Pressure Dependence of the Infrared Laser Lines in Barium Vapor

We have studied nine laser transitions in Ba vapor at wavelengths between 1.13 and 3.05 micrometer. Three of these laser lines have not been reported previously. The relative intensities of the four strongest transitions (1.13, 1.50, 2.55, and 2.92 micrometer) vary with buffer gas pressure, suggesting that collisional deexcitation of the 6p 1^P_1 state occurs at higher pressure and is the main mechanism populating the upper states of the 2.55 and 2.33 micrometer lines