Patent ID: 7630147

Claim:
An optical system for producing a laser beam having a two prong pitchfork profile comprising: a lasing device for providing an input Gaussian beam; an input and an output Gaussian lens for converting the input Gaussian beam into an expanded super Gaussian beam, the input Gaussian lens having a lens surface defined by the condition z = 4.091 · r 2 1 + 1 - ( 1 - 2.492 ) · 4.091 2 · r 2 - 1.158 · r 2 + 3.242 · r 4 and the output Gaussian lens having a lens surface defined by the condition Z=0.070·R 2 +0.019·R 4 where r and R are two arbitrary radii in which the relationship between r and R is defined by r = - r 0 2 2 · ln ⁢ { 1 - I 0 ′ I 0 · ∫ 0 R ⁢ exp ⁡ [ - 2 ⁢ ( R R 0 ) 10 ] ⁢ R ⁢ ⁢ ⅆ R } ; a focusing lens for focusing the expanded super Gaussian beam, wherein by diffraction effect after the focusing lens, the beam profile near a focal spot is a two prong pitchfork shaped beam, the two prong pitchfork profile refers to the longitudinal cross-section of the laser beam at the focal spot.