Abstract

High intensity femtosecond solid-state lasers in mid-infrared (mid-IR) region are of significant interest for many applications such as laser processing, ultrafast spectroscopy, high-order harmonic generation, and laser plasma acceleration. Transition metal (TM) doped chalcogenides (Cr:ZnSe, Cr:CdSe, Fe:ZnSe etc.) are attractive laser media for high intensity mid-IR femtosecond lasers, since they have broad fluorescence spectrum and large stimulated-emission cross section in the mid-IR region [1]. Extension of lasing region by combining of fluorescence region of TM doped chalcogenides can contribute to generate mid-IR ultrashort pulses. Combined active medium method [2-4], by which multiple laser media are used inside a laser cavity simultaneously, is suitable for equipping lasing characteristics of multiple laser media on one laser oscillator. This method has high potential to oscillate ultrashort pulses directly from a solid-state laser, however the method has not been realized in the mid-IR region. In this study, we report on extension of mid-IR lasing region using Cr:ZnSe and Cr:CdSe combined active medium (CAM). We obserbed that wavelength tunability was extended when using Cr:ZnSe and Cr:CdSe CAM than when using Cr:ZnSe and Cr:CdSe indipendently. This is the first report that CAM technique based on Cr²⁺ doped chalcogenides was demonstrated in the mid-IR region.

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