Publications by authors named "David Welford"
Article Synopsis
- A recent study explored the effectiveness of a new 5,500 nm wavelength carbon monoxide (CO) laser for medical applications, noting its higher optical penetration and potential benefits for tissue treatments compared to traditional CO lasers and thulium fiber lasers.
- The research involved testing various laser systems on ex vivo human skin samples to analyze their ablation and coagulation abilities under similar exposure conditions.
- Results indicated that the CO laser achieved significantly deeper ablation compared to the CO laser, suggesting its potential for advanced skin resurfacing and other medical uses.
Background: Traditionally, fractional laser treatments are performed with focused laser sources operating at a fixed wavelength. Using a tunable laser in the mid-infrared wavelength range, wavelength-dependent absorption properties on the ablation process and thermal damage formation were assessed with the goal to obtain customizable tissue ablations to provide guidance in finding optimized laser exposure parameters for clinical applications.
Methods: Laser tissue experiments were carried out on full thickness ex vivo human abdominal skin using a mid-infrared tunable chromium-doped zinc selenide/sulfide chalcogenide laser.
Article Synopsis
- Fractional Photothermolysis (FP) creates tiny columns of thermal damage in the skin using focused laser beams, but deviation from the focal plane can lead to larger damage spots and inconsistent treatment outcomes.
- The study aimed to determine how variations in distance from the focal plane affect the depth and diameter of laser-induced skin lesions using an ablative fractional laser on human skin samples.
- Results showed that distance variations significantly impacted the lesion size, confirming the importance of maintaining the correct distance during FP treatments.
Unabsorbed pump light in passively Q-switched microlasers leads to suboptimal pulse generation by bleaching the saturable absorber. This mechanism increases the effective unsaturated transmission of the absorber, which leads to a change in the system dynamics that results in increased pulse durations and decreased pulse energies. We report experimental evidence of pump-induced bleaching of the saturable absorber, an increase in the pulse duration from 360 to 880 ps, and develop a simple analytical treatment that includes this effect within the framework of existing passive Q-switching models.
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