TY - JOUR T1 - The influence of the walk-off effect on the output beam profile in OPCPA in biaxial materials TT - تاثیر پدیده انحراف پرتو بر نیمرخ پرتوهای خروجی در OPCPA در مواد دومحوری JF - opsi JO - opsi VL - 24 IS - 0 UR - http://opsi.ir/article-1-1450-en.html Y1 - 2018 SP - 453 EP - 456 KW - parametric amplification KW - walk-off KW - beam profile KW - biaxial crystal N2 - Optical parametric chirped pulse amplification (OPCPA) is numerically investigated in a nonlinear biaxial crystal by taking into account the walk-off effect. By considering a Gaussian signal beam with the wavelength of 800 nm and a third-order super-Gaussian pump beam at the wavelength of 532 nm, the influence of the walk-off effect on the spatial profile of the amplified beam is investigated and the conditions under which the influence of walk-off effect is minimized are extracted. Based on the calculations, the optimum crystal length for maximum energy gain is obtained and the best possible beam quality for the amplified signal is achieved. Our results reveal that the unwanted influence of the walk-off effect on the energy conversion from pump beam to the signal would be minimized under the properly chosen conditions and leads to an improved amplification gain. M3 ER -