Pit and rim formation on the acrylonitrile butadiene styrene (ABS) plastic surface was evaluated after it was irradiated by CO 2 and Nd:yttrium-aluminum-garnet (YAG) laser beams. Our results show that the thermal effect floor was well observed at the outer wall of the pit with CO 2 laser irradiation while it was not the case with Nd:YAG laser irradiation. The volume and depth of the pit formation increase proportionally with laser irradiation energy while there are significant differences in the slope, width, and full width at half maximum of the pit formation with two different types of laser irradiations. This result shows that CO 2 laser irradiation leads to a better cooling contraction effect while Nd:YAG laser irradiation induces a better recoil pressure effect during the interaction between ABS plastic and laser beam irradiation. The shape of the laser marking could vary significantly depending on the traveling path of molten plastic during injection molding of ABS plastic. Therefore, the selection of material and molding process can have a great impact on the laser micromachining of plastic. © 2005 Laser Institute of America.

We propose a novel application of optical coherence tomography (OCT) to monitor pit formation in laser irradiated optical storage materials. A multilayer optical storage recordable compact disk, is composed of multiple layers, each of different structure. Disks were irradiated with a Q-Switched Nd:YAG laser with an energy of 373 mJ. Post-irradiated disks were evaluated by OCT and those images were compared with optical microscopy. Our results indicate that OCT is a useful instrument to investigate pit formation in multilayer optical storage disks and might also provide information to optimize optical memory technology.

We demonstrate the use of optical coherence tomography (OCT) as a non-destructive diagnostic tool for evaluating laser-processing performance by imaging the features of a pit and a rim. A pit formed on a material at different laser-processing conditions is imaged using both a conventional scanning electron microscope (SEM) and OCT. Then using corresponding images, the geometrical characteristics of the pit are analyzed and compared. From the results, we could verify the feasibility and the potential of the application of OCT to the monitoring of the laser-processing performance.

In quantitative evaluation of facial skin chromophore content using color imaging, several factors such as view angle and facial curvature affect the accuracy of measured values. To determine the influence of view angle and facial curvature on the accuracy of quantitative image analysis, we acquire cross-polarized diffuse reflectance color images of a white-patched mannequin head model and human subjects while varying the angular position of the head with respect to the image acquisition system. With the mannequin head model, the coefficient of variance (CV) is determined to specify an optimal view angle resulting in a relatively uniform light distribution on the region of interest (ROI). Our results indicate that view angle and facial curvature influence the accuracy of the recorded color information and quantitative image analysis. Moreover, there exists an optimal view angle that minimizes the artifacts in color determination resulting from facial curvature. In a specific ROI, the CV is less in smaller regions than in larger regions, and in relatively flat regions. In clinical application, our results suggest that view angle affects the quantitative assessment of port wine stain (PWS) skin erythema, emphasizing the importance of using the optimal view angle to minimize artifacts caused by nonuniform light distribution on the ROI. From these results, we propose that optimal view angles can be identified using the mannequin head model to image specific regions of interest on the face of human subjects.

We suggest that Optical coherence tomography (OCT) is a potential imaging modality capable of assisting diagnosis in pulmonary medicines. OCT can provide extremely high resolution imaging and be performed with flexible fiber-optic bronchoscopy with small diameter endoscopic probes. In this study, animal models of trachea, and lung surface were to investigate utility of OCT in pulmonary. Normal, malignant, and infectious disease animal model samples measured by OCT were compared to standard histologic H&E light microscopic imaging of the same sites.