Robuta

https://experts.arizona.edu/en/publications/room-temperature-spectral-hole-burning-and-elimination-of-photoda/ Room temperature spectral hole burning and elimination of photodarkening in sol-gel derived CdS... https://eprints.soton.ac.uk/340639/ Ytterbium doped nano-crystalline optical fiber for reduced photodarkening - ePrints Soton optical fiber ytterbium nano crystalline