Generation of multiple sub wavelength focal spot segments using radially polarized Bessel Gaussian beam with complex phase filter

Based on vector diffraction theory and inverse Faraday effect, the light induced magnetization distribution of a tightly focused azimuthally polarized Bessel-Gauss beam superimposed with a helical phase and modulated by an optimized multi belt complex phase filter (MBCPF) is analyzed numerically. It is noted that by adjusting the radii of different rings of the complex phase filter, one can achieve many novel magnetization focal distributions, such as sub-wavelength scale (0.29λ) and super-long (71λ) pure longitudinal magnetic probe and magnetization chain composed of nine, six and four magnetic spots of sub-wavelength scale. The authors expect that these results pave the path for fabricating magnetic lattices for spin wave operation, multiple atoms or magnetic particle trapping and transportation, confocal and magnetic resonance microscopy, as well as multilayer ultrahigh density magnetic storage.Keywords: inverse Faraday effect, high NA lens, multi belt complex phase filter, azimuthally polarized Bessel-Gauss beam.

show abstract

“…1b. The phase and amplitude function A(θ) of the multi belt complex phase filter MBCPF(θ) is given by [52] (5)…”

Section: Focusing With Multi Belt Complex Phase Filter (Mbcpf)mentioning

confidence: 99%

Manipulating the magnetization focal patterns using complex phase filters

Udhayakumar¹,

Prabakaran²,

Rajesh³

et al. 2019

Optica Applicata

Self Cite

View full text Add to dashboard Cite

show abstract

“…Complex phase filter could be regarded as an extension of the ternary phase-amplitude filter. This filter has recently been reported which can generate pure ultra-long optical needles by modulating the phase of polarized beam [14,15,20,[34][35][36]. Using the complex phase filter, Prabakaran et al obtained optical needle with 5.7λ of DOF and 1.4λ of FWHM by tightly focusing radially polarized BG beam in 2014 [34].…”

Section: Introductionmentioning

confidence: 99%

“…This filter has recently been reported which can generate pure ultra-long optical needles by modulating the phase of polarized beam [14,15,20,[34][35][36]. Using the complex phase filter, Prabakaran et al obtained optical needle with 5.7λ of DOF and 1.4λ of FWHM by tightly focusing radially polarized BG beam in 2014 [34]. The radial component of the optical needle is 70% in the total intensity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The generation of ultra-long longitudinally polarized optical needle with multi-belt complex phase filter

Liu,

Zhang,

et al. 2024

Phys. Scr.

View full text Add to dashboard Cite

In the paper, a multi-belt complex phase filter was optimized by increasing the number of belts and changing phase and amplitude parameters of the filter. By focusing radially polarized sinh-Gaussian beams in single objective system with high-NA lens, longitudinal polarized optical needles were obtained with super-resolution in focal plane. And the super-resolution optical needle owned 36.6λ depth of focus and 0.42λ of full–width at half-maximum. The aspect ratio of the obtained optical needle was 87.14. The beam quality reached to 87.7%. The results demonstrated that the optimized multi-belt complex phase filter can lengthen depth of focus and compress transverse size simulta-neously. The obtained longitudinally polarization optical needles can be used in the fields of optical data storage, super-resolution imaging, particle trapping, nanolithogra-phy and so on.

show abstract