Segregation Coefficient Of Nd3 Research Articles

Growth, thermal, and polarized spectroscopic properties of Nd:CeF3 crystal for dual-wavelength lasers

A Nd:CeF3 crystal was grown successfully by the vertical Bridgman method. The polarized optical properties were investigated for the first time. Based on the Judd–Ofelt theory, the spectral parameters of Nd3+ were studied in detail by using the spectrum of the as-grown crystal. The peak absorption cross-section of σ-polarization at 791 nm is 1.59 × 10−20 cm2, the full width at half maximum (FWHM) is 10 nm. The peak emission cross-section of σ-polarization at 1070 nm is approximately 2.53 × 10−20 cm2, and the three peaks that make up the broadband peak have comparable value. The measured 4F3/2 level fluorescence lifetime is 0.406 ms. Moreover, segregation coefficient of Nd3+, thermal diffusivity coefficient, and thermal conductivity were also measured. We propose that the Nd:CeF3 crystal may be a promising material for 1 μm dual-wavelength laser applications.

Crystal growth, optical properties and laser performance of new mixed Nd3+ doped Gd0.1Y0.9AlO3 crystal

A Nd3+ doped Gd0.1Y0.9AlO3 crystal was successfully grown using the Czochralski method. The segregation coefficient of Nd3+ ions was found to be as large as 0.76 in Gd0.1Y0.9AlO3 host. Based on the Judd-Ofelt theory, the three intensity parameters Ω2,4,6, radiative lifetimes, branching ratios were calculated to analyze the absorption and emission properties of the as-grown crystal. It is found that the width of the absorption band at around 880 nm is 29 nm, indicating that the Nd:Gd0.1Y0.9AlO3 crystal can be pumped efficiently by laser diodes. Furthermore, the large full width at half maximum at 1083 nm and long fluorescence lifetime (189.53 μs) were obtained, which means that the Nd:Gd0.1Y0.9AlO3 crystal may be an attractive host for ultrashort pulse and tunable broadband lasers. Being pumped by an 880 nm laser diode, the laser operation of Nd:Gd0.1Y0.9AlO3 crystal at 1.0 μm was obtained for the first time. A maximum output power of 677 mW was obtained with the 10% output coupler, corresponding to an optical-to-optical conversion efficiency of 22.16% and a slope efficiency of 27.80%. All these results show that Nd:Gd0.1Y0.9AlO3 crystal is a new mixed laser host which is suitable for 880 nm laser diode pump.

Spectral and laser properties of Nd:YSAG single crystal

In order to solve the problem of low segregation coefficient of Nd3+ ions in YAG crystal, Sc3+ ions are used to replace some Al3+ ions in YAG, so that the YAG cell becomes bigger, thereby the segregation coefficient of Nd3+ ion increases. In this paper, the spectra and laser characteristics of Nd:YSAG single crystal are studied. The (1.5 at.%) Nd3+:Y3Sc2Al3O12 (YSAG) laser crystal is grown by Czochralski method, and X-ray rocking curve shows that the crystal quality is good. The concentration of ions in Nd:YSAG is measured by an electronic probe. The segregation coefficient of Nd3+ ion is calculated to be 0.35, which is approximately twice as much as that of Nd3+ in YAG. The absorption and emission spectra are measured, which indicates that it can be pumped by an 808 nm-laser diode (LD). The strongest emission from the transition 4F3/24I11/2 of Nd:YSAG peaks at 1059 nm with an emission cross section of 1.0310-19 cm2, and the lifetime of 4F3/2 is about 253 s, which indicates that Nd:YSAG has roughly an efficiency equal to that of Nd:YAG, but the laser upper level lifetime is longer than that of Nd:YAG, which is more favorable for Q-switched laser operation. The 808 nm-LD is used to pump Nd:YSAG rod of 2 mm2 mm6 mm, the laser operation with a threshold of 0.85 W and a maximum output power of 1.1 W is realized:the laser slope efficiency is 21.1%, and the optical conversion efficiency is 18.3%. All of the above results show that Nd:YSAG single crystal is a good solid state laser material, which is more favorable for Q-switched laser operation.

Spectroscopic properties of Nd3+:Lu3ScAl4O12 single crystal

Nd:Lu3ScAl4O12 single crystal has been grown by the Czochralski method. The segregation coefficient of Nd3+ ions in LuSAG crystal is 0.22. X-ray powder diffraction (XRD) experiments show that the Nd:LuSAG crystal crystallizes in cubic structure with space group Ia3d and its cell parameters are a = 1.1953 nm. The absorption and fluorescence spectra of Nd:LuSAG crystal were investigated at room temperature. The spectral parameters were calculated based on Judd–Ofelt (J–O) theory, and the intensity parameters Ω2, Ω4 and Ω6 were obtained to be 0.14, 3.38, and 4.88 × 10−20 cm2, respectively. The calculated spontaneous radiative probabilities, branching ratios, radiative lifetime and quantum efficiency have been evaluated for the 4F3/2 excited state using the calculated intensity parameters. The results indicate that this crystal can be considered as a promising material for solid-state laser application.