Radiation effects of IR laser on graphene oxide irradiated in vacuum and in air

Phys. Rev. Accel. Beams

Costa

2020

Self Cite

The ions acceleration through an fs laser irradiating a reduced graphene oxide foil in a target-normalsheath-acceleration regime is investigated using a SiC detector connected in time-of-flight configuration. The experimental data indicated maximum proton energy of 1.8 MeV and a large number of carbon ions accelerated at different energies depending on their charge state. Particle-in-cell (PIC) simulations were applied to the studied target given the electron density as a function of the space and time and permitted one to evaluate the electrical field developed in the rear side of the foil driving the forward ion acceleration. The simulation indicates that the carbon ions are subjected to a lower acceleration with respect to protons, due to their slow velocity, depending on the charge-to-mass ratio. The latter does not permit carbon ions to be affected by the maximum electric field but a lower intensity due to the fast time decay of the electric field. Considering the angular emission of protons and the six carbon ions, the charge particles assume a Boltzmann energy distribution with a fixed cutoff at high energy, in agreement with the experimental measurements of ion energy.

Section: Methodsmentioning

confidence: 99%

Ion acceleration by fs laser in target-normal-sheath-acceleration regime and comparison of time-of-flight spectra with particle-in-cell simulations

Phys. Rev. Accel. Beams

Costa

2020

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“…rGO does not have the perfect graphene structure because it contains always some defects and oxygen functional groups and its carbon‐to‐oxygen ratio can be different depending on the method used for the reduction process. At low intensity, the laser‐generated plasma from GO, for example, produces graphene reduction with significant decrease of the oxygen content with respect to the carbon content . It is expected that laser irradiation of GO immediately reduces the graphene, freeing the oxygen atoms before the ions are accelerated from the rear side of the target.…”

Section: Introductionmentioning

confidence: 99%

Near‐3‐MeV protons from target‐normal‐sheath‐acceleration femtosecond laser irradiating advanced targets

Contributions to Plasma Physics

Cutroneo

Rosiński

et al. 2019

Self Cite

Advanced targets based on graphene oxide and gold thin film were irradiated at high laser intensity (10 18 -10 19 W/cm 2 ) with 50-fs laser pulses and high contrast (10 8 ) to investigate ion acceleration in the target-normal-sheath-acceleration regime. Time-of-flight technique was employed with SiC semiconductor detectors and ion collectors in order to measure the ion kinetic energy and to control the properties of the generated plasma. It was found that, at the optimized laser focus position with respect to the target, maximum proton acceleration up to about 3 MeV energy and low angular divergence could be generated. The high proton energy is explained as due to the high electrical and thermal conductivity of the reduced graphene oxide structure. Dependence of the maximum proton energy on the target focal position and thickness is presented and discussed.

“…36 In the case of visible and infrared (IR) laser irradiation, instead, photothermal processes are induced with GO thermal desorption of water, oxygen, and other gases and thermal ablation of carbon and other molecular species. [33][34][35]37 The Raman spectroscopy of the pristine and irradiated GO at different laser pulse energies both in air and in vacuum was performed in the shift region of about 400-3500 cm À1 . The typical vibrational modes are evident in all the μRaman spectra acquired on different UV laser pulse energy irradiating GO samples between 900 and 2000 cm À1 (D and G peaks) and between 2400 and 3400 cm À1 (2D, D + G and C peaks).…”

Section: Resultsmentioning

confidence: 99%

Graphene oxide modifications induced by excimer laser irradiations

Surface & Interface Analysis

Velardi

Serra

et al. 2022

The properties of graphene oxide foils were modified by excimer laser irradiation at different fluences and times. The irradiations were performed in air and in vacuum using a pulsed UV laser operating at 248-nm wavelength and 23-ns pulse duration.Measurements of ablation yield, microscope surface morphology and Raman spectroscopy were performed. The residual surface shows a significant oxygen reduction due to the removing of functional oxygen groups, a thickness reduction due to the removal of graphene layers depending on the used laser shots and a presence of defects in the graphene sheets as evident by the Raman spectroscopy investigation.