Laser spectroscopy on the Stark effect of the level of He I

Abstract

In electric fields 0 F 160 kV cm −1 , shift and splitting of the λ(1s2s 3 S-1s3p 3 P) = 389 nm line of He I were measured spectroscopically by crossing a beam of metastable He atoms with a frequency-doubled cw Ti:sapphire laser beam. We deduced the difference α sc = α sc (3 3 P) − α sc (2 3 S) = 4.20(3) MHz (kV cm −1 ) −2 of the scalar polarizabilities, the tensor polarizability α ten (3 3 P) = 84.0(7) kHz (kV cm −1 ) −2 and the energy separation of closest approach hν min = E(3 3 P 0 , 0 − ) − E(3 3 P 2 , 0 − ) = 8257(5) MHz • h of the Stark sublevels with m = 0 and negative reflection parity at F = 154(3) kV cm −1 . The polarizabilities agree with calculated values. By comparing the measured energy separation with theory, we deduced that the scalar polarizabilities of the 3 P 2 and 3 P 0 differ slightly by {α sc ( 3 P 2 ) − α sc ( 3 P 0 )}/α sc ( 3 P) = (1.8 ± 1.2) × 10 −4 .

Electric-field-induced redistribution of radiation transition probabilities in atomic multiplet lines

“…The most important results in this area during the last decade have been obtained for helium triplet states, both experimentally [1][2][3] and theoretically [5][6][7]. Together with field-induced variation of energy structure of atomic levels, the reconstruction of wavefunctions in atomic multiplets has been studied, which may cause essential changes in radiation matrix elements and transition probabilities.…”

Precision measurements of electric-field 1snℓ singlet-triplet anticrossings of HeIusing radio frequency spectroscopy

“…By detecting rf transitions between the sublevels at the closest-approach electric-field position, a broadening of the resonance signals due to a residual field inhomogeneity is avoided in the first order. In that respect this experimental technique is superior to high-resolution laser spectroscopy of anticrossing separations [9,10].…”

“…In that case, the electric-field rf-resonance technique could also be applied to thermal atomic beams or trapped ensembles of metastable He * (1s2s 3 S 1 ) atoms, which can be excited to selected Stark substates of the 1s2p 3 P and 1s3 3 L levels using photon excitation [18]. In particular, precision measurements of the 0 − × 0 − anticrossings of the 1s2p and 1s3p 3 P levels would be highly desirable [9,10] in view of the importance of these levels with respect to the investigation of relativistic and QED corrections in two-electron systems [1,6].…”

“…Due to the Stark mixing of states with different orbital angular momenta , as well as h off of the 1sn configurations with 2, h off of the 1snp configurations can also be deduced from the energy separations E min . First measurements of energy separations at electricfield anticrossings have been performed using laser spectroscopy [9,10] and level-crossing techniques [11]. Both techniques are afflicted by deficiencies.…”

Design study of an optical cavity for a future photon collider at ILC

“…Passive build-up cavities for generating a region of enhanced intensity are routinely used in combination with both continuous wave (cw) and mode-locked sources in a number of laser-related experiments such as frequency doubling [16,17,18,19] (cw-laser), [20,21,22] (mode-locked laser), high-resolution spectroscopy [23,24,25,26,27], high sensitive detection of absorption [28,29,30,31] or cavity ring-down absorption spectroscopy [32]. For the latter, linear cavities for micro-pulse energy enhancement in the mid-infrared region at 5.3 µm have been investigated at the Stanford free-electron laser [33,34].…”