The effect of varying the relative arrival time of the two laser pulses employed in doubly resonant four-wave sum mixing, enhanced by induced transparency, is studied with the aim of optimizing the efficiency of vacuum-ultraviolet generation. With atomic hydrogen as the nonlinear medium, pulsed radiation with wavelengths of 243 and 656 nm and durations of 8 and 14 ns, respectively, is mixed to generate 103-nm coherent radiation. It is shown that by delaying the arrival time of the ground-state pump beam (243 nm) by 2.5–3.5 ns relative to the arrival of the upper-state coupling beam (656 nm), it is possible to enhance the generated intensity by a factor of 2 or more.
© 2000 Optical Society of America
(020.6580) Atomic and molecular physics : Stark effect
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(260.5210) Physical optics : Photoionization
(270.1670) Quantum optics : Coherent optical effects
(270.4180) Quantum optics : Multiphoton processes
R. I. Thompson, L. Marmet, and B. P. Stoicheff, "Effect of counterintuitive time delays in nonlinear mixing," Opt. Lett. 25, 120-122 (2000)