Abstract
We employ an extreme ultraviolet (XUV) pulse to impulsively excite dipole polarization in atoms or molecules, which corresponds to coherently prepared superposition of excited states. A delayed near infrared (NIR) pulse then perturbs the fast evolving polarization, and the resultant absorbance change is monitored in dilute helium, dense helium, and sulfur hexafluoride (SF6) molecules. We observe and quantify the time-dependence of various transient phenomena in helium atoms, including laser-induced phase (LIP), time-varying (AC) Stark shift, quantum path interference, and laser-induced continuum structure. In the case of dense helium targets, we discuss nonlinear macroscopic propagation effects pertaining to LIP and resonant pulse propagation, which account for the appearance of new spectral features in transient lineshapes. We then use tunable NIR photons to demonstrate the wavelength dependence of the transient laser induced effects. In the case of molecular polarization experiment in SF6, we show suppression of XUV photoabsorption corresponding to inter-valence transitions in the presence of a strong NIR field. In each case, the temporal evolution of transient absorption spectra allows us to observe and understand the transient laser induced modifications of the electronic structure of atoms and molecules.
| Original language | English (US) |
|---|---|
| Article number | 17 |
| Journal | Photonics |
| Volume | 4 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 1 2017 |
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Keywords
- Atomic
- Attosecond
- Fano
- Lineshape
- Molecular
- Strong field
- Transient absorption
- XUV
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Instrumentation
- Atomic and Molecular Physics, and Optics
Cite this
XUV transient absorption spectroscopy : Probing laser-perturbed dipole polarization in single atom, macroscopic, and molecular regimes. / Liao, Chen Ting; Sandhu, Arvinder Singh.
In: Photonics, Vol. 4, No. 1, 17, 01.03.2017.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - XUV transient absorption spectroscopy
T2 - Probing laser-perturbed dipole polarization in single atom, macroscopic, and molecular regimes
AU - Liao, Chen Ting
AU - Sandhu, Arvinder Singh
PY - 2017/3/1
Y1 - 2017/3/1
N2 - We employ an extreme ultraviolet (XUV) pulse to impulsively excite dipole polarization in atoms or molecules, which corresponds to coherently prepared superposition of excited states. A delayed near infrared (NIR) pulse then perturbs the fast evolving polarization, and the resultant absorbance change is monitored in dilute helium, dense helium, and sulfur hexafluoride (SF6) molecules. We observe and quantify the time-dependence of various transient phenomena in helium atoms, including laser-induced phase (LIP), time-varying (AC) Stark shift, quantum path interference, and laser-induced continuum structure. In the case of dense helium targets, we discuss nonlinear macroscopic propagation effects pertaining to LIP and resonant pulse propagation, which account for the appearance of new spectral features in transient lineshapes. We then use tunable NIR photons to demonstrate the wavelength dependence of the transient laser induced effects. In the case of molecular polarization experiment in SF6, we show suppression of XUV photoabsorption corresponding to inter-valence transitions in the presence of a strong NIR field. In each case, the temporal evolution of transient absorption spectra allows us to observe and understand the transient laser induced modifications of the electronic structure of atoms and molecules.
AB - We employ an extreme ultraviolet (XUV) pulse to impulsively excite dipole polarization in atoms or molecules, which corresponds to coherently prepared superposition of excited states. A delayed near infrared (NIR) pulse then perturbs the fast evolving polarization, and the resultant absorbance change is monitored in dilute helium, dense helium, and sulfur hexafluoride (SF6) molecules. We observe and quantify the time-dependence of various transient phenomena in helium atoms, including laser-induced phase (LIP), time-varying (AC) Stark shift, quantum path interference, and laser-induced continuum structure. In the case of dense helium targets, we discuss nonlinear macroscopic propagation effects pertaining to LIP and resonant pulse propagation, which account for the appearance of new spectral features in transient lineshapes. We then use tunable NIR photons to demonstrate the wavelength dependence of the transient laser induced effects. In the case of molecular polarization experiment in SF6, we show suppression of XUV photoabsorption corresponding to inter-valence transitions in the presence of a strong NIR field. In each case, the temporal evolution of transient absorption spectra allows us to observe and understand the transient laser induced modifications of the electronic structure of atoms and molecules.
KW - Atomic
KW - Attosecond
KW - Fano
KW - Lineshape
KW - Molecular
KW - Strong field
KW - Transient absorption
KW - XUV
UR - http://www.scopus.com/inward/record.url?scp=85030856722&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85030856722&partnerID=8YFLogxK
U2 - 10.3390/photonics4010017
DO - 10.3390/photonics4010017
M3 - Article
VL - 4
JO - Photonics
JF - Photonics
SN - 2304-6732
IS - 1
M1 - 17
ER -