3531.
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Henkel, Carsten, Klaus Mølmer, Robin Kaiser, and Christoph I. Westbrook. "Atomic diffraction assisted by a stimulated Raman transition." Physical Review A 56, no. 1 (July 1, 1997): R9—R12. http://dx.doi.org/10.1103/physreva.56.r9.
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Karpf, Sebastian, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber. "Shot-Noise Limited Time-Encoded Raman Spectroscopy." Journal of Spectroscopy 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/9253475.
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Raman scattering, an inelastic scattering mechanism, provides information about molecular excitation energies and can be used to identify chemical compounds. Albeit being a powerful analysis tool, especially for label-free biomedical imaging with molecular contrast, it suffers from inherently low signal levels. This practical limitation can be overcome by nonlinear enhancement techniques like stimulated Raman scattering (SRS). In SRS, an additional light source stimulates the Raman scattering process. This can lead to orders of magnitude increase in signal levels and hence faster acquisition in biomedical imaging. However, achieving a broad spectral coverage in SRS is technically challenging and the signal is no longer background-free, as either stimulated Raman gain (SRG) or loss (SRL) is measured, turning a sensitivity limit into a dynamic range limit. Thus, the signal has to be isolated from the laser background light, requiring elaborate methods for minimizing detection noise. Here, we analyze the detection sensitivity of a shot-noise limited broadband stimulated time-encoded Raman (TICO-Raman) system in detail. In time-encoded Raman, a wavelength-swept Fourier domain mode locking (FDML) laser covers a broad range of Raman transition energies while allowing a dual-balanced detection for lowering the detection noise to the fundamental shot-noise limit.
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Kien, Fam Le, and K. Hakuta. "Stimulated Raman scattering with slow light." Canadian Journal of Physics 78, no. 5-6 (April 5, 2000): 543–59. http://dx.doi.org/10.1139/p00-014.
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We study the propagation dynamics of weak Raman sideband fields in a far-off-resonance Raman medium driven by a strong coupling field. We show that the interaction of the system with the strong field, under the conditions of high density, narrow Raman-transition width, and small two-photon detuning, results ina slow group velocity and a substantial enhancement of the injected anti-Stokes sideband field as well as an efficient generation of a Stokes sideband field. We find that the effective group velocity is the same for the two weak fields and is proportional to the field frequency difference instead of the frequency of the corresponding field. We also discuss the condition for exponential growth of the two sideband fields in the medium. We perform numerical calculations for solid hydrogen, a realistic system where the requirements for high density and small Raman width can be met. We demonstrate that the group velocity can be slowed down by several orders, and that the slow light plays a key role for the stimulated Raman scattering process in solid hydrogen.PACS Nos.: 42.50Gy, 42.50Hz, 42.65Ky, 42.79Nv
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Shen, Chencheng, Xianglong Cai, Tiancheng Zheng, Yuxi Jia, Dong Liu, Jinbo Liu, and Jingwei Guo. "Mid-Infrared Multispectral Gaseous Stimulated Raman Scattering Laser." Applied Sciences 11, no. 24 (December 14, 2021): 11875. http://dx.doi.org/10.3390/app112411875.
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We demonstrated mid-infrared gaseous stimulated Raman scattering lasers in free space. Mixed gases of hydrogen and deuterium were used as Raman gain media in one Raman cell. Pumped by laser pulses at 1064 nm, the first Stokes Raman components at 1560 nm and 1907 nm were generated. A four-wave mixing process with the pump laser at 1064 nm and Raman lasers at 1560 nm and 1907 nm contributed to dramatically reducing the threshold of mid-IR laser generation at 4432 nm. The maximum output peak power of a mid-IR laser at 4432 nm reached 121 kW. Furthermore, by scattering on the rotational transition of deuterium, multispectral mid-IR Raman lasers at wavelengths of 2071 nm, 2266 nm, 2604 nm, 2920 nm, 3322 nm, 3743 nm, 4432 nm, and 5431 nm were also generated. Our results show that this is a convenient method to reduce the threshold and achieve a high power output with mid-IR Raman lasers.
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Huang, Chunjia, Huiyong He, and Lijun Tang. "Generating of squeezed atom laser via stimulated Raman transition." Optics Communications 282, no. 15 (August 2009): 3177–80. http://dx.doi.org/10.1016/j.optcom.2009.04.042.
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Katsuragawa, M., M. Suzuki, R. S. D. Sihombing, J. Z. Li, and K. Hakuta. "Nonlinear optics in solid hydrogen." Laser and Particle Beams 16, no. 4 (December 1998): 641–48. http://dx.doi.org/10.1017/s0263034600011459.
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We show through experiments of stimulated Raman scattering how solid hydrogen (parahydrogen) can open new perspectives on nonlinear optics. Two phenomena are described: One is the self-induced phase matching in parametric anti-Stokes stimulated Raman scattering (SRS) in which the phase matching is self-organized automatically without the stringent restriction of refractive-index dispersion of the medium, and the other is the extremely slow coherence decay behavior for the Raman transition that may result in the Raman width of 80 kHz full width at half maximum (FWHM).
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Baklanov, E. V., S. M. Kobtsev, and A. V. Taichenachev. "Precision Measurements of Forbidden Transition Frequencies Using Stimulated Raman Scattering." Optics and Spectroscopy 125, no. 5 (November 2018): 679–83. http://dx.doi.org/10.1134/s0030400x18110061.
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Sanborn, F., and C. R. Menyuk. "Transition from transient to stationary behavior in stimulated Raman scattering." Journal of the Optical Society of America B 13, no. 9 (September 1, 1996): 1921. http://dx.doi.org/10.1364/josab.13.001921.
Full textDissertations / Theses on the topic "Stimulated Raman transition"
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Archibald, Lawrence. "Construction of a 408 nm Laser System for Use in Ion Interferometry." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5622.
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This work reports on the construction of a 408 nm laser system designed to drive stimulated Raman transitions between the F = 4 and F = 5 2 S 1/2 states of 87 Sr + using the 2 P 3/2 state as the intermediate state. This laser system will be used as part of a 87 Sr + ion interferometer. This work also includes a discussion of relevant theory describing the interaction of the ions and laser, along with a calculation of the transition rates as a function of laser power and detuning.
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Le, Gouët Julien. "Étude des performances d'un gravimètre atomique absolu : sensibilité limite et exactitude préliminaire." Paris 11, 2008. https://theses.hal.science/tel-00311422.
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L'interférométrie atomique est appliquée à la mesure absolue de l'accélération de pesanteur g, afin de fournir une mesure exacte à l'expérience de balance du watt réalisée au LNE. La source atomique est obtenue à partir d'un nuage d'atomes froids de Rubidium 87. Deux faisceaux lasers contra-propageants verticaux sont utilisés pour réaliser des transitions Raman stimulées, qui permettent de séparer et faire interférer les paquets d'onde. Lors des transitions, la différence de phase entre les lasers est imprimée sur la phase des atomes en chute libre. Le déphasage atomique entre les deux chemins verticaux est alors sensible à l'accélération des atomes et permet d'accéder à une valeur exacte de g. Une partie du manuscrit est consacrée à l'étude des sources de bruit affectant la sensibilité de la mesure. Nous détaillons notamment la contribution des vibrations, que nous réduisons d'un facteur 3 à 10 selon les configurations, grâce à la mesure d'un sismomètre et au traitement numérique de cette mesure. La meilleure sensibilité mesurée, dans les conditions d'environnement optimales, est de 1,4 10−8~g/Hz1/2. Par ailleurs, l'étude de l'exactitude de la mesure occupe une part importante de ce travail. Bien que l'enceinte à vide utilisée ne soit que provisoire, nous avons entrepris le recensement des effets systématiques. D'après deux comparaisons avec des gravimètres absolus basés sur une technique éprouvée d'interférométrie optique, notre mesure présente un biais résiduel de 16 10−9~gAtom interferometry is applied to absolute measurement of gravity acceleration g, to provide an accurate value for the realization of the LNE watt balance. The atomic source is obtained from a cloud of cold 87 Rubidium atoms. Two vertical counter-propagating are used to generate stimulated Raman transitions, that separate the wave-packets and make them interfere. During the transitions, the phase difference between the beams is printed on the phase of the free-falling atoms. Then the atomic phase shift between the two vertical paths becomes sensitive to the atom acceleration and allows obtaining an accurate value of g. A part of this manuscript is dedicated to the study of noise sources which deteriorate the measurement sensitivity. In particular, we detail the vibrations contribution, which we are able to reduce by a factor of 3 to 10, depending on the configurations, thanks to the measurement of a seismometer and to its analog processing. The best reported sensitivity, in optimal environment, is 1,4 10−8~g/Hz1/2. The study of the measurement accuracy also represents an important part of this work. Although the vacuum chamber was only temporary, we started to list the systematic shifts. According to two comparisons with well-known absolute gravimeters based on optical interferometry, our measurement shows a residual bias of 16 10−9~g
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Chopinaud, Aurélien. "Atomes et vortex optiques : conversion de moments orbitaux de lumière en utilisant la transition à deux photons 5S-5D du rubidium." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS155/document.
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Le moment orbital angulaire (OAM) de la lumière est une grandeur quantifiée associée à la phase d’un vortex optique et est actuellement une des variables explorées pour les technologies quantiques.Dans ce contexte, cette thèse étudie expérimentalement la conversion de vortex optiques par une vapeur de rubidium, via la transition Raman stimulée à deux photons 5S₁/₂ − 5D₅/₂. Quand les atomes sont soumis à deux lasers respectivement à 780 nm et 776 nm, ils génèrent des rayonnements cohérents, infrarouge à 5,23 μm et bleu à 420 nm. On examine le rayonnement bleu lorsque l’un des lasers ou les deux sont des vortex, en particulier des modes de Laguerre-Gauss. Dans une première partie nous montrons que si l’OAM est porté par le laser à 776 nm, alors le rayonnement bleu émis porte un OAM qui respecte l’accord de phase azimutale et de phase de Gouy. Nous montrons aussi que la conversion est efficace sur une grande plage d’OAM allant de -50 à +50, que l’efficacité est gouvernée par le produit des intensités des lasers incidents et que le rayonnement bleu se comporte comme un mode de Laguerre-Gauss pur. Dans une deuxième partie nous montrons qu’il est possible de convertir une superposition de vortex ou une paire de vortex coaxiaux et que l’OAM du rayonnement bleu émis obéit à la règle de somme des OAM incidents. Pour les cas étudiés, nous proposons un modèle de mélange à quatre ondes qui établit les règles de sélection du processus de conversion d’OAM. Ce travail ouvre la voie vers la conversion d’OAM utilisant des transitions vers des niveaux atomiques plus élevésThe orbital angular momentum of light (OAM) is a quantized quantity arising from the azimuthal phase carried by optical vortices and is well-known for quantum technology applications. Its set of values is theoretically infinite.In this context this thesis experimentally study the conversion of optical vortices in a rubidium vapor through the 5S₁/₂ − 5D₅/₂ stimulated Raman transition. When the atoms are illuminated with laser beams at 780 nm and 776 nm they generate two coherent light beams at 5,23 μm and 420 nm. We investigate the blue light when one laser or both are optical vortices, in particular Laguerre-Gaussian modes. In a first part we show that if the laser at 776 nm carries an OAM the blue light is an optical vortex with an OAM which respects azimutal and Gouy phase matchings. We further show that the conversion is efficient on a large set of OAM from -50 to +50, that the efficiency is governed by the product of the input laser intensities and that the blue light behaves like a pure Laguerre-Gaussian mode. In a second part we demonstrate the conversion of a vortex superposition or a pair of coaxial vortices and that the OAM of the emitted light obeys the conservation rule of total OAM. For each studied case we propose a four wave mixing model establishing selection rules for the conversion process. This work opens possibilities towards OAM conversion using higher atomic levels
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Geiger, Remi. "Senseur inertiel à ondes de matière aéroporté." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00651016.
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cette thèse porte sur l'étude d'un accéléromètre à ondes de matière fonctionnant à bord d'un avion effectuant des vols paraboliques et permettant des expériences en micro-gravité (0-g). Un interféromètre à atomes de 87Rb refroidis par laser, et dont les états quantiques sont manipulés à l'aide de transitions Raman stimulées, constitue l'élément physique du capteur. Lors de la conception du dispositif expérimental, un effort particulier a été apporté au choix d'une source laser transportable, stable, et robuste. Nous démontrons pour la première fois le fonctionnement aéroporté d'un senseur inertiel à ondes de matière, à la fois en 0-g et durant les phases de gravité des vols (1-g). Nous proposons une technique combinant le signal de l'interféromètre à celui d'accéléromètres mécaniques auxiliaires pour effectuer des mesures au dela de la dynamique intrinsèque du capteur atomique. Nous expliquons comment bénéficier du haut niveau de sensibilité de l'interféromètre dans l'avion, et indiquons des voies d'améliorations significatives de notre dispositif pour le futur. En 0-g, nous montrons une amélioration de la sensibilité de l'accéléromètre jusque 2 x 10-4 m.s-2 à une seconde, et étudions une réjection des vibrations de l'avion à l'aide d'un interféromètre à quatre impulsions Raman. L'objectif de notre projet consiste en un test du principe d'universalité de la chute libre avec un double accéléromètre à atomes de 87Rb et de 39K. Notre système laser double-espèce emploie des composants optiques fibrés aux longueurs d'onde de 1.56 et 1.54 μm, ainsi qu'un doublage de fréquence pour obtenir la lumière utile à 780 et 767 nm pour le refroidissement et la manipulation des deux atomes. Nous étudions théoriquement la sensibilité d'une mesure de leur différence d'accélération en tenant compte des vibrations de l'avion, et précisons comment une résolution de l'ordre de 10-10 m.s-2 pourra être atteinte dans le futur avec notre expérience aéroportée.
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Geiger, Remi. "Senseur inertiel à ondes de matière aéroporté." Electronic Thesis or Diss., Paris 11, 2011. http://www.theses.fr/2011PA112207.
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: cette thèse porte sur l’étude d’un accéléromètre à ondes de matière fonctionnant à bord d’un avion effectuant des vols paraboliques et permettant des expériences en micro-gravité (0-g). Un interféromètre à atomes de 87Rb refroidis par laser, et dont les états quantiques sont manipulés à l’aide de transitions Raman stimulées, constitue l’élément physique du capteur. Lors de la conception du dispositif expérimental, un effort particulier a été apporté au choix d’une source laser transportable, stable, et robuste. Nous démontrons pour la première fois le fonctionnement aéroporté d’un senseur inertiel à ondes de matière, à la fois en 0-g et durant les phases de gravité des vols (1-g). Nous proposons une technique combinant le signal de l’interféromètre à celui d’accéléromètres mécaniques auxiliaires pour effectuer des mesures au dela de la dynamique intrinsèque du capteur atomique. Nous expliquons comment bénéficier du haut niveau de sensibilité de l’interféromètre dans l’avion, et indiquons des voies d’améliorations significatives de notre dispositif pour le futur. En 0-g, nous montrons une amélioration de la sensibilité de l’accéléromètre jusque 2 x 10-4 m.s-2 à une seconde, et étudions une réjection des vibrations de l’avion à l’aide d’un interféromètre à quatre impulsions Raman. L’objectif de notre projet consiste en un test du principe d’universalité de la chute libre avec un double accéléromètre à atomes de 87Rb et de 39K. Notre système laser double-espèce emploie des composants optiques fibrés aux longueurs d’onde de 1.56 et 1.54 μm, ainsi qu’un doublage de fréquence pour obtenir la lumière utile à 780 et 767 nm pour le refroidissement et la manipulation des deux atomes. Nous étudions théoriquement la sensibilité d’une mesure de leur différence d’accélération en tenant compte des vibrations de l’avion, et précisons comment une résolution de l’ordre de 10-10 m.s-2 pourra être atteinte dans le futur avec notre expérience aéroportéeThis thesis reports the study of a matter-wave accelerometer operated aboard a 0-g plane in ballistic flights. The acceleration measurements are performed with a cold 87Rb atom interferometer using stimulated Raman transitions to manipulate the quantum states of the atoms. When designing the instrument, we took special care to make the laser source transportable, robust, and stable. With our setup, we demonstrate the first operation of a matter-wave inertial sensor aboard a plane, both in 0-g and during the gravity phases of the flights (1-g). Thanks to additional mechanical accelerometers probing the coarse inertial effects, we are able to detect acceleration fluctuations much greater than the intrinsic measurement range of the interferometer. We explain our method to benefit from the full sensitivity of the matter-wave sensor in the plane, and suggest significant improvements of our system for the future. In 0-g, we show the enhancement of the accelerometer sensitivity up to 2 x 10-4 m.s-2 in one second, and investigate a rejection of the vibrations of the plane with a four Raman pulses interferometer. The goal of our project is to perform a test of the universality of free fall with two atom accelerometers using 87Rb and 39K. The laser system for the two-species interferometer is based on fiber optical components at wavelengths of 1.56 and 1.54 μm, and optical frequency doubling to generate the useful light at 780 and 767 nm to cool and manipulate the atoms. We study theoretically the sensitivity of the differential acceleration measurement by taking into account the vibrations of the plane, and discuss how a resolution of the order of 10-10 m.s-2 could be achieved in the future with our airborne experiment
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Altorio, Matteo. "Novel atom interferometry techniques for a cold-atom gyroscope of large Sagnac area Atom interferometry with top-hat laser beams Improving the phase response of an atom interferometer by means of temporal pulse shaping." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS449.
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Cette thèse décrit la mise en œuvre de nouvelles techniques d'interférométrie atomique améliorant la stabilité et l’exactitude d'un gyromètre à atomes froids situé au laboratoire SYRTE. Des transitions Raman stimulées permettent de séparer et recombiner les ondes atomiques. Une séquence de quatre impulsions lumineuses génère un interféromètre avec une aire Sagnac de 11 cm2. Je présente la mise en œuvre d'un schéma d'interrogation entrelacé dans un interféromètre dont le temps d'interrogation est de 801 ms, dans lequel trois nuages atomiques sont interrogés simultanément résultant en une cadence de mesure de 3,75 Hz. Avec ce schéma, nous démontrons une sensibilité de 30 nrad/s/sqrt(Hz). Nous présentons ensuite des mesures de rotation dynamiques dans une plage jusqu'ici inexplorée pour un capteur à atomes froids. Un biais important du capteur provient d'un couplage entre un désalignement relatif des miroirs rétroréfléchissant les faisceaux Raman et la trajectoire de l'atome. Une technique est introduite pour réduire ce biais au niveau de 3 nrad/s et atteindre une stabilité à long terme de 0,3 nrad/s qui représente l'état de l'art des gyromètres atomiques. Le manuscrit décrit ensuite la première caractérisation du facteur d'échelle du gyromètre à l'aide de différentes techniques. En particulier, la mise en place d’une plateforme de rotation sous le capteur permet de faire varier la projection du vecteur rotation de la Terre sur l'interféromètre et donc de moduler le déphasage de rotation. Les techniques présentées dans cette thèse ouvrent la voie à un test de l'effet Sagnac pour les ondes de matière avec une précision relative inférieure à 100 parties par millionThis thesis describes the implementation of new atom interferometry techniques to improve the stability and accuracy of a cold-atom gyroscope located at the SYRTE laboratory. Stimulated Raman transitions are used to split and recombine the atomic waves. A sequence of four light pulses generates an interferometer with a Sagnac area of 11 cm2. I present the implementation of an interleaved interrogation scheme, where three atomic clouds are interrogated simultaneously in an atom interferometer featuring a sampling rate of 3.75 Hz and an interrogation time of 801 ms. With this scheme we demonstrate a short-term sensitivity of 30 nrad·s-1·Hz-1/2. We then present measurements of dynamic rotation rates in a so far unexplored range for a cold atom sensor. An important bias of the sensor originates from a coupling between a relative misalignment of the mirrors which retro-reflect the Raman beams and the trajectory of the atom. A technique is introduced to reduce this bias at the level of 3 nrad·s-1 and to achieve a long-term stability of 0.3 nrad·s-1 which represents the state of the art for atomic gyroscopes. The manuscript then describes the first characterization of the scale factor of the gyroscope using different techniques. In particular, the implementation of a rotation stage below the sensor enables us to vary the projection of the Erath rotation rate vector onto the interferometer area and therefore to modulate the rotation phase shift. The implementation of the techniques presented in this thesis pave paving the way to a test of the Sagnac effect for matter waves with a relative accuracy level below 100 parts per million
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Perrin, Isadora. "Développement expérimental d’un capteur inertiel multi-axe à atomes froids hybride embarquable." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS326.
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Ce manuscrit présente le développement expérimental d’un capteur inertiel à atomes froids mesurant l’accélération de pesanteur, la composante verticale du gradient de gravité et l’accélération horizontale, en choisissant des technologies qui permettent d’obtenir un capteur inertiel embarquable et hybridé avec des capteurs classiques. Le dispositif expérimental permet d’effectuer des séquences d’interférométrie verticales et horizontales avec des transitions Raman stimulées rétroréfléchies contra-propageantes. La séquence d’interférométrie à quatre impulsions Raman a été utilisée pour mesurer le gradient de gravité. Les effets systématiques ont été étudiées afin d’obtenir l’exactitude de la mesure. Notre mesure extrapolée avec une chute libre de 1 mètre et limitée par le bruit de projection quantique permettrait d’atteindre des sensibilités du même ordre que l’état de l’art. Cette méthode est intéressante pour un capteur embarquable car elle est facile à mettre en place, et elle est insensible à la force de Coriolis, qui cause une grosse chute de contraste pour un interféromètre Mach-Zehnder en dynamique. Cette méthode peut être utilisée pour la mesure de rotation dans un capteur inertiel embarqué. Une mesure de l’accélération horizontale a été effectuée en simple diffraction avec des faisceaux lasers Raman horizontaux contra-propageants et rétro-réfléchis. Pour la mesure de l'accélération horizontale, un interféromètre Mach-Zehnder horizontal a été utilisé. Une rampe de fréquence est appliquée sur les faisceaux Raman pour levée la dégénérescence des deux paires Raman. La mesure effectuée a une sensibilité proche de l'état de l'artThis work focuses on the development of a cold-atom inertial sensor measuring the gravity, the vertical gravity gradient and the horizontal acceleration, by choosing technologies enabling to obtain an onboard and hybrid inertial sensor. The experimental setup generates a cold atom cloud of 87Rb, allows vertical et horizontal interferometry sequences using retroreflected contrapropagating stimulated Raman transitions, and allows a maximum free fall distance of 20 cm. The sensitivity obtained for the measurement of the gravity is 68 microGal/VHz and the optimal resolution reached 1,4 microGal after 6000 s of integration. The four-pulses interferometry sequence has been used for the measurement of the vertical gravity gradient. The sensitivity and the systematics have been studied. Our measurement, extrapolated with a sensor allowing 1 meter free fall and limited by quantum projection noise, could reach a sensitivity of 13 E/VHz, competitive with state of the-art. This method could be used for the measurement of rotations in an onboard inertiel sensor. A measurement of horizontal acceleration using simple diffraction interferometer with horizontal retroreflected contrapropagation stimulated Raman transitions. To lift the degeneracy of the two Raman transitions in the horizontal axis with zero-velocity atoms, we chirp the frequency of the Raman beam. It allows us to realize a Mach-Zehnder atom interferometer to measure the horizontal acceleration
Book chapters on the topic "Stimulated Raman transition"
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He, Guang S. "Stimulated Raman Scattering." In Laser Stimulated Scattering and Multiphoton Excitation, 61–143. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192895615.003.0004.
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The gain of stimulated Raman scattering (SRS) is based on the fact that the photon degeneracy of the pump beam (n¯p) and that of the scattering beam (n¯s) can be both >> 1, and therefore the latter can be increased exponentially. The SRS can be generated in both forward and backward directions. Owing to Raman resonance-enhanced refractive-index change, the self-focusing effect, the four-wave frequency mixing (FWFM) effect, the spectral broadening effect, and the opto-thermal influence-induced self-defocusing effect may take place during the SRS processes. These additional effects can be distinguished from each other using appropriate experimental design. Most SRS studies are related to the molecular vibrational transitions, although some SRS studies are also related to the spin-flip transition in a low-temperature semiconductor crystal, to the electronic transition in a metal vapor, and to the rotational transition in a molecular gas medium.
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He, Guang S. "Quantum Electrodynamic Theory of Light Radiation." In Laser Stimulated Scattering and Multiphoton Excitation, 42–60. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192895615.003.0003.
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The quantum electrodynamic theory, based on the quantization of the electromagnetic field, introduces the concept of photon and the related photon creation operator, photon annihilation operator, and photon number operator. It is used to describe stimulated Raman scattering, stimulated Kerr scattering, and various multiphoton excitation processes. Within this theoretical regime the light (as a photon field) and molecules are treated as a combined quantum mechanical system. The light emission or absorption is always accompanied by the quantum transition of the whole system from its initial eigenstate to the final eigenstate. The molecular emission or absorption probability rate is determined by the corresponding transition matrix elements of the interaction Hamiltonian operator.
Conference papers on the topic "Stimulated Raman transition"
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Kasevich, Mark, and Steven Chu. "Atomic interferometry using stimulated Raman transitions." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.tuvv1.
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Sodium atoms prepared in hyperfine ground-state 11 > are driven to the other ground-state hyperfine level 12> when two laser beams nearly resonant with an optical transition have a frequency difference equal to the ground-state hyperfine splitting. When the two laser beams are counterpropagating, conservation of momentum between the atom and the light field requires that the atom acquire a velocity kick ~22 ħk/m during the 11> and 12> transition (~6 cm/sec in our experiment). When the lasers are detuned far from the optical transition, spontaneous emission from the intermediate optical level becomes negligible, and the atom behaves as a two-level system coupled to a resonant rf driving field. We have created an interferometer by applying a π/2-π-π/2 Raman pulse sequence: a first π/2 pulse coherently splits the atomic wave packet by putting it in a superposition of states 11> and 12>, a second π pulse occurring a time Δt later redirects each wave packet and a final π/2 pulse recombines the wave packets at time 2Δt. We have observed wave packet interference for wave packet separations of 2.4 mm and, by using the interferometer as an accelerometer, have measured the atom’s acceleration due to gravity to 3 parts in 106.
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Wood, C. S., S. C. Bennett, D. Cho, and C. E. Wieman. "Stimulated Raman Spectroscopy with a Modulated External Cavity Diode Laser." In Semiconductor Lasers: Advanced Devices and Applications. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/slada.1995.mb.3.
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The usefulness of stimulated Raman transitions has been demonstrated in a variety of different applications. These two-photon transitions have the capability of very high resolution because the transition linewidths depend on the relative jitter between two frequencies, rather than absolute jitter on either one. Recent demonstrations include laser cooling and atomic interferometry [1]. They may also be needed for improved atomic clocks [2]. Due to this high resolution, stimulated Raman transitions can be a direct replacement for a microwave cavity and are often more compatible with optical experiments because a laser beam requires less space.
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Han, Xiaofeng, Zhenguo Lu, Yongkang Cheng, and Zuguang Ma. "Stimulated electronic Raman scattering in sodium vapor." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.tum5.
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Wiederrecht, Gary P., Thomas P. Dougherty, and Keith A. Nelson. "Impulsive Stimulated Raman Scattering Study of Soft Mode Dynamics in Ferroelectric Crystals." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/up.1992.tha5.
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Soft Modes, ISRS, and Perovskite Ferroelectrics The dynamics of cooperative ordering in crystals near structural phase transitions have long been elusive. Most picosecond and femtosecond time-resolved measurements have involved rapid laser heating of a sample whose phase transition (e.g. melting) dynamics are then monitored1. In this case many lattice degrees of freedom are excited, and little information is provided about the roles or dynamics of particular lattice motions. In structural phase transitions, the order parameter is described by one or a very few specific ("soft") lattice modes whose motions bring crystalline constituents from their initial positions into their positions in a new crystalline phase. Experimental characterization of the dynamics is possible in some cases through Raman spectroscopy, but often the highly damped character of the soft mode leads to a central peak in the Raman spectrum which cannot be analyzed accurately. In many cases it is not even possible to tell whether the ordering motion is a heavily damped vibration, Debye relaxation, or some combination of the two. This information is essential for understanding the microscopic mechanism of a transition since vibrational or relaxational character is an indication of ionic motion within a single potential energy minimum (i.e. a displacive transition) or hopping between different sites (an order-disorder transition) respectively.
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Flusberg, A., S. Fulghum, M. Tekula, H. Lotem, and M. Rokni. "Multifield, circularly polarized seeded stimulated Raman scattering." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1990. http://dx.doi.org/10.1364/oam.1990.mu3.
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Multifield Raman seeding may be applied to stimulated rotational Raman scattering and is promising for beam-quality control when the Raman gain-length product is large (50). The laser is seeded by two copropagating seed beams, e.g., 1st and 2nd Stokes. The rotational Raman polarization selection rules dictate that each beam must be circularly polarized with alternate heliocities. Because gain suppression is then absent, the Raman gain for seed amplification is high and discriminates well against noise (spontaneous Raman scattering). A parametric process coupling any four distinct waves recursively generates arbitrarily high-order Stokes waves. Because the beam quality of parametrically generated waves should be determined by that of the incident beams, good-quality conversion can occur at very high gain–length products. Code predictions support this conclusion under the following conditions: (1) seeds intense enough to discriminate against initiation by noise, (2) reasonably good beam quality and smooth edges of the incident beams, and (3) good spatial and temporal overlap between the incident beams. In a two-seed experiment on the S(1) transition of H2, it was found that a goodbeam-quality beam core was converted and amplified, but a poor-quality background was also amplified. The Raman code indicates that the observed mixture between good and bad beam quality arises from competition between noise and seeds, which is exacerbated by imperfect temporal overlap between the laser and seed pulses.
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Kurosawa, K., W. Sasaki, Y. Uehara, K. Takeuchi, E. Fujiwara, Y. Kato, M. Yamanaka, and C. Yamanaka. "Stimulated Raman scattering in highly dispersive media." In International Laser Science Conference. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/ils.1986.we9.
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Stimulated Raman scattering in the VUV spectral region is of much interest for nonlinear optics, because of the strong dispersion of the refractive indices, as well as for generation of coherent radiation. We have investigated stimulated Raman scattering in molecular hydrogen (and deuterium) gases with an argon excimer laser that produces pulsed high-power coherent light tunable around 126 nm. Since the Lyman-α transition lies in this spectral region, the resonance effect was expected and the intense first and second Stokes lines were actually observed for narrowband pulsed-laser pumping with a 0.3-nm bandwidth. However, no anti-Stokes lines appeared. The relative intensities of the respective Raman lines were found to depend largely on the bandwidth of the laser. By using the broadband laser oscillation of 1 nm, in addition to the intense first Stokes line the second Stokes and anti-Stokes lines were observed. These differences of the relative intensities come from the dispersive properties of the gas. For these experiments laser pulses with a 4-6-ns pulse width were used. The transient effect is discussed.
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Lin, J. T. "Theory of parametric instability in stimulated Raman scattering." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.fg6.
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Parametric instability induced by the medium saturation in stimulated Raman scattering is investigated theoretically via a generalized detuning (1) where ω p,s,o are the frequency of the pump, Stokes, and phonon, ϕ ˙ p s is the phase modulation, and the last term is the nonlinear correction of the highly excited anharmonic molecule with an amplitude Q.The steady-state gain and hence the Stokes efficiency, in the presence of the anharmonic term, are governed by a cubic equation of |Q|2which is to be solved from the Bloch and Maxwell equations including the pump depletion. Numerical results are shown for the transition diagram of Stokes efficiency vs input pump intensity at various system conditions at the steady-state. For the transient regime, with pulse duration shorter than the dephasing time, we analyze the temporal profiles of the Stokes and the depleted pump based on a transformed equation which combines Bloch and Maxwell equation as follows: (2) where Tis a nonlinear time, G s is the steady-state gain, l0is the input pump intensity, and Uis the real part of the phonon amplitude Q.For an input pulse intensity given by sech2(t/t p ), Eq. (2) is solved numerically to study the transient pulse profiles in the presence of pump depletion and medium saturation.
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Baklanov, E. V., V. I. Denisov, and A. V. Taichenachev. "Stimulated Raman scattering at the forbidden 11S-23S transition of the helium atom." In THE VIII INTERNATIONAL SYMPOSIUM “MODERN PROBLEMS OF LASER PHYSICS” (MPLP-2018). Author(s), 2019. http://dx.doi.org/10.1063/1.5098146.
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DeSavage, Sara, Danielle Braje, Jon Davis, and Frank Narducci. "Increasing the Coherence Time in a Magnetically-Sensitive Stimulated Raman Transition in 85Rb." In Frontiers in Optics. Washington, D.C.: OSA, 2014. http://dx.doi.org/10.1364/fio.2014.ftu1c.3.
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Herring, G. C., Mark J. Dyer, and William K. Bischel. "Density and temperature dependence of the rotational Raman gain in N2." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.tuq5.
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Rotational stimulated Raman scattering in N2 was recently observed1 at Lawrence Livermore National Laboratory when the Nova beam was propagated through 100 m of air. Stimulated Raman scattering in N2 will limit the maximum intensity that can be transmitted by air if the frequency and divergence of the laser are to remain unchanged. Modeling of this process requires knowledge of the Raman gain as a function of density and temperature for the N2 Raman lines. Using stimulated Raman gain spectroscopy, we have measured the temperature dependence of the density broadening coefficient for the Stokes branch rotational lines of N2. At 295 K, our experimental broadening coefficients are in agreement with the corrected ab initio theory.2 The absolute value of the S(10) gain coefficient was determined by ratioing the N2 gain to that observed for the S(0) transition in H2. From these data, we have calculated the temperature, wavelength, and J dependence of the Raman gain coefficient in the high density limit, which is in agreement with the value derived from the Livermore experiments.
Reports on the topic "Stimulated Raman transition"
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Neumark, Daniel M. Spectroscopy of Anion and Transition States Using Stimulated Raman Pumping. Fort Belvoir, VA: Defense Technical Information Center, January 2000. http://dx.doi.org/10.21236/ada379582.
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