Upconversion spectra of Nd:GdVO₄ crystal under CW 808 nm diode-laser pumping

Higher order processes that produced visible fluorescence observed in Nd:GdVO₄ laser crystals pumped by 808 nm diode-laser were studied in the spectroscopic measurements. These processes were the energy transfer upconversion and the excited state absorption. The green, orange and the red emissions can be attributed to the transitions from the ⁴G_7/2 excited state, which is populated by the ETU, the UV and blue emissions can be attributed to the ESA. The upconversion spectra indicate that ETU and ESA process seem to be responsible for the observed visible luminescence. A graph is presented.