Second-harmonic generation from high-lying P-states of potassium

Doseok Kim, Christopher S. Mullin, Y. R. Shen

Virgilijus Vaičaitis

Stoyan Dinev

Second harmonic generation in potassium atoms has been studied under two-photon resonant excitation. High-lying s, p and d states (n=7-34) are involved. Intensity, density and polarisation characteristics of the second harmonic have been measured as well as the influence of a foreign gas. Comparison with two theoretical models (multiphoton ionisation DC-induced field and collisional l-mixing of states) shows a reasonable agreement.

E L Lewis, M. M. Rebbeck, Janet Maria Vaughan

Michael S.-C. Lu, J Tsai

Optical second harmonic generation has been observed on or near the 4s 2 S 1/2 -6s 2 S 1/2 , 4s 2 S 1/2 -np 2 P 1/2, 3/2 (n=5, 6) and 4s 2 S 1/2 -nd 2 D 5/2, 3/2 (n=3,4) two-photon resonances in potassium vapour, as laser scanning in the 660-940 nm wavelength range. The second harmonic intensities and ionisation currents have been measured as a function of pumping laser detuning from the two-photon resonances. On or near the two-photon resonances, the intensity and vapour-density dependence of second harmonic generation have also been investigated. The saturation of second harmonic generation has been observed. Some calculations and analyses have been made with the chi (3) model. The results have been compared with the measurements. Based on these analyses, the mechanisms for second harmonic generation in isotropic vapours are discussed.

M. Kozierowski, Vladimir I. Man’ko