Ultraviolet SO lasers optically pumped by a tunable, line-narrowed KrF laser

Thesis/Dissertation · Mon Jun 01 04:00:00 EDT 1992

OSTI ID:10188545

Stuart, B C.D.

The feasibility of an ultraviolet energy storage laser based on the long-lived sulfur monoxide A{sup 3}{pi}-{chi}{sup 3}{Sigma}{sup {minus}} electronic transition was investigated, and an ultraviolet laser based on the short-lived SO(B{sup 3} {Sigma}{sup {minus}}-{chi}{sup 3}{Sigma}{sup {minus}}) transition was demonstrated and modeled. Both were optically pumped by a continuously tunable, line-narrowed KrF laser developed for efficient rotationally resolved excitation of SO. SO was produced by both microwave discharge and excimer laser photolysis of the precursor molecules SO{sub 2} and SOCl{sub 2}, with a maximum SO concentration (10{sup 16} cm{sup {minus}3}) generated by ArF (193 nm) photodissociation of SO{sub 2}. Laser induced fluorescence of SO was used to study the excitation spectroscopy, vibrational branching ratios, lifetimes and deactivation rates. The radiative lifetime of SO(A{sup 3}{pi}{sub 2},v{prime} = 5) was measured to be 6.9 {mu}s and that of SO(B,v{prime} = 1) to be 33 ns. Lifetimes in the highly perturbed SO(B,v{prime} = 2) level ranged from 28--90 ns. Measurements and modeling of the excitation saturation fluence as a function of buffer gas pressure determined what fraction of the ground state SO(X) molecules could be excited to SO(A) or SO(B). No evidence of excited state absorption was seen. Lasing on six new ultraviolet SO(B-X) vibrational bands in the range 262--315 nm was demonstrated. SO(B-X) pulse energies of up to 11 {mu}J were obtained and the gain coefficient was estimated to be 0.1 cm{sup {minus}1}. A multi-level rate equation model of the SO(B-X) excitation and lasing transitions, including collisional rotational mixing, described the dynamics of the lasing and measured output very well. Modeling showed and experiments confirmed that the maximum possible SO laser gain simply corresponded to saturating the excitation of a single rotational level. Collisional coupling of the rotational levels increased the laser output energy.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 10188545
• Report Number(s): UCRL-LR--110935; ON: DE93001624
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700411
CHEMICAL PREPARATION
ENERGY-LEVEL TRANSITIONS
EXCITATION
GAS LASERS
INERTIAL CONFINEMENT
INERTIAL CONFINEMENT DEVICES
KRYPTON FLUORIDE LASERS
LASERS AND MASERS
LIFETIME
OPTICAL PUMPING
SULFUR OXIDES
TUNING
ULTRAVIOLET RADIATION