Formation of sub-half-wavelength focal spot with ultra long depth of focus

✍ Scribed by Cuifang Kuang; Xiang Hao; Xu Liu; Tingting Wang; Yulong Ku

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 473 KB
• Volume: 284
• Category: Article
• ISSN: 0030-4018
• DOI: 10.1016/j.optcom.2010.12.055

✦ Synopsis

We theoretically demonstrate the creation of sub-wavelength focal spot with ultra long depth of focus (DOF) non-diffracting. To achieve a sub-half-wavelength focal spot (0.4λ) with modulation, extended DOF (over 9.5λ) in vacuum, an integration of amplitude phase encoding, cylindrical polarization and the combination of dual-beams is utilized. Further analysis also predicts that a flattop intensity distribution along z axis can be observed around the ideal focus point.