Continuum emission in Nd3+/Yb3+ co-doped Ca12Al14O33 phosphor: Charge transfer state luminescence versus induced optical heating

An unusual phenomenon of local heating and associated emission of continuum in lanthanide doped material has attracted much interest currently because of its use in white light generation and in localized heating. In the present work, Nd3+/Yb3+ co-doped Ca12Al14O33 phosphor has been synthesized, which gives broad continuum emission both by downconversion (DC) and upconversion (UC) processes. On 266 nm excitation, broad continuum emission is achieved through charge transfer state (CTS) luminescence of Yb3+ ion. On the other hand on 976 nm excitation, UC emission is observed from Nd3+ ion, which at higher pump power gives continuum emission.