Hollow Gaussian beam generated by beam shaping with phase-only liquid crystal spatial light modulator

• Published in: Optics and laser technology Vol. 44; no. 2; pp. 384 - 389
• Main Authors: Nie, Yongming, Li, Xiujian, Qi, Junli, Ma, Haotong, Liao, Jiali, Yang, Jiankun, Hu, Wenhua
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2012
• Subjects: Beam shaping; Hollow Gaussian beam; Phase modulation; Hollow Gaussian beam; Beam shaping; Phase modulation
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/j.optlastec.2011.07.021

Based on the refractive beam shaping system, the transformation of a quasi-Gaussian beam into a dark hollow Gaussian beam by a phase-only liquid crystal spatial light modulator (LC-SLM) is proposed. According to the energy conservation and constant optical path principle, the phase distribution of the aspheric lens and the phase-only LC-SLM can modulate the wave-front properly to generate the hollow beam. The numerical simulation results indicate that, the dark hollow intensity distribution of the output shaped beam can be maintained well for a certain propagation distance during which the dark region will not decrease whereas the ideal hollow Gaussian beam will do. By designing the phase modulation profile, which loaded into the LC-SLM carefully, the experimental results indicate that the dark hollow intensity distribution of the output shaped beam can be maintained well even at a distance much more than 550 mm from the LC-SLM, which agree with the numerical simulation results. ► The generation of dark hollow Gaussian beam based on refractive shaping system is studied. ► One phase-only LC-SLM substitutes the aspherical lens to modulate the beam wave-front directly. ► Design principle and propagation properties of the shaped beam are investigated in detail. ► The dark hollow Gaussian beam is generated effectively and high energy conversion is obtained.