Two-photon detachment cross section of H-

The differential and total cross sections for two-photon detachment of H- are computed analytically within the asymptotic model for both linearly and circularly polarized light. The total cross section for unit flux is of the order 10-48 cm2. The differential cross section for linearly polarized light is nearly isotropic near the two-photon absorption threshold but is sharply peaked along the polarization direction just below the threshold for one-photon detachment. The circular polarization efficiency is very small near the two-quantum threshold but is close to its theoretical maximum near the one-quantum threshold.