Analysis of second-harmonic conversion efficiency by type Ⅰ phase matching in uniaxial crystals

Coupled-wave equations and conversion efficient theory formulas for second harmonic plane wave of type Ⅰ phase matching in uniaxial crystals were obtained from wave equation of medium when second-harmonic wave absorption was taken into account. Based on the formulas, theoretical conversion efficiency formulas for second harmonic plane wave were gotten when second-harmonic wave walk-off effect was taken into account. Using type Ⅰ phase matching in uniaxial crystal K2Al2B2O7 (KABO) for example, conversion efficient of second harmonic plane wave was calculated according to the formulas. The result indicates that the optimum length of frequency doubling crystal was in existence when second-harmonic wave absorption was taken into account. The conversion efficient of second harmonic plane wave