Ultrafast visible radiation is of great importance for many applications ranging from spectroscopy to metrology. Because some regions in the visible range are not covered by laser gain media, optical parametric oscillators offer an added value. Besides a high-power broadband laser source, the ability to rapidly tune the frequency of pulses with high-power spectral density offers an extra benefit for experiments such as multicolor spectroscopy or imaging. Here, we demonstrate a broadband, high-power, rapidly tunable femtosecond noncollinear optical parametric oscillator with a signal tuning range of 440–720 nm in the visible range. The oscillator is pumped by the third harmonic of an Yb-fiber laser at 345 nm with a repetition rate of 50.2 MHz. Moreover, the signal wavelength is tuned by changing the cavity length only, and output powers up to 452 mW and pulse durations down to 268 fs are achieved. This is, to the best of our knowledge, the first demonstration of a quickly tunable femtosecond optical parametric oscillator that covers nearly the entire visible spectral range with high output power.

中文翻译：

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可见光谱范围内可广泛调谐的高功率飞秒非共线光学参量振荡器

超快可见光辐射对于从光谱学到计量学的许多应用都非常重要。由于激光增益介质未覆盖可见光范围内的某些区域，因此光学参量振荡器提供了附加值。除了高功率宽带激光源之外，快速调谐具有高功率光谱密度的脉冲频率的能力为多色光谱或成像等实验提供了额外的好处。在这里，我们展示了一种宽带、高功率、快速可调的飞秒非共线光学参量振荡器，其信号调谐范围在可见光范围内为 440-720 nm。振荡器由 Yb 光纤激光器的三次谐波泵浦，波长为 345 nm，重复率为 50.2 MHz。此外，仅通过改变腔长来调整信号波长，并且实现了高达 452 mW 的输出功率和低至 268 fs 的脉冲持续时间。据我们所知，这是第一次演示快速可调的飞秒光学参量振荡器，它几乎覆盖了整个可见光谱范围，具有高输出功率。