Numerical computation of the excitation of a quantum nonlinear oscillator by a harmonic force

It is shown that, in a laser radiation field of I ≈ 10⁸ W/cm² intensity, an oscillator having a dipole moment d₀₁ ≈ 0.1 D is excited in a time t ≤ 100 nsec to levels with n = 4–5 and the probability of such excitation is 10 %. Such excitation is only possible fpr a nonlinear oscillator; it is essentially a quantum effect and can be interpreted as "tunneling in the energy space."