Tunable nonlinear absorption and optical limiting behavior of NaBi(MoxW1-xO4)2 single crystals with ratio of Molybdenum/Tungsten

Pepe, Yasemin
Yıldız, Elif Akhüseyin
Işık, Mehmet
Karatay, Ahmet
Gasanly, Nizami Mamed
Elmali, Ayhan
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Physica Scripta
The compositional effect of Mo/W ratio on linear, nonlinear absorption and optical limiting behavior of the NaBi(MoxW1-xO4)2 single crystals grown by Czochralski technique was investigated. X-ray diffraction patterns of the studied crystals presented well-defined peaks associated with the tetragonal crystalline structure. The nonlinear absorption performance and optical limiting threshold were determined using an open-aperture Z-scan technique. A theoretical model including one photon absorption (OPA), two photon absorption (TPA) and free carrier absorption was used to determine the nonlinear absorption parameters. All of the results showed that defect states, which strongly affect nonlinear absorption (NA) and optical limiting behaviors, can be tuned with the Mo/W ratio, enabling NaBi(MoxW1-xO4)2 single crystals to be used in desired optoelectronic applications. Linear optical absorption analysis revealed that bandgap energy and defect states can be tuned by changing the Mo/W ratio in the crystal structure. The obtained results showed that all the studied crystals had NA behavior and the nonlinear absorption coefficient decreased with increasing Mo/W ratio. Sequential TPA is the main NA mechanism for these crystals due to the fact that the incident light energy is lower than the bandgap energies and the existence of the real intermediate state around 2.32 eV.
Open Access, Published by Physica Scripta, https://doi.org/10.1088/1402-4896/acdb03, Y. Pepe, E. A. Yildiz, A. Karatay, A. Elmali, Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Ankara, Turkey, M. Isik, Department of Electrical and Electronics Engineering, Atilim University, 06836 Ankara, Turkey, N.M. Gasanly, Department of Physics, Middle East Technical University, 06800, Ankara, Turkey.
NaBi(MoxW1-xO4)2 single crystals, Open aperture Z-scan technique, Nonlinear absorption, Defect states, Optical limiting, Double tungstates and molybdates