Multiphoton absorption in europium(III) doped YVO4 nanoparticles

We report the synthesis and physicochemical characterization of YVO4 nanocrystals doped with Eu3+ ions. The adopted solvothermal synthesis procedure rendered YVO4 nanoparticles with tetragonal crystal structure and rod-like morphology. The absorption and excitation spectra of the studied nanoparticles showed UV bands which were attributed to the 1A1 → 1T2 and 1A1 → 1T1 electronic transitions in the vanadate group, respectively. The nonlinear optical properties of both undoped YVO4 nanocrystals and those doped with Eu3+ ions were studied by wide wavelength range (600–1600 nm) femtosecond Z-scan measurements. The experiments revealed strong multiphoton absorption in the wavelengths around 650 and 1300 nm, within the first and second biological window. This nonlinear absorption results in multiphoton excitation of red europium emission from the nanoparticles, making them potential candidates for application as markers in nonlinear microscopy imaging techniques.