I watched the video. But there it is not mentioned about how to write the .mat file and what are the information need to be there. Like as I want to include the time parameter here, like whenever the laser of light source falls on it, some charge carriers will be generated inside the material. So in this .mat file the contained information would be the creation time of the source and will last for a certain time. Please suggest some .mat files so I can modify them accordingly. Thank you.