光动力治疗仪是利用光动力疗法进行癌症治疗的一种新型医疗仪器。为了解决光动力治疗仪照射光色纯度不高的问题，引入光子晶体理论，采用传输矩阵法进行MATLAB编程分析光子晶体禁带特性，甄选合适的光子晶体材料，确定其结构参量。结果表明，所设计的新型光子晶体掺杂结构，对一定频率范围内的入射光，只允许对肝癌、胃癌等内脏器官癌症具有治疗效果的980nm的近红外光通过，具有良好的滤波特性。利用此特性可以制作光子晶体滤波器，将此滤波器应用到普通光动力治疗仪上，对癌症的治疗起到很大的作用。

Photodynamic therapy instrument is one of the new types of cancer treatment instruments by using photodynamic therapy. In order to solve the color purity problem of photodynamic irradiation treatment, photonic crystal theory was applied and transfer matrix method was used. The bandgap properties of photonic crystals were analyzed by MATLAB programming to select appropriate photonic crystal materials and to determine its structural parameters. The results show that, newly designed photonic crystal structure has good filtering characteristic, which allows only the pass-through of 980nm near infrared light, and has therapeutic effect on liver cancer, gastric cancer and other visceral organ cancers. Photonic crystal filters based on such structure can be applied to ordinary photodynamic therapy instruments and play the greater role in cancer treatment.