Progress in the study of PPKTP crystal preparation and its application in quantum field

The need for high-performance optoelectronic functional materials has increased in recent years due to the expansion of the optoelectronic information sector. Potassium Titanium Oxygen Phosphate (KTiOPO₄,KTP) is internationally recognized as a material with excellent comprehensive optoelectronic performance. After periodic polarization, KTiOPO₄(PPKTP) can produce laser and entangled photon outputs of any wavelength within the crystal transmittance range using quasi-phase matching (QPM) technology, making it an ideal material for generating entangled photons for efficient frequency conversion and quantum communication. Its applications include laser manufacturing, quantum communication, electro-optical modulators, and optical waveguide devices. In this paper, the preparation of PPKTP crystal materials, the current status of development at home and abroad, and the applications in the quantum field are reviewed, and some challenges encountered in the preparation of the current hydrothermal PPKTP are also highlighted, and in future related research, the solution of these challenges is of great significance to improve the quality of the polarization reversal of the PPKTP and to promote the device's wider application.