Fig. 1. Schematic diagram of grating diffraction laser alarm

Fig. 2. Schematic diagram of diffraction

Fig. 3. Optical system in laser alarm

Fig. 4. Area-array detector used by system and some of its parameters

Fig. 5. Diffraction spot and its three-dimensional gray distribution diagram

Fig. 6. Experimental installation

Fig. 7. Diffraction spot pattern of different wavelengths

Fig. 8. Fitting plane diagram of laser angle and center of 0-level spot

Fig. 9. Error of fitting plane and calibration image