Four-wave mixing with short pulses and optimized atomic coherence - art. no. 043811

We present a lime-dependent calculation for four-wave mixing using a combin ation of long, short, and time delayed laser pulses in the context of elect romagnetically induced transparency. Two transform limited nanosecond laser s are used to create a highly coherent mixture of the ground state and an e xcited state via a two-photon process. Once the induced transparency is est ablished, a laser with short pulse length is injected after a suitable dela y to generate four-wave mixing. We show that the wave mixing process is pha se matched for all detunings, and with appropriately selected atomic cohere nce and populations, near 100% photon flux conversion efficiency can be obt ained, independent of the intensity of the short pulse laser. In addition, we show that for small detunings for the short pulse laser, the four-wave m ixing field travels with the speed of light in vacuum and suffers no pulse distortion even though the medium is highly dispersive at the frequency of the generated wave. These advantages open a door for future applications of the scheme for highly efficient, very stable UV generation.