Spectral analyses of Dy/Sr: LaF and Dy/Ca: LaF mixed crystals for laser applications.

Mixed crystals of Dy/Sr: LaF and Dy/Ca: LaF were grown by Bridgman technique and their spectral properties were investigated. Spectra broadening and peak shifts were observed, indicating the co-doping of Sr/Ca brings about a more disordered local symmetry of Dy, which makes both crystals favorable for tunable lasing action. Low-temperature high resolution excitation and emission spectra were carried out for exploring the types of luminescent center of Dy in crystals.

Ultrasensitive nonlinear absorption response of large-size topological insulator and application in low-threshold bulk pulsed lasers.

Dirac-like topological insulators have attracted strong interest in optoelectronic application because of their unusual and startling properties. Here we report for the first time that the pure topological insulator Bi2Te3 exhibited a naturally ultrasensitive nonlinear absorption response to photoexcitation. The Bi2Te3 sheets with lateral size up to a few micrometers showed extremely low saturation absorption intensities of only 1.

[Study on the growth and spectral characteristics of LiNbO3:Cr:ZnO crystal].

The LiNbO3:Cr:ZnO crystals with the size up to phi20 mm x 50 mm were grown by the Czochralski technique. The absorption spectrum shows that there are two strong absorption wideband peaks and one weak absorption peak of to Cr3+ ion in the crystal. The peak values of the two strong absorption wideband peaks are 480 and 660 nm, which correspond to 4A2-->4 T1 and 4A2-->4 T2 transitions, respectively.

[Crystal growth and spectroscopy of Er/Yb:KGW crystal].

The Er3 /Yb3+:KGW crystal with the dimensions of 30 mm x 25 mm x 15 mm was grown from K2W2O7 solvent by modified Czochralski method. The absorption spectrum was measured at room temperature and its absorption peaks were assigned. The emission spectrum was obtained under the excitation of 980 nm.

[Study on the growth and spectral characteristics of Cr3+: Al2 (WO4)3 crystal].

Cr3+:Al2(WO4)3 Crystal was grown from the Na2WO4 solvent system by using the TSSG method. The absorption spectrum shows that there are two strong absorption wideband peaks and one we ak absorption peak belonging to Cr3+ ion in the crystal. The peak values of two strong absorption wideband peaks are at 422 and 595 nm, respectively.

[The up-conversion of frequency in Yb3+ :KGd(WO4)2 material].

By using the method of solid phase synthesis, a series of samples of KYbxGd(1 - x) (WO4)2 with different Yb3+ mole fraction of x = 0.03, 0.08, 0.