Our VK group: https://vk.com/scimfiz
Basic formulas in the optics section: https://infotables.ru/fizika/92-osnov...
You can also find additional information on the following topics:
Interference - https://ege-study.ru/ru/ege/materialy...
Diffraction - https://ege-study.ru/ru/ege/materialy...
Dispersion - http://light-fizika.ru/index.php/11-k...
Light absorption - https://spravochnick.ru/fizika/optika...