আলোকীয় পাম্পিংআলোকীয় বৰ্ণালীমেতা
আলোকীয় পৃষ্ঠ (Assamese)
1. An optical flat is an optical-grade piece of glass lapped and polished to be extremely flat on one or both sides, usually within a few tens of nanometres (billionths of a metre). They are used with a monochromatic... from wikipedia.org