1. Introduction . Laser technology has been developing rapidly in the fields of light-matter interaction, precision measurement and sensing, quantum information, biophotonics [ 1 – 8 ], etc. However, the wavelength of a laser is limited by the energy level structure of the gain medium. Nonlinear optical frequency conversion techniques were usually adopted to expand laser spectra and even prepare quantum states for wider applications. Quasi-phase-matching is a widely used nonlinear f...