laser pointer has the high power and big size

 laser pointer can be examined one by one.
The latter formula for where to record changes in the number of stripes through a fixed diffraction angle. Therefore, as long as the determination of ΔN will be able to obtain the displacement value of δ. This situation is similar to the stripe count of the interferometer. The gap method as a sensitive optical sensor can be used to change the determination of various physical quantities such as strain, pressure, temperature, flow, acceleration, etc.. Reflection diffraction measurements. The reflection diffraction is the edge of the measured object and the mirror constitutes the slit to the diffraction measurements, as shown in Figure 6-12, its principle. The optical path difference at the point P, the first level of dark stripes should meet. Where the angle between the incident parallel laser beams and mirrors, the diffraction angle connection and meet the angle between the law of reflection of the reflection light from the slit and the mirror intersection point P. It is the same for laser pointer .laser pointer has the high power and big size
Performance of anti-yaw and pitch, you can eliminate the error caused by deflection, is a commonly used device in the interferometer. Right angle prism reflector (Figure 6-2b) only two reflecting surfaces, processing up relatively easy and only sensitive to a direction of deflection. Lens and mirror cat's eye reflector (Figure 6-2c) by a lens L and a concave mirror M components, mirror on the lens at the focus, if the mirror center of curvature C 'coincide with the lens optical center C, when mirror with rotation around the C, the optical path remains unchanged. The cat's eye reflector advantage of easy processing and does not affect the transmission of polarized light, and when can the optical path is not too long with a flat mirror instead of the concave mirror, easier processing and adjustment. It is the strict sampling inspection standard of laser pointer .
Airy measurements. Called Airy measurements based on the measurement of the hole Fraunhofer diffraction. Usually owned by one of the light intensity measurement of the size of the Airy to determine the measured hole diameter. Figure 6-15 is a schematic Airy spinneret aperture measured in man-made fibers or glass fiber processing. Measuring instruments and measured for relative motion, to ensure that each hole sequentially through the laser beam. Usually different from the spinneret, the pore diameter of about 10-90μm range within. Issued by the laser a laser beam irradiation to the measured hole through the hole after the diffracted beam by the beam splitter 3 is divided into two parts, respectively, exposure to the optical receiver 5 and 7.