Here, we investigate a method to distinguish the counterfeits by patterning multiple reflective type grating directly on the surface of the original product and analyze the serial number from its rotation angles of diffracted fringes. The micro-sized gratings were fabricated on the surface of the material at high speeds by illuminating the interference fringe generated by passing a high-energy pulse laser through the Fresnel biprism. In addition, analysis of the grating's diffraction fringes was performed using a continuous wave laser.

Previous research presented the structured illumination confocal scanning microscope (SICSM) so as to improve the lateral resolution of the confocal microscope. However, the image acquisition speed of the SICSM is very slow and also an alignment error due to the mechanical rotation of a grating and a slit can easily occur. As a theoretical study, in this paper we propose a new SI method, the cross SI method, which improves lateral resolution and image acquisition speed. Performances of the conventional SI and the proposed SI methods are compared by analysis of the modulation transfer function. The proposed SI method shows similar lateral resolution and can shorten the image acquisition time compared to the conventional SI method. The cross structured illumination confocal microscope (CSICM) is combined with the cross SI pattern optics and the line scanning confocal microscope. We have introduced a 2-D diffractive grating, four linear polarizers and four cylindrical lenses in order to create the cross SI pattern. The effects of the cross SI pattern, intensity and visibility, on the system performance are analyzed. The CSICM has double the lateral resolution of the conventional microscope, an optical sectioning ability and a fast image acquisition speed.

We describe a new approach for locating the focal position in laser micromachining. This approach is based on a feedback system that uses a charge-coupled device (CCD) camera, a beam splitter, and a mirror to focus a laser beam on the surface of a work piece. We tested the proposed method for locating the focal position by using Zemax simulations, as well as physically carrying out drilling processes. Compared with conventional methods, this approach is advantageous because: the implementation is simple, the specimen can easily be positioned at the focal position, and the dynamically adjustable scan amplitude and the CCD camera can be used to monitor the laser beam’s profile. The proposed technique will be particularly useful for locating the focal position on any surface in laser micromachining.

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In this paper, we propose new SI method, the cross SI method that improves the lateral resolution and the image acquisition speed. The cross SI pattern is generated by using the 2-D diffractive grating. The acquisition of a total of 6 raw images shortens the image acquisition time. The cross structured illumination confocal microscope (CSICM) is combined with the cross SI pattern generation optics and the line scanning confocal microscope. Performances of the conventional and the cross SI are compared by the analysis of the modulation transfer function. As a result, the cross SI method shows similar resolution to conventional SI method. The CSICM has the two times enhanced lateral resolution than the conventional microscope, the optical sectioning ability and the fast image acquisition speed.