Left- and right-circularly polarized light-sensing based on colored and mechano-responsive chiral nematic liquid crystals

Soft Matter ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 27-30 ◽  
Author(s):  
Jun Yoshida ◽  
Shuhei Tamura ◽  
Hidetaka Yuge ◽  
Go Watanabe

A liquid crystal host–guest system composed of achiral organic molecules (host) and colored chiral metal complexes (guest) was fabricated to sense both right- and left-handed circularly polarized light (r- and l-CPL), depending on the guest (dopant) concentration.

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3098
Author(s):  
Boyu Zhang ◽  
Sixiang Zhao ◽  
Yingying Yu ◽  
Ming Li ◽  
Liancheng Zhao ◽  
...  

Circularly polarized light (CPL) detection and polarization state recognition are required for a wide range of applications. Conventional polarization detection with optical components causes difficulties for miniaturization and integration. An effective design strategy is proposed for direct CPL detection with chiral material. Here, we realized direct CPL detection based on the combination of chiral photonic cellulose nanocrystal (CNC) and ultraviolet-sensitive ZnO photoconductive material. The CNC layer deposited by evaporation-induced self-assembly established the left-handed chiral nematic structure with a photonic bandgap (PBG) to recognize left-handed CPL (LCPL) and right-handed CPL (RCPL) at specific wavelengths. The PBG of CNC layer has been modulated by the adjustment of chiral nematic pitch to match the semiconductor bandgap of ZnO film in ultraviolet region. The photocurrents under RCPL and LCPL are 2.23 × 10−6 A and 1.77 × 10−6 A respectively and the anisotropy factor Δgpc of 0.23 is acquired for the CPL detection based on the chiral photonic CNC. This design provides a new approach to the detection of CPL polarization state with competitive performance.


2021 ◽  
Vol 2094 (2) ◽  
pp. 022071
Author(s):  
V V Yatsyshen

Abstract The article presents the results of the analysis of the angular spectra of the ellipsometric parameters of the reflected wave when a circularly polarized light wave is incident on an anisotropic plate. The given dependences show a very high sensitivity of the ellipsometric parameters of the reflected light on the angle of incidence and the angle between the optical axis and the normal to the plate boundary. The energy reflection spectra themselves show much less variability when these parameters change. It should be especially emphasized the nature of the change in the ellipsometric angle Δ, which is responsible for the type of elliptical polarization - when Δ> 0, the polarization is left-handed, and when Δ <0, it is right-handed. It is shown that a thin anisotropic plate at certain angles can serve as a polarization converter of the incident radiation. The ellipsometry parameter ρ characterizes the degree of compression of the ellipse - when ρ = 1, the ellipse is transformed into a circle, and the light is circularly polarized in this case. Thus, a thin anisotropic plate can not only convert left-handed polarization to right-handed, but it can also control the very shape of the polarization ellipse. Such a plate can be used in conjunction with a layered medium, for example, a one-dimensional photonic crystal, to control the polarization of the incident circularly polarized light.


2015 ◽  
Vol 3 (26) ◽  
pp. 6891-6900 ◽  
Author(s):  
Taichi Hamamoto ◽  
Masahiro Funahashi

A dimer bearing two phenylterthiophene parts linked by a chiral moiety with a minimized molecular volume has been synthesized.


2016 ◽  
Vol 16 (4) ◽  
pp. 3394-3397 ◽  
Author(s):  
Takaaki Manaka ◽  
Mitsumasa Iwamoto

Asymmetric polymerization of polydiacetylene (PDA) from commercially available achiral derivative of diacetylene monomer using circularly polarized pulse laser is demonstrated. Chiral source was only circularly polarized laser, and irradiation of left- and right-circularly polarized light effectively promoted the polymerization of chiral PDAs with opposite handedness. Difference between the laser wavelength and the absorption peak of monomer suggested the contribution of the multiphoton excitation to the photo-polymerization. Laser power dependence of the polymerization rate indicated the possibility of three-photon polymerization.


2017 ◽  
Vol 7 (4) ◽  
pp. 20160129 ◽  
Author(s):  
Luke T. McDonald ◽  
Ewan D. Finlayson ◽  
Bodo D. Wilts ◽  
Pete Vukusic

Helicoidal architectures comprising various polysaccharides, such as chitin and cellulose, have been reported in biological systems. In some cases, these architectures exhibit stunning optical properties analogous to ordered cholesteric liquid crystal phases. In this work, we characterize the circularly polarized reflectance and optical scattering from the cuticle of the beetle Chalcothea smaragdina (Coleoptera: Scarabaeidae: Cetoniinae) using optical experiments, simulations and structural analysis. The selective reflection of left-handed circularly polarized light is attributed to a Bouligand-type helicoidal morphology within the beetle's exocuticle. Using electron microscopy to inform electromagnetic simulations of this anisotropic stratified medium, the inextricable connection between the colour appearance of C. smaragdina and the periodicity of its helicoidal rotation is shown. A close agreement between the model and the measured reflectance spectra is obtained. In addition, the elytral surface of C. smaragdina possesses a blazed diffraction grating-like surface structure, which affects the diffuse appearance of the beetle's reflected colour, and therefore potentially enhances crypsis among the dense foliage of its rainforest habitat.


2020 ◽  
Vol 44 (5) ◽  
pp. 691-698
Author(s):  
V.V. Kotlyar ◽  
S.S. Stafeev ◽  
L. O'Faolain ◽  
M.V. Kotlyar

Using electronic beam lithography and reactive ion beam etching, a metalens is manufactured in a thin layer of amorphous silicon of a 130-nm depth, a 30-µm diameter, and a 633-nm focal length (equal to the illumination wavelength). The metalens is composed of 16 sectored subwavelength binary gratings with a 220-nm period. The uniqueness of this metalens is that when illuminated by left-handed circularly polarized light, it is capable of generating a left-handed circularly polarized vortex beam with a topological charge of 2, generating a second-order cylindrical vector beam when illuminated by linearly polarized light. Both for linear and circular incident polarization, an energy backflow is found to be generated in the vicinity of the tight focus. Transverse intensity distributions measured with a scanning near-field optical microscope near the focus of the metalens are in qualitative agreement with the intensity distributions calculated by the FDTD method. This confirms that a backward energy flow takes place at the focus of the metalens. A metalens generating an energy backflow near its focus is fabricated and characterized for the first time.


2021 ◽  
Vol 45 (4) ◽  
pp. 520-524
Author(s):  
S.S. Stafeev

We have shown that a reverse energy flow (negative projection of the Poynting vector onto the optical axis) at the sharp focus of an optical vortex with topological charge 2 and left-hand circular polarization arises because the axial spin flow has a negative projection onto the optical axis and is greater in magnitude than positive projection onto the optical axis of the orbital energy flow (canonical energy flow). Also, using the Richards-Wolf formulas, it is shown that when focusing a left-handed circularly polarized light, in the region of the on-axis reverse energy flow, the light is right-handed circularly polarized.


2008 ◽  
Vol 4 (S251) ◽  
pp. 311-312 ◽  
Author(s):  
V. Rosenbush ◽  
N. Kiselev ◽  
L. Kolokolova

AbstractPolarimetric observations demonstrated that all comets with significant values of circular polarization show predominantly left–handed circularly polarized light. We discuss the presence of homochiral organics in cometary materials as a source of the observed circular polarization. We have studied the effect of chirality on light–scattering properties of cometary dust considering particles that possess optical activity. Our investigations show that the cometary dust may include optically active materials which can be prebiological homochiral organics.


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