Beam shaping in the ultraviolet spectral range with the spatial light modulator

• Applicant: Professor Dr.-Ing. Michael Schmidt
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Joining and Separation Technology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 521150885

Ultrashort-pulsed ultraviolet (UV) laser radiation is often applied to highly sensitive materials which only absorb in the UV spectral range as particularly the human cornea or specific temperature-sensitive elements. Through the characteristics of ultrashort- pulsed laser interaction, the surrounding material is only little affected and damaged. In the visible and infrared spectral range, beam shaping nowadays helps to shape the spatial intensity profile and adapt the applied energy to the ablation process. Besides an increase in efficiency, unwanted heat accumulation in the surrounding area can be reduced to enable laser material processing with highest standards in precision and quality. Beam shaping in the UV spectral region can only be performed with strongly restricted methods and under the admission of huge losses since the available devices majorly absorb the radiation. In the scope of this project, an efficient and applicable method shall be developed to perform beam shaping in the UV region with commercially available spatial light modulators (SLMs) by making use of nonlinear optical effects. An SLM shapes the wave front to obtain a certain intensity distribution. Since the frequency conversion is a coherent process, this information is maintained in the frequency converted light. It is therefore possible to apply a certain phase information to the fundamental beam to shape the desired intensity profile of the frequency converted light field. This project is conceived to develop algorithms for the required phase masks and to design a robust experimental setup. This enables an efficient method to shape light in the UV region and simultaneously paves the way for industrial applications in the future.

• DFG Programme: Research Grants