Structure of the R1 and R2 Bands of Isotopes of Cr3+ Ion in a Single Crystal of Ruby at Room Temperature

Optics and Spectroscopy - Room-temperature absorption and luminescence spectra of the R1 and R2 bands in a single crystal of Ruby Al2O3:Cr3+ (0.05%) are analyzed. The luminescence in these bands...     

Localization of targets in CW-LFM radars with combined modulating signal

An improved algorithm of detecting multiple targets by cw radars with linear frequency modulation (LFM) is presented. A combined modulating signal consisting of successive LFM and pure Doppler periods has been used. Processing of pure Doppler periods does not require large computational resources and the obtained results are more accurate. This construction of algorithm allows reducing the probability of false alarm in the localization regime and simplifying the processing in the detection regime.     

Luminescence kinetics of LiNbO3:Yb3+-Er3+, LiNbO3:Er3+, and LiNbO3:Yb3+ crystals under selective excitations in the impurity subsystem

The results of investigations of luminescent radiations’ kinetic characteristics for LiNbO₃:Yb³⁺-Er³⁺, LiNbO₃:Er³⁺, and LiNbO₃:Yb³⁺ crystals under optical excitations at 532 nm and 1064 nm wavelengths are presented. The shapes and times of rise and damping of luminescent signals at 550 nm, 980 nm and 1555 nm wavelengths under selective excitations in the impurity subsystem of the investigated materials are determined. Comparison of the temporal characteristics of luminescent responses of LiNbO₃ crystals doped separately with Yb³⁺ and Er³⁺ ions with those of the LiNbO₃:Yb³⁺-Er³⁺ crystal allows identifying the contributions from different energy transfer processes of optical excitation taking place in the impurity subsystem of the material.     

Absorption and photoluminescence of YAG:Er3+, YAG:Ce3+, and YAG:Er3++Ce3+ crystals

We have studied absorption and luminescence spectra of yttrium-aluminum garnets doped with Er³⁺ and Ce³⁺ ions, as well as co-doped with Er³⁺+Ce³⁺ impurity ions. Luminescence of studied crystals was excited by cw laser radiation at the wavelengths 457 and 980 nm. We revealed obvious display of the energy transfer processes occurring in the impurity subsystem of a YAG: Er³⁺+Ce³⁺ crystal.     

Photoluminescence of LiNbO3 crystals doped with Er3+ and Yb3+ ions

Results of cooperative phenomena investigations in the impurity subsystem of lithium niobate crystals doped with Er³⁺ and co-doped with Yb³⁺ impurity ions under continuous wave and pulsed excitation at 975 nm and 1064 nm wavelengths are presented. Dependences of some spectroscopic characteristics on the intensity of laser pumping are studied. Based on the pair centers model the analysis of the cooperative luminescence behavior in LiNbO₃:Yb³⁺+Er³⁺ crystals is performed.