Abstract
A new type of circular Airy beams is demonstrated by using a bandpass filter, in order to enhance the field intensity at the focal point of light beam, based on the angular spectrum representation and the ray optics picture. The specific ring and the key spatial frequency corresponding to the focal point are obtained, via the ray optics picture, to make the initial field concentrate near the specific ring in the real space. It is found that the field intensity at the focal point of the new type circular Airy beams is better enhanced than the common circular Airy beams and the modified circular Airy beams, and the enhancement effect can be tuned via the central spatial frequency, apodization steepness and width of the bandpass filter. The enhanced field intensity gives a very strong gradient force and may find applications on optical manipulation.
Highlights
Structured light [1] is a kind of light beam that is well designed with different types of field intensity and propagation trajectory via the optical modulation of field amplitude and phase on the initial plane or the angular spectrum in the Fourier space
Using the ray optics picture, the field intensity at the focal point is mainly contributed from the light rays emitted from the specific ring on the initial plane, which are tangent to the focal point, so the initial field is engineered to concentrate near the specific ring
In the real space, the light beam will be concentrated near the specific ring on the initial plane and its maximum of filed intensity will be located near the specific ring, with the result that the field intensity will be enhanced at the focal point
Summary
Structured light ( called shaped light or tailored light) [1] is a kind of light beam that is well designed with different types of field intensity and propagation trajectory via the optical modulation of field amplitude and phase on the initial plane or the angular spectrum in the Fourier space. For the enhancement of the field intensity at the focal point, since the first few rings almost have no contribution on the field intensity at the focal point, the blocked circular Airy beams [22] and modified circular Airy beams [23] were proposed via the suppression of the first few rings with larger field intensity by using an annular aperture directly on the initial plane or adding an apodization mask in the Fourier space, respectively. A new type of circular Airy beams based on a bandpass filter (BCABs) is proposed to suppress the first few rings and the redundant side rings located outside the specific ring on the initial plane, the light beam is concentrated within the region near the specific ring to achieve a higher field intensity at the focal point. The enhanced field intensity of the BCABs demonstrated here will give a very strong gradient force near the focal point and the discussed results may provide applications on optical manipulation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
