Focusing flattop beam shaping with complex modulation holography
Jing Shao,
Thomas Haase,
Ruolan Zhang,
Claude Aguergaray,
Neil Broderick,
Shufeng Sun
Affiliations
Jing Shao
Shandong Collaborative Innovation Center of Laser Green Intelligent Manufacturing Technology and Equipment, Qingdao University of Technology, Qingdao, Shandong 266520, China
Thomas Haase
The Photon Factory, Department of Physics, University of Auckland, Auckland 1010, New Zealand
Ruolan Zhang
Shandong Collaborative Innovation Center of Laser Green Intelligent Manufacturing Technology and Equipment, Qingdao University of Technology, Qingdao, Shandong 266520, China
Claude Aguergaray
The Photon Factory, Department of Physics, University of Auckland, Auckland 1010, New Zealand
Neil Broderick
The Photon Factory, Department of Physics, University of Auckland, Auckland 1010, New Zealand
Shufeng Sun
Shandong Collaborative Innovation Center of Laser Green Intelligent Manufacturing Technology and Equipment, Qingdao University of Technology, Qingdao, Shandong 266520, China
A complex modulation algorithm for focusing beam shaping with a phase-only spatial light modulator is designed. This method modulates the amplitude and phase of a collimated beam synchronously, and the modulated beam passing through an objective lens will generate a shaped focusing beam. The characteristic of the complex modulation was studied, while the Mixed-Region Amplitude Freedom (MRAF) method was selected as a comparative reference in this research. In the theoretical simulation, the complex modulation shows excellent performance with a roughness of 0.32% RMS and 0.54% MAX. Otherwise, to further verify this complex modulation algorithm, an experiment was implemented to generate a square-shaped focusing flattop beam. The complex modulation generated a flattop beam with a roughness of 3.1% RMS and 6.1% MAX, better than the MRAF method. This result also proves that this complex modulation has better robustness.
