Effect Of Laser Diode Research Articles

Combination effect of laser diode for photodynamic therapy with doxycycline on a wistar rat model of periodontitis

BackgroundPeriodontitis is a chronic inflammatory disease characterized by progressive damage on the structure of tooth-supporting tissues. The aim of the study is determining the combination photodynamic effect of diode laser 405 nm treatments and the administration of doxycycline 0.1% within 1, 3, 5, and 7 days on a Wistar rat model of periodontitis.MethodsSamples were induced with Porphyromonas gingivalis ATCC33277 to allow periodontitis development and were treated with combination of doxycycline and laser diode, then statistical analysis was carried out (One-Way ANOVA test and the post-hoc Duncan test; Kruskal–Wallis test and Mann–Whitney follow-up test for non-parametric data). Samples were divided into five groups, laser exposure used was 405-nm diode laser with energy density of 8 J/cm2. The expression level of histomorphometric was calculated by measuring the number of macrophages, lymphocytes, fibroblasts and the distance between the CEJ-AV.ResultsThe results showed that the combination treatment of doxycycline and laser exposure yielded immunomodulatory effects. The expression level of fibroblast and the distance between CEJ-AV bone showed that the combination of doxycycline and laser therapy exerted healing effect in rat models of periodontitis on day 5 and 7.ConclusionThe combination of doxycycline 0.1% and diode laser therapy provides a healing effect in rats models of periodontitis.

Temperature distribution in GaAs lasers with diamond film heatsink

Thermal effects in laser diodes can strongly influence their performance. The Letter describes the thermal analysis of a double-heterostructure laser diode for a range of heatsink combinations. The effects of indium solder thickness and the incorporation of a thin film of diamond are illustrated for both transient and steady state cases.

Non-contact optical probing sensor — applying optical feedback effects in laser diodes

The possibility of a non-contact optical distance/displacement sensor, making use of optical intensity variations caused by optical feedback effects in laser diodes, was investigated. A compact sensor system and a simple signal processing technique were proposed to realise the sensor system. The experimental results indicated that the resolutions were of sub-mm order in distance measurements and about 40 nm in displacement measurements. The allowable maximum speed of displacement can be improved up to several cm/s. The influence of temperature variation on the measurement accuracy was discussed and the advanced sensing technique utilising a synthetic wavelength of laser diodes was proposed. These methods are applicable even to an object with rough surfaces.

Surface effects in laser diodes

Changes in the current-voltage characteristics below the threshold current were observed in gain-guided stripe laser diodes after preliminary lasing. This effect was not fully understood. Similar changes in the laser characteristics appeared as a result of etching in a gaseous medium. The observed changes were attributed tentatively to surface currents.