Yuheng Xu

Growth and properties of Zn doped lithium niobate crystal

Abstract By adopting proper temperature field, growth parameters and pulling–annealing technique a series of high quality ZnO doped lithium niobate (LN) crystals were grown by Czochralski method from the congruent melt. The defect structure of Znxa0:xa0LN crystals was studied by X-ray analyses, IR and Raman spectrum. It is suggested that Zn ions first occupied Nb ions on Li sites, then Zn ions occupied the ordinary Li sites. Its photo-refraction threshold indicated crystal containing 6xa0mol% Znxa0:xa0LN has the highest resistance to optical damage, similar to Mg doped LN (5xa0mol% MgO), having increased two orders of magnitude.

Effect of Li/Nb ratio on growth and photorefractive properties of Ce:Fe :LiNbO3 crystals

Zn:Fe:LiNbO3 crystals with different Li/Nb ratios in the melts (Li/Nb = 0.946, 0.97, 1.00, 1.10, 1.20, 1.44) have been grown for the first time. The UV–Vis absorption spectra, exponential gain coefficient, diffraction efficiency and response time of the crystals were measured. With the ratio of Li/Nb increasing, the absorption edge shifts to a shorter wavelength, the exponential gain coefficient and response speed increase, but the diffraction efficiency decreases.

Enhancement of the exponential gain coefficient as a result of the light-fanning effect in thin doped LiNbO 3 crystals

The enhancement of the exponential gain coefficient of two-beam coupling in several thin samples of doped LiNbO3 crystals is reported. The mechanism is analyzed by light crawling that originates from the light-fanning effect. Some experimental results to support the explanation are presented.

Growth and properties of RE:Zn:LiNbO3 crystals

Double-doped Nd:Zn:LN and Er:ZN:LN single crystals were grown by Czochralski method from a congruent melt. The optical absorption and fluorescence spectra of RE:Zn:LN were measured. The pumping wavelengths and the laser oscillation wavelengths of RE:Zn:LN were confirmed at the first time. The laser oscillation wavelength of Nd:Zn:LN is 1090 nm, which is longer by 30 nm than that of Nd:YAG and Nd:Mg:LN

Optical damage resistance in Zn:Nd:LiNbO3 laser crystals

Abstract A series of Zn, Nd co-doped LiNbO 3 crystals were grown by Czochralski technique with 0.5xa0mol% of Nd 2 O 3 and with 0, 4.0, and 7.0xa0mol% of ZnO, respectively. Their optical damage resistance was characterized by measurement of the photo-induced birefringence change. The optical damage resistance of Zn (7.0xa0mol%):Nd:LiNbO 3 was much higher than that of Nd:LiNbO 3 . The ultraviolet-visible (UV-Vis) absorption spectra and the infrared (IR) transmission spectra of Nd:Zn:LiNbO 3 crystals were measured and investigated. The defects were discussed in this paper to explain the optical damage resistance in the Zn:Nd:LiNbO 3 crystals.

Investigation on photorefractive properties of In:Mn:Fe:LiNbO3

Abstract In:Mn:Fe:LiNbO 3 crystal was grown by the Czochralski method and oxidized for the first time. The OH − absorption band of In(3 mol%):Mn:Fe:LiNbO 3 crystal was found to be at 3507 cm −1 . The nonvolatile holographic recording in In(3 mol%):Mn:Fe:LiNbO 3 crystal was realized by the two-photon fixed method. The recording time of In:Mn:Fe:LiNbO 3 crystal is only a half of that of Mn:Fe:LiNbO 3 crystal, and the ratio of signal to noise is improved, too. At last, the mechanism of OH − absorption band shifting and two-photon fixed was discussed.

Photorefractive properties of potassium lithium niobate doped with copper

Summary Potassium lithium niobate doped with copper (Cu:KLN) were grown by the Czochralski method for the first time. The structure of Cu:KLN was measured by the x-ray powder diffraction method, and its lattice constants were obtained. The position of copper ions in KLN crystal was determined. The exponential gain coefficient, response time and erasure time were measured. It was found that the exponential gain coefficient of Cu:KLN is 10.5 cm−1, as two times high as that of KLN, and its response time of 1.53 s is one order of magnitude shorter than that of Cu:LiNbO3. The type of light exciting carriers in Cu:KLN has been investigated. The result showed that the electron acts the main role in Cu:KLN.

Study on photodamage of Mg:Ga:LiNbO3 crystal wave-guide substrate

Abstract MgO and Ga 2 O 3 were doped in LiNbO 3 (LN) to grow Mg:Ga:LN crystals. The OH − absorption spectra and photoredamage resistance threshold of Mg:Ga:LN were measured. The mechanism of the shift of OH − absorption peak was investigated. LN crystal was manufactured into proton transfer wave-guide substrate. By using the holograph method, the photodamage resistance ability of wave-guide substrate was measured. It was found that the photodamage resistance ability of Mg:Ga:LN wave-guide substrate was much higher than that of LN wave-guide substrate.

Photorefractive Zn-Fe:LiNbO3 crystal for real-time double-exposure interferometry application

Zn, Fe:LiNbO3 crystal, with fine photorefractive properties, has been grown by Czochralski technique. Its response time was measured to be about ten seconds, the diffraction efficiency to be higher than 70 percent. Employing Zn, Fe:LiNbO3 as a holographic record media, another photorefractive crystal Cu:KNSBN as a self-pump phase conjugate mirror, the double-exposure interferometry has been studied in this paper.

Holographic storage property of In:Fe:LiNbO 3

In2O3 and Fe2O3 were doped in LiNbO3 and Czochralski method was used to grow In:Fe:LiNbO3 crystals. The light scattering ability resistance, exponential gain coefficient, diffraction efficiency and response time of the crystals were measured. The light scattering ability resistance and response time of In:Fe:LiNbO3 is one magnitude higher than Fe:LiNbO3. In:Fe:LiNbO3 was used as storage element to make the large capacity holographic storage and the holographic associative storage reality. The excellent results were gained.