Observing Doubly Charged Higgs Bosons in Photon-Photon Collisions
  We discuss the possibility of observing doubly charged Higgs bosons in $\gamma \gamma$ collisions. We find that one can increase the range of observability close to the kinematic limit by a judicious choice of the polarisations of the initial $e^-/ e^+$ beams as well as the initial laser beam photons which are made to back-scatter from the former. We also note that, in a large region of parameter space, the generally used lepton number violating decay mode is dominated by the decay into a singly charged Higgs and a real or virtual $W$-boson, giving rise to a large number of fermions in the final state. This can qualitatively alter the strategy for discovering doubly-charged scalars. 
Surajit Chakrabarti, Debajyoti Choudhury, Rohini M. Godbole and   Biswarup Mukhopadhyaya