Implementation of uniform beam shape of medical picosecond laser for effective treatment

In the case of the medical lasers used for skin diseases and skin beauty, picosecond lasers with pulse durations of hundreds of picoseconds are mainly used. The picosecond laser breaks the pigment of the lesion into small pieces, enabling effective treatment without damaging the surrounding tissue. In the case, the beam profile is important because the laser must be uniformly irradiated to the desired area. In this paper, in order to obtain a uniform beam profile, the size of Nd:YAG Rod, which is a laser gain medium for each amplification stages, is different, and cap is used for the pre amplification stage. In addition, a beam shape compensator with an aspherical lens at the front of the handpiece was designed to realize a uniform beam in all handpieces.