Pair Production of Two-Higgs-Doublet_Model Light Higgs Bosons in $\gamma   \gamma$ Collisions
  We study the production of a pair of light, neutral, CP-even Higgs bosons in photon--photon collisions within the general Two Higgs Doublet Model (THDM). This is a process for which the lowest order contribution in both, the Standard Model and the THDM, appears at one loop. We find that the cross section for this process can be much larger in the THDM than in the Standard Model and the number of events expected at the Photon Collider will allow a determination of some of the parameters in the scalar potential. 
Fernando Cornet and Wolfgang Hollik