Fig. 1. Diagram of beam propagation in micro-lens system

Fig. 2. Diagram of tilted beam propagation in micro-lens system

Fig. 3. Frequency spectra distributions of diffraction images. (a) Positive incident; (b) incident angle of 5°

Fig. 4. Distributions of diffraction optical field under the condition of different detection distances. (a) L=0.2 m; (b) L=0.7 m; (c) L=2.0 m; (d) L=3.0 m

Fig. 5. Distributions of diffraction optical field under the condition of different incident angles. (a) θ=0°; (b) θ=1°; (c) θ=2°; (d) θ=3°; (e) θ=4°; (f) θ=5°

Fig. 6. Distributions of diffraction optical field under the condition of different diaphragm diameters. (a) D=0.8 mm; (b) D=1.2 mm; (c) D=2.0 mm; (d) D=2.8 mm

Fig. 7. Variations of light intensity with incident angle under the condition of different diaphragm diameters

Fig. 8. Experimental setup of active laser detection

Fig. 9. Diffraction patterns under the condition of different detection distances. (a) L=0.2 m; (b) L=0.7 m; (c) L=2.0 m; (d) L=3.0 m

Fig. 10. Diffraction patterns under the condition of different incident angles. (a) θ=0°; (b) θ=1°; (c) θ=2°; (d) θ=3°; (e) θ=4°; (f) θ=5°