Generation Of Ultra-broadband Pulses Research Articles

Ultra-broadband pulse generation via hollow-core fiber compression and frequency doubling for ultra-intense lasers

Abstract We demonstrate an ultra-broadband high temporal contrast infrared laser source based on cascaded optical parametric amplification, hollow-core fiber (HCF) and second harmonic generation processes. In this setup, the spectrum of an approximately 1.8 μm laser pulse has near 1 μm full bandwidth by employing an argon gas-filled HCF. Subsequently, after frequency doubling with cascaded crystals and dispersion compensation by a fused silica wedge pair, 9.6 fs (~3 cycles) and 150 μJ pulses centered at 910 nm with full bandwidth of over 300 nm can be generated. The energy stability of the output laser pulse is excellent with 0.8% (root mean square) over 20 min, and the temporal contrast is >1012 at –10 ps before the main pulse. The excellent temporal and spatial characteristics and stability make this laser able to be used as a good seed source for ultra-intense and ultrafast laser systems.

Generation of ultra-broadband pulses in the near-IR by non-collinear optical parametric amplification in potassium titanyl phosphate

Non-collinear optical parametric amplification in potassium-titanyl phosphate (KTP) pumped with 800 nm pulses is reported. Broadband phase matching is achieved with non-collinear geometry and a slightly divergent signal seed. This enables a gain bandwidth up to approximately 2500 cm(-1) in near-IR region. Introducing a chirp into the pump pulse makes it possible to amplify the white light seed in a broad spectral region from approximately 1050 to approximately 1400 nm simultaneously. Pulse compression to sub-40 fs is readily achieved, while the spectrum should support approximately 8.5 fs pulses. Angular dispersion of the broadband output is discussed.

Effects of cavity-dispersion noncoaxiality on the generation of ultrabroadband femtosecond pulses

The effects of cavity-dispersion noncoaxiality (CDN) on the generation of ultrabroadband femtosecond pulses in KLM Ti:sapphire laser were investigated theoretically and experimentally. It was predicted that when the laser sub-cavity works near the coaxial operation point, the limitation of CDN on the bandwidth broadening is minimum, which is favorable for ultrabroadband pulse generation. On the basis of this prediction, femtosecond pulses with bandwidth of 650 to 1000 nm were directly generated from a home built KLM Ti:sapphire laser. To our knowledge, they are the broadest bandwidth pulses produced from KLM Ti:sapphire laser with similar oscillator configuration and gain crystal length of 3 mm.