Compression of Ultrafast Laser Beams
Technical Report,01 Dec 2014,31 Dec 2014
US Army Research Laboratory Adelphi United States
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Compression of ultrafast laser pulses is critical to obtain optimal results from many experiments that use a femtosecond laser system. However, as the pulse lengths decrease and peak pulse power increases, pulse compression using static elements such as prisms may not be sufficient to completely compress the laser pulse. This report details the complete construction of a spatial light modulator SLM-based 4 frequency Fourier pulse shaper that is used in femtosecond laser pulse compression. First, the theory behind compression of femtosecond lasers is covered and initial pulse compression efforts using static elements are discussed. Next, all aspects of the SLM pulse shaper construction are covered, including part selection, alignment, and calibration curve determination. This technical report also discusses the theory, construction, and evaluation of 2 separate algorithms, a modified genetic algorithm and the multiphoton intrapulse interference phase scan MIIPS algorithm, used to optimally compress the femtosecond laser pulses using the pulse shaper. The efficacy of these 2 algorithms when used for pulse compression was evaluated, and it was found that the MIIPS algorithm was superior to the genetic algorithm for pulse compression.