Abstract

Since its first demonstration as a solid optical gain medium [1], Cr²⁺:ZnSe (λ = 2.5μm) has shown interesting lasing properties, such as a wide emission spectrum, and has become a promising mid-infrared source. Until now, wide tunability (2000nm - 3000nm) has been obtained in CW regime, and ultrashort-pulse generation has been demonstrated from SESAM [2] or self-starting Kerr lens mode-lock [3]. These techniques generally require high pump power (several Watts in CW regime), or specific devices (SESAM based on multiple InAs/GaSb quantum wells). Here, we propose to apply to Cr²⁺:ZnSe an original mode-locking technique, using an intracavity second order nonlinear mirror (Fig. 1), proposed by K. A. Stankov [4], and efficiently demonstrated on near-infrared (λ = 1 μm) laser sources. Indeed, efficiency and reliability reached by second order non linear crystals, such as PPLN, allow a transposition of the nonlinear mirror concept from near-infrared to mid-infrared laser sources.

© 2009 IEEE