Оптика и спектроскопия
Решетки населенностей, создаваемые в газе атомов водорода с помощью ультрафиолетовых аттосекундных импульсов
Р. М. Архипов, М.В. Архипов, А.В. Пахомов, Yu.M. Artem'ev, Н.Н. Розанов
Abstract
The possibility of population density grating in a gas of hydrogen atoms using a pair ultraviolet (UV) attosecond pulses that do not overlap in the medium is studied. Wherein the central frequency of the pulses can both coincide with the frequency of the resonant transition 1−2 from the main state in the first excited state (the main line of the Lyman series), and be detuned from it. The results of numerical calculations are in agreement with the analytical values obtained on the basis of approximate solution of Schrödinger equation using perturbation theory. It is shown that under resonant excitation the greatest efficiency of the grating is achieved with an increase in the pulse duration. When nonresonant excitation, on the contrary, the system is more efficiently excited by short quasi-unipolar subcycle pulses than bipolar multicycle pulses. The results obtained can be applicable to coherent excitation of a single atom (thin layer) using a pair of UV pulses. The possibility of controlling the modulation depth of the gratings by changing the carrier envelope phase (CEP) of attosecond pulses is shown.