Linearly polarized second harmonic generation microscopy reveals chirality

Abstract

Abstract:In optics, chirality is typically associated with circularly polarized light. Here we present a novel way to detect the handedness of chiral materials with linearly polarized light. We performed Second Harmonic Generation (SHG) microscopy on G-shaped planar chiral nanostructures made of gold. The SHG response originates in distinctive hotspots, whose arrangement is dependent of the handedness. These results uncover new directions for studying chirality in artificial materials.

Octupolar Plasmonic Meta-Molecules for Nonlinear Chiral Watermarking at Subwavelength Scale

“…Among the geometrical properties that can be addressed by SHG microscopy, chirality stands-out as one of the most interesting probes of light-matter interactions, especially in the context of chiral plasmonic meta-materials which have been reported to exhibit giant optical activity in the linear regime [20,21]. Valev et al have thus reported extensive work on chirality in SHG from specially patterned superchiral meta-surfaces [7,[22][23][24]. The location of plasmonic hot spots and their influence on the chiroptical response have been thoroughly addressed [22,23], leading to reports of nonlinear chiroptical effects reaching magnitudes as high as 52 % [24].…”

“…Valev et al have thus reported extensive work on chirality in SHG from specially patterned superchiral meta-surfaces [7,[22][23][24]. The location of plasmonic hot spots and their influence on the chiroptical response have been thoroughly addressed [22,23], leading to reports of nonlinear chiroptical effects reaching magnitudes as high as 52 % [24]. However, the basic building blocks of the investigated meta-materials were relatively large, with lateral sizes of the order of 1 micron, which is not compatible with the encoding of chirality-based information below the typical diffraction limit of SHG microscopy.…”

Optical second harmonic generation from V-shaped chromium nanohole arrays

“…In order to ensure that the laser beam always illuminated the V-shaped nanoholes during the rotation of the stage, care was taken that both the laser spot and the V-shaped area were on the rotation axis. In order 5 to avoid damaging the sample, the average energy of the incoming beam was kept about 30 µJ/pulse. The reflected radiation at the doubled frequency 2ω was passed through an ω cut filter, an analyzer, a focus lens and was detected by a photomultiplier through a monochromator.…”

“…At the nanoscale, artificial structures tend to show unusual characteristics, such as negative electric permittivity 2) , optical cloaks 2) , super lensing 3) and many more [4][5][6][7][8] .…”

Linear and nonlinear Fano resonance on two-dimensional magnetic metamaterials

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] By using enhanced optical nonlinearity in metallic nanostructures, plasmonic/metamaterial devices have been used for ultrafast optical switching applications. [17][18][19] In the field of nonlinear optics, while second-order processes have been extensively studied on various plasmonic/metamaterial nanostructures, [2][3][4][5][6][7][8][9][10] third-order nonlinear optical phenomena on metallic nanostructures are attracting more attention. For example, surface enhanced four-wave mixing on gold plasmonic nanostructures 11,12,14 and a plasmon-enhanced third harmonic generation 15,16 were demonstrated by virtue of a light confinement effect of plasmonic excitations.…”