Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots
We report on the impulsive generation of coherent optical phonons in CdTe0.68Se0.32 nanocrystallites embedded in a glass matrix. Pump-probe experiments using femtosecond laser pulses were performed by tuning the laser central energy to resonate with the absorption edge of the nanocrystals. We identi...
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todo:paper_01631829_v69_n20_p205306_Bragas2023-10-03T15:01:58Z Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots Bragas, A.V. Aku-Leh, C. Costantino, S. Ingale, A. Zhao, J. Merlin, R. cadmium derivative glass selenium derivative tellurium derivative article crystal density dielectric constant electronics energy absorption infrared radiation laser nanoparticle optics phonon quantum mechanics Raman spectrometry We report on the impulsive generation of coherent optical phonons in CdTe0.68Se0.32 nanocrystallites embedded in a glass matrix. Pump-probe experiments using femtosecond laser pulses were performed by tuning the laser central energy to resonate with the absorption edge of the nanocrystals. We identify two longitudinal optical phonons, one longitudinal acoustic phonon and a fourth mode of a mixed longitudinal-transverse nature. The amplitude of the optical phonons as a function of the laser central energy exhibits a resonance that is well described by a model based on impulsive stimulated Raman scattering. The phases of the coherent phonons reveal coupling between different modes. At low power density excitations, the frequency of the optical coherent phonons deviates from values obtained from spontaneous Raman scattering. This behavior is ascribed to the presence of electronic impurity states which modify the nanocrystal dielectric function and, thereby, the frequency of the infrared-active phonons. Fil:Bragas, A.V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Costantino, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01631829_v69_n20_p205306_Bragas |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
cadmium derivative glass selenium derivative tellurium derivative article crystal density dielectric constant electronics energy absorption infrared radiation laser nanoparticle optics phonon quantum mechanics Raman spectrometry |
| spellingShingle |
cadmium derivative glass selenium derivative tellurium derivative article crystal density dielectric constant electronics energy absorption infrared radiation laser nanoparticle optics phonon quantum mechanics Raman spectrometry Bragas, A.V. Aku-Leh, C. Costantino, S. Ingale, A. Zhao, J. Merlin, R. Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots |
| topic_facet |
cadmium derivative glass selenium derivative tellurium derivative article crystal density dielectric constant electronics energy absorption infrared radiation laser nanoparticle optics phonon quantum mechanics Raman spectrometry |
| description |
We report on the impulsive generation of coherent optical phonons in CdTe0.68Se0.32 nanocrystallites embedded in a glass matrix. Pump-probe experiments using femtosecond laser pulses were performed by tuning the laser central energy to resonate with the absorption edge of the nanocrystals. We identify two longitudinal optical phonons, one longitudinal acoustic phonon and a fourth mode of a mixed longitudinal-transverse nature. The amplitude of the optical phonons as a function of the laser central energy exhibits a resonance that is well described by a model based on impulsive stimulated Raman scattering. The phases of the coherent phonons reveal coupling between different modes. At low power density excitations, the frequency of the optical coherent phonons deviates from values obtained from spontaneous Raman scattering. This behavior is ascribed to the presence of electronic impurity states which modify the nanocrystal dielectric function and, thereby, the frequency of the infrared-active phonons. |
| format |
JOUR |
| author |
Bragas, A.V. Aku-Leh, C. Costantino, S. Ingale, A. Zhao, J. Merlin, R. |
| author_facet |
Bragas, A.V. Aku-Leh, C. Costantino, S. Ingale, A. Zhao, J. Merlin, R. |
| author_sort |
Bragas, A.V. |
| title |
Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots |
| title_short |
Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots |
| title_full |
Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots |
| title_fullStr |
Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots |
| title_full_unstemmed |
Ultrafast optical generation of coherent phonons in CdTe 1-xSex quantum dots |
| title_sort |
ultrafast optical generation of coherent phonons in cdte 1-xsex quantum dots |
| url |
http://hdl.handle.net/20.500.12110/paper_01631829_v69_n20_p205306_Bragas |
| work_keys_str_mv |
AT bragasav ultrafastopticalgenerationofcoherentphononsincdte1xsexquantumdots AT akulehc ultrafastopticalgenerationofcoherentphononsincdte1xsexquantumdots AT costantinos ultrafastopticalgenerationofcoherentphononsincdte1xsexquantumdots AT ingalea ultrafastopticalgenerationofcoherentphononsincdte1xsexquantumdots AT zhaoj ultrafastopticalgenerationofcoherentphononsincdte1xsexquantumdots AT merlinr ultrafastopticalgenerationofcoherentphononsincdte1xsexquantumdots |
| _version_ |
1782025023044714496 |