Higher-order Bessel like beams with z-dependent cone angles

Abstract

As in the case of zero-order Bessel beam being produced by illuminating an axicon with a Gaussian beam, higher-order Bessel beams are generated by substituting the Gaussian beam with a Laguerre Gaussian (LG) beam. These beams hold similar properties to zero-order Bessel beams except they carry orbital angular momentum (OAM). They also undergo an abrupt spatial transformation at the boundary of their non-diffracting regime whereby the near-field intensity distribution is a Bessel function which transforms into an annular ring (far-field profile). This can be considered a disadvantage to such beams in comparison to a Gaussian beam that is propagation invariant. By using a double axicon lens system this Bessel beams with z-dependent cone angles can be produced however at the expense of its non-diffracting nature. Here we outline an optical design to produce higher-order Bessel-like beams with z-dependent cone angles that will retains its spatial distribution as z 8.