GB/T 44538-2024 specifies the technical requirements for the determination of Optical Properties of amorphous carbon-based films by elliptical Light spectrum method. The standard specifies the measurement range, test principle, sample prepative, test flow and data processing methods, which are suitable for the detection and evaluation of Optical Properties of related films. It can provide a unified technical basis for the research and development, production quality control and application selection of carbon-based films to ensure product performance conformity.