Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses

Transient absorption spectroscopy allows the observation of excited state dynamics following optical excitation across a wide range of time scales, from femtoseconds to milliseconds. This article presents an ultrafast transient absorption spectroscopy setup based on the pump-probe method, utilizing...

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Main Authors: Fereshteh Hajiesmaeilbaigi, Hosein Razzaghi, Eftekhar Sadat Bostandoost, Asama Sadat Motamedi
Format: Article
Language:fas
Published: Alzahra University 2025-03-01
Series:فیزیک کاربردی ایران
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Online Access:https://jap.alzahra.ac.ir/article_8225_b7fe858041eeff99c0057452aaabf136.pdf
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author Fereshteh Hajiesmaeilbaigi
Hosein Razzaghi
Eftekhar Sadat Bostandoost
Asama Sadat Motamedi
author_facet Fereshteh Hajiesmaeilbaigi
Hosein Razzaghi
Eftekhar Sadat Bostandoost
Asama Sadat Motamedi
author_sort Fereshteh Hajiesmaeilbaigi
collection DOAJ
description Transient absorption spectroscopy allows the observation of excited state dynamics following optical excitation across a wide range of time scales, from femtoseconds to milliseconds. This article presents an ultrafast transient absorption spectroscopy setup based on the pump-probe method, utilizing femtosecond pulses from a Ti:sapphire laser at both fundamental and second harmonic wavelengths. We investigated the transient absorption spectrum of deionized water, the most common solvent, with femtosecond time resolution in two modes: one with a fixed delay time for probe wavelengths ranging from 740 to 820 nm, and the other with a fixed probe wavelength for various time delays up to 1.1 picoseconds. The transient absorption spectra reveal a negative signal peaking at 788 nm, attributed to ground state bleaching caused by the depopulation of the ground state induced by the pump. Additionally, a negative signal at 798 nm, resulting from stimulated emission, overlaps with a 10 nm Stokes shift of the ground state bleaching band. The temporal evolution of the transient absorbance spectra shows an absorption peak at a 70 femtosecond delay between the pump and probe pulses, indicating an unstable intermediate level resulting from a two-photon absorption process—one photon from the pump pulse at 392 nm and another from the probe pulse at 784 nm. Fitting a biexponential function to the relaxation data yields a lifetime of approximately 150 femtoseconds for this intermediate leve.
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publishDate 2025-03-01
publisher Alzahra University
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series فیزیک کاربردی ایران
spelling doaj-art-ca8bb6e03eec414593cad460dd10a2e12025-08-20T02:25:43ZfasAlzahra Universityفیزیک کاربردی ایران2783-10432783-10512025-03-01151658110.22051/ijap.2024.48277.14258225Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser PulsesFereshteh Hajiesmaeilbaigi0Hosein Razzaghi1Eftekhar Sadat Bostandoost2Asama Sadat Motamedi3Professor, Photonic & Quantum Technologies Research School, Nuclear Since & Technologies Research Institute, Tehran, IranMSc Graduated, Photonic & Quantum Technologies Research School, Nuclear Since & Technologies Research Institute, Tehran, IranMSc Graduated, Photonic & Quantum Technologies Research School, Nuclear Since & Technologies Research Institute, Tehran, IranAssistant Professor, Photonic & Quantum Technologies Research School, Nuclear Since & Technologies Research Institute, Tehran, Iran.Transient absorption spectroscopy allows the observation of excited state dynamics following optical excitation across a wide range of time scales, from femtoseconds to milliseconds. This article presents an ultrafast transient absorption spectroscopy setup based on the pump-probe method, utilizing femtosecond pulses from a Ti:sapphire laser at both fundamental and second harmonic wavelengths. We investigated the transient absorption spectrum of deionized water, the most common solvent, with femtosecond time resolution in two modes: one with a fixed delay time for probe wavelengths ranging from 740 to 820 nm, and the other with a fixed probe wavelength for various time delays up to 1.1 picoseconds. The transient absorption spectra reveal a negative signal peaking at 788 nm, attributed to ground state bleaching caused by the depopulation of the ground state induced by the pump. Additionally, a negative signal at 798 nm, resulting from stimulated emission, overlaps with a 10 nm Stokes shift of the ground state bleaching band. The temporal evolution of the transient absorbance spectra shows an absorption peak at a 70 femtosecond delay between the pump and probe pulses, indicating an unstable intermediate level resulting from a two-photon absorption process—one photon from the pump pulse at 392 nm and another from the probe pulse at 784 nm. Fitting a biexponential function to the relaxation data yields a lifetime of approximately 150 femtoseconds for this intermediate leve.https://jap.alzahra.ac.ir/article_8225_b7fe858041eeff99c0057452aaabf136.pdftransient absorption spectrati: sapphire laserfemtosecond deionized water
spellingShingle Fereshteh Hajiesmaeilbaigi
Hosein Razzaghi
Eftekhar Sadat Bostandoost
Asama Sadat Motamedi
Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses
فیزیک کاربردی ایران
transient absorption spectra
ti: sapphire laser
femtosecond deionized water
title Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses
title_full Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses
title_fullStr Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses
title_full_unstemmed Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses
title_short Research Paper: Transient Absorption Spectroscopy of Deionized Water by Ti: sapphire Femtosecond Laser Pulses
title_sort research paper transient absorption spectroscopy of deionized water by ti sapphire femtosecond laser pulses
topic transient absorption spectra
ti: sapphire laser
femtosecond deionized water
url https://jap.alzahra.ac.ir/article_8225_b7fe858041eeff99c0057452aaabf136.pdf
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AT eftekharsadatbostandoost researchpapertransientabsorptionspectroscopyofdeionizedwaterbytisapphirefemtosecondlaserpulses
AT asamasadatmotamedi researchpapertransientabsorptionspectroscopyofdeionizedwaterbytisapphirefemtosecondlaserpulses