Number Of Laser Shots Research Articles

Interactions of microwaves with alumina surface in microwave-enhanced laser-induced breakdown spectroscopy

In laser-induced breakdown spectroscopy (LIBS), when the target material is radioactive, the total amount of ablated materials presents a challenge. High-efficiency particulate air (HEPA) filters prevent the release of the fumes of radioactive materials into the atmosphere. Microwave enhances LIBS without increasing the number of laser shots, potentially reducing the production of fumes. In this study, we analyzed the interaction of microwaves with an alumina target surface during laser ablation. Time-series images of the plasma evolution on the surface of an alumina target were captured. Moreover, the ablation crater characteristics and temporal temperature profiles were measured to evaluate the non-equilibrium plasma characteristics of the microwave-enhanced laser-induced plasma. The results show no direct correlations of the ablation crater depth and volume with the microwaves, and the number of laser shots primarily influences the volume of the crater. The absorption of microwaves by the plasma took 100 µs after the laser shot, suggesting that microwaves did not contribute to the ablation process. Although laser ablation was not influenced by the microwave input, it is the primary cause of the volume expansion of the plasma.

Surface hardness of pristine and laser-treated zinc as a function of indentation load and its correlation with crystallite size valued by Williamson-Hall analysis, size-strain plot, Halder-Wagner and Wagner-Aqua models

To get a range of crystallite size, 5 N pure polycrystalline zinc specimens were shined with 50–100 Nd:YAG laser shots. Williamson-Hall, Size-Strain Plot, Halder-Wagner, and Wagner-Aqua models were employed to evaluate the crystallite size and lattice strain of pristine and laser-treated specimens. Surface hardness of the specimens were measured under 0.2 and 0.3 kgf indentation loads for 10 s. In each case, the surface hardness followed inverse Hall – Petch Relation. For a fixed number of laser shots, the surface hardness was greater for 0.2 kgf indentation load than that for 0.3 kgf. The surface hardness of pristine zinc specimen increased on treatment with 50 laser shots. With further rise in laser shots up to 80, the surface hardness progressively decreased close to that of pristine specimen. Later, it again increased for 90 laser shots and then slightly decreased for 100 laser shots.

Binder-free vertical graphene nanosheets templated NiO petals for high-performance supercapacitor applications

Transition metal oxide and carbon-based hybrid nanostructures with high charge capacity and rate capabilities are emerging as promising electrodes for commercial supercapacitor devices. Herein, we report the fabrication of binder-free supercapacitor electrodes of vertical graphene nanosheets (VGN) templated NiO petals. The NiO petals are grown under different background O2 pressure, deposition temperature, and the number of laser shots using pulsed laser deposition (PLD). The morphology, microstructure, and stoichiometry of the NiO petals are greatly influenced by the background O2 pressure and deposition temperature. The increase in deposition temperature has been found to increase the particle size, whereas the number of laser shots affected the morphology and stoichiometry. Further, the VGN templated growth facilitates the NiO to possess a high surface area and, in turn, results in ∼2.5 times higher areal capacitance than the NiO directly grown on carbon paper substrate without VGN. In the present study, the VGN templated NiO petals exhibited areal capacitance as high as 175 mF/cm2 @ 0.1 V/s. The high areal capacitance is correlated with morphology, microstructure, particle size, and mass loading. An asymmetric coin cell device fabricated using NiO/VGN hybrid and oxygenated VGN electrodes exhibited energy and power densities of 0.4 μWh/cm2 and 102 μW/cm2, respectively. Further, LED lighting using the coin cell reveals the potential utilization of NiO/VGN hybrid electrodes for commercial applications.

Controlled Drug Release from Laser Treated Polymeric Carrier

In this study, we present the effect of laser treatment on polymeric poly(lactic acid) drug carrier films. Our goal was to demonstrate the control of the drug-release kinetics of a polymeric carrier as a function of total absorbed laser energy. The controlled drug release kinetic was achieved by modifying the amorphous polymeric carrier's molecular weight via low energy density laser-exposure. According to gel permeation chromatography results, the decrease of molecular weight correlates with an increasing laser-shot number and shows a distinct saturation-like behavior. The dissolution test also suggests the presence of such dependency, as the rate and amount of caffeine released from the sample shows an increasing tendency up to 2000 laser shots. This fact proves that the laser treatment modifies the drug release. The approach presented here may complement other methods used for controlled drug release in various medical and pharmacological applications.

Risk factors for early-onset high myopia after treatment for retinopathy of prematurity.

To investigate the prevalence of myopia and high myopia and the risk factors for high myopia in infants at 3 years of age with retinopathy of prematurity (ROP). Retrospective, observational. We retrospectively analyzed all 89 preterm infants (178 eyes) with medical records of ROP between October 2008 and March 2018 at Toho University Medical Center Omori Hospital; these infants had a birth weight of less than 1,500 g and were followed up at least until 3 years of age. Cycloplegic autorefraction was performed to measure refractive outcomes. Multivariate analysis was performed to determine the risk factors for early-onset high myopia at 3 years of age. The prevalence of myopia and high myopia was significantly higher in the treated group (59.7% and 17.9%, respectively) than in the untreated group (19.7% and 0%, respectively) (p<0.001). Spherical equivalent (SE) at age 3 was more myopic in the treatment group (-1.72 ± 3.53 D) than in the untreated group (0.54 ± 1.08 D) (p<0.001). In the sub-analysis of the treatment group, there was a significant correlation between SE at age 3 and the number of laser shots (R2 = 0.36, p<0.001). Multivariate logistic analysis showed that the number of laser shots was an independent risk factor for early onset high myopia (p<0.05). The number of laser shots is an independent risk factor for early onset high myopia, and preterm infants who have undergone laser treatment for severe ROP should be considered for early optical correction with cycloplegic refractive examination.

Clinical Observation of Laser Peripheral Iridoplasty with Number of Laser Shots in the Treatment of Acute Angle-Closure Glaucoma.

Objective To quantitatively study the intraocular pressure (IOP) control and chamber angle opening degree of patients with acute angle-closure glaucoma (stage of attack) treated by laser peripheral iridoplasty (LPIP) with different numbers of laser shots, and to evaluate the efficacy and safety of different numbers of laser shots. Methods Fifty-five patients (60 eyes) with acute angle-closure glaucoma treated in our hospital from May 2019 to December 2020 were selected as the research subjects. All patients had poor intraocular pressure control (≥40 mmHg) after IOP-lowering drug therapy. The patients were randomly divided into three groups, 20 eyes in each group, and underwent laser peripheral iridoplasty (LPIP) with different numbers of laser shots (group I: 35 laser shots, group II: 45 laser shots, and group III: 60 laser shots). The best-corrected visual acuity, IOP, corneal condition, and opening degree of anterior chamber angle (ACA), namely, the trabecular-iris angle (TIA), angle opening distance at 500 μm (AOD500), and complications of patients before LPIP, 2 hours after LPIP, and 24 hours after LPIP were observed, and the opening degree of ACA were quantitatively measured. Results The corrected visual acuity of the three groups after LPIP was improved to varying degrees, and the IOP decreased, TIA and AOD500 were increased compared with those before operation, and the differences were statistically significant (P < 0.05). There were statistically significant differences between group II and group I (P < 0.05). Four eyes in group I underwent LPIP again due to increased IOP. In group III, iris hemorrhage occurred in one eye and iris depigmentation occurred in one eye, and there was no statistical difference compared with group II (P > 0.05). Conclusions LPIP can effectively reduce preoperative IOP and increase ACA width in patients with persistent high IOP that failed to respond to drug therapy, and moderate numbers of laser shots can achieve satisfactory results and highest safety.

Topical 0.1% Nepafenac versus 0.09% Bromfenac Eye Drops for Inflammation after Laser Peripheral Iridotomy: A Randomized Controlled Trial

To assess the safety and efficacy of 0.1% nepafenac versus 0.09% bromfenac eye drops in controlling inflammation after neodymium yttrium-aluminum-garnet (YAG) laser peripheral iridotomy (LPI). Single-masked, single-center, randomized controlled trial. One hundred and sixty eyes of patients with primary angle-closure suspect (PACS) and primary angle closure (PAC) undergoing bilateral LPI. Patients were randomized in a 1:1 ratio to receive 0.1% nepafenac thrice daily or 0.09% bromfenac eye drops twice daily for 2 weeks after neodymium YAG LPI. Assessment was performed by masked investigators at 2 weeks after LPI. A Glaucoma Symptom Scale (GSS) questionnaire was administered both at baseline and 2 weeks after LPI. Subjective comfort scores to the study medications were assessed on the basis of a Likert scale at 2 weeks after LPI. In patients with bilateral PACS or PAC, the right eye was analyzed, and in asymmetrical disease (i.e., when one eye had PACS and the other eye had PAC), the eye with PAC was analyzed. The primary outcome (end point) was uncontrolled inflammation, defined as symptomatic inflammation within 1 week after LPI, the presence of anterior chamber cells at 2 weeks, or rebound inflammation after medication discontinuation. The secondary outcome was patient-reported comfort levels with study medications based on the GSS and Likert scale. At 2 weeks after LPI, 7 patients (6 with PACS and 1 with PAC) in the nepafenac group and 2 patients with PACS in the bromfenac group achieved the primary end point, without a difference between the medication groups (P= 0.09). Post-LPI burning, smarting, and stinging was more common in the bromfenac group (P= 0.01), which also had a higher comfort score on the Likert scale (P= 0.004). The need for repeat LPI was comparable (10.0% in the nepafenac group vs. 15.4% in the bromfenac group; P= 0.22). A multivariate analysis revealed that a greater number of laser shots was associated with the need for repeat LPI (odds ratio, 1.05; 95% confidence interval, 1.00-1.10; P= 0.04). Topical 0.09% bromfenac is noninferior to 0.1% nepafenac in controlling inflammation after LPI in eyes with PACS and PAC. Nepafenac may be associated with higher patient-reported comfort.

Effect of Femtosecond Laser Polarization on the Damage Threshold of Ta2O5/SiO2 Film

The study used linearly and circularly polarized femtosecond pulsed lasers to irradiate a Ta2O5/SiO2 film. Firstly, the damage thresholds of the film for linearly and circularly polarized femtosecond pulsed lasers were measured in 1-on-1 mode. The results showed that the damage threshold (1.70 J/cm2) under a circularly polarized laser was higher than that (1.68 J/cm2) under a linearly polarized laser. For femtosecond lasers, the multi-photon ionization cross-section under circular polarization was lower than that under linear polarization. The lower ionization rate under circular polarization led to a higher damage threshold compared to the case under linear polarization. Secondly, the damage morphology of the film irradiated by linearly and circularly polarized femtosecond lasers was observed by microscope. The damage caused by linearly polarized laser was more evident than that caused by the circularly polarized laser. Finally, the damage thresholds induced by linearly and circularly polarized femtosecond pulsed lasers were measured in S-on-1 (S = 2, 5, and 10) mode. For the same S value (2, 5, or 10), the damage threshold under the circularly polarized laser was higher than that under the linearly polarized laser. The damage thresholds under two polarized laser pulses decreased with an increase in the number of laser shots, indicating that repeated laser pulses had a cumulative effect on the damage of the film.

Laser induced damage threshold and incubation effects of high-power laser system optics

We present a laser induced damage threshold (LIDT) measurement technique where a mm-diameter non-Gaussian laser beam is used. This allows both a large number of measurements points and a large range of fluence to be sampled with a single measure. The method is used in-situ, inside the laser radiation – matter interaction vacuum vessel used for high power experiments with a 100 TW-class laser system. With our 2.5-Hz repetition rate laser system, the well-known incubation effect is observed where the laser damage threshold on the optics decreases with increasing number of laser shots. The incubation effect is studied with 22-fs laser pulses at a laser 2.5-Hz nominal repetition rate with several optics like dielectric mirrors and gold compression gratings irradiated by up to 9 × 103 laser shots.

Measuring the concentration of gold in ore samples by laser-induced breakdown spectroscopy and comparison with the gravimetry/atomic absorption techniques

Using a calibration model built from 14 compressed powders of reference materials doped with gold in solution, the gold concentration of 32, 6-sided, ore samples was determined by LIBS and then compared to those obtained by conventional laboratory techniques (gravimetry/atomic absorption). The studied samples are on average ~ 4 cm long and they were collected from 6 different gold mines of the Abitibi greenstone belt (Canada). LIBS measurements are found to be accurate for homogeneous powder samples but can differ significantly from laboratory measurements for solid ore samples depending on the uniformity of the gold distribution at the sampling scale due to the diferent sampling approaches adopted by both techniques, i.e. surface sampling versus bulk. In addition, the LIBS sampling strategy, which consists of scanning along diagonals oriented transversely to the natural ore layers, was evaluated on the same 32 samples. This sampling strategy results in a gold concentration very close to that obtained by scanning the entire rock surface, but with only a small fraction (of the order of the square root) of the number of laser shots. Further, the influence of the chemical composition of the calibration samples on the properties of the plasma was studied by measuring the electron number density and temperature of the plasma. These parameters were found to be almost identical (1.70 ± 0.15 × 1016 cm−3 and 6200 ± 1000 K) within the uncertainty of the measurements despite the large difference in iron content (3% to 50%) of the samples.

Impact of Neodymium-Doped Yttrium Aluminum Garnet (ND-YAG) Posterior Capsulotomy Laser Treatment on Central Macular Thickness: A Prospective, Observational Study From a Tertiary Care Center.

IntroductionOpacification of the posterior capsule is labeled as a secondary cataract. The objective of the current study was to assess central macular thickness (CMT) changes following neodymium-doped yttrium aluminum garnet (ND-YAG) posterior capsulotomy and to find out the correlation between CMT with the age, energy, and total shots utilized during the procedure.MethodologyIn this single-centered prospective observational study, 137 patients with a mean age of 57 ± 12.61 years, who had cataract surgery previously and were candidates for ND-YAG posterior capsulotomy were recruited through consecutive sampling. The study was conducted at Layton Rahmatulla Benevolent Trust (LRBT) Free Eye Hospital, Township, Lahore, Pakistan, between April 2020 to April 2021. The CMT, total energy, and sum total of shots used were recorded. The thickness of the central macula was measured preoperatively and postoperatively after two weeks. The paired sample t-test was used to find out any significant changes in CMT pre and two weeks postoperatively. The comparison of changes in CMT to age, energy, and the total number of shots was made through Pearson correlation. Means of CMT were compared using an independent sample t-test, at two weeks postoperatively among two energy groups.ResultsNo statistically significant differences were found between preoperative and two weeks postoperative values of the CMT (P-value= 0.209). No significant difference was found in CMT statistically among the two energy groups (p=0.11). The patient's age, sum total of laser shots, and aggregate of laser energy did not have any significant correlation with CMT changes. The time period between cataract surgery and ND-YAG surgery showed a moderately positive correlation with a p-value of 0.01.ConclusionThe current study revealed that ND-YAG capsulotomy does not affect the CMT significantly postoperatively. The patient's age, total energy applied, and the total number of laser shots used do not influence the macular thickness. However, the length of duration from the last cataract surgery to the current surgery was significantly associated with a change in the CMT.

Towards optimization of femtosecond laser pulse nanostructuring of targets for high-intensity laser experiments in vacuum

The interaction of intense femtosecond laser pulses with solid targets is a topic that has attracted a large amount of interest in science and applications. For many of the related experiments a large energy deposition or absorption as well as an efficient coupling to extreme ultraviolet (XUV), X-ray photon generation, and/or high energy particles is important. Here, much progress has been made in laser development and in experimental schemes, etc. However, regarding the improvement of the target itself, namely its geometry and surface, only limited improvements have been reported. The present paper investigates the formation of laser-induced periodic surface structures (LIPSS or ripples) on polished thick copper targets by femtosecond Ti:sapphire laser pulses. In particular, the dependence of the ripple period and ripple height has been investigated for different fluences and as a function of the number of laser shots on the same surface position. The experimental results and the formation of ripple mechanisms on metal surfaces in vacuum by femtosecond laser pulses have been analysed and the parameters of the experimentally observed “gratings” interpreted on base of theoretical models. The results have been specifically related to improve high-intensity femtosecond-laser matter interaction experiments with the goal of an enhanced particle emission (photons and high energy electrons and protons, respectively). In those experiments the presently investigated nanostructures could be generated easily in situ by multiple pre-pulses irradiated prior to a subsequent much more intense main laser pulse.

The Effect of Quasi-Spherical Gold Nanoparticles on Two-Photon Induced Reactive Oxygen Species for Cell Damage.

The performance of quasi-spherical gold nanoparticles (GNPs) on the generation of reactive oxygen species (ROS) to cause cell damage, as irradiated by a two-photon laser, is studied. In this mechanism, hot electrons are generated from GNPs as irradiated by the two-photon laser, reacting with the molecules in the medium to produce ROS. We used laser scanning confocal microscopy with a low-fluence femtosecond Ti:Sapphire laser of 800 nm to observe the generated ROS in A431 cells, which were incubated with GNPs in advance. Subsequently, the cell morphology, cytoskeleton, and viability were investigated. In comparison with the control (no GNPs), the expression of ROS in these GNP-treated cells was enhanced after irradiation by the two-photon laser. Additionally, the disruption of cytoskeletons and the follow-up apoptosis of these GNP-treated cells are significantly increased as the number of laser shots increases. Moreover, we used N-acetyl-L-cysteine (NAC), an antioxidant, to inhibit the formation of ROS, to clarify whether the cytoskeletal disruption is caused by ROS rather than photothermal effects. Our results show that after two-photon irradiation, the ROS expression in these cells treated with GNPs plus NAC was significantly reduced. In addition, the cytoskeletal damage of these cells treated with GNPs and NAC was less than that of those treated with GNPs but without NAC; their cell viability after three days was almost the same with the control. These results illustrate that the induced ROS from the two-photon excited GNPs is the main cause of cell damage. The study may pave a way for the use of GNPs as a photosensitized therapeutic agent for two-photon photodynamic therapy on tumor treatment.

Effect of Thermal Annealing on the Electrical Properties and Gas Sensing for Pulsed Laser Deposition Cr2O3 Thin Films

In this study, a double frequency Nd: YAG deposited by Pulsed Laser Deposition (laser beam 1064 nm, 6 Hz repetition rate and 10 ns pulse duration) were used for a thin Cr2O3 deposit on glass substrate. Many growth parameters have been considered to specify the optimum condition, namely substrate temperature at room temperature, oxygen pressure (2.8×10-4 mbar), laser energy (600) mJ and the number of laser shots was 500 pulses. The thickness was of about 160 nm and annealing temperature at (300, 400 and 500) °C. Using DC method, the conductivity and Hall coefficient of Cr2O3 films were measured. The sensing properties of the p-type (Hall coefficient was positive) films for NO2 gas have been studied, and the result revealed that the Cr2O3 films have low sensitivity at room temperature, and it’s improved by increasing the annealing temperature to 500° C.

Laser‐Induced Reversible and Irreversible Surface Nanostructuring

AbstractHarnessing the 4D transmission electron microscopy (4D‐TEM) technique capable of in situ study of light‐material interactions with high spatiotemporal resolution, the authors are able to demonstrate the formation of a reversible laser‐induced periodic surface structure (RLIPSS) on the top few‐nanometer surface of free‐standing amorphous thin films of silicon nitride and silicon dioxide. Compared with commonly reported permanent laser‐induced periodic surface structures (LIPSS) grown on thermal ablation of materials, highly ordered RLIPSS here develop in a nonthermal manner by femtosecond laser irradiation with unprecedented low intensity down to 10 000 times lower than their reported ablation thresholds. This reversible structure can undergo a transition to permanent structure with increasing laser intensity and number of laser shots. The orientation of the RLIPSS exhibits an unexpected memory of laser polarization, making it a potential candidate for future ultrafast rewritable photo‐image recording. These experimental results exclude the widely accepted formation mechanism of LIPSS based on the interference between the incident light with the surface scattering waves or the surface plasmon polaritons, and suggest a novel mechanism for surface laser micromachining, relevant to the laser‐induced production of charged point defects and the polarization‐dependent generation of tensile stress induced by electrostatic repulsion.

Fabrication and tribological characterization of laser textured engineering ceramics: Si3N4, SiC and ZrO2

Ceramics have been widely used in the field of tribology due to their superior corrosion resistance and low friction coefficient. The tribological properties of ceramics can be improved by machining proper surface texture. This work uses a nanosecond laser to process dimples on different ceramic surfaces. The morphology and size of dimples as a function of the number of laser shots and laser power are investigated. A theoretical model relating laser parameters and dimple size is established. In the initial point contact friction test, based on the experimental parameters mentioned in this paper, the existence of surface texture reduces the wear volume of Si3N4 balls in water by 41.5% and the wear volume of ZrO2 balls in oil by 51%.

Effect of position on the safety and efficacy of neodymium-doped: Yttrium aluminium garnet laser peripheral iridotomy in patients with primary angle-closure disease

Purpose: The aim is to evaluate the safety and efficacy of neodymium-doped: yttrium–aluminum–garnet laser peripheral iridotomy (LPI) in the superior versus inferior quadrant in the treatment of primary angle-closure (PAC) disease. Design: Randomized, prospective, single-masked, comparative clinical study. Materials and Methods: Patients with PAC or PAC suspects were recruited and randomized to receive LPI in the superior or inferior quadrant in both eyes. Patients were masked to the location of treatment in each eye. The main outcome measures assessed were patency of iridotomy, laser parameters, complications, and visual symptoms between the two groups at 1 week and 1 month after the laser intervention. Results: A total of 100 patients were recruited, 50 into each group. The mean age was 51.46 ± 7.91 years. Average intraocular pressure (IOP) measurements before LPI was 18.24 ± 5.37 mm Hg and 18.6 ± 5.63 mm Hg in superior LPI and inferior LPI eyes, respectively. After LPI, average IOP was 17.4 ± 3.31 mm Hg and 17.1 ± 3.13 mmHg in superior LPI and inferior LPI eyes, respectively. Inferior LPIs required less use of mean total laser energy (P = 0.001) and less number of laser shots (P = 0.016) to perforate the iris tissue. There was a lower incidence of iris bleeding and focal corneal damage at the time of treatment; a lower postlaser iritis and lower need for PI enlargement in the inferior LPI group. All the iridotomies were patent at 1 month follow-up. There was no statistically significant difference between the two groups in terms of the dysphotopsias and visual symptoms experienced after the LPI (P = 0.122). Conclusions: LPI in the inferior quadrant appears to be a safe and efficient alternative to superior LPI with fewer complications in the treatment of PAC disease. Dysphotopsias and visual symptoms following inferior LPI are similar to superior LPI.

Investigation of compositional analysis and physical properties for Ni-Cr-Nb alloys using laser-induced breakdown spectroscopy

In this work, laser-induced breakdown spectroscopy (LIBS) analysis is optimized for direct estimation of elemental composition, thermal conductivity and hardness for Ni-Cr-Nb alloys. These alloys were chosen with a variable elemental content of niobium and chromium. The influence of laser energy and shot numbers on measuring line intensity was investigated. Based on the ratio between two spectral lines, calibration curves were formed to estimate the element concentration and LIBS results were confirmed with related energy-dispersive X-ray spectroscopy (EDS) data. Hardness and thermal conductivity estimation using LIBS were done by measuring the ratio between two spectral lines, plasma excitation temperature and electron density for different samples. Semi-empirical formulas correlated hardness and thermal conductivity with plasma temperature were established.

Laser power and wavelength dependence of alumina reduction using YAG laser ablation considering inverse bremsstrahlung

Among the lunar surface regolith, alumina is confirmed to be present in about 10% in the whole moon, especially in the highlands about 23%, which is one of the representative substances. Although alumina itself is not a very versatile material, reduced aluminum has a lot of applications for future lunar activities including a base construction. The laser ablation is one of the promising reduction methods because it does not require reducing agency. In this study, alumina was reduced through YAG laser ablation and generated aluminum was collected using a copper plate. The collected aluminum mass was estimated by the volume of hydrogen gas evaporated in hydrochloric acid titration. Then, the reduction efficiency was estimated as the ratio of collected aluminum to the total ablated mass. They were investigated in terms of the variation of the three laser wavelengths: 355, 532 and 1064 nm. Besides as the experimental condition, the peak power, number of laser shots, and ambient pressure were set as 5–15 MW, 3000–12000 shots, and 1.0–600 Pa, respectively. As a result, we verified alumina reduction by observation of Al I, Al II, Al III spectra. Al mass of 0.34 mg and energy conversion efficiency of 13% were achieved in 355 nm and 9000 shots and 1.0 Pa.

The effect of sub-second intervals of ArF laser irradiation on the formation of periodic micro-swelling structures on silicone rubber surfaces

Surface modification and microstructure formation of silicone rubber are gathering attention as popular methods of wettability control for microfluidic devices and biomedical applications. In this report, micro-swelling structures were fabricated on silicone rubber surfaces by ArF laser irradiation at various pulse repetition rates. The average height of the swelling structures shows a negative correlation with the pulse repetition rates of 2 Hz–20 Hz. The relationship between the microstructure height and the number of ArF laser shots was investigated at 2 Hz, 6 Hz, and 20 Hz pulse repetition rates, and it is presented that the growth of microstructures saturates with the smaller number of shots at the higher pulse repetition rate. These results imply the possibility of other competing mechanisms that disturb the swelling of silicone rubber by the ArF laser irradiation. The Attenuated Total reflection Fourier Transform Infrared spectroscopy measurement of the silicone rubber surface shows that the desorption of the –CH3 group proceeds more efficiently at the higher pulse repetition rate. It is concluded that the modification of silicone to the silica-like structure that increases in surface hardness disturbs the growth of the swelling structure, and the sub-second intervals of the ArF laser pulse suppress the modification of silicone to the silica-like structure. The understanding of the processes after photodissociation contributes not only to the effective formation of microstructures but also to the chemical modification of the silicone rubber surface.