Generation and self-healing of a radially polarized Bessel-Gauss beam

We report experimental generation of a radially polarized Bessel-Gauss (RPBG) beam of order 1 with the help of a spatial light modulator, a spiral phase plate, and a radial polarization converter. Furthermore, we carry out a comparative study of the self-healing properties of a RPBG beam and a linearly polarized Bessel-Gauss (LPBG) beam which are blocked by a sector-shaped opaque obstacle both experimentally and numerically. Our results clearly show that the self-healing ability of a RPBG beam indeed is superior to that of a LPBG beam, and some physical interpretations are given. Our results will be useful for particle trapping and microscopy.

Figure 1

Normalized intensity distribution (contour graph) of a RPBG or LPBG beam of order 1 after passing through a thin lens with focal length $f$ = 300 mm at several propagation distances.

Figure 2

Experimental setup for generating a RPBG beam of order 1 and measuring its intensity on propagation. RM, reflecting mirror; BE, beam expander; SLM, spatial light modulator; CA, circular aperture; SPP, spiral phase plate; RPC, radial polarization converter; OO, sector-shaped opaque obstacle; L, thin lens; BPA, beam profile analyzer; PC, personal computer.

Figure 3

Experimental results of the normalized intensities (contour graphs) and the corresponding cross lines ($y$ = 0) of the generated LPBG beam of order 1 and the generated RPBG beam of order 1 in the source plane. The dark solid line denotes the theoretical fit of the experimental data.

Figure 4

Experimental results (a)–(c) and theoretical results (d)–(f) of the intensity distribution of the generated LPBG beam of order 1 after passing through a sector-shaped opaque obstacle with center angle $\varphi =\pi /4$ and a thin lens with focal length $f$ = 300 mm at several propagation distances.

Figure 5

Experimental results (a)–(c) and theoretical results (d)–(f) of the intensity distribution of the generated RPBG beam after passing through a sector-shaped opaque obstacle with center angle $\varphi =\pi /4$ and a thin lens with focal length $f$ = 300 mm at several propagation distances.

Figure 6

Transverse power flows ${\vec{S}}_{\perp }$ (blue arrows) of the generated LPBG beam of order 1 and the generated RPBG beam of order 1 after passing through a sector-shaped opaque obstacle with center angle $\varphi =\pi /4$ and a thin lens with focal length $f$ = 300 mm at several propagation distances

Figure 7

Experimental results (a)–(c) and theoretical results (d)–(f) of the intensity distribution of the generated LPBG beam after passing through a sector-shaped opaque obstacle with center angle $\varphi$ and a thin lens with focal length $f$ = 300 mm in the focal plane for different values of $\varphi$.

Figure 8

Experimental results (a)–(c) and theoretical results (d)–(f) of the intensity distribution of the generated RPBG beam after passing through a sector-shaped opaque obstacle with center angle $\varphi$ and a thin lens with focal length $f$ = 300 mm in the focal plane for different values of $\varphi$.

Figure 9

Polarization ellipse of a RPBG beam of order 1 after passing through a sector-shaped opaque obstacle with center angle $\varphi$ and a thin lens with focal length $f$ = 300 mm in the focal plane for different values of $\varphi$.