7 research outputs found
High-Precision Spectroscopy with Counter-Propagating Femtosecond Pulses
An experimental realization of high-precision direct frequency comb
spectroscopy using counter-propagating femtosecond pulses on two-photon atomic
transitions is presented. Doppler broadened background signal, hampering
precision spectroscopy with ultrashort pulses, is effectively eliminated with a
simple pulse shaping method. As a result, all four 5S-7S two-photon transitions
in a rubidium vapor are determined with both statistical and systematic
uncertainties below 10, which is an order of magnitude better than
previous experiments on these transitions.Comment: 5 pages, 4 figures. Accepted to PR
Spatial and Spectral Coherent Control with Frequency Combs
Quantum coherent control (1-3) is a powerful tool for steering the outcome of
quantum processes towards a desired final state, by accurate manipulation of
quantum interference between multiple pathways. Although coherent control
techniques have found applications in many fields of science (4-9), the
possibilities for spatial and high-resolution frequency control have remained
limited. Here, we show that the use of counter-propagating broadband pulses
enables the generation of fully controlled spatial excitation patterns. This
spatial control approach also provides decoherence reduction, which allows the
use of the high frequency resolution of an optical frequency comb (10,11). We
exploit the counter-propagating geometry to perform spatially selective
excitation of individual species in a multi-component gas mixture, as well as
frequency determination of hyperfine constants of atomic rubidium with
unprecedented accuracy. The combination of spectral and spatial coherent
control adds a new dimension to coherent control with applications in e.g
nonlinear spectroscopy, microscopy and high-precision frequency metrology.Comment: 12 page
Ramsey-comb spectroscopy with intense ultrashort laser pulses
Optical frequency combs based on mode-locked lasers have revolutionized the field of metrology and precision spectroscopy by providing precisely calibrated optical frequencies and coherent pulse trains. Amplification of the pulsed output from these lasers is very desirable, as nonlinear processes can then be used to cover a much wider range of transitions and wavelengths for ultra-high precision, direct frequency comb spectroscopy. Therefore full repetition rate laser amplifiers and enhancement resonators have been employed to produce up to microjoule-level pulse energies. Here we present a spectroscopic method to obtain frequency comb accuracy and resolution by using only two frequency comb pulses amplified to the millijoule pulse energy level, orders of magnitude more energetic than what has previously been possible. The new properties of this approach, such as cancellation of optical light-shift effects, are demonstrated on weak two-photon transitions in atomic rubidium and caesium, thereby improving the frequency accuracy by up to thirty times