Autor/a:
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Chaitanya Kumar, Suddapalli; Esteban-Martin, Adolfo; Ideguchi, Takuro; Yan, Ming; Holzner, Simon; Hänsch, Theodor W.; Picqué, Nathalie; Ebrahim-Zadeh, Majid
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Abstract:
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A few-cycle, broadband, singly-resonant optical
parametric oscillator (OPO) for the mid-infrared based on MgOdoped
periodically-poled LiNbO3 (MgO:PPLN), synchronously
pumped by a 20-fs Ti:sapphire laser is reported. By using
crystal interaction lengths as short as 250 μm, and careful
dispersion management of input pump pulses and the OPO
resonator, near-transform-limited, few-cycle idler pulses tunable
across the mid-infrared have been generated, with as few
as 3.7 optical cycles at 2682 nm. The OPO can be continuously
tuned over 2179-3732 nm (4589-2680 cm-1) by cavity delay
tuning, providing up to 33 mW of output power at 3723 nm. The
idler spectra exhibit stable broadband profiles with bandwidths
spanning over 422 nm (FWHM) recorded at 3732 nm. The effect
of crystal length on spectral bandwidth and pulse duration is
investigated at a fixed wavelength, confirming near-transformlimited
idler pulses for all grating interaction lengths. By locking
the repetition frequency of the pump laser to a radio-frequency
reference, and without active stabilization of the OPO cavity
length, an idler power stability better than 1.6% rms over >2.75
hours is obtained when operating at maximum output power,
in excellent spatial beam quality with TEM00 mode profile. |