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Successful treatment of ephelides in Asian skin using the picosecond 785‐nm laser
摘要： Background: For ethnic skin, laser surgery for pigmented lesions presents a special challenge due to the increased risk of postprocedural complications—erythema, blistering, and postinflammatory dyspigmentation. Aims: To describe the treatment of ephelides in Asian skin treated with a picosecond 785-nm laser. Patients/Methods: The first patient with ephelides on the cheeks and nose was treated with a picosecond 785-nm laser with the treatment parameter of 1.2 J/cm2 and 3-mm spot size. The second patient with ephelides on the cheeks was treated with a picosecond 785-nm laser with the treatment parameter of 1.3 J/cm2 and 3-mm spot size. Results: After a single laser session, both patients achieved appreciable improvement without any complications. Conclusion: This is the first case series demonstrating the efficacy and safety of the picosecond 785-nm laser for the treatment of ephelides in Asian skin.
关键词： ephelides,785-nm,Asian,picosecond,freckle
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Dual-Wavelength Y-Branch DBR-RW Diode Laser at 785 nm with Adjustable Spectral Distance from 0 up to 1.6 nm
摘要： For several applications compact light sources are requested providing two stabilised wavelengths with a narrow linewidth. Applications are shifted excitation Raman difference spectroscopy (SERDS) which separates the Raman lines from disturbing background signals such as ambient daylight or fluorescence or concentration measurements using absorption spectroscopy. Moreover, two slightly different wavelengths are needed for the difference frequency generation into THz radiation. Beside the narrowing and stabilization of the emission wavelength using an internal grating, heater elements above the implemented grating can be used to adjust the spectral distance to meet the demands for the above-mentioned applications. In this contribution, dual-wavelength Y-branch DBR-RW diode lasers emitting at 785 nm with on-chip implemented resistor heaters close to the DBR gratings similar to [1] will be presented. In contrast to the already presented work the heaters are controlled individually and thus the emission wavelength of each laser cavity can be tuned via temperature for each DBR grating separately. This enables the device to provide a flexible spectral distance of the two emission wavelengths in common laser operation of both cavities and fast alteration between both laser lines as recently demonstrated in [2]. The total length of the devices is 3 mm. Two 500 μm long 10th order passive DBR gratings, a 2 mm long S-bend shaped Y-branch coupler section and a 500 μm RW output section form the two laser resonators. The on-chip resistor heater elements are separately controllable as well the two S-bend shaped RW branches and the output RW section. The grating periods are chosen to generate two slightly different emission wavelengths with a spectral distance of 0.6 nm, i.e. 10 cm-1, suitable for SERDS. After a description of the device, electro-optical and spectral properties will be discussed with respect to the above- mentioned applications. In Fig. 1 the power-current characteristic for such dual-wavelength diode lasers is shown. Here the current IY in the Y-coupler was 0 mA, the current Iout in the RW output section was 35 mA and the heatsink temperature is 25°C. Lasing starts for both cavities at about 30 mA with a slope efficiency of 0.6 W/A. An optical output power of more than 200 mW was measured at an injection current of 400 mA. For an output power of 100 mW the spectral tuning with the individual heater elements is shown in Fig. 2 and Fig 3. Here, a flexible spectral range between 0 and 1.6 nm can be obtained while the emission of both branches shows single mode operation with a narrow bandwidth below 11 pm.
关键词： adjustable spectral distance,dual-wavelength,785 nm,Y-branch DBR-RW diode laser,absorption spectroscopy,THz radiation,SERDS
更新于2025-09-12 10:27:22