Accurate measurement of grating period of periodically poled crystal by using broad band chirp pulse second harmonic generation

According to quasi-phase matching relationship between the second harmonic center wavelength and the grating period length of periodically poled crystal, a new experimental method to measure the grating period of periodically poled crystal accurately was presented by using broad band chirp pulse second harmonic generation technique. The relationships between the second harmonic center wavelength and the grating period, the spectra bandwidth and the crystal length were analyzed theoretically. The grating period of PPKTP crystal with the size of 10 mm×7 mm×1 mm was measured experimentally. The results show that the real grating period is 9 303.9 nm depending on the second harmonic central wavelength of 537.25 nm, while the theoretical one is 9 300 nm. The method advances the measurement p