Widely tunable, high-power, femtosecond noncollinear optical parametric oscillator in the visible spectral range

Abstract

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.

Visible, femtosecond, high power, ultra-broadband noncollinear optical parametric oscillator (VIS-NOPO)

“…In the past, the most common approaches to generate tunable femtosecond laser pulses in the visible were either to generate intracavity SHG or SFG in near-infrared OPOs [1,2] or by pumping the OPO directly with the second harmonic of a Ti:sapphire laser (VIS-OPO) [3,4]. In this work, we demonstrate the full potential of the noncollinear phase matchings scheme in the visible by pumping the OPO with the third-harmonic of an Yb-fiber laser [5]. The resulting visible radiation can just be tuned by changing the cavity length.…”