Hot-isostatic-pressed Cr:ZnSe ultrafast laser at 2.4 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"><mml:mrow><mml:mi mathvariant="normal">μ</mml:mi></mml:mrow></mml:math>m

• Kerr-lens mode-locking of hot-isostatic-pressed Cr:ZnSe polycrystal. Four optical cycles pulse generation at 2.4 μ m. Laser comparison between untreated and HIP-treated polycrystals. We report on a room temperature mode-locked chromium-doped zinc selenide (Cr:ZnSe) laser emitting four optical-cycles pulses in the mid-infrared spectral region which polycrystal has been treated by hot isostatic pressing (HIP). The emits 34 fs m, with repetition rate 171 MHz average output power capabilities up to 150 mW. This is first investigation conducted using HIP material our knowledge, shortest width demonstrated, date, from polycrystalline Cr:ZnSe. experimental respect an indicates that treatment advantageous for action this active material.