Crystalline perfection, EPR, prism coupler and UV-VIS-NIR studies on Cz-grown Fe-doped LiNbO3: A photorefractive nonlinear optical crystal

Abstract

The Fe-doped (0.05 mol%) lithium niobate (LiNbO 3 ) bulk single crystal was gown by the Czochralski (Cz) method using a co-axial two zone low thermal gradient furnace. The crystalline perfection of the grown crystal was evaluated by high resolution X-ray diffractometry which showed that it does not contain any structural grain boundaries, and the dopants predominantly occupied vacancy sites of Li + in the lattice. Electron paramagnetic resonance studies revealed the incorporation of Fe 3+ ions at Li sites. The Z-cut optically polished 450 mm thick wafer was used for birefringence measurements on a prism coupler spectrometer with 632.8 nm wavelength and it was found that the difference in refractive index (Dn) for ordinary and extraordinary rays is 0.0833. The optical transmission/ absorption spectra were studied by UV-VIS-NIR spectroscopy and this showed that the grown crystal has good optical sensitivity for 482 nm wavelength radiation. The present studies reveal that the crystal grown with a two zone low thermal gradient furnace has very good device properties which are needed for holographic data storage applications.

Investigation of the Defect Structure of Congruent and Fe-Doped LiNbO3 Powders Synthesized by the Combustion Method

“…It visualizes the absorption peak at 480 nm in each spectrum of Fe-doped LiNbO 3 and the intensity increases as the doping concentration increases, which is proportional to Fe +2 concentration. These features coincide with previous reports [ 26 , 27 , 28 , 29 , 30 , 48 , 49 ]. The peak at 480 nm is assigned to the excitation of the electrons of Fe 2+ to the conduction band by the photon and the intervalence transfer between Fe +2 and Nb +5 at d band [ 27 ].…”

Crystal growth of Ru-doped congruent LiNbO3and investigation of crystalline perfection and optical properties

“…The redshifts in both the direct and the indirect band transitions in the Rudoped sample are a typical characteristic of transition metal impurity due to their broad impurity-impurity level transitions and intrinsic defects. A similar observation is also reported in Fe-doped samples (Kushwaha et al, 2011).…”

“…This may be attributed to the absorption band at 490 nm due to Ru, which influences the RI measured at 532 nm. Similar results are observed in Fe-doped LN (Kushwaha et al, 2011) and Zr-Fe:LN . This shows that the Ru dopant is a promising material for photorefractive application.…”

Crystalline perfection, Raman, UV-VIS-NIR and prism coupler investigations on Cz-grown pure and Zn-doped LiNbO3 single crystals

“…Pure and Zn-doped (1.0 mol%) LN (Zn:LN) single crystals have been grown successfully using an in-house developed CZ crystal puller whose details are made available in our recent publication. 33 The 4N purity chemicals of LiNbO 3 and ZnO were used for crystal growth. For the growth of doped crystals, ZnO mixed charge was properly ball milled and sintered at 1273 K for 8 h before its melting.…”