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A Study of the Optical and Acoustic Spectral Characteristics by Laser Breakdown of Water in an Ultrasonic Field
摘要： A strong dependence of the optical breakdown in a liquid in the ultrasonic field on the amplitude and frequency of ultrasound is demonstrated. The increase in the intensity of spectral lines of potassium and oxygen during the optical breakdown is detected by the increase in the amplitude and frequency of ultrasound. At the same time, the effect of saturation is observed at high frequencies (above 200 kHz) and for high ultrasonic powers, when the growth in the intensity of spectral lines slows sharply down. This shows that there is no necessity to use high powers and frequencies of ultrasound to study the opto-acoustic effects during optical breakdown in a liquid.
关键词： ultrasound,spectral lines,optical breakdown,laser-spark spectroscopy,opto-acoustic effects
更新于2025-09-23 15:21:01
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A Randomized, Splita??Face, Doublea??Blind Comparison Trial Between Fractionated Frequencya??Doubled 1064/532a??nm Picosecond Nd:YAG Laser and Fractionated 1927a??nm Thulium Fiber Laser for Facial Photorejuvenation
摘要： Fractionated lasers are a popular therapeutic option for facial photorejuvenation. In this study, we compare the safety, tolerability, and efficacy of a fractionated frequency‐doubled 1064/532 nm picosecond Nd:YAG fractionated picosecond laser (FPL) versus a fractionated 1927 nm thulium fiber laser (TFL) for facial rejuvenation. This was a double‐blind, randomized, split‐face comparison study involving 20 subjects. Facial halves were randomized to receive either FPL or TFL treatment. Three treatments were delivered at 1‐month intervals. Subjects were followed up for 1, 3, and 6 months post‐final treatment session and evaluated by blinded, non‐treating investigators for dyspigmentation, erythema, keratosis, texture, and rhytids on a standardized scale. Subjects also recorded a quantitative daily diary rating healing progress for 14 days after every treatment session. Statistically significant improvements in elastosis, erythema, keratosis, dyschromia, and skin texture were noted in both treatment groups. There were no significant differences detected in clinical efficacy between the two groups. Subject daily diaries revealed statistically significant differences in tolerability during the immediate 14‐day post‐operative recovery period. The facial half treated with FPL displayed significantly less redness on days 3 and 4; significantly less swelling on day 5; significantly less crusting on days 1 through 9; significantly less peeling on days 3 through 9; and significantly less itch on days 4 and 7. There were no unexpected adverse effects observed. Both FPL and TFL are safe and effective treatment options for facial rejuvenation. FPL may be associated with significantly less downtime.
关键词： photodamage,laser induced optical breakdown,photothermolysis,thulium fiber,picosecond laser,photoacoustolysis,Nd:YAG,holographic lens,clinical trial,rejuvenation
更新于2025-09-19 17:13:59
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STUDY OF PROPERTIES OF LASER-INDUCED PLASMA CHANNELS FODMED BY FEMTOSECOND LASER RADIATION
摘要： Laser-induced plasma channels (LIPC) formed during the interaction of ultrashort laser pulses with argon are studied. LIPC characteristics are studied at various pressures.
关键词： laser-induced plasma channel,electron concentration,electron temperature,optical breakdown
更新于2025-09-19 17:13:59
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Electrical Parameters of a Laser Beam Channel in the Atmosphere. II
摘要： Results of measurements of the conductivity and electric field strength in the laser radiation propagation channel and near it are presented. An experimental setup and measurement scheme are described. The data have been obtained in the prebreakdown regime. The dependences of the laser-induced field strength on the laser radiation power and the optical characteristics of the propagation channel are investigated. The feasibility of ionization channel diagnostics using the electro-optical effects in the atmosphere is shown.
关键词： laser radiation,propagation channel,electrical parameters,optical breakdown
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen, China (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Research on the Characteristics of Optoacoustic Signal Induced by Optical Breakdown
摘要： Optical breakdown is a mechanism of Laser-generated sound effect, based on the theory of optical breakdown mechanism in this paper, Characteristics of the photo-acoustic signal of the optical breakdown are studied through experimental, including the excitation threshold and the photoacoustic signal, Domain and frequency domain characteristics and characteristics of acoustic signals as a function of laser pulse energy. Study on the relationship between photoacoustic signal and laser source may serve for further study on laser-generated sound and underwater applications.
关键词： optical breakdown,laser-generated sound,plasma,breakdown threshold
更新于2025-09-10 09:29:36