Pulse-front matching of ultrabroadband near-infrared noncollinear optical parametric amplified pulses

Noncollinear optical parametric amplifiers (NOPAs) pumped with ultrashort subpicosecond pulses often suffer from pulse-front tilting, resulting in angular dispersion and noncompressibility of the amplified signal pulses. We show that pulse-front matching (PFM) with a prism-telescope setup corrects for pulse-front tilts in a near-IR NOPA. We discuss the conditions that lead to pulse-front tilt and angular dispersion in NOPA-amplified signal pulses, thus requiring pulse-front mismatch correction. We review the method of PFM and describe the application of PFM to an 800 nm pumped near-IR NOPA based on a 2-mm-thick bulk potassium-titanyl phosphate (KTP) crystal. The introduction of pulse-front matching into the KTP-NOPA reduces the signal pulse angular dispersion significantly over the >35 THz bandwidth, thus nearly removing the pulse-front tilt. Compression of 1200 nm pulses to ~25 fs can be readily achieved with a fused-silica prism pair compressor.