High-intensity Laser Radiation Research Articles

Near-Infrared Light-Driving Organic Photothermal Agents with an 88.9% Photothermal Conversion Efficiency for Image-Guided Synergistic Phototherapy.

Photothermal agents (PTAs) with desirable near-infrared (NIR) absorption and excellent photothermal conversion efficiency (PCE) are ideal candidates for cancer treatment. However, numerous PTAs still require high-intensity and long-duration laser irradiation to completely ablate the tumor during the photothermal therapy (PTT) process, resulting in light damage to healthy skin and tissue as well as limiting their biomedical applications. Integrating intense NIR absorption and high PCE into a single small-molecule PTA is an important prerequisite for realizing efficient PTT, but is a serious challenge. Herein, a series of donor-acceptor type PTAs (CC1 to NC4) are designed through a molecular engineering strategy. Theoretical calculations and experimental results show that the NIR absorption and photothermal effect from CC1 to NC4 are significantly enhanced as expected. Notably, NC4 nanoparticles exhibit intense NIR absorption, superhigh PCE of up to 88.9% for PTT, photoacoustic imaging and photothermal imaging, and effective reactive oxygen species generation for photodynamic therapy (PDT). The superior PTT/PDT synergistic phototherapeutic efficacy is well demonstrated by the complete elimination of tumor in vivo upon one-time, low-intensity, and short-duration laser irradiation (808nm, 330mW cm-2, and 3min). This work provides a valuable guideline for rational design of PTAs for cancer phototherapy.

Laser-induced changes on the upconversion luminescence properties of BiF3:Yb,Er nanoparticles

BiF3 nanoparticles doped with Yb3+ and Er3+ ions in varying ratios were prepared by co-precipitation method and its upconversion luminescence (UCL) properties were investigated in detail before and after high-intensity laser treatment. Green-to-red ratio (GRR) of luminescence from cubic-BiF3:Yb,Er nanoparticles is found to increase with an increase in laser power for as prepared sample. Unlike this, for conventional Yb,Er doped upconversion nanoparticles (UCNPs) such as cubic NaYF4:Yb,Er and hexagonal-NaYF4:Yb,Er, a decrease in GRR values is observed with an increase in laser power. This has been explained based on the reduced extent of Er3+-Er3+ interaction in BiF3:Yb,Er nanoparticles compared to that existing in cubic and hexagonal forms of NaYF4:Yb,Er, nanoparticles. Reduced interaction is brought about by higher lattice parameter of BiF3 host compared to the NaYF4 host which leads to a lesser extent of cross-relaxation in the former host thereby favoring the population of 4S3/2 and 2H11/2 levels of Er3+. Effect of high-intensity laser (180W/cm2) irradiation on BiF3:Yb,Er nanoparticles resulted in an irreversible five-fold increase in upconversion luminescence intensity and this is attributed to combined effect of partial conversion of BiF3 to cubic Bi2O3 and removal of adsorbed water molecules. These inferences are confirmed by XRD and TEM measurements carried out on laser-treated sample. Improved luminescence intensity from the laser-treated sample is also confirmed by the high-contrast clear images obtained from impressions made using high-intensity laser irradiation on BiF3:Yb,Er nanoparticles. BiF3:Yb,Er nanoparticles showed an excellent thermal sensitivity of 0.3% K−1 at room temperature and the value is comparable with that of conventional β-NaYF4:Yb,Er nanoparticles.

Investigation of laser-induced contamination on dielectric thin films in MHz sub-ps regime

High-repetition rate diode-pumped sub-ps lasers are widely used in the industrial sector for high-quality material processing applications. However, for their reliable operation, it is crucial to study the power handling capabilities of the optical components used in these systems. The optical components, such as mirrors, gratings, dichroic filters, and gain media, are designed based on dielectric thin films. When subjected to high-intensity laser radiation, the phenomenon of laser-induced contamination (LIC) can lead to the growth of a nanometric, highly absorbent layer on an irradiated optical surface, which can result in transmission or reflection loss and eventual permanent damage. In this study, we investigate LIC growth on dielectric oxide thin films in an air environment irradiated by MHz sub-ps laser at 515 nm. We examine the effect of thin film deposition method, material, and thickness on LIC growth dynamics. The irradiated spots on the surface are inspected using multiple observation methods, including white light interference microscopy and fluorescence imaging. Our results show that the LIC growth dynamics depend on the laser intensity and irradiation time and can be affected by the thin film deposition method, material, and thickness. These findings could be used to inform the development of more resistant optical components, ensuring long-term reliable laser operation required for industrial applications. The study highlights the need for validating optical components using tests that closely mimic real-world applications and provides insight into the complex processes that lead to LIC.

Complex diagnostic and numerical study of x-ray and particle emissions under relativistic ultra-short laser-solid interaction

In this report, we present the experimental results on the generation of x-ray emission and particle acceleration using high temporal contrast (∼10–9 at picosecond time scale), ultrashort (), relativistic () near-IR laser pulses interacting with Titanium foils. Complex diagnostics, including the energy spectra of accelerated electrons from both front and rear target sides, electron angular distribution and x-ray spectroscopy of the plasma emission were employed. Analysis of the characteristic radiation produced by highly charged Ti+20 ions led to the conclusion that laser-plasma interaction, which leads to the generation of keV hot plasma, occurs at plasma densities 10x higher than relativistic critical electron density. Numerical simulations, including hydrodynamic calculations to model pre-plasma, generated on nanosecond-picosecond time scale under our experimental conditions and relativistic particle-in-cell simulations for main pulse interaction with the plasma reproduce well electron energy and angular distributions. They show the onset of hole boring effect under near normal incidence that leads to plasma density steepening and enables penetration of high intensity laser radiation into the overcritical plasma to much higher densities (up to 30 ), what is in a good agreement with the results of x-ray spectroscopy.

Effectiveness of High-intensity Laser Therapy for Pain and Function in Knee Osteoarthritis: A Randomized Controlled Trial

Background: High-intensity laser therapy (HILT) is still a controversial physical therapy modality for individuals with knee osteoarthritis (OA). Objectives: This study aimed to evaluate the effect of HILT on pain and function in patients with knee OA. Methods: This randomized controlled trial included 56 patients with knee OA referred to Amin Hospital affiliated with Isfahan University of Medical Sciences, Isfahan, Iran, from April 19 to August 30, 2022. Patients were randomized into two groups (HILT and control), receiving isometric exercises targeting the quadriceps muscle, meloxicam 15 mg tablet, and Rahamin ointment for two weeks. The HILT group also received high-intensity laser irradiation three times a week for two weeks. The primary outcome was pain assessed using a Visual Analog Scale (VAS), and the secondary outcome was the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) and its subscales (pain, stiffness, and physical function). Outcomes were evaluated at baseline, immediately, and three months after the last treatment session. Results: After adjusting for age, sex, and baseline values, immediately and three months after treatment, VAS pain scores were significantly lower in the HILT group than in controls (P < 0.001), with a large effect (standardized mean difference (SMD) = -1.22, 95% confidence interval (CI): -1.81; -0.62 and SMD = -1.31, 95% CI: -1.90; -0.70, respectively). The results were similar for WOMAC's pain subscale. Despite the difference in WOMAC stiffness score was not significant between the two groups immediately after treatment (P = 0.135), this score was significantly lower in the HILT group than in the control group (SMD = -0.98, 95% CI: -1.56; -0.40, P = 0.002) three months after treatment. Furthermore, WOMAC physical function scores were significantly lower with HILT immediately and three months after treatment (P < 0.001). The same was true for the total WOMAC score. Conclusions: High-intensity laser therapy significantly improved pain and the WOMAC score in patients with knee OA immediately and three months after the last treatment session compared to the control group.

Probing shock dynamics inside micro-wire targets after high-intensity laser irradiation using small angle x-ray scattering of a free-electron laser

In this paper, we present an experiment that explores the plasma dynamics of a diameter carbon wire after being irradiated with a near-relativistic-intensity short pulse laser. Using an x-ray free electron laser pulse to measure the small angle x-ray scattering signal, we observe that the scattering surface is bent and prone to instability over tens of picoseconds. The dynamics of this process are consistent with the presence of a sharp, propagating shock front inside the wire, moving at a speed close to the hole boring velocity or that expected from a thermal shock at a few tens of Mbar.

The Role of Stepwise Photoionization in Measurements of the Ionization Potentials in Dense Plasma

The interaction of high-contrast high-intensity laser radiation with solids allows us to create hot or warm plasma of solid or even over-solid density, such as in the case of inertial fusion particularly. The multicharged ions contained in it can no longer be considered isolated. As a result, this leads to a decrease in the ionization potentials and to the disappearance of a number of bound ionic states. To describe the ionization potential depression, two major approaches are now used predominantly, where the key parameter is either average interelectronic or interionic distance. Since neither of the approaches can be substantiated purely theoretically, their applicability can only be established by comparison with experimental results. In recent experiments with X-ray free-electron lasers, it was concluded that the ionization potential depression rather depends on the interelectronic distance. However, when measuring ionization potentials, it was assumed that the main role in ionization processes is played by the direct photoionization of the ion ground state. In the present paper, we show that stepwise photoionization processes should play a significant role in dense plasma, disrupting a straight correspondence between the threshold in direct photoionization by X-ray laser photons and the actual ionization potential of multicharged ions. It means that the measurement results mentioned above are not correct, and the main conclusion about the importance of the interelectronic distance for depression of the ionization potential is not correct.

Nonlinear Optical Response of Dispersed Medium Based on Conjugates Single-Walled Carbon Nanotubes with Phthalocyanines

Nanosecond lasers have recently been widely involved in human activity. However, high-intensity laser radiation can cause severe damage to organs of vision and expensive photonic devices. Radiation in the near UV range is especially dangerous for human eyes, since it is strongly absorbed by biological media and is also invisible, i.e., the reaction time of the eye to such radiation is much lower than that of visible light. Passive limiters have high transmission (>70%) at a low light intensity and begin to “darken” only when the threshold value of the laser radiation intensity is reached. In this work, we studied liquid nanodispersed nonlinear optical limiters based on hybrids of single-walled carbon nanotubes (SWCNTs) with metal-free tetra(hydroxy)phthalocyanine (OH)4PcHH). The value of the hydrodynamic radius of separate particles after (OH)4PcHH binding increased from 288 ± 55 nm to 350 ± 60 nm, which confirms the attachment of phthalocyanine complexes to nanotubes. The third harmonic of a Nd:YAG nanosecond laser (355 nm, 20 ns) was used to study the nonlinear optical response. Based on a Z-scan with open-aperture and input-output dependence curves, third-order nonlinear optical absorption coefficients of 149, 236, and 229 cm/GW were obtained for dispersions of composites of SWCNTs and (OH)4PcHH in water, dimethylformamide (DMF), and dimethylsulfoxide (DMSO), respectively. Threshold values did not exceed 100 mJ/cm2. The Z-scan showed a gradual decrease in the duration of the laser pulse by 53%; however, near the focus, there was a sharp increase in the duration of the transmitted pulse, reaching a value of 29 ns in z = 0. This phenomenon confirms the occurrence of reverse saturable absorption in the investigated media and can be used in photonic devices to control the temporal characteristics of the signal. Thus, the possibility of protection of sensitive photonic devices and human eyes from nanosecond laser pulses in the near UV range by nanodispersed liquid media based on composites of SWCNTs with (OH)4PcHH has been discussed in this paper.

High-intensity laser therapy in clinical medicine: scientometric analysis of evidence of effectiveness

High-intensity laser technologies are widely used in modern restorative medicine, and indications for their use are expanding annually. These technologies are effective, potentially safe methods of treating many diseases. with pronounced therapeutic effects. Analysis of scientific evidence of the effectiveness and safety of high-intensity laser therapy in patients with various diseases. A comprehensive scientometric analysis of evidence-based studies of the effectiveness and safety of high-intensity laser therapy methods was carried out according to electronic databases (Google scholar, PEDro, PubMed, Cochrane DATABASE) for the period from 2006 to 2021. High-intensity laser therapy has a wide range of significantly pronounced therapeutic effects. and it is an effective method of treating patients with various diseases. Various technologies and methods of its application are widely used in various fields of clinical medicine. Individually developed therapy protocols are needed, with optimal exposure parameters for each patient, intervals between procedures. It is advisable to develop more reliable and standard evaluation criteria, regular generalization and analysis of existing evidence, careful planning and implementation of further large-scale randomized controlled trials to study the effects of high-intensity laser radiation both as a single effect and as part of combinations with other treatment methods. The effectiveness of combination therapy requires further analysis in the course of conducting new benign clinical trials.

The Effect of Laser Shock Peening on the Thermophysical Parameters of Metals

Using Ti64 titanium alloy as an example, the article discusses the change in the thermophysical parameters of metals under the influence of a hardening method such as laser shock peening the essence of which is the formation of residual compressive stresses in the material under the influence of high-intensity laser radiation. The experiments are carried out with plates made of Ti64 titanium alloy, which is one of the most common construction materials in modern industry. One of the plates is a control specimen, and the surface of the second one is subjected to laser processing. The thermophysical parameters of specimens are determined using the infrared thermography method, the advantage of which is the ability to simultaneously measure two coefficients, thermal diffusivity and thermal conductivity of an explored material. The specimen is heated by the laser for some time, which can be perceived as a point heat source on the surface of the plate. Simultaneously with the laser action, the surface temperature of the specimen is recorded by an infrared camera. The thermophysical coefficients are determined as optimization parameters when matching experimental data with the analytical solution of the heat equation for a geometry similar to the experimental setup.

Opto-thermal dynamics of thin-film optical limiters based on the VO2 phase transition

Protection of human eyes or sensitive detectors from high-intensity laser radiation is an important challenge in modern light technologies. Metasurfaces have proved to be valuable tools for such light control, but the actual possibility of merging multiple materials in the nanofabrication process hinders their application. Here we propose and numerically investigate the opto-thermal properties of plane multilayered structures with phase-change materials for optical limiters. Our structure relies on thin-film VO2 phase change material on top of a gold film and a sapphire substrate. We show how such a multi-layer structure can act as a self-activating device that exploits light-to-heat conversion to induce a phase change in the VO2 layer. We implement a numerical model to describe the temporal evolution of the temperature and transmittivity across the device under both a continuous wave and pulsed illumination. Our results open new opportunities for multi-layer self-activating optical limiters and may be extended to devices based on other phase change materials or different spectral regions..

The Motion of a Charged Particle in the Electromagnetic Field of a Polarization-Modulated Wave

This article presents an exact solution of the equation of motion of a charged particle in the electromagnetic field of a high-intensity polarization-modulated wave. Expressions for the average kinetic energy of a particle without regard to its rest energy in the case of circular and linear polarization of a modulated wave are obtained. The motion of a charged particle in the field was analyzed and expressed in terms of dependences of its average kinetic energy on the electromagnetic wave intensity and on various types of modulation depths. The contribution of each type of modulation to the energy characteristics of a charged particle was demonstrated. Solving the equation of motion of a charged particle in the electromagnetic field of a plane wave opens up possibilities for various applications related, in particular, to various developments of multi-frequency lasers and laser modulation technology. This study was proposed due to the growing interest in experiments using high-intensity femtosecond laser radiation and high-temperature plasma

Lightweight Flexible Polyimide-Derived Laser-Induced Graphenes for High-Performance Thermal Management Applications

Laser pyrolysis of polyimide (PI) is a promising approach for preparing porous graphenes with hierarchical structures. In this study, we used a dual-focusing lens with a collimator to generate a highly concentrated CO2 laser beam with a high focal energy density. The resulting PI-derived graphene (PIDG) obtained under high-intensity laser irradiation possessed a high degree of graphitization, a low sheet resistance (27.4 Ω/sq.), and a large surface area (240.4 m2/g). Through optimization of the high-intensity laser parameters, we obtained a hierarchical PIDG possessing a fiber-like structure. We used this PIDG as a flexible heater and efficient heat sink for Si photovoltaic (PV) and light-emitting diode (LED) modules. The developed heater could reach a temperature of 202.6 °C under an applied voltage of 16 V, with rapid responses and remarkable flexibility. As a result of improved convective and radiative heat dissipation, the PIDG-based heat sink lowered the operating temperatures of the Si PV and LED modules efficiently. Accordingly, the power conversion efficiency of the Si PV and the lifetime of the LED module both increased dramatically.

Nanoscale subsurface dynamics of solids upon high-intensity femtosecond laser irradiation observed by grazing-incidence x-ray scattering

Observing ultrafast laser-induced structural changes in nanoscale systems is essential for understanding the dynamics of intense light-matter interactions. For laser intensities on the order of 1014W/cm2, highly collisional plasmas are generated at and below the surface. Subsequent transport processes such as heat conduction, electron-ion thermalization, surface ablation, and resolidification occur at picosecond and nanosecond timescales. Imaging methods, e.g., using x-ray free-electron lasers (XFEL), were hitherto unable to measure the depth-resolved subsurface dynamics of laser-solid interactions with appropriate temporal and spatial resolution. Here we demonstrate picosecond grazing-incidence small-angle x-ray scattering (GISAXS) from laser-produced plasmas using XFEL pulses. Using multilayer (ML) samples, both the surface ablation and subsurface density dynamics are measured with nanometer depth resolution. Our experimental data challenges the state-of-the-art modeling of matter under extreme conditions and opens new perspectives for laser material processing and high-energy density science.Received 11 December 2021Accepted 23 May 2022DOI:https://doi.org/10.1103/PhysRevResearch.4.033038Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHigh intensity laser-plasma interactionsHigh-energy-density plasmasPhysical SystemsPlasma sheaths & surfacesStrongly-coupled plasmasWarm-dense matterTechniquesHydrodynamicsLaser ablationParticle-in-cell methodsX-ray reflectivityX-ray scatteringPlasma PhysicsCondensed Matter, Materials & Applied Physics

Kinetic Model Evaluation of the Resilience of Plasmonic Nanoantennas for Laser-Induced Fusion

A kinetic model of the plasmonic response and stability of gold nanorods under high-intensity laser irradiation is used to evaluate their suitability as amplifiers for laser-induced inertial confinement fusion.

High-intensity laser therapy of patients with atrophic scars: results of a comparative prospective interventional cohort study

BACKGROUND: Scars of various sizes and localization are formed in more than 100 million patients annually. Atrophic scarring defects of the skin are verified in more than 80% of patients with acne and in 30% of patients with other injuries. Different skin remodeling technologies have different effectiveness, which actualizes the search for optimal methods of scar correction. The most promising of them are combinations of high-intensity laser radiation.
 AIMS: Determination of therapeutic effects of high-intensity laser therapy in patients with atrophic skin scars.
 MATERIALS AND METHODS: A prospective interventional cohort comparative study of the therapeutic effects of high-intensity laser therapy in patients with atrophic skin scars was conducted. In patients with emerging scars, a combination of homogeneous photothermolysis by long-pulse Nd:YAG laser radiation (l=1.064 microns) followed by fractional ablative photothermolysis of CO2 laser (l=10.6 microns) was used, and in patients with mature scars, a combination of homogeneous photothermolysis of long-pulse Nd:YAG laser (l=1.064 microns) and planar laser photodestruction of CO2 laser (l=10.6 microns).
 115 patients with the diagnosis of "atrophic scars" (ICD-X, Class XII "Diseases of the skin and subcutaneous tissue", L90.5) were examined, among which groups with emerging (49 patients) and mature (66 patients) scars were identified. Empirical research methods ― clinical, instrumental, and medico-sociological ― have been applied. The analysis of the obtained data was carried out using the methods of descriptive, parametric and multifactorial statistics with the determination of the specific weight of the studied features.
 RESULTS: The improvement of the clinical status, pronounced remodeling of the skin in the area of atrophic scars, under the influence of various combinations of high-intensity laser therapy was revealed. An increase in the quality of life indicators according to the Skindex-29 and Dermatology Life Quality Index (DLQI) scales was determined, more pronounced in the groups of patients with atrophic scars in comparison with the group of patients with mature scar deformities. Combinations of high-intensity laser therapy have a favorable safety profile, are characterized by a high degree of compliance and satisfaction with the results of treatment. The effectiveness of variant high-intensity laser therapy in patients with atrophic scars is 8690%.
 CONCLUSIONS: Combinations of high-intensity laser therapy in patients with developing atrophic scars cause dermoplastic and fibromodeling therapeutic effects, in patients with mature ones ― reepithelizing, fibrocorrecting therapeutic effects.

Using laser in the treatment of chronic skin diseases

In most cases, the treatment of skin diseases, especially chronic processes, is a difficult task due to the low effectiveness of the traditional methods of treatment, the emergence of drug resistance, the development of frequent allergic and other adverse reactions. In total, the impact of the above factors has led to the need to find new ways and methods in the treatment of dermatological lesions. Against the background of using ultrasound, cryotherapy and magnetotherapy, good efficiency was also noted as a result of exposure to laser beams. For the first time, the laser began to be used to treat skin diseases about 40 years ago. When laser radiation is applied to the skin, the processes of photostimulation, photothermolysis and photodynamic reactions occur in its layers. Photostimulation processes began to be used to activate wound healing, and photodynamic reactions were used to treat acne vulgaris, vitiligo, psoriasis, urticaria, and lichen planus. At the same time, low-intensity laser radiation is used for therapeutic purposes, and high-intensity laser radiation is used in surgical practice, in particular, for the removal of warts, papillomas, and genital warts. The use of laser radiation in the treatment of skin diseases contributes to the activation of tissue respiration processes, a decrease in the activity of free radicals, and the stabilization of lipid complexes of cell membranes. In general, improvement in the condition after laser therapy is noted in 40–80 % of patients.

Reflection and thermal characteristics of a novel reflective phase-change coating irradiated by high-power continuous laser

In order to improve the smart control performance of laser protective materials under the high-power laser irradiation, a novel smart phase-change laser protective coating is proposed and prepared by using phenolic resin and zirconia, combined with the slow-gradient heating and drying technique and spraying process. The influences of laser ablation on the macrostructure of coating shows that the prepared coating can withstand the laser irradiation up to 3102 W/cm2 for 7 s at the wavelength of 1064 nm. The effect of high-intensity laser irradiation on structure evolution has been further investigated. It is found that increasing the laser power density will change the coating microscopic structure from the initial lumpy structure to a flocculent crystal structure, and finally form a flake structure, which is considered as the main reason for the increase of reflectivity. The experimental results show that the reflectivity on the coating surface can be increased by 75.7% before and after laser irradiation. Finally, the phase transition temperature of the coating is investigated, and the thermal insulation performances between coating and substrate have also been compared. The temperature insulation performance of the novel phase-change coating is found to be 1.2–15 times higher than that of the substrate.

Impedance spectroscopy of lithium triborate crystals interacting with high-intensity laser radiation

Impedance spectroscopy of lithium triborate crystals interacting with high-intensity laser radiation

ИЗМЕНЕНИЯ ТЕМПЕРАТУРНЫХ ПОЛЕЙ И МИКРОЦИРКУЛЯЦИИ В СТЕНКАХ ПИЛОНИДАЛЬНЫХ КИСТ КОПЧИКОВОЙ ОБЛАСТИ ВО ВРЕМЯ И ПОСЛЕ ЛАЗЕРИНДУЦИРОВАННОЙ ТЕРМОТЕРАПИИ

Introduction. As of today, many options for conservative and surgical treatment of patients with pilonidal cysts have been developed. Our studies on the use of laser radiation in the treatment of epithelial coccygeal passage, which began in 2007, showed its positive clinical effect, which is expressed in a decrease in the number of complications and relapses. The principle of the method is the thermal ablation of the walls of the coccygeal passage with laser radiation. The aim. To study the effect of high-intensity laser radiation on the tissues of pilonidal cyst in patients with epithelial coccygeal passage, in order to improve the results of their treatment. Materials and methods. The study was conducted from 2018 to 2021. The patients were divided into 2 groups depending on the type of surgical treatment. The first group consisted of 124 patients who underwent cyst excision with primary sutures. The second group included 60 patients who underwent laser-induced interstitial thermotherapy. To study microcirculatory changes in the tissues of the pilonidal cyst while doing operational injury, SPECTROTEST (Spectro Analytical Instruments, Germany) spectrometer was used. Results. We have revealed changes in microcirculation and tissue saturation parameters depending on the type of surgical treatment. In the first group, a statistically significant microcirculatory and tissue saturation disorders were found in the walls of postoperative wounds. In the second group, microcirculatory disorders were less pro-nounced, and their normalization occurred much earlier. This indicates the absence of ischemia of the surrounding tissues around the treated area. Temperatures in the walls of pilonidal cysts at laser-induced interstitial thermom-etry vary from 56 to 65 °C, which are the temperatures of destruction of proteins that make up the structure of the cyst walls. On the surface and in the tissues surrounding the cyst, the maximum recorded temperature was 40 °C, and this does not cause protein destruction. Conclusions. High-intensity laser radiation leads to obliteration of the cystic cavity, the formation of scar tissue, the elimination of specific symptoms and the decrease in the risk of recurrence of pilonidal disease, which is confirmed by spectroscopy, thermometry and histological studies.