30 research outputs found
Optical frequency measurement of the 1S-3S two-photon transition in hydrogen
This article reports the first optical frequency measurement of the
transition in hydrogen. The excitation of this
transition occurs at a wavelength of 205 nm which is obtained with two
frequency doubling stages of a titanium sapphire laser at 820 nm. Its frequency
is measured with an optical frequency comb. The second-order Doppler effect is
evaluated from the observation of the motional Stark effect due to a transverse
magnetic field perpendicular to the atomic beam. The measured value of the
frequency splitting is with a relative uncertainty of
. After the measurement of the
frequency, this result is the most precise of the optical frequencies in
hydrogen
Generation of phase-coherent laser beams for Raman spectroscopy and cooling by direct current modulation of a diode laser
Measurement of the Rydberg Constant by Doppler Free Optical Spectroscopy of the Hydrogen Atom
High Resolution Spectroscopy of the Hydrogen Atom. I. Method and Experiment
In order to determine the Rydberg constant Râ to a very high accuracy, we have performed a Doppler-free two-photon absorption experiment on atomic hydrogen and deuterium. We have obtained a new value of Râ which is in excellent agreement with other recent measurements and the most precise one at the present time. Here we give a detailed report on the method and apparatus we have used. A metastable beam of 2S H and D atoms has been prepared and laser excited to Rydberg nS and nD levels (nâœ8) in a two-photon transition. The experimental geometry has been carefully designed to make the atomic beam collinear with the two counterpropagating laser beams. With this set-up we have observed very narrow resonances, with relative linewidths smaller than 10-9. Among all the transitions investigated we have selected three transitions (2S-8D, 2S-10D and 2S-12D) in hydrogen and deuterium to determine R â.Pour mesurer la constante de Rydberg Râ avec une trĂšs grande prĂ©cision, nous avons fait une expĂ©rience d'absorption Ă deux photons sans effet Doppler sur les atomes d'hydrogĂšne et de deutĂ©rium. Nous avons obtenu une nouvelle valeur de Râ qui est en excellent accord avec les autres mesures rĂ©centes, et la plus prĂ©cise Ă ce jour. Nous dĂ©crivons ici en dĂ©tail la mĂ©thode et l'appareillage utilisĂ©s. Un jet d'atomes d'hydrogĂšne mĂ©tastables est excitĂ© vers les Ă©tats de Rydberg nS et nD (nâœ8) dans une transition Ă deux photons. La gĂ©omĂ©trie expĂ©rimentale a Ă©tĂ© choisie de façon Ă rendre colinĂ©aires le jet atomique et les faisceaux laser. Avec ce montage, nous avons observĂ© des rĂ©sonances trĂšs Ă©troites avec une largeur relative infĂ©rieure Ă 10- 9. Parmi toutes les transitions observĂ©es, nous avons sĂ©lectionnĂ© trois transitions (2S-8D, 2S-10D et 2S-12D) dans l'hydrogĂšne et le deutĂ©rium pour dĂ©terminer Râ
High resolution spectroscopy of the hydrogen atom. I. Method and experiment
In order to determine the Rydberg constant Râ to a very high accuracy, we have performed a Doppler-free two-photon absorption experiment on atomic hydrogen and deuterium. We have obtained a new value of Râ which is in excellent agreement with other recent measurements and the most precise one at the present time. Here we give a detailed report on the method and apparatus we have used. A metastable beam of 2S H and D atoms has been prepared and laser excited to Rydberg nS and nD levels (nâœ8) in a two-photon transition. The experimental geometry has been carefully designed to make the atomic beam collinear with the two counterpropagating laser beams. With this set-up we have observed very narrow resonances, with relative linewidths smaller than 10-9. Among all the transitions investigated we have selected three transitions (2S-8D, 2S-10D and 2S-12D) in hydrogen and deuterium to determine R â.Pour mesurer la constante de Rydberg Râ avec une trĂšs grande prĂ©cision, nous avons fait une expĂ©rience d'absorption Ă deux photons sans effet Doppler sur les atomes d'hydrogĂšne et de deutĂ©rium. Nous avons obtenu une nouvelle valeur de Râ qui est en excellent accord avec les autres mesures rĂ©centes, et la plus prĂ©cise Ă ce jour. Nous dĂ©crivons ici en dĂ©tail la mĂ©thode et l'appareillage utilisĂ©s. Un jet d'atomes d'hydrogĂšne mĂ©tastables est excitĂ© vers les Ă©tats de Rydberg nS et nD (nâœ8) dans une transition Ă deux photons. La gĂ©omĂ©trie expĂ©rimentale a Ă©tĂ© choisie de façon Ă rendre colinĂ©aires le jet atomique et les faisceaux laser. Avec ce montage, nous avons observĂ© des rĂ©sonances trĂšs Ă©troites avec une largeur relative infĂ©rieure Ă 10- 9. Parmi toutes les transitions observĂ©es, nous avons sĂ©lectionnĂ© trois transitions (2S-8D, 2S-10D et 2S-12D) dans l'hydrogĂšne et le deutĂ©rium pour dĂ©terminer Râ
High Resolution Spectroscopy of the Hydrogen Atom. III. Wavelength Comparison and Rydberg Constant Determination
This paper is the last of a series giving a detailed description of our recent determination of the Rydberg constant. Here we carefully describe the wavelength comparison procedure. The wavelengths of the three two-photon transitions 2S-8D, 2S-10D, and 2S-12D in hydrogen and deuterium are compared to that of an I2-stabilized He-Ne laser which is the present best reference in the optical domain. The key of this comparison is a high stability Fabry-Perot cavity etalon. The reflective phase shifts are taken into account by changing the length of this cavity ("virtual mirrors method"). In order to measure the Fresnel phase shift we study the frequency difference between the first transverse mode and the fundamental mode of the cavity. From the six measured wavelengths we deduce a new value for the Rydberg constant, Râ = 109737.315709(18) cm-1, currently the most precise one. The H-D isotopic shifts have been also measured and a value for the proton-to-electron mass ratio is deduced: mp/me = 1836.15259(24)
High resolution spectroscopy of the hydrogen atom - III. Wavelength comparison and Rydberg constant determination
This paper is the last of a series giving a detailed description of our recent determination of the Rydberg constant. Here we carefully describe the wavelength comparison procedure. The wavelengths of the three two-photon transitions 2S-8D, 2S-10D, and 2S-12D in hydrogen and deuterium are compared to that of an I2-stabilized He-Ne laser which is the present best reference in the optical domain. The key of this comparison is a high stability Fabry-Perot cavity etalon. The reflective phase shifts are taken into account by changing the length of this cavity ("virtual mirrors method"). In order to measure the Fresnel phase shift we study the frequency difference between the first transverse mode and the fundamental mode of the cavity. From the six measured wavelengths we deduce a new value for the Rydberg constant, Râ = 109737.315709(18) cm-1, currently the most precise one. The H-D isotopic shifts have been also measured and a value for the proton-to-electron mass ratio is deduced: mp/me = 1836.15259(24).Cet article est le dernier d'une sĂ©rie de trois donnant une description dĂ©taillĂ©e de notre mesure rĂ©cente de la constante de Rydberg. Nous y dĂ©crivons soigneusement la mĂ©thode de mesure des longueurs d'onde. Les longueurs d'onde des trois transitions A deux photons 2S-8D, 2S-10D et 2S-12D dans l'hydrogĂšne et le deutĂ©rium sont comparĂ©es Ă celle d'un laser He-Ne stabilisĂ© sur l'iode, laser qui est actuellement la meilleure rĂ©fĂ©rence dans le domaine optique. Cette comparaison est faite Ă l'aide d'un Ă©talon Fabry-Perot de grande stabilitĂ©. Les dĂ©phasages Ă la rĂ©flexion sont pris en compte en changeant la longueur de cette cavitĂ© ("mĂ©thode des miroirs virtuels"). Pour mesurer le dĂ©phasage de Fresnel nous Ă©tudions la diffĂ©rence de frĂ©quence entre le premier mode transverse et le mode fondamental de cette cavitĂ©. A partir des six longueurs d'onde mesurĂ©es, nous dĂ©duisons une nouvelle valeur de la constante de Rydberg Râ = 109737, 315709(18) cm-1, la plus prĂ©cise Ă l'heure actuelle. A partir des dĂ©placements isotopiques entre l'hydrogĂšne et le deutĂ©rium nous dĂ©duisons aussi une valeur pour le rapport de masse entre le proton et l'Ă©lectron: mp/me = 1836.15259 (24)
High resolution spectroscopy of the hydrogen atom. II. Study of line profiles
As second part of the detailed description of our recent work on the Rydberg constant measurement, here (paper II) we present our calculations of the line profiles of the hydrogen 2S-nS and 2S-nD Doppler-free two-photon signals observed in our experiment. Various broadening and shift effects have been considered and detailed calculations of the two-photon transition probability and of the light-shift have been done. The contributions of all possible trajectories of the atoms in the metastable beam have been summed to get the detected signal. The fit of each observed line with the corresponding calculated profile provides the line position with a relative accuracy of a few parts in 1011.Cet article est le deuxiÚme d'une série de trois articles décrivant en détail notre récente mesure de la constante de Rydberg. Nous y présentons le calcul théorique des formes de raies attendues dans notre expérience de spectroscopie à deux photons des transitions 2S-nS et 2S-nD de l'atome d'hydrogÚne. Les différents effets d'élargissement et de déplacement des raies ont été pris en compte, et nous avons calculé la probabilité de transition à deux photons et le déplacement lumineux sous l'effet de l'interaction des atomes metastables 2S avec le laser. Les contributions au signal de toutes les trajectoires atomiques possibles ont été sommées. La comparaison de chaque profil expérimental avec le profil théorique correspondant donne la position de la raie avec une précision de quelques 10-11