conclusions caffeic acid treatment reduced bacterial growth and resulted in a decreased number of colony formation. the simultaneous effect of caffeic acid and laser at three time courses showed a synergic effect in reducing colony formation compared to the control and caffeic acid, and laser alone. objectives the aim of this study was to investigate the effect of caffeic acid and low-power las...

A laser produces electromagnetic radiation which is both spatially coherent and of narrow spectral width via a mechanism known as Light Amplification by Stimulated Emission of Radiation. The first working laser was developed in 1960 by Theodore Maiman at Hughes Research Laboratories. Since then laser technology has proliferated, with uses in industry, medicine, research, military and law enforc...

Second harmonic generation (SHG) obtained using a potassium dihydrogen phosphate (KDP) nonlinear crystal from a CW He–Ne laser as a pump source, which emits at 632.8 nm, is reported. The SHG efficiency at the power of the He–Ne laser utilized (18 mW) and the fundamental beam waist available (0.1 mm), was evaluated theoretically; the same efficiency was measured experimentally obtaining a value ...

We have observed kilohertz and sub-kilohertz resonance structures in RF-optical double resonance experiments of rare-earth-doped solids, when the frequency of the RF ® eld is scanned across the hyper® ne transitions while monitoring the resonant optical absorption of a CW laser. The eå ect is observed only when the laser spectral width is broad compared to the hyper® ne structure. The observed ...

In this paper we report our investigations on the frequency stabilization and frequency measurements of 543 nm HeNe laser. It contains following four di€erent works. (1) Using a metal laser tube we have built an iodine-stabilized 543 nm HeNe laser by the Frequency-Modulation (FM) spectroscopy. The signal-to-noise ratio of the hyper®ne spectrum reached 2 ́ 10 at 1 s sampling time. (2) We have bu...

Under general anesthesia and sterile conditions, incision wound was induced in the hard palate mucosa of adult male mice. The wounds of groups 1 and 2 were irradiated daily with He-Ne laser at 3 and 7.5 J/cm2 for 120 and 300 s, respectively, while the incision wound of group 3 not exposed served as controls. On day 3 of injury, the laser-treated wounds contained significantly lower neutrophils ...

This paper presents the calculation of amplitude and relative phase of signals at the three outputs available in a self-mixing interferometer, i.e. the front output on the target side, the back output on the rear of the chip, and, for diode laser, the junction voltage output. Front and rear outputs are observed to be in phase for the He-Ne laser while they are in phase opposition in the diode l...

A new heterodyne nano-displacement with error reduction is presented. The main errors affecting the displacement accuracy of the nano-displacement measurement system including intermodulation distortion error, cross-talk error, cross-polarization error and phase detection error are calculated. In the designed system, a He-Ne laser having three-longitudinal-mode is considered as the stabiliz...