Polarization-Division Interferometry: Time-Resolved Infrared Vibrational Dichroism Spectroscopy

1995 ◽  
Vol 49 (2) ◽  
pp. 229-236 ◽  
Author(s):  
Prasad L. Polavarapu ◽  
Zhengyu Deng ◽  
Gang-Chi Chen
Keyword(s):  
Circular Dichroism ◽  
Fourier Transforms ◽  
External Perturbation ◽  
Linear Dichroism ◽  
Central Component ◽  
Input Beam ◽  
Time Resolved ◽  
Direct Measurements ◽  
Ft Ir ◽  
Circular Dichroïsm

We report the first direct measurements of time-resolved Fourier transform infrared vibrational dichroism (TR/FT-IR/VD). The central component for these measurements is a polarization-division interferometer (PDI). This interferometer uses an in-house-designed beamsplitter constructed in-house from a BaF2 polarizer and a matching substrate. In conjunction with a linear polarizer in front of the source and two rooftop mirrors, one in each arm of the interferometer, the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of input beam. The signals measured as a function of the moving mirror position in the PDI represent the linear/circular dichroism interferograms, whose cosine/sine Fourier transforms yield linear/circular dichroism spectra. Time-resolved dichroism interferograms were measured with the use of this PDI with the asynchronous external perturbation method. Microsecond time-resolved linear dichroism spectra of a nematic liquid crystal, under the influence of bipolar electric field oscillating at 2 kHz, were measured and presented as the first examples.

Polarization-Division Interferometry: Far-Infrared Dichroism

1994 ◽  
Vol 48 (11) ◽  
pp. 1410-1418 ◽  
Author(s):  
Prasad L. Polavarapu ◽  
Gang-Chi Chen
Keyword(s):  
Circular Dichroism ◽  
Far Infrared ◽  
Linear Dichroism ◽  
Infrared Region ◽  
Input Beam ◽  
Free Standing ◽  
Reflecting Surfaces ◽  
Infrared Dichroism ◽  
Linear Polarizer ◽  
Circular Dichroïsm

We report the first far-infrared dichroism measurements using a polarization-division interferometer (PDI) developed in our laboratory. This interferometer uses a free-standing wire-grid beamsplitter made of tungsten wires. In conjunction with a linear polarizer in front of the source and two roof-top mirrors (one in each arm of the interferometer), the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of the input beam. Light exiting the interferometer is manipulated with far-infrared lenses, to avoid polarization distortions that are inherent to the reflecting surfaces of the mirrors. The performance of the PDI is evaluated by measuring the linear dichroism of oriented PVF2 [poly(vinylidenefluoride) and circular dichroism of α-pinene, camphor, and 3-methylcyclohexanone. The dichroic multiplex advantage (ability to measure dichroism in the entire far-infrared region from a single measurement) and throughput advantage are demonstrated. These measurements establish the utility of the PDI in measuring transmission and linear dichroism spectra simultaneously without the need for any additional components. Additional developments appear necessary to establish the circular dichroism measurements when the magnitudes are less than one part in one thousand.

Development, Justification, and Applications of a Mid-Infrared Polarization-Division Interferometer

1994 ◽  
Vol 48 (10) ◽  
pp. 1224-1235 ◽  
Author(s):  
Prasad L. Polavarapu ◽  
Gang-Chi Chen ◽  
Stephen Weibel
Keyword(s):  
Circular Dichroism ◽  
Linear Dichroism ◽  
Infrared Region ◽  
Input Beam ◽  
Output Beam ◽  
Mid Infrared ◽  
Oriented Polypropylene ◽  
Reflecting Surfaces ◽  
Linear Polarizer ◽  
Circular Dichroïsm

We report the development of a polarization-division interferometer (PDI) for the mid-infrared region. This interferometer uses a self-designed beamsplitter constructed in-house from a BaF2 polarizer and a matching substrate. In conjunction with a linear polarizer in front of the source and two roof-top mirrors, one in each arm of the interferometer, the PDI divides the input beam into two orthogonal linear polarization components, recombines them for interference at the beamsplitter, and directs the output beam at 90° to the direction of the input beam. Light exiting the interferometer is manipulated entirely with lenses, to avoid polarization distortions that are inherent to the reflecting surfaces of the mirrors. Details of the instrumental design for this mid-infrared PDI are presented. The performance of the PDI is evaluated by measuring the circular dichroism of α-pinene and camphor and the linear dichroism of oriented polypropylene and polystyrene. These measurements establish the utility of the PDI to measure transmission, circular dichroism, and linear dichroism spectra simultaneously without need for any additional components. The dichroic multiplex advantage (ability to measure dichroism in the entire mid-infrared region from a single measurement) and throughput advantage are demonstrated.

scholarly journals Capturing ultrafast magnetic dynamics by time-resolved soft x-ray magnetic circular dichroism

2017 ◽  
Vol 110 (16) ◽  
pp. 162401 ◽  
Author(s):  
Kou Takubo ◽  
Kohei Yamamoto ◽  
Yasuyuki Hirata ◽  
Yuichi Yokoyama ◽  
Yuya Kubota ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Time Resolved ◽  
Magnetic Dynamics ◽  
X Ray ◽  
Circular Dichroïsm

Time-resolved UV circular dichroism of phytochrome A: folding of the N-terminal region

1993 ◽  
Vol 115 (21) ◽  
pp. 9854-9855 ◽  
Author(s):  
Eefei Chen ◽  
William Parker ◽  
James W. Lewis ◽  
Pill Soon Song ◽  
David S. Kliger
Keyword(s):  
Circular Dichroism ◽  
Terminal Region ◽  
Phytochrome A ◽  
Time Resolved ◽  
Circular Dichroïsm

Conformation of membrane-bound proteins revealed by vacuum-ultraviolet circular-dichroism and linear-dichroism spectroscopy

2016 ◽  
Vol 84 (3) ◽  
pp. 349-359 ◽  
Author(s):  
Koichi Matsuo ◽  
Yasuyuki Maki ◽  
Hirofumi Namatame ◽  
Masaki Taniguchi ◽  
Kunihiko Gekko
Keyword(s):  
Circular Dichroism ◽  
Vacuum Ultraviolet ◽  
Linear Dichroism ◽  
Membrane Bound ◽  
Circular Dichroïsm

Ultrafast relaxation investigated by Photoelectron Circular Dichroism : an isomeric comparison of Camphor and Fenchone

2021 ◽  
Author(s):  
Valérie Blanchet ◽  
Dominique Descamps ◽  
stephane Petit ◽  
Yann Mairesse ◽  
bernard Pons ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Imaging Technique ◽  
Velocity Map Imaging ◽  
Relaxation Dynamics ◽  
Time Resolved ◽  
Pump Probe ◽  
Ultrafast Relaxation ◽  
Circular Dichroïsm ◽  
Isomeric Effects

We study isomeric effects using time resolved photoelectron circular dichroism (PECD). By a (1+1’)pump-probe ionisation with photoelectron collected by velocity map imaging technique, we compare relaxation dynamics from the 3s-Rydberg...

A Solution to the Artifact Problem in Fourier Transform Vibrational Circular Dichroism

1988 ◽  
Vol 42 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Petr Malon ◽  
Timothy A. Keiderling
Keyword(s):  
Fourier Transform ◽  
Circular Dichroism ◽  
Vibrational Circular Dichroism ◽  
Band Shape ◽  
Ft Ir ◽  
Circular Dichroïsm

Using a newly constructed FT-IR vibrational circular dichroism (VCD) instrument, we have found that elimination of the ellipsoidal collection mirror before the detector and its replacement by a lens leads to a significant improvement in the absorption artifact problem seen previously in FT-IR/VCD. In the mid-IR region, we have been able to measure VCD of a single enantiomer for molecules such as α-pinene, 3-methylcyclohexanone, and dimethyltartrate. More importantly, this reduction in artifact level brings the FT-IR/VCD band shape of some particularly-difficult-to-measure bands, such as carbonyl stretches, into better agreement with those found in dispersive measurements. These results imply that the dispersive results are reliable, though of lower resolution than those obtained with the use of FT-IR/VCD.

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