External Talbot cavity with in-phase mode selection

Two new variants of an external Talbot cavity with in-phase selection are proposed. The cavity contains a plane mirror located at a distance L_T/4 (L_T is the Talbot length) from a laser array. In the first variant this external plane mirror is tilted by an angle, so that the diffraction image of a laser array coincides with the array itself. In the second variant a binary phase plate, modulating the phase of the output radiation, is placed at the exit from the laser array inside the cavity. The field distributions and the losses experienced by the fundamental collective mode are calculated numerically for both variants. A report is given of experiments on the first variant (with a tilted mirror) serving a linear array of waveguide CO₂ lasers.