We report on results of design and fabrication of a microfluidic dye laser that consists of a ring resonator, a waveguide for laser emission output, and microfluidic elements for flow control, all integrated on a chip. The optical resonator and the waveguide were obtained by photolithography, whereas microfluidic elements such as channels, valves, and pumps were fabricated by multilayer soft lithography. As results, the prototype device worked with a few nanoliters of Rhodamine 6G dye molecules in ethanol solution and showed a laser threshold of ∼15μJ∕mm2 when optically pumped with a frequency doubled Nd:YAG laser at 532nm wavelength. The modification of the laser output intensity due to photobleaching effect was characterized by changing the dye flow velocity through the cavity. In addition, the emission wavelength of the laser could be easily tuned by changing the dye molecule concentration with the integrated microfluidic elements.

Low-level laser therapy (LLLT) has proved to have biostimulating effects on tissues over which they are applied, therefore accelerating the healing process. Most studies in implantology were focused on a reduction of the duration of osseointegration. There exist few articles analyzing the potential effects of these therapies on the osseointegration of titanium dental implants. The aim of this study was to assess the effect of LLLT on the interaction between the bone and the titanium dental implant and the methodological quality of the studies. We conducted an electronic search in PubMed, ISI Web, and Cochrane Library. From 37 references obtained, only 14 articles met the inclusion criteria. The analysis of the studies shows that most of the experiments were performed in animals, which have a high risk of bias from the methodological point of view. Only two studies were conducted in human bone under different conditions. Several protocols for the use of low-power laser and different types of laser for all studies analyzed were used. Although animal studies have shown a positive effect on osseointegration of titanium implants, it can be concluded that it is necessary to improve and define a unique protocol to offer a more conclusive result by meta-analysis.

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In order to determine the angular geometry that satisfies quasi-phase matching conditions for enhanced second-harmonic generation (SHG), the equi-frequency surfaces of the resonant photonic modes (that lie above the light line) of a one-dimensional GaN photonic crystal have been experimentally and theoretically studied as a function of frequency, angle of incidence, and azimuthal direction. Enhancement of the SHG has been observed when the angular configuration satisfies the quasi-phase matching conditions, i.e., when both the fundamental and second-harmonic fields coincide with resonant modes of the photonic crystal. The SHG enhancement achieved to the double resonance was 5000 times with respect to the unpatterned GaN layer. A smaller, but still substantially enhanced SHG level was also observed when the fundamental field is coupled into a resonant mode, while the second-harmonic field is not