When 1182-Å radiation is generated by frequency tripling in xenon, interference is observed between the radiation generated at the two orthogonal-line foci that result from the astigmatism introduced by the focusing optics. Effects produced by a rotation of the focusing lens of only 2° or even less from the normal plane may elucidate experimental curves in the literature that deviate from the expected F′(bΔk) dependence at higher pressures and that are usually attributed to the presence of higher-order spatial modes. The modulation persists when the xenon is phase matched with either krypton or argon.
© 1981 Optical Society of America
Frank S. Tomkins, David Drapcho, and Rita Mahon, "Effect of astigmatism on frequency tripling," Opt. Lett. 6, 27-29 (1981)