Heavy Quark Production at a Linear e^+e^- and Photon Collider and its Sensitivity to the Gluon Content of the Photon

A high energy linear e^+e^- collider (LC) can also be used as a Photon Collider (PC), using Compton scattering of laser photons on the e^+/e^- beams. The leading order cross-section for the production of heavy quarks, e^+e^- -> e^+e^- Q(\bar{Q}) X, at high transverse momenta is calculated for both LC and PC modes. The sensitivity of this process to the parton distribution parametrizations of real photons, especially the gluon content, is tested for both modes.