摘要
Based on the inverse Faraday effect, a super-long longitudinal magnetization needle can be induced by a trans- versely polarized needle-shaped electric field. This needle-shaped electric field can be obtained in the focal vol- ume of the objective by focusing an azimuthally polarized vortex beam that is modulated both radially and azimuthally by a specifically designed annular phase filter. The numerical calculation shows that the full widths at half-maximums in longitudinal direction and in transverse direction of the magnetization needle are 282 and 0.27λ. The corresponding needle aspect ratio of 103 is more than ten times larger than that of the magnetization needle fabricated by electron beam lithography.
Based on the inverse Faraday effect, a super-long longitudinal magnetization needle can be induced by a trans- versely polarized needle-shaped electric field. This needle-shaped electric field can be obtained in the focal vol- ume of the objective by focusing an azimuthally polarized vortex beam that is modulated both radially and azimuthally by a specifically designed annular phase filter. The numerical calculation shows that the full widths at half-maximums in longitudinal direction and in transverse direction of the magnetization needle are 282 and 0.27λ. The corresponding needle aspect ratio of 103 is more than ten times larger than that of the magnetization needle fabricated by electron beam lithography.
