Diode lasers are coupled to a multi-mode fiber (with 100-400 μm core) using a reflector in the form of a regular pyramid. The optimization of the optical setup allows to couple 60%-90% of light into the fiber. The demonstrator achieves 3.5 W in the 100/125 μm fiber with 8 violet (405 nm) diodes, 5.5 W in the 100/125 μm fiber with 8 blue (445 nm) diodes, and 3.3 W in the 200/250 μm fiber with red (638 nm) diodes. The device can work with lasers emitting at many different wavelengths, including green (532 nm) frequency-doubled lasers. Our work was motivated by potential medical applications of these laser sources.

Light emitting diode structures with InGaN quantum wells have been studied as a function of hydrostatic and uniaxial pressure (along the c-axis) under different values of reverse voltage. Photocurrent measurements (with light parallel to the epitaxial layers) allow determining energies in transverse electric (TE) and transverse magnetic (TM) polarizations, which we attribute to transitions from the heavy-hole (HH) and crystal-field split (CH) band to the conduction band. The comparison of theory and experiment suggests that the electric fields are about 25% lower than the calculated values. The transitions in TE polarization agree with the theoretical predictions, while those in TM polarization do not. In particular, the splittings between HH and CH bands are lower than the theoretical predictions.

This study aimed to test a blue light source for the treatment of port wine stains (PWS) and telangiectasia and to compare this with the application of green and yellow lasers based on data in the literature. A total of 22 patients with PWS were treated with radiation from a novel, high-power 450 nm blue laser that was created for this project. The group contained 15 patients with red PWS and 7 with pink PWS. The best results were achieved for red PWS, using 15–20 ms light pulses and 47 W power. For patients with pink malformations, the results were unsatisfactory. The group with telangiectasia consisted of six patients with facial lesions and three with leg lesions. The recovery was completed for all patients with facial telangiectasia, while the blue laser therapy was ineffective for patients with leg telangiectasia. This study shows that, in some cases, the use of a blue laser may be an alternative to the use of green and yellow lasers.