Deciphering Carrier Dynamics in Polycarbonate Following Excitation with Ultrashort Laser Pulses

Fuente: arXiv
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Main Authors: Tsibidis, George D., Vlahou, Matina, Maragkaki, Stella, Konidakis, Ioannis, Stratakis, Emmanuel
Format: Preprint
Published: 2025
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author Tsibidis, George D.
Vlahou, Matina
Maragkaki, Stella
Konidakis, Ioannis
Stratakis, Emmanuel
author_facet Tsibidis, George D.
Vlahou, Matina
Maragkaki, Stella
Konidakis, Ioannis
Stratakis, Emmanuel
contents Polymers exposed to ultrashort pulsed lasers (UPL) experience a range of physical and chemical changes that play a key role in applications ranging from material processing to advanced photonics, and biomedicine. To elucidate the interaction of UPL with polymeric materials, ultrafast phenomena such as carrier dynamics, recombination and relaxation are investigated assuming polycarbonate (PC) as a test material exposed to laser pulses of moderate energies. A theoretical model developed for dielectric materials is extended to describe the, previously, unexplored excitation and carrier dynamics for PC while femtosecond Transient Absorption Spectroscopy is used to elucidate the evolution of the materials response and ultrafast dynamics. Interpreting the experimental measurements using the theoretical model suggests the existence of an energy level that facilitates the formation of self-trapped exciton metastates between the conduction and valence bands (approximately 2.4-2.8 eV below the conduction band). It also predicts the electron-plasma lifetime (around 110-150 fs), the recombination time (about 34 ps), and the non-linear part of the refractive index due to Kerr effect (with n_2 values ranging from (1.1-1.5)x10^{-16} cm2/W). Furthermore, the dominant character of multi-photon assisted ionisation is emphasised while the optical breakdown threshold is also calculated and found to be equal to 2.55 x10^12 W/cm2. The results are expected to support future efforts aimed at elucidating how intense ultrashort laser pulses interact with polymeric materials which is crucial for optimizing the manufacturing processes of these materials for potential applications.
format Preprint
id arxiv_https___arxiv_org_abs_2502_05639
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Deciphering Carrier Dynamics in Polycarbonate Following Excitation with Ultrashort Laser Pulses
Tsibidis, George D.
Vlahou, Matina
Maragkaki, Stella
Konidakis, Ioannis
Stratakis, Emmanuel
Optics
Materials Science
Computational Physics
Polymers exposed to ultrashort pulsed lasers (UPL) experience a range of physical and chemical changes that play a key role in applications ranging from material processing to advanced photonics, and biomedicine. To elucidate the interaction of UPL with polymeric materials, ultrafast phenomena such as carrier dynamics, recombination and relaxation are investigated assuming polycarbonate (PC) as a test material exposed to laser pulses of moderate energies. A theoretical model developed for dielectric materials is extended to describe the, previously, unexplored excitation and carrier dynamics for PC while femtosecond Transient Absorption Spectroscopy is used to elucidate the evolution of the materials response and ultrafast dynamics. Interpreting the experimental measurements using the theoretical model suggests the existence of an energy level that facilitates the formation of self-trapped exciton metastates between the conduction and valence bands (approximately 2.4-2.8 eV below the conduction band). It also predicts the electron-plasma lifetime (around 110-150 fs), the recombination time (about 34 ps), and the non-linear part of the refractive index due to Kerr effect (with n_2 values ranging from (1.1-1.5)x10^{-16} cm2/W). Furthermore, the dominant character of multi-photon assisted ionisation is emphasised while the optical breakdown threshold is also calculated and found to be equal to 2.55 x10^12 W/cm2. The results are expected to support future efforts aimed at elucidating how intense ultrashort laser pulses interact with polymeric materials which is crucial for optimizing the manufacturing processes of these materials for potential applications.
title Deciphering Carrier Dynamics in Polycarbonate Following Excitation with Ultrashort Laser Pulses
topic Optics
Materials Science
Computational Physics
url https://arxiv.org/abs/2502.05639