Phototherapy, photodynamic therapy and lasers in the treatment of acne

Acne - therapeutic challenges to the cooperation between a dermatologist and a cosmetologist

Acne vulgaris is one of the most common skin diseases in adolescence, causing a significant negative impact on the quality of life of young people who - in a large percentage of cases - do not accept their appearance. The complex pathogenesis of this disease requires appropriate preventive and curative treatment from both a dermatologist and a cosmetologist. The aim of the study was to discuss the methods currently used by dermatologists in local therapy for mild and intermediate forms of acne vulgaris, and to provide an overview of possible preventive and caring activities in the cosmetologist's office. Possible directions of cooperation between the dermatologist and the cosmetologist in the prevention of acne relapse and treatment of possible acne complications were also discussed.

YVO4 cascaded Raman laser for five-visible-wavelength switchable emission

We report switchable emission of visible light at five wavelengths generated in a $\text{YVO}_4$YVO₄ cascaded Raman cavity driven by an acousto-optic ${Q}$Q-switched Nd:YAP laser at 1080 nm. The second-harmonic generation and sum-frequency generation of the fundamental, first-Stokes, and second-Stokes waves were realized based on the angle-tuned BBO crystal. The phase-match angle tuning span of a BBO crystal is only approximately 2.3° to allow the frequency mixing to produce five visible wavelengths on demand. At an absorbed pump power of 5.96 W and a pulse repetition frequency of 10 kHz, average output powers of 800, 340, 460, 190, and 326 mW were obtained for 539.9, 567.2, 597.4, 631.0, and 668.5 nm lasers, respectively. The results show that the cascaded Raman laser system with an angle-tuned BBO crystal can provide a convenient and efficient method to achieve wavelength-switchable visible emission for multi-wavelength laser applications.