Second harmonic generation in sodium vapor by laser of wavelength 570-603 nm

Tianjie Chen

D.I. Metchkov, Valentin Mitev, Lubomir I. Pavlov +1 more

Maria Grozeva, D.I. Metchkov, Valentin Mitev +2 more

Chao Wu, J. K. Chen

Bruce Sinclair, Malcolm H. Dunn

We investigated the process of magnetic field- induced optical second harmonic generation (SHG) in sodium vapor with a cw single-frequency dye laser tuned in the vicinity of the resonantly enhancing 3S-4D two-photon transition at 578.7 nm.1 All previous investigators have used pulsed dye lasers with relatively large linewidths.2 By exploiting the narrow linewidth capability of the cw dye laser (0.5 MHz) we have been able to investigate in detail for the first time properties of the SHG process which change across the line profile. We modeled the process on a theory developed from that reported by Uchlki et al.2 The two-photon absorption creates coherent quadrupole moments which rotate in the magnetic field due to Zeeman splitting to allow generation of the second harmonic.

Sergey M. Bobrovnikov, Lidia A. Bolbasova, Evgeniy V. Gorlov +2 more

Abstract The efficiency of ten sodium atom excitation schemes that can potentially be used to generate a sodium polychromatic laser guide star (PLGS) and a monochromatic laser guide star (LGS) is compared. It is shown that for creating an LGS in sodium vapor using the cascade fluorescence effect with single-photon excitation, the most suitable is the 42P3/2 ← 32S1/2 transition excited at a wavelength of 330.237 nm and demonstrating the highest LGS characteristics, while the efficiency decreases by two orders of magnitude compared to a monochromatic LGS at a wavelength of 588.995 nm.