Probing ultrafast dynamics of chiral molecules using time-resolved photoelectron circular dichroism

2016 ◽  
Vol 194 ◽  
pp. 325-348 ◽  
Author(s):  
Samuel Beaulieu ◽  
Antoine Comby ◽  
Baptiste Fabre ◽  
Dominique Descamps ◽  
Amélie Ferré ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Extreme Ultraviolet ◽  
Single Photon ◽  
Rydberg States ◽  
Chiral Discrimination ◽  
Infrared Range ◽  
Ultrafast Dynamics ◽  
Chiral Molecules ◽  
Time Resolved ◽  
Circular Dichroïsm

Measuring the ultrafast dynamics of chiral molecules in the gas phase has been a long standing and challenging quest of molecular physics. The main limitation to reach that goal has been the lack of highly sensitive chiroptical measurement. By enabling chiral discrimination with up to several 10% of sensitivity, photoelectron circular dichroism (PECD) offers a solution to this issue. However, tracking ultrafast processes requires measuring PECD with ultrashort light pulses. Here we compare the PECD obtained with different light sources, from the extreme ultraviolet to the mid-infrared range, leading to different ionization regimes: single-photon, resonance-enhanced multiphoton, above-threshold and tunnel ionization. We use single and multiphoton ionization to probe the ultrafast relaxation of fenchone molecules photoexcited in their first Rydberg states. We show that time-resolved PECD enables revealing dynamics much faster than the population decay of the Rydberg states, demonstrating the high sensitivity of this technique to vibronic relaxation.

scholarly journals Relaxation Dynamics in Photoexcited Chiral Molecules Studied by Time-Resolved Photoelectron Circular Dichroism: Toward Chiral Femtochemistry

2016 ◽  
Vol 7 (22) ◽  
pp. 4514-4519 ◽  
Author(s):  
Antoine Comby ◽  
Samuel Beaulieu ◽  
Martial Boggio-Pasqua ◽  
Dominique Descamps ◽  
Francois Légaré ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Relaxation Dynamics ◽  
Chiral Molecules ◽  
Time Resolved ◽  
Circular Dichroïsm

scholarly journals Time-Resolved XUV Absorption Spectroscopy and Magnetic Circular Dichroism at the Ni M2,3-Edges

2020 ◽  
Vol 11 (1) ◽  
pp. 325
Author(s):  
Marcel Hennes ◽  
Benedikt Rösner ◽  
Valentin Chardonnet ◽  
Gheorghe S. Chiuzbaian ◽  
Renaud Delaunay ◽  
...  
Keyword(s):  
Thin Films ◽  
Circular Dichroism ◽  
Degrees Of Freedom ◽  
Extreme Ultraviolet ◽  
Magnetic Circular Dichroism ◽  
Magnetic Thin Films ◽  
Time Resolved ◽  
Ultrashort Optical Pulses ◽  
Spin Populations ◽  
Circular Dichroïsm

Ultrashort optical pulses can trigger a variety of non-equilibrium processes in magnetic thin films affecting electrons and spins on femtosecond timescales. In order to probe the charge and magnetic degrees of freedom simultaneously, we developed an X-ray streaking technique that has the advantage of providing a jitter-free picture of absorption cross-section changes. In this paper, we present an experiment based on this approach, which we performed using five photon probing energies at the Ni M2,3-edges. This allowed us to retrieve the absorption and magnetic circular dichroism time traces, yielding detailed information on transient modifications of electron and spin populations close to the Fermi level. Our findings suggest that the observed absorption and magnetic circular dichroism dynamics both depend on the extreme ultraviolet (XUV) probing wavelength, and can be described, at least qualitatively, by assuming ultrafast energy shifts of the electronic and magnetic elemental absorption resonances, as reported in recent work. However, our analysis also hints at more complex changes, highlighting the need for further experimental and theoretical studies in order to gain a thorough understanding of the interplay of electronic and spin degrees of freedom in optically excited magnetic thin films.

scholarly journals Tunable circular dichroism through absorption in coupled optical modes of twisted triskelia nanostructures

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Javier Rodríguez-Álvarez ◽  
Antonio García-Martín ◽  
Arantxa Fraile Rodríguez ◽  
Xavier Batlle ◽  
Amílcar Labarta
Keyword(s):  
Circular Dichroism ◽  
Near Infrared ◽  
Single Photon ◽  
Twist Angle ◽  
Polarized Light ◽  
Infrared Range ◽  
Single Element ◽  
Circularly Polarized Light ◽  
Optical Modes ◽  
Circular Dichroïsm

AbstractWe present a system consisting of two stacked chiral plasmonic nanoelements, so-called triskelia, that exhibits a high degree of circular dichroism. The optical modes arising from the interactions between the two elements are the main responsible for the dichroic signal. Their excitation in the absorption cross section is favored when the circular polarization of the light is opposite to the helicity of the system, so that an intense near-field distribution with 3D character is excited between the two triskelia, which in turn causes the dichroic response. Therefore, the stacking, in itself, provides a simple way to tune both the value of the circular dichroism, up to 60%, and its spectral distribution in the visible and near infrared range. We show how these interaction-driven modes can be controlled by finely tuning the distance and the relative twist angle between the triskelia, yielding maximum values of the dichroism at 20° and 100° for left- and right-handed circularly polarized light, respectively. Despite the three-fold symmetry of the elements, these two situations are not completely equivalent since the interplay between the handedness of the stack and the chirality of each single element breaks the symmetry between clockwise and anticlockwise rotation angles around 0°. This reveals the occurrence of clear helicity-dependent resonances. The proposed structure can be thus finely tuned to tailor the dichroic signal for applications at will, such as highly efficient helicity-sensitive surface spectroscopies or single-photon polarization detectors, among others.

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

scholarly journals Photoexcitation circular dichroism in chiral molecules

2018 ◽  
Vol 14 (5) ◽  
pp. 484-489 ◽  
Author(s):  
S. Beaulieu ◽  
A. Comby ◽  
D. Descamps ◽  
B. Fabre ◽  
G. A. Garcia ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Chiral Molecules ◽  
Circular Dichroïsm

SINGLE-PHOTON LINEAR-CIRCULAR DICHROISM IN NARROW-GAP CRYSTALS. TAKING INTO ACCOUNT THE EFFECT OF COHERENT SATURATION

2021 ◽  
pp. 44-47
Author(s):  
V. R. Rasulov ◽  
R. Y. Rasulov ◽  
B. B. Axmedov ◽  
I. A. Muminov ◽  
S. Niyozov
Keyword(s):  
Circular Dichroism ◽  
Single Photon ◽  
Narrow Gap ◽  
Circular Dichroïsm
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