The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Martin Kiffner - One of the best experts on this subject based on the ideXlab platform.
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directional thz generation in hot rb vapor excited to a Rydberg State
Optics Letters, 2021Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Martin KiffnerAbstract:We optically excite 85Rb atoms in a heated vapor cell to a low-lying Rydberg State 10D5/2 and observe directional terahertz (THz) beams at 3.3 THz and 7.8 THz. These THz fields are generated by amplified spontaneous emission from the 10D5/2 State to the 11P3/2 and 8F7/2 States, respectively. In addition, we observe ultraviolet (UV) light produced by four-wave mixing of optical pump lasers and the 3.3 THz field. We characterize the generated THz power over the detuning and power of pump lasers, and identify experimental conditions favoring THz and UV generation, respectively. Our scheme paves a new pathway towards generating high-power narrowband THz radiation.
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collimated uv light generation by two photon excitation to a Rydberg State in rb vapor
Optics Letters, 2019Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Christian Gross, Martin KiffnerAbstract:We use two continuous-wave laser beams of 780 nm and 515 nm to optically drive Rb85 atoms in a heated vapor cell to a low-lying Rydberg State 10D5/2. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to the transition frequency from the 11P3/2 State to the 5S1/2 State. This indicates the presence of a coherent four-wave mixing process, built up by two input laser fields as well as terahertz (THz) radiation of 3.28 THz, which is generated by amplified spontaneous emission between the 10D5/2 and 11P3/2 States. We characterize the 311 nm UV light generation and its dependence on various physical parameters. This scheme could open up a new possibility for generating narrow-band THz waves as well as deep UV radiation.
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collimated uv light generation by two photon excitation to a Rydberg State in rb vapor
arXiv: Atomic Physics, 2019Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Christian Gross, Martin KiffnerAbstract:We use two continuous-wave (CW) laser beams of 780 nm and 515 nm to optically drive $^{85}$Rb atoms in a heated vapor cell to a low-lying Rydberg State 10D$_{5/2}$. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to the transition frequency from the 11P$_{3/2}$ State to the 5S$_{1/2}$ State. This indicates the presence of a coherent four-wave mixing process, built up by two input laser fields as well as a terahertz (THz) radiation of 3.28 THz that is generated by amplified spontaneous emission between the 10D$_{5/2}$ and the 11P$_{3/2}$ States. We characterize the 311 nm UV light generation and its dependence on various physical parameters. This scheme could open up a new possibility for generating narrow-band THz waves as well as deep UV radiation.
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lensing effect of electromagnetically induced transparency involving a Rydberg State
Physical Review A, 2015Co-Authors: Jingshan Han, Thibault Vogt, Manukumara Manjappa, Ruixiang Guo, Martin KiffnerAbstract:We study the lensing effect experienced by a weak probe field under conditions of electromagnetically induced transparency (EIT) involving a Rydberg State. A Gaussian coupling beam tightly focused on a laser-cooled atomic cloud produces an inhomogeneity in the coupling Rabi frequency along the transverse direction and makes the EIT area acting like a gradient-index medium. We image the probe beam at the position where it exits the atomic cloud and observe that a red-detuned probe light is strongly focused with a greatly enhanced intensity whereas a blue-detuned one is defocused with a reduced intensity. Our experimental results agree very well with the numerical solutions of Maxwell-Bloch equations.
Luis Bañares - One of the best experts on this subject based on the ideXlab platform.
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the 3s versus 3p Rydberg State photodissociation dynamics of the ethyl radical
Physical Chemistry Chemical Physics, 2019Co-Authors: Sonia Marggi Poullain, Luis Bañares, David V Chicharro, Alexandre Zanchet, Luis Rubiolago, A GarciavelaAbstract:The photodissociation dynamics of the ethyl radical following excitation into the 3s and 3p Rydberg States are revisited in a joint experimental and theoretical study. Two different methods to produce the ethyl radical, pyrolysis and in situ photolysis, are employed in order to modify the initial ro-vibrational energy distribution characterizing the ethyl radical beam. H-atom velocity map images following excitation of the radical at 243 nm and at 201 nm are presented and discussed along with ab initio potential energy curves focussing on the bridged C2v geometry. The reported results show that the dynamics following excitation to the 3s Rydberg State is insensitive to the initial internal energy of the parent radical, in contrast to the dynamics on the 3p Rydberg State, which is strongly modified. The role of the bridged C2v geometry on both photodynamics is highlighted and discussed.
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Femtosecond predissociation dynamics of ethyl iodide in the B-band
Physical Chemistry Chemical Physics, 2019Co-Authors: Marta Murillo-sánchez, Vincent Loriot, Sonia Marggi Poullain, Maria Corrales, Luis BañaresAbstract:Femtosecond time-resolved velocity map ion imaging experiments are reported on the second absorption band (B-band) of ethyl iodide at 201.19 and 200.08 nm, corresponding to the 000 and 1810 transitions, i.e., the origin of the band and the first most intense vibronic State assigned to one quantum of excitation in the methyl torsion mode. Electronic predissociation lifetimes and the temporal evolution of the anisotropy have been determined by time-resolved resonance-enhanced multiphoton ionization of iodine and ethyl fragment images. A shorter lifetime measured at the origin of the band in comparison with methyl iodide indicates that predissociation in ethyl iodide is more favorable due to a stronger coupling between the initial Rydberg State and the valence repulsive State correlating with the dissociation fragments. Moreover, vibrational activity in the methyl torsion in the Rydberg State seems to enhance the probability of transfer of population to the valence repulsive State leading to a faster dissociation. The perpendicular character of the transition at early times and the loss of anisotropy as a function of time have been determined from the time-resolved angular distributions of the iodine and ethyl ion images. The initial anisotropy value is consistent with a purely perpendicular transition compatible with the excitation of the [6A′′, 7A′] States with a minor parallel component to the C–I bond. The loss of initial anisotropy over time highlights the parent molecular rotation during predissociation and is compatible with a rotational temperature of the parent molecule of 100 K.
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femtosecond predissociation dynamics of the methyl radical from the 3pz Rydberg State
Physical Chemistry Chemical Physics, 2016Co-Authors: Garikoitz Balerdi, Rebeca De Nalda, A Garciavela, J Woodhouse, Maria Luisa Senent, Alexander Zanchet, Luis BañaresAbstract:The real time dynamics of electronic predissociation of the CH3 radical (and its deuterated variant CD3) from selected vibrational States of the 3pz Rydberg State have been measured for the first time using a novel methodology based on a femtosecond three-color experiment to generate, two-photon excite and ionize methyl radicals as a function of time in combination with velocity map imaging detection. Subpicosecond lifetimes have been measured, showing a decreasing trend as vibrational excitation in the symmetric stretch and bending umbrella modes increases for both species. High-level ab initio calculations have been carried out in order to elucidate the CH3 3pz predissociation mechanism and support the lifetime measurements. The observed lifetimes are relevant for the understanding of the resonance enhanced multiphoton ionization spectroscopy of this radical.
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femtosecond predissociation dynamics of the methyl radical from the 3p z Rydberg State
Physical Chemistry Chemical Physics, 2016Co-Authors: Garikoitz Balerdi, Rebeca De Nalda, A Garciavela, J Woodhouse, Maria Luisa Senent, Alexander Zanchet, Luis BañaresAbstract:The real time dynamics of electronic predissociation of the CH3 radical (and its deuterated variant CD3) from selected vibrational States of the 3pz Rydberg State have been measured for the first time using a novel methodology based on a femtosecond three-color experiment to generate, two-photon excite and ionize methyl radicals as a function of time in combination with velocity map imaging detection. Subpicosecond lifetimes have been measured, showing a decreasing trend as vibrational excitation in the symmetric stretch and bending umbrella modes increases for both species. High-level ab initio calculations have been carried out in order to elucidate the CH3 3pz predissociation mechanism and support the lifetime measurements. The observed lifetimes are relevant for the understanding of the resonance enhanced multiphoton ionization spectroscopy of this radical.
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imaging the predissociation dynamics of the methyl radical from the 3pz Rydberg State
Journal of Physics: Conference Series, 2015Co-Authors: Garikoitz Balerdi, Rebeca De Nalda, A Garciavela, J Woodhouse, Maria Luisa Senent, Luis BañaresAbstract:Direct, time-domain measurements are reported for the lifetimes of the lower-lying vibrational levels of the 3pz Rydberg State of the methyl radical. Lifetimes measured are in the region of hundreds of femtoseconds, and show a decrease with increasing vibrational activity. The mechanism is interpreted with the aid of ab initio calculations.
Etienne Brion - One of the best experts on this subject based on the ideXlab platform.
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spontaneous emission of a sodium Rydberg atom close to an optical nanofibre
Journal of Physics B, 2019Co-Authors: E Stourm, Nic S Chormaic, Etienne Brion, Klaus Mølmer, Maxence Lepers, Romain Guérout, J Robert, Y ZhangAbstract:We report on numerical calculations of the spontaneous emission rate of a Rydberg-excited sodium atom in the vicinity of an optical nanobre. In particular, we study how this rate varies with the distance of the atom to the bre, the bre's radius, the symmetry s or p of the Rydberg State as well as its principal quantum number. We nd that a fraction of the spontaneously emitted light can be captured and guided along the bre. This suggests that such a setup could be used for networking atomic ensembles, manipulated in a collective way due to the Rydberg blockade phenomenon.
Thibault Vogt - One of the best experts on this subject based on the ideXlab platform.
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directional thz generation in hot rb vapor excited to a Rydberg State
Optics Letters, 2021Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Martin KiffnerAbstract:We optically excite 85Rb atoms in a heated vapor cell to a low-lying Rydberg State 10D5/2 and observe directional terahertz (THz) beams at 3.3 THz and 7.8 THz. These THz fields are generated by amplified spontaneous emission from the 10D5/2 State to the 11P3/2 and 8F7/2 States, respectively. In addition, we observe ultraviolet (UV) light produced by four-wave mixing of optical pump lasers and the 3.3 THz field. We characterize the generated THz power over the detuning and power of pump lasers, and identify experimental conditions favoring THz and UV generation, respectively. Our scheme paves a new pathway towards generating high-power narrowband THz radiation.
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collimated uv light generation by two photon excitation to a Rydberg State in rb vapor
Optics Letters, 2019Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Christian Gross, Martin KiffnerAbstract:We use two continuous-wave laser beams of 780 nm and 515 nm to optically drive Rb85 atoms in a heated vapor cell to a low-lying Rydberg State 10D5/2. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to the transition frequency from the 11P3/2 State to the 5S1/2 State. This indicates the presence of a coherent four-wave mixing process, built up by two input laser fields as well as terahertz (THz) radiation of 3.28 THz, which is generated by amplified spontaneous emission between the 10D5/2 and 11P3/2 States. We characterize the 311 nm UV light generation and its dependence on various physical parameters. This scheme could open up a new possibility for generating narrow-band THz waves as well as deep UV radiation.
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collimated uv light generation by two photon excitation to a Rydberg State in rb vapor
arXiv: Atomic Physics, 2019Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Christian Gross, Martin KiffnerAbstract:We use two continuous-wave (CW) laser beams of 780 nm and 515 nm to optically drive $^{85}$Rb atoms in a heated vapor cell to a low-lying Rydberg State 10D$_{5/2}$. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to the transition frequency from the 11P$_{3/2}$ State to the 5S$_{1/2}$ State. This indicates the presence of a coherent four-wave mixing process, built up by two input laser fields as well as a terahertz (THz) radiation of 3.28 THz that is generated by amplified spontaneous emission between the 10D$_{5/2}$ and the 11P$_{3/2}$ States. We characterize the 311 nm UV light generation and its dependence on various physical parameters. This scheme could open up a new possibility for generating narrow-band THz waves as well as deep UV radiation.
-
lensing effect of electromagnetically induced transparency involving a Rydberg State
Physical Review A, 2015Co-Authors: Jingshan Han, Thibault Vogt, Manukumara Manjappa, Ruixiang Guo, Martin KiffnerAbstract:We study the lensing effect experienced by a weak probe field under conditions of electromagnetically induced transparency (EIT) involving a Rydberg State. A Gaussian coupling beam tightly focused on a laser-cooled atomic cloud produces an inhomogeneity in the coupling Rabi frequency along the transverse direction and makes the EIT area acting like a gradient-index medium. We image the probe beam at the position where it exits the atomic cloud and observe that a red-detuned probe light is strongly focused with a greatly enhanced intensity whereas a blue-detuned one is defocused with a reduced intensity. Our experimental results agree very well with the numerical solutions of Maxwell-Bloch equations.
Mark Lam - One of the best experts on this subject based on the ideXlab platform.
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directional thz generation in hot rb vapor excited to a Rydberg State
Optics Letters, 2021Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Martin KiffnerAbstract:We optically excite 85Rb atoms in a heated vapor cell to a low-lying Rydberg State 10D5/2 and observe directional terahertz (THz) beams at 3.3 THz and 7.8 THz. These THz fields are generated by amplified spontaneous emission from the 10D5/2 State to the 11P3/2 and 8F7/2 States, respectively. In addition, we observe ultraviolet (UV) light produced by four-wave mixing of optical pump lasers and the 3.3 THz field. We characterize the generated THz power over the detuning and power of pump lasers, and identify experimental conditions favoring THz and UV generation, respectively. Our scheme paves a new pathway towards generating high-power narrowband THz radiation.
-
collimated uv light generation by two photon excitation to a Rydberg State in rb vapor
Optics Letters, 2019Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Christian Gross, Martin KiffnerAbstract:We use two continuous-wave laser beams of 780 nm and 515 nm to optically drive Rb85 atoms in a heated vapor cell to a low-lying Rydberg State 10D5/2. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to the transition frequency from the 11P3/2 State to the 5S1/2 State. This indicates the presence of a coherent four-wave mixing process, built up by two input laser fields as well as terahertz (THz) radiation of 3.28 THz, which is generated by amplified spontaneous emission between the 10D5/2 and 11P3/2 States. We characterize the 311 nm UV light generation and its dependence on various physical parameters. This scheme could open up a new possibility for generating narrow-band THz waves as well as deep UV radiation.
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collimated uv light generation by two photon excitation to a Rydberg State in rb vapor
arXiv: Atomic Physics, 2019Co-Authors: Mark Lam, Thibault Vogt, Sambit Bikas Pal, Christian Gross, Martin KiffnerAbstract:We use two continuous-wave (CW) laser beams of 780 nm and 515 nm to optically drive $^{85}$Rb atoms in a heated vapor cell to a low-lying Rydberg State 10D$_{5/2}$. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to the transition frequency from the 11P$_{3/2}$ State to the 5S$_{1/2}$ State. This indicates the presence of a coherent four-wave mixing process, built up by two input laser fields as well as a terahertz (THz) radiation of 3.28 THz that is generated by amplified spontaneous emission between the 10D$_{5/2}$ and the 11P$_{3/2}$ States. We characterize the 311 nm UV light generation and its dependence on various physical parameters. This scheme could open up a new possibility for generating narrow-band THz waves as well as deep UV radiation.
