CP-odd Higgs Boson Production in $e\gamma$ Collisions

We investigate the CP-odd Higgs boson production via two-photon processes in $e\gamma$ collisions. The CP-odd Higgs boson, which we denote as $A^0$, is expected to appear in the Two-Higgs Doublet Models (2HDM) as a minimal extension of Higgs sector for which the Minimal Supersymmetric Standard Model (MSSM) is a special case. The scattering amplitude for $e\gamma\rightarrow eA^0$ is evaluated at the electroweak one-loop level. The dominant contribution comes only from top-quark loops when $A^0$ boson is rather light and $\tan \beta$ is not large. There are no contributions from the $W$-boson and $Z$-boson loops nor from the scalar top-quark (stop) loops. The differential cross section for the $A^0$ production is analysed.