According to reports, researchers at Osaka University in Japan have developed a technique: By optimizing the virtual phase grating, the accuracy of laser pointer beam shaping and wavefront obtained by traditional methods can be improved without additional cost. The research results have been published in Scientific Reports.
High-quality square flat-top beams have been widely used in various fields, such as uniform laser processing, medicine, and ultra-high-intensity laser applications in accelerators and nuclear fusion. The beam shape is the key to realizing the potential performance and effect of the laser. However, since the beam shape and wavefront vary with laser light, beam shaping is essential to produce the desired shape to meet various needs.
Static and adaptive beam shaping methods have been developed for various applications. As a static method, the diffractive optical element (DOE) has low edge steepness and flatness, and the wavefront deformation occurs after beam shaping. In addition, computer-generated holograms (CGH), as a typical adaptive method, also have the same difficulties.
However, because the extracted and residual components overlap in the Fourier plane, the high spatial frequency (HSF) component needs to be separated from the extracted components, thereby limiting the flatness and edge steepness of the resulting beam shape. In this research, the research team has developed a high-precision universal beam shaping technology that can be used in various green laser pointer from ultraviolet to near-infrared.
This method uses a virtual diagonal phase grating to spatially separate the residual and extracted components in the Fourier plane, and eliminates the overlap by making the grating vector kg not parallel to the normal vector kx or ky of the desired beam profile; in the traditional scheme , These vectors are parallel to each other.
The corresponding author of the paper said: “Our method can optimize the beam shape by improving the resolution and accuracy, which will contribute to basic research, manufacturing, and medical engineering. In traditional beam shaping systems, only the space needs to be changed. The frequency filter and the phase grating encoded on the SLM can significantly improve the accuracy of beam shaping without additional costs.”