Biphoton holographic storage in Methyl Orange and Ethyl Orange dyes

Abstract
Biphoton holograms are recorded by a He–Ne laser in Methyl Orange and Ethyl Orange dyes on exposure to 514.5-nm argon-ion laser, and the dynamic of holographic recording is reported. The recording utilizes an unusual photochemistry that is due to either to a triplet–triplet transition from a long-lived triplet lower state of the cis configuration or a transition back to the trans state.