Abstract

Recently, the field of ultrafast optics has been revolutionized by the introduction of diode-pumped Yb-based systems, enabling the generation of 200÷400 fs pulses with 1÷10 μJ energy at repetition rates of R2 MHz [1]. These efficient and stable sources operate at a fixed wavelength (≈1 μm) while several applications, such as time-resolved optical spectroscopy, require frequency tunability. This can be obtained by optical parametric amplifiers (OPAs), which require a suitable seed pulse, typically produced by white-light generation in a sapphire plate [2], by spectral broadening in a nonlinear photonic crystal fiber [3] or by synchronization with a broadband Ti:sapphire laser [3]. Due to the complexity of these setups, no system providing two independently tunable pulses at MHz repetition rate has been reported so far.

© 2009 IEEE