Multimillijoule optical parametric chirped-pulse amplifier as an alternative to Yb:YAG regenerative amplifiers at 1030 nm

The broad absorption bandwidth of ytterbium (Yb) is well-suited to laser diode pumping at 940 nm. Because Yb is known for its low quantum defect, thermal loading is significantly reduced. Consequently, Yb doped crystals, especially Yb:YAG, show promise for developing compact, high peak power laser systems at high repetition rates. For high energy pulses of short duration Yb:YAG regenerative amplifiers have mainly been studied where the generation of significant prepulse and amplified spontaneous emission (ASE) is known. At higher intensities (for example ∼ 10 18 Wcm −2 and beyond) laser-matter interactions can require suppression of prepulse and ASE intensity in order to maintain or control the target state that a short or ultrashort main pulse would irradiate. In many cases it is therefore critical to avoid significant preplasma formation. To solve these problem, the optical parametric chirped pulse amplification (OPCPA) can efficiently provide high gain of the main pulse while suppressing prepulse amplification and reducing gain narrowing of the spectrum. We present in this conference the first Yb femtosecond oscillator based OPCPA demonstration at 1030 nm and with spectral bandwidth adequate for amplifying femtosecond pulses. Direct laser diode (LD) amplification of 1030 nm light makes this OPCPA a feasible preamplifier for a compact, high contrast, energetic, short pulse laser systems that can be considered for development of laser-driven proton accelerators.