Highly optical damage resistant crystal: Zirconium-oxide-doped lithium niobate

Chapron

Journal of Applied Physics

et al. 2017

Raman measurements were investigated on Zr -doped lithium niobate LiNbO 3 crystals with different concentrations. Spectra were treated by fitting procedure and principal component analysis which both provide results consistent with each other. The concentration dependence of the frequency of the main low-frequency optical phonons gives an insight of site incorporation of Zr ions in the host lattice. The threshold concentration of about 2% is evidenced, confirming the interest of Zr doping as an alternative to Mg doping for the reduction of the optical damage in lithium niobate.

Section: Introductionmentioning

confidence: 92%

“…A problem remains with this dopant owing to difficulties to grow large high optical quality MgO doped LN crystals. Recently, a set of tetravalent impurity ions (Hf 4+ , Sn 4+ , Zr 4+ ) as new ODR ions were checked [7][8][9][10][11]. It was shown that for these ions, the concentration threshold for ODR can be strongly reduced.…”

Section: Introductionmentioning

confidence: 99%

Zr doping on lithium niobate crystals: Raman spectroscopy and chemometrics

Chapron

Journal of Applied Physics

et al. 2017

“…% realized in our samples, monotonously increases with increasing concentration of Zr in the starting flux. The relatively high distribution coefficient of Zr as compared to that observed in the melt-grown congruent crystals [3] may be related to the different growing technique, similarly to the case of Mg [12].…”

mentioning

confidence: 97%

“…The optical damage resistance of LN crystals can be improved by doping with certain divalent, trivalent, or tetravalent cations (e.g., Mg 2 , Zn 2 , In 3 , Sc 3 , Hf 4 ) above a critical amount [1]. Increased damage resistance in the visible optical range has been reported recently in tetravalent Zr- [2,3] and Sn-doped [4] LN crystals as well. Ferroelectric domain engineering with auxiliary UV light is of growing interest in damage-resistant lithium niobate [5].…”

mentioning

confidence: 98%

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Photorefractive damage resistance threshold in stoichiometric LiNbO_3:Zr crystals

et al. 2013

Several optical methods including ultraviolet absorption, infrared absorption of the hydroxyl ions, Raman spectroscopy, and the Z-scan method have been used to determine the damage resistance threshold in 0-0.72 mol. % Zr-containing, flux-grown, nearly stoichiometric LiNbO 3 single crystals. All spectroscopical methods used indicate that samples containing at least ≈0.085 mol: % Zr in the crystal are above the threshold while Z-scan data locate the photorefractive damage threshold between 0.085 and 0.314 mol. % Zr. For LN grown from congruent melt the threshold concentration of the optical damage resistant (ODR) ions is roughly 5, 4, and 2 mol. % for di-, tri-, and tetravalent ions, respectively. For example, the threshold concentration for Zr-doped congruent LN crystals was found to be at about 2 mol. % [3,10,11]. Another factor beside the ODR ions and their valency strongly effecting the threshold concentration is stoichiometry of the crystal. The incorporation of ODR ions reduces the amount of antisite Nb Li in the lattice. In nearly stoichiometric LiNbO 3 (sLN) crystals where the Nb Li concentration is almost zero, the threshold value of the dopant concentration can be lower than 0.2 mol. % as was observed for Mg-doped sLN [12] used for instance for terahertz pulse generation [13]. Zr-doped nearly stoichiometric LN crystals prepared by the vapor transport equilibration method were found to have high resistance against optical damage when doped above 0.5 mol. % Zr [14]. The basic advantage of choosing tetravalent ODR dopants comes from their lower damage threshold concentrations; lower built-in dopant content facilitates the growth of more homogeneous crystals, resulting in high-quality samples for device applications.The aim of the present work is to characterize the damage resistance properties of tetravalent Zr-doped sLN crystals by ultraviolet (UV), infrared (IR), and Raman spectroscopies as well as by the Z-scan method. These methods proved earlier very efficient to determine the threshold concentration of the dopants.A series of stoichiometric LN crystals doped with Zr in the 0-0.45 mol. % concentration range were grown by the high-temperature top-seeded solution growth method using K 2 O flux [12]. The Zr concentration in the crystal was determined by inductively coupled plasma mass spectroscopy (ICP-MS). As shown in Fig. 1, the amount of incorporated Zr, at least in the range 0-0.715 mol. % realized in our samples, monotonously increases with increasing concentration of Zr in the starting flux. The relatively high distribution coefficient of Zr as compared to that observed in the melt-grown congruent crystals [3] may be related to the different growing technique, similarly to the case of Mg [12].For optical spectroscopical measurements 1-2 mm thick z-and y-cut samples have been prepared. The UV-visible absorption spectra of z-cut sLN:Zr crystals were measured by a Jasco V-550 spectrometer at room temperature. The spectra of the stretching vibrational bands of the hydroxyl ions (OH − ) in sLN:Zr were

Recent Progress in Lithium Niobate: Optical Damage, Defect Simulation, and On‐Chip Devices

et al. 2019

Lithium niobate (LN) is one of the most important synthetic crystals. In the past two decades, many breakthroughs have been made in material technology, theoretical understanding, and application of LN crystals. Recent progress in optical damage, defect simulation, and on‐chip devices of LN are explored. Optical damage is one of the main obstacles for the practical usage of LN crystals. Recent results reveal that doping with ZrO2 not only leads to better optical damage resistance in the visible but also improves resistance in the ultraviolet region. It is still awkward to extract defect characteristics and their relationship with the physical properties of LN crystals directly from experimental investigations. Recent simulations provide detailed descriptions of intrinsic defect models, the site occupation of dopants and the variation of energy levels due to extrinsic defects. LN is considered to be one of the most promising platforms for integrated photonics. Benefiting from advances in smart‐cut, direct wafer bonding and layer transfer techniques, great progress has been made in the past decade for LNs on insulators. Recent progress on on‐chip LN micro‐photonic devices and nonlinear optical effects, in particular photorefractive effects, are briefly reviewed.