scholarly journals Photoluminescence nonlinearity and picosecond transient absorption in an LYSO:Ce scintillator excited by a 266 nm ultraviolet laser

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17020-17024
Author(s):  
Kun Wei ◽  
Dongwei Hei ◽  
Qing Xu ◽  
Jun Liu ◽  
Quan Guo ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Excitation Density ◽  
Uv Laser ◽  
High Excitation ◽  
Pump Probe ◽  
Ultraviolet Laser ◽  
Absorption Experiment ◽  
Probe Absorption

PL nonlinearity of LYSO:Ce studied by a UV laser at high excitation density, and the pump–probe absorption experiment used to look into the possible reasons for the nonlinearity effects occurring at high fluxes.

scholarly journals Singlet fission in thin films of metallo-supramolecular polymers with ditopic thiophene-bridged terpyridine ligands

2017 ◽  
Vol 5 (32) ◽  
pp. 8041-8051 ◽  
Author(s):  
David Rais ◽  
Jiří Pfleger ◽  
Miroslav Menšík ◽  
Alexander Zhigunov ◽  
Pavla Štenclová ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Supramolecular Polymers ◽  
Uv Laser ◽  
Singlet Fission ◽  
Thin Solid Films ◽  
Singlet Exciton ◽  
Solid Films ◽  
Terpyridine Ligands ◽  
Singlet Exciton Fission

Ultrafast singlet exciton fission in thin solid films after UV laser photoexcitation was observed using transient absorption spectroscopy.

scholarly journals Transient Absorption Spectra of Vibrationally Excited Water Molecule on Zeolite Surface

1999 ◽  
Vol 19 (1-4) ◽  
pp. 317-320
Author(s):  
Tatsuya Fujino ◽  
Akihide Wada ◽  
Satoru S. Kano ◽  
Kazunari Domen ◽  
Chiaki Hirose
Keyword(s):  
Water Molecule ◽  
Transient Absorption ◽  
Excited Level ◽  
Rapid Decay ◽  
Vibrationally Excited ◽  
Pump Probe ◽  
Zeolite Surface ◽  
Transient Absorption Spectra ◽  
Spectroscopic Feature ◽  
Hot Band

By means of infrared pump-probe technique, spectroscopic feature of vibrationally excited water molecule (D2O) on mordenite zeolite (OD) has been investigated. Populational lifetime of the OD stretching band (ν3:2730cm-1) was determined to be 43±5 ps at 123 K by the time evolution of hot band. The transient bleachings and absorptions appeared when the D2O molecule was promoted to the vibrationally excited level of the OD stretching modes. Especially, the transient absorption at 2680 cm-1 has rapid decay time (≈15 ps) and it was assigned as the overtone between ν3 mode and vibrationally excited ν1 mode (2620 cm-1).

scholarly journals Coherent Exciton Dynamics in Ensembles of Size-Dispersed CdSe Quantum Dot Dimers Probed via Ultrafast Spectroscopy: A Quantum Computational Study

2020 ◽  
Vol 10 (4) ◽  
pp. 1328 ◽  
Author(s):  
Hugo Gattuso ◽  
Barbara Fresch ◽  
Raphael D. Levine ◽  
Françoise Remacle
Keyword(s):  
Transient Absorption ◽  
Computational Study ◽  
Laser Pulses ◽  
Transient Absorption Spectroscopy ◽  
Basis Set ◽  
Charge Migration ◽  
Pump Probe ◽  
Electronic Response ◽  
Charge Transfer Excitons ◽  
Interdot Coupling

Interdot coherent excitonic dynamics in nanometric colloidal CdSe quantum dots (QD) dimers lead to interdot charge migration and energy transfer. We show by electronic quantum dynamical simulations that the interdot coherent response to ultrashort fs laser pulses can be characterized by pump-probe transient absorption spectroscopy in spite of the inevitable inherent size dispersion of colloidal QDs. The latter, leading to a broadening of the excitonic bands, induce accidental resonances that actually increase the efficiency of the interdot coupling. The optical electronic response is computed by solving the time-dependent Schrodinger equation including the interaction with the oscillating electric field of the pulses for an ensemble of dimers that differ by their size. The excitonic Hamiltonian of each dimer is parameterized by the QD size and interdot distance, using an effective mass approximation. Local and charge transfer excitons are included in the dimer basis set. By tailoring the QD size, the excitonic bands can be tuned to overlap and thus favor interdot coupling. Computed pump-probe transient absorption maps averaged over the ensemble show that the coherence of excitons in QD dimers that lead to interdot charge migration can survive size disorder and could be observed in fs pump-probe, four-wave mixing, or covariance spectroscopy.

scholarly journals Temperature dependence of ultrasharp luminescence lines in AlyIn1−yAs/AlxGa1−xAs self-assembled quantum dots

1996 ◽  
Vol 74 (S1) ◽  
pp. 216-219 ◽  
Author(s):  
S. Raymond ◽  
S. Fafard ◽  
S. Charbonneau
Keyword(s):  
Quantum Dots ◽  
Ground State ◽  
State Transition ◽  
Thermionic Emission ◽  
Excitation Density ◽  
High Excitation ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Self Assembled ◽  
Intensity Evolution

Ensembles of~600 AlyIn1−yAs/AlxGa1−xAs self-assembled quantum dots (QDs) are investigated using photoluminescence (PL) and time-resolved PL in the visible. At very low excitation intensities, the PL spectrum shows multiple ultranarrow luminescence lines (FWHM ~200 μeV), which are attributed to the ground-state transition of a few dots (4 or less). The temperature and intensity evolution of these sharp lines is then monitored. The temperature-dependent measurements show that the line width and lifetime of the narrow lines remain constant up to the onset of thermionic, emission. Intensity-dependent measurements show that for high excitation density the collective background, emitted by the ensemble of QDs, is enhanced relative to the amplitude of individual ultranarrow lines.

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