We propose a new design for fabrication of a highly power-efficient double axicon to generate self-imaged three-dimensional intensity voids along the propagation of a beam. The conventional conical structure of an axicon is modified and shaped like an axiconlike structure with a double-gradient surface profile. The gradient conical surfaces generate Bessel beams with varying radial wave vectors that are superimposed and interfere to generate a sequence of three-dimensional intensity voids. The proposed element was fabricated using electron-beam lithography, and experimental verification of the design is reported.
"Recently, a subwavelength focal hole (0.5) with a quite long depth of focus (48) is achieved near the focus by tight focusing of double-ring-shaped azimuthally polarized beam with high numerical aperture (NA) lens axicon . Optical beams with oscillating on-axis intensity due to interference resulting in 3D intensity voids and 3D optical chains were proposed recently for trapping of multiple particles along the beam propagation and for controllable particle delivery . Azimuthally polarized light and beam with optical vortex owe their interesting in optical trapping    which have captured particles experimentally. "
[Show abstract][Hide abstract] ABSTRACT: Based on the vector diffraction theory, the effect of complex phase plate on the intensity distribution of TEM11 mode azimuthally polarized Laguerre–Gaussian beam in the focal region of high NA lens is investigated theoretically. It is observed that a properly designed complex phase plate can generate a subwavelength focal hole having FWHM of 0.332λ with an extended focal depth of 54.4λ. We also observe that by using properly designed complex phase plate generates novel focal patterns including splitting of focal holes and multi focus are obtained. The author expects such investigation is worthwhile for optical manipulation and material processing technologies.
Optik - International Journal for Light and Electron Optics 08/2014; 125(15). DOI:10.1016/j.ijleo.2014.03.002 · 0.68 Impact Factor
"Such beams are also known as twice-closed tubular optical structure (TCTOS) , optical bubbles , and hollow dark spherical spots . Optical beams with oscillating on-axis intensity due to interference resulting in 3D intensity voids and 3D optical chains were proposed recently for trapping of multiple particles along the beam propagation and for controllable particle delivery . Over the past years, a variety of techniques have been proposed for generating such optical bottle beams for applications in optical tweezers and atom traps        . "
[Show abstract][Hide abstract] ABSTRACT: We investigated the focusing properties of a double-ring-shaped azimuthally polarized beam tightly focused with a high NA lens and a binary phase filter. We observe that by using 3 belts and 5 belts binary phase filters novel focal patterns including splitting of focal rings and multiring focus are obtained. We also found that a suitably designed phase structure can shift the focal rings along optical axis. The author expects such investigation is worthwhile for optical manipulation and material processing technologies.
[Show abstract][Hide abstract] ABSTRACT: We present techniques to generate multiple vortex with different topological charge by means of diffractive optical elements. Analytical formulae to describe the Fresnel and Fraunhofer diffraction of the Gaussian beam by a helical axicon (HA) are introduced. The relations are presented as a series of the hypergeometric functions. By setting the axicon parameter equal to zero, the solution for the HA changes to that for the spiral phase plate (SPP). The performance of the aforesaid optical elements is tested both through computer simulation and by experiments using a spatial light modulator, in view of optical miroparticle manipulation.
Conference on Nanoengineering - Fabrication, Properties, Optics and; 01/2006
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