High fidelity femtosecond pulses from an ultrafast fiber laser system via adaptive amplitude and phase pre-shaping

• Main Authors: Prawiharjo, Jerry (Author), Daga, Nikita K. (Author), Geng, Rui (Author), Price, Jonathan H.V (Author), Hanna, David C. (Author), Richardson, David J. (Author), Shepherd, David P. (Author)
• Format: Article
• Language: English
• Published: 2008-09-10.
• Subjects: Article
• Online Access: Get fulltext; Get fulltext

The generation of high-fidelity femtosecond pulses is experimentally demonstrated in a fiber based chirped-pulse amplification (CPA) system through an adaptive amplitude and phase pre-shaping technique. A pulse shaper, based on a dual-layer liquid crystal spatial light modulator (LC-SLM), was implemented in the fiber CPA system for amplitude and phase shaping prior to amplification. The LC-SLM was controlled using a differential evolution algorithm, to maximize a two-photon absorption detector signal from the compressed fiber CPA output pulses. It is shown that this approach compensates for both accumulated phase from material dispersion and nonlinear phase modulation. A train of pulses was produced with an average power of 12.6W at a 50MHz repetition rate from our fiber CPA system, which were compressible to high fidelity pulses with a duration of 170 fs.