Fig. 1. (a) Diagrams of SHG generated by incident and reflected fundamental waves. (b) The triangle phase-matching type of the SHG spot. (c) The photographs of SHG with different fundamental wavelengths (1180 nm, 1200 nm, 1220 nm, 1240 nm, and 1260 nm).

Fig. 2. (a) Experiment setup. (b) Comparison of the refractive index of an extraordinary-polarized second harmonic beam and that of an ordinary-polarized fundamental beam in a lithium niobate crystal.

Fig. 3. (a) The measured energy of SHG with the relationship of angles (fundamental wavelength of 1200 nm) and the energy changing process. (b) The measured energy of SHG with the relationship of angles (fundamental wavelength of 1240 nm) and energy changing process. (c) The measured energy of SHG with the relationship of angles (fundamental wavelength of 1280 nm) and energy changing process. (d) The measured energy of SHG with the relationship of angles (fundamental wavelength of 1300 nm) and energy changing process.

Fig. 4. (a) The measured energy of SHG with the relationship of temperature (fundamental wavelength of 1200 nm) and the energy changing process. (b) The measured energy of SHG with the relationship of temperature (fundamental wavelength of 1240 nm) and the energy changing process. (c) The measured energy of SHG with the relationship of temperature (fundamental wavelength of 1280 nm) and the changing process of energy. (d) The measured energy of SHG with the relationship of temperature (fundamental wavelength of 1300 nm) and the energy changing process.