Extreme-ultraviolet Ramsey-type spectroscopy

Abstract

Using a Ramsey-type setup, the lambda-doublet transition in the J = 1, Ω = 1 level of the a 3 Π state of CO was measured to be 394 064 870(10) Hz. In our molecular beam apparatus, a beam of metastable CO is prepared in a single quantum level by expanding CO into vacuum and exciting the molecules using a narrow-band UV laser system. After passing two microwave zones that are separated by 50 cm, the molecules are state-selectively deflected and detected 1 meter downstream on a position sensitive detector. In order to keep the molecules in a single m B J level, a magnetic bias field is applied. We find the field-free transition frequency by taking the average of the m B J = +1 → m B J = +1 and m B J = −1 → m B J = −1 transitions, which have an almost equal but opposite Zeeman shift. The accuracy of this proof-of-principle experiment is a factor of 100 more accurate than the previous best value obtained for this transition.

Attosecond Electron Spectroscopy Using a Novel Interferometric Pump-Probe Technique

“…The created WP evolves freely during a certain delay (II). The bound part of the WP is finally ionized by a few-cycle IR pulse (III), which is locked in phase to the attosecond pulse and interferences with the previously created free WP are observed in the photoelectron spectra.ditional Ramsey spectroscopy, might be easier to implement for time-resolved measurements [13]. In this paper we present a novel interferometric technique, using a single attosecond pulse and a delayed IR pulse, that resolves both issues previously discussed: The spectral resolution is much better than the Fourier limit of the exciting pulse and the delayed probe pulse does not perturb the excitation process (see Fig.…”

Ablation of nanoparticles and efficient harmonic generation using a 1-kHz laser

“…Those include optimization of the Gouy phase, addition to the nonlinear medium of a species with positive or negative dispersion for achieving phase matching, application of quasi-phase-matching conditions using few gas jets, laser beam aperturing, etc. ( [2,[6][7][8][9][10]; also see monograph [11] and references therein).…”

Precision Laser Spectroscopy in the Extreme Ultraviolet

“…However, it is very difficult to control and measure the phase differences between the pulses from a Michelson interferometer. Therefore, no absolute calibration could be performed with this method so far (Pirri et al 2008).…”

“…Experiments have also been performed with time-delayed (≈100 fs) XUV pulses made by HHG (Cavalieri et al 2002, Pirri et al 2008, leading to interference effects in the excitation probability of krypton. Therefore, phase coherence is probably also maintained to a large degree for high harmonics generated in an enhancement cavity.…”