Abstract: From nonlinear optics theory, type Ⅱ frequency-doubling walk-off angle and interaction length of LBO crystal whose fundamental frequency wavelength is at 1064 nm were respectively calculated with numerical method . In the range of whole phase-matching angle, the angle range between the slow and the fast lights of 1064 nm is 0~1.0°. θ≈0°,φ≈90°, the angle is 0°;θ≈45°,φ≈55°, the maximum angle is approximately 1.0°. When the light-spot dimensions of slow and the fast lights are the same and wave vector incidents along the direction (θ≈0°,φ≈88°), the interactional length is the maximum.

Key words: From nonlinear optics theory, type Ⅱ frequency-doubling walk-off angle and interaction length of LBO crystal whose fundamental frequency wavelength is at 1064 nm were respectively calculated with numerical method . In the range of whole phase-matching angle, the angle range between the slow and the fast lights of 1064 nm is 0~1.0°. θ≈0°,φ≈90°, the angle is 0°;θ≈45°,φ≈55°, the maximum angle is approximately 1.0°. When the light-spot dimensions of slow and the fast lights are the same and wave vector incidents along the direction (θ≈0°,φ≈88°), the interactional length is the maximum.