Watt-level optical parametric amplifier at 42 MHz tunable from 1.35 to 4.5 µm coherently seeded with solitons.

We report on an optical parametric amplifier at high repetition rate of 41.7 MHz seeded by an optical soliton from a tapered fiber. Gap-free signal tuning from 1.35 µm to 1.95 µm with corresponding idler wavelengths from 2.2 µm to 4.5 µm is demonstrated. The system provides up to 1.8 W average power at 1.4 µm, more than 1.1 W up to 1.7 µm, and more than 400 mW up to 4.0 µm with a signal pulse duration of 200 to 300 fs. It is directly pumped by a solid-state oscillator providing up to 7.4 W at 1.04 µm wavelength with 425 fs pulse duration. Soliton-seeding is shown to lead to excellent pulse-to-pulse stability, but it introduces a timing-jitter on the millisecond timescale. Using a two-stage concept the timing-jitter is efficiently suppressed due to the passive synchronization of both conversion stages.

Broadly tunable femtosecond near- and mid-IR source by direct pumping of an OPA with a 41.7 MHz Yb:KGW oscillator.

We generate over half a watt of tunable near-IR (1380-1830 nm) and several hundred milliwatts in the mid-IR (2.4-4.2 µm) as well as milliwatt level mid-IR (4.85-9.33 µm) femtosecond radiation by pumping an optical parametric amplifier directly with a 7.4 W Yb:KGW oscillator at 41.7 MHz repetition rate. We use 5 mm PPLN and 2 mm GaSe as downconversion crystals and seed this process by a supercontinuum from a tapered fiber. The system is extremely simple and very stable and could replace more complex OPOs as tunable light sources.

Milliwatt-level mid-infrared (10.5-16.5 µm) difference frequency generation with a femtosecond dual-signal-wavelength optical parametric oscillator.

We demonstrate the generation of mid-infrared radiation using a femtosecond dual-signal-wavelength optical parametric oscillator and difference frequency generation in an extracavity gallium selenide or silver gallium diselenide crystal. This system generates up to 4.3 mW of average mid-infrared power. Its spectra can be tuned to between 10.5 µm and 16.5 µm wavelength (952 cm(-1)-606 cm(-1)) with more than 50 cm(-1) spectral bandwidth. We demonstrate that the power and spectra of this system are temporally very stable.