Power dependent photoacoustic and photoluminescence studies on a Ho<sup>3+</sup>/Yb<sup>3+</sup> doped Y<sub>2</sub>O<sub>3</sub> phosphor
Minarul I. Sarkar, Kaushal Kumar
Abstract
transition and found that lifetime values follow the trend of upconversion intensity. The maximum lifetime of 224 μs is observed for the sample annealed at 1000 °C. A photoacoustic cell & a pre-amplifier was fabricated and optimized for maximum sensitivity of the system. The PA signal was found to increase with increase of excitation power within the studied range, while UC emission was found to saturate after a certain pump power. The increase in PA signal is due to the increase in non-radiative transitions in the sample. The wavelength-dependent photoacoustic spectrum of sample has shown absorption bands around 445, 536, 649 and 945 (970) nm with maximum absorption at 945 (970) nm. This indicates its potential for photo-thermal therapy using infrared excitation.