We report a femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on the Kerr-lens-mode-locked (KLM) Ti:sapphire laser as the pump source. By deploying a novel cascaded intracavity arrangement comprising a femtosecond OPO based on the nonlinear crystal, CdSiP2 (CSP), synchronously pumped internal to a MgO:PPLN femtosecond OPO, we have generated broadly tunable radiation across 5958- 8117 nm using rapid static cavity delay tuning, with a maximum power of 64 microW at 6791 nm, limited by the absorption in mirror substrates as well as polarization-dependent intracavity losses. The deep-IR idler power exhibits excellent passive stability of better than 1.1% rms over 2 hours, with a spectral bandwidth as large as ~650 nm at ~6800 nm. The demonstrated concept is generic and can be similarly deployed in other operating time-scales and wavelength regions, also using different laser pump sources and nonlinear materials.
Ramaiah-Badarla, V., Chaitanya Kumar, S., Esteban-Martin, A., Devi, K., Zawilski, K. T., Schunemann, P. G., & Ebrahim-Zadeh, M. (2016). Ti:sapphire-pumped deep-infrared femtosecond optical parametric oscillator based on CdSiP_2. En Optics Letters (Vol. 41, Issue 8, p. 1708). The Optical Society. https://doi.org/10.1364/ol.41.001708
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