Alteration of MCD Spectra Due to thin film Interference Effects

1997 ◽  
Vol 475 ◽  
Author(s):  
D. Rioux ◽  
B. Allen ◽  
H. Höchst ◽  
D. Zhao ◽  
D.L. Huber
Keyword(s):  
Line Shape ◽  
Magnetic Moments ◽  
Polarized Light ◽  
Excitation Wavelength ◽  
Interference Effects ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Left And Right ◽  
Thin Film Interference ◽  
Film Substrate

ABSTRACTMCD spectra at the M2,3 edge of thin Fe films exhibit thickness-dependent variations in line shape as well as in the absolute MCD-effect. Our data indicate that more information is contained in the MCD spectra than simply the evolution of a magnetic moment and ferromagnetic order. We developed a model to predict line shape modulations as a function of film thickness and angle of light incidence. Using the Fresnel-Maxwell formalism we calculate interference effects between left and right circularly polarized light reflected from the vacuum-film-substrate interfaces which are verified by our MCD measurements. Since the observed interference effects are a function of the excitation wavelength, our results can be directly scaled to show the significance of these effects in the more commonly used L2,3 region of 3d ferromagnets. Our data point out that one might be ill advised to rely onL2,3 MCD experiments to try to extract the formation of magnetic moments in films of several 10s of Å in thickness.

Preparation of Chiral Polydiacetylene Films by Using Three-Photon Polymerization

2016 ◽  
Vol 16 (4) ◽  
pp. 3394-3397 ◽  
Author(s):  
Takaaki Manaka ◽  
Mitsumasa Iwamoto
Keyword(s):  
Laser Power ◽  
Polarized Light ◽  
Laser Wavelength ◽  
Polymerization Rate ◽  
Power Dependence ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Photo Polymerization ◽  
Left And Right ◽  
Asymmetric Polymerization

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.

Switchable 3D liquid crystal grating generated by periodic photo-alignment on both substrates

Soft Matter ◽  
2015 ◽  
Vol 11 (39) ◽  
pp. 7802-7808 ◽  
Author(s):  
I. Nys ◽  
J. Beeckman ◽  
K. Neyts
Keyword(s):  
Liquid Crystal ◽  
Diffraction Pattern ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Left And Right ◽  
Photo Alignment ◽  
Alignment Layers ◽  
Liquid Crystal Grating

A planar liquid crystal (LC) cell is developed in which two photo-alignment layers have been illuminated with respectively a horizontal and a vertical diffraction pattern of interfering left- and right-handed circularly polarized light.

Optically active triptycenes containing hexa-peri-hexabenzocoronene units

2019 ◽  
Vol 55 (76) ◽  
pp. 11386-11389 ◽  
Author(s):  
Yuya Wada ◽  
Ken-ichi Shinohara ◽  
Tomoyuki Ikai
Keyword(s):  
Polarized Light ◽  
Optically Active ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Left And Right

We have successfully generated both left- and right-handed circularly polarized light using crystals prepared from a racemic triptycene containing hexa-peri-hexabenzocoronene units.

Hameka theory of optical rotation

1968 ◽  
Vol 46 (4) ◽  
pp. 599-604 ◽  
Author(s):  
D. A. Hutchinson
Keyword(s):  
Scattering Amplitudes ◽  
Optical Rotation ◽  
Polarized Light ◽  
Electric Quadrupole ◽  
Refractive Indices ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Alternative Approach ◽  
Left And Right ◽  
The Difference

sRosenfeld's formula, for off-resonance optical rotation, is derived by an alternative approach. The scattering amplitudes are determined for the scattering of right circularly polarized light and left circularly polarized light by a molecule. The calculation is carried out to the order of approximation which includes electric quadrupole and magnetic dipole terms. From the real parts of the forward scattering amplitudes the corresponding indices of refraction are determined for left and right circularly polarized light. Rosenfeld's formula then follows from the difference between the two refractive indices.

scholarly journals Macroscopic chirality of twist-bend nematic phase in bent dimers confirmed by circular dichroism

2020 ◽  
Vol 8 (3) ◽  
pp. 1041-1047 ◽  
Author(s):  
Warren D. Stevenson ◽  
Xiangbing Zeng ◽  
Chris Welch ◽  
Anil K. Thakur ◽  
Goran Ungar ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Long Range ◽  
Nematic Phase ◽  
Polarized Light ◽  
Circular Dichroism Spectroscopy ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Left And Right ◽  
Circular Dichroïsm

Long-range global chirality is confirmed in the twist-bend nematic phase of bent dimers using circular dichroism spectroscopy. The phase absorbs left and right circularly polarized light differently, confirming its helical rather than wavy character.

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
Keyword(s):  
Organic Molecules ◽  
Dopant Concentration ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Light Sensing ◽  
Left Handed ◽  
Chiral Nematic ◽  
Left And Right ◽  
Guest System

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.

scholarly journals The Fresnel triprism and the circular polarization of light

Photoniques ◽  
2019 ◽  
pp. 44-45
Author(s):  
Oriol Arteaga ◽  
Enric Garcia-Caurel ◽  
Razvigor Ossikovski
Keyword(s):  
Circular Polarization ◽  
Polarized Light ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Polarized Beam ◽  
Left And Right ◽  
Polarization Of Light

In 1822 Augustin Fresnel discovered the circular polarization of light with an experiment in which a plane polarized beam was resolved into its left- and right- circularly polarized components after refraction at slightly different angles at the interface between two different species of quartz that formed a composite prism, called the Fresnel triprism. Fresnel’s landmark experiment, once popular, remains today a very little known method for producing circularly polarized light.

scholarly journals Resonance in Chirogenesis and Photochirogenesis: Colloidal Polymers Meet Chiral Optofluidics

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 199
Author(s):  
Michiya Fujiki
Keyword(s):  
Light Source ◽  
Nuclear Physics ◽  
Optical Rotation ◽  
Surrounding Medium ◽  
Polarized Light ◽  
Excitation Wavelength ◽  
Light Sources ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Resonance Effects

Metastable colloids made of crystalline and/or non-crystalline matters render abilities of photonic resonators susceptible to chiral chemical and circularly polarized light sources. By assuming that μm-size colloids and co-colloids consisting of π- and/or σ-conjugated polymers dispersed into an optofluidic medium are artificial models of open-flow, non-equilibrium coacervates, we showcase experimentally resonance effects in chirogenesis and photochirogenesis, revealed by gigantic boosted chiroptical signals as circular dichroism (CD), optical rotation dispersion, circularly polarized luminescence (CPL), and CPL excitation (CPLE) spectral datasets. The resonance in chirogenesis occurs at very specific refractive indices (RIs) of the surrounding medium. The chirogenesis is susceptible to the nature of the optically active optofluidic medium. Moreover, upon an excitation-wavelength-dependent circularly polarized (CP) light source, a fully controlled absolute photochirogenesis, which includes all chiroptical generation, inversion, erase, switching, and short-/long-lived memories, is possible when the colloidal non-photochromic and photochromic polymers are dispersed in an achiral optofluidic medium with a tuned RI. The hand of the CP light source is not a determining factor for the product chirality. These results are associated with my experience concerning amphiphilic polymerizable colloids, in which, four decades ago, allowed proposing a perspective that colloids are connectable to light, polymers, helix, coacervates, and panspermia hypotheses, nuclear physics, biology, radioisotopes, homochirality question, first life, and cosmology.

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