The saturation effect of the parametric emission in potassium atoms under two-photon excitation

Saturation and population transfer of a two-photon excited four-level potassium atom

“…In order to improve our understanding of the dynamics of the system, we have proceeded with a detailed formulation of the self-consistent propagation of all internally generated fields. A preliminary account of our results was presented in a conference paper [8] and a fuller, yet still partial and incomplete, account in a subsequent conference presentation [10].…”

Emissions from high-density potassium atoms excited by either nanosecond or femtosecond laser pulses

“…The calculated results are compared with the experimental ones, in order to investigate the features and the properties of the atomic path-1 and also the conditions which describe the path-2 emissions (|4S 1/2 ↔ |6S 1/2 ↔ |4P 3/2 ↔ |4S 1/2 ). For the ns excitation, we show that QI and the population distribution depend crucially on the atomic density, as we have partially presented in our previous works [11,12]. For the fs excitation, we present only the experimental results demonstrating the influence of the destructive QI on the path-1 at high atomic densities and we compare the obtained results with the ones taken using ns excitation.…”

“…The fields corresponding to the transitions |6S 1/2 ↔ |5P 3/2 (|2 ↔ |4 ), |5P 3/2 ↔ |4S 1/2 (|4 ↔ |1 ), |6S 1/2 ↔ |4P 3/2 (|2 ↔ |3 ) and |4P 3/2 ↔ |4S 1/2 (|3 ↔ |1 ) are internally generated during the atom-laser interaction and population transfer may lead to significant change of the refraction index and thus can limit the conversion efficiency for the wave mixing process. It is interesting to note that destructive QI can cause a linear response of a nonlinear atomic system [6,9,11,12]. It was also shown that, for the ns excitation of sodium [1][2][3][4][5] and potassium [6,9,11,12] atoms, the pump laser intensity and the atomic density were the crucial factors which determined whether the destructive QI effect is insignificant (nonlinear region) or significant (linear region), respectively.…”

“…Thus, the nonlinear wave mixing in gaseous media [1][2][3] has been widely used for a variety of applications, such as the frequency conversion of laser radiation, the optical quantum memory induction and the internal emission of strong coherent fields [4][5][6][7][8][9][10][11][12]. Parametric light generation [1,13], stimulated hyper Raman scattering (SHRS), amplified spontaneous emission (ASE) [1,3], six-and four-wave mixing (FWM) [2,8,14,15] and third-harmonic generation [16] are the most widely studied nonlinear processes that take place in these atomic systems.…”

Action of counter-propagating laser beams on two-photon excitation of potassium vapour

“…We also observe that above certain excitation intensity saturation takes place. Recent theoretical simulations of the potassium atom as a four level system indeed predicts saturation for the I FWD as the result of the redistribution of the population among the excited states [13].…”