No abstract available

[en] Published in summary form only

[en] A quasi-cw flashlamp-pumped Pr³⁺ : LiYF₄ laser was developed. It emits in the red part of the spectrum (λ_las=0.6395 μm) and it is repetitively pulsed. Its average output power is 2.3 W at a repetition rate of f=10 Hz and 650 mW at f=50 Hz. (letters to the editor)

[en] Experiments on the observation of optical superradiance in a LaF₃:Pr³⁺ crystal are described. The multipulse regime of excitation of optical superradiance in both two- and multilevel systems is theoretically investigated. It is demonstrated that this regime is the generalization of the triggering regime of superradiance excitation. The developed formalism is used for the description of gamma superradiance

[en] Photoluminescence of Ce³⁺- and Pr³⁺-activated Sr₂GeO₄ powders was measured between 17 and 600 K. For both ions strong 4fⁿ⁻¹5dⁿ→4fⁿ (d-f) emission is observed at low temperatures, around 410 nm (Ce³⁺) and 280 nm (Pr³⁺). The Ce³⁺ d-f emission quenches starting at 150 K and disappearing completely just above room temperature. Pr³⁺ d-f luminescence shows an onset of quenching also around 150 K and disappears completely between 250 and 300 K. For Pr³⁺ quenching of the d-f emission was connected with an increasing intensity of the ³P₀ luminescence at first and ¹D₂ emission at even higher temperatures. Both these 4fⁿ→4fⁿ emissions were observed up to 600 K. Based on the similar quenching temperatures, thermally stimulated photoionization of the 5d electrons from 5d level of Ce³⁺ or Pr³⁺ to the conduction band is proposed as the most probable mechanism for quenching of the d-f emissions.

[en] Published in summary form only

No abstract available

[en] To date, the white light lanthanide upconvertion consisting of RGB components usually originated from more than one type of emitter. Alternatively, Pr³⁺ is a fascinating lanthanide ion featuring multiple visible emission bands, including RGB components that in principle enable Pr³⁺ to emit white light. In this paper, we report, for the first time to our knowledge, white light upconversion through dual sensitization routes in Nd/Yb/Pr triply doped NaYF₄ microrods upon 800 nm excitation. It is found that the dual sensitization is more efficient than single sensitization for Pr³⁺ upconversion. In addition, the temperature sensing behaviors of the proposed triply doped microrods are comparatively investigated using different emission bands. This work presents a novel white light emitting material upon 800 nm excitation, and further demonstrates the feasibility of multichannel thermometry using the proposed material.

[en] We demonstrate visible-light all-fiber vortex lasers by incorporating the home-made mode selective couplers (MSCs). The MSC at green or red wavebands is fabricated by specially designing and fusing a single-mode fiber (SMF) and a few-mode fiber (FMF). The MSCs inserted into visible fiber cavities act as power splitters and mode converters from the LP₀₁ to LP₁₁ mode at green and red wavelengths, respectively. The red-light all-fiber vortex laser is formed by a 10-cm Pr³⁺/Yb³⁺:ZBLAN fiber, a fiber Bragg grating, a fiber end-facet mirror and the MSC at 635 nm, which generates vortex beams with OAM_±1 at 634.4 nm and an output power of 13 mW. The green-light all-fiber vortex laser consists of a 12-cm Ho³⁺:ZBLAN fiber, two fiber pigtail mirrors, and the MSC at 550 nm, which generates vortex beams with OAM_±1 at 548.9 nm and an output power of 3 mW. (special topic)

[en] We report on the direct generation of optical vortex lattice (OVL) modes from a diode-pumped Pr³⁺:LiYF₄ (Pr:YLF) laser achieved by employing off-axis (transverse) and defocused (longitudinal) pumping geometries in the laser medium. OVL modes with more than 40 phase singularities are generated. The experimentally observed OVL modes are well supported by a theoretical analysis based on the superposition of Hermite-Gaussian modes. We also discuss the intracavity frequency doubling of the OVL modes. The proposed OVL mode laser system can be applied to fundamental optical science and advanced material engineering. (paper)