Non-diffracting light in nature: Anomalously reflected self-healing Bessel beams from jewel scarabs

Abstract

We report a study of spatial light modulation in the photonic structure of jewel scarabs, revealing the interplay of the polarization and phase control of light, which is not possible with the current optical technology. Phase measurements performed on jewel scarabs demonstrate that the polarization anomalous (helicity-preserving) reflection of light occurs together with alteration of the dynamic phase associated with the optical path length. This control of light differs from the operation of artificially prepared polarization-sensitive structures, shaping light through the geometric phase altered by the polarization transformation. Challenging three-dimensional imaging of the cuticle, requiring high-resolution quantitative mapping of steep phase changes, has been achieved owing to the optical performance of recently developed geometric-phase microscopy. We find that the cuticle of jewel scarabs is formed of micrometer-sized axicon cells, generating thousands of Bessel beams with subwavelength spot size. The nondiffracting features and the self-healing ability of the Bessel beams originating from the beetle Chrysina gloriosa are demonstrated experimentally. Considering Bragg reflection and shaping of RGB components of white light Bessel beams, we explain the spatial structuring of colors in microscopic images of jewel scarabs and reveal the conversion of colors when changing the distance from the cuticle. The functionality and performance of the cuticle axicon cells are discussed in comparison with high-aperture dielectric meta-axicons, and potential applications in colorimetric refractive index sensing are outlined.

Biomimetic design of iridescent insect cuticles with tailored, self-organized cholesteric patterns

“…1d). Previous studies on the cuticle of C. gloriosa have reported the following: the cellular structure of the concentric rings in the green bands, as established through TEM investigations 20 or fluorescence confocal microscopy 21 ; the variation in the optical properties with the incidence angle, as established through Mueller matrix spectroscopic ellipsometry 22,23 ; the existence of an array of multiwavelength micromirrors in the green bands 24 ; and the generation of self-healing Bessel beams from polygonal cells 25 .…”

Biomimicry of iridescent, patterned insect cuticles: comparison of biological and synthetic, cholesteric microcells using hyperspectral imaging

“…Previous studies on the polygonal texture of C. gloriosa have reported a cellular structure of concentric rings, as shown by TEM [32] or fluorescence confocal microscopy [33]; a low degree of circular polarization, as shown by Mueller matrix spectroscopic ellipsometry [34]; a multiwavelength micromirror nature of the polygonal cells [29]; and the generation of self-healing Bessel beams from the polygonal cells, which may be approached as axicon cells [35].…”

“…Previous studies on the polygonal texture of C. gloriosa have reported a cellular structure of concentric rings, as shown by transmission electron microscopy (TEM) 31 or fluorescence confocal microscopy; 32 a low degree of circular polarization, as shown by Mueller matrix spectroscopic ellipsometry; 33 a multiwavelength micromirror nature of the polygonal cells; 28 and the generation of self-healing Bessel beams from the polygonal cells, which may be approached as axicon cells. 34 In synthetic CLCs, polygonal textures consisting of a mosaic of polygons of various sizes (Fig. 2a) are easily available from flat cholesteric films when the helical axis is tilted with respect to the surfaces of the films.…”

Modern Types of Axicons: New Functions and Applications

“…In this paper, we have reviewed the recent developments related to the methods used for the generation of NDBs by employing diffractive axicons [ 39 , 40 ], meta-axicons-flat optics [ 41 ], spatial light modulator [ 42 ], and photonic integrated circuits-based axicons [ 43 , 44 ], as shown in Figure 2 . The range of NDBs produced by a real axicon is determined by the axicon’s parameters such as diameter and refractive angle [ 45 , 46 ]. When adjusting measuring ranges, it may be necessary to substitute the axicons with distinct angles or adjust the axicon’s cone angle [ 47 ].…”