Self-starting mode-locked ring-cavity Ti:sapphire laser

A self-mode-locked ring-cavity Ti:sapphire laser is described that is self-starting within milliseconds and completely unperturbed by the self-starting mechanism while mode locked. This technique makes use of a position-modulated mirror in an external cavity in which the cavity length and alignment are noncritical. Other benefits of the ring cavity over the linear cavity configuration are described.