Propagation of high-order circularly polarized Bessel beams and vortex generation in uniaxial crystals

Abstract

Abstract. We investigate the generation and transformation of Bessel beams through linear and nonlinear optical crystals. We outline the gen-eration of high-order vortices due to propagation of Bessel beams along the optical axis of uniaxial crystals and expand this to the nonlinear regime by outlining a new phase-matching process (full conical phase matching) in second harmonic generation of vector Bessel beams for various sym-metries in uniaxial crystals. We demonstrate the principles experimentally in a uniaxial BBO crystal and find excellent agreement between the ex-perimental and theoretical results. The results imply a coupling of the intrinsic and extrinsic optical angular momentum of the resulting fields, which may have importance in studies involving quantum entanglement of the angular momentum basis of light. C©2011 Society of Photo-Optical Instru-mentation Engineers (SPIE). [DOI: 10.1117/1.3572109] Subject terms: Bessel beams; optical vortices; uniaxial crystals; second harmonic generation. Paper 100866PR received Nov. 2, 2010; revised manuscript received Feb. 28, 2011; accepted for publication Mar. 8, 2011; published online May 2, 2011.

Harmonic spin–orbit angular momentum cascade in nonlinear optical crystals

“…Extending the present results to the non-paraxial regime is a task for a future work, with the aim of reaching phase-matching conditions [31][32][33] and thereby higher efficiencies in harmonic generation. Another option to increase efficiency could be to implement a single-pass quasi-phase-matching process 34 or an intracavity design 6 .…”

“…Interestingly, the non-paraxial regime-where the longitudinal field component enters explicitly in the second-harmonic generation process-has been explored in a couple of previous works [31][32][33] with experimental demonstration of azimuthally modulated total SHW intensity. However, there are only theoretical predictions regarding the spin-orbit content of the harmonic field generated from non-paraxial Bessel beams: a FW characterized by a transverse state (σ, 0) ω has been predicted to lead to SHW transverse states (−σ, 0) 2ω , (σ, −σ) 2ω , (−σ, 3σ) 2ω and (σ, 4σ) 2ω , where the states with OAM components ℓ 2ω = −σ and 3σ are of a non-paraxial nature [31][32][33] . In contrast, we demonstrate that the paraxial regime allows axisymmetric harmonic intensity distributions to be obtained.…”

Spin-to-orbital angular momentum conversion for Bessel beams propagating along the optical axes of homogeneous uniaxial and biaxial crystals

“…This is justified by the fact that the thickness of a crystal is usually small (∼1 cm), and the transverse Bessel beam size is relatively large. Moreover, as is well known, the diffraction effect in the central area of the Bessel beams is not essential [4][5][6].…”

“…The transformation of the polarization state and spatial structure of circularly polarized quasi-nondiffracting Bessel light beams (BLBs), propagating along the optical axis in homogeneous uniaxial and biaxial crystals, was studied in papers [4][5][6][7]. The appearance of the optical vortex in one of the beam components while the initial circularly polarized beams have no optical vortex is associated with the appearance of the OAM in the output beam.…”

Comparison of three kinds of polarized Bessel vortex beams propagating through uniaxial anisotropic media*

“…The vortex beams carrying orbital angular momentum (OAM) [1] have been widely studied over a few past decades, including generation, [2,3] characteristics, [4][5][6] and applications in optical communication, [7] imaging, [8] microparticle manipulation, [9] etc. In particular, the different OAM states are mutually orthogonal while propagating coaxially and thus promote potential applications in improving the capacity of communication systems.…”