Tb 3 + -doped KPb2Br5: Low-energy phonon mid-infrared laser crystal

Abstract

Crystals of potassium lead bromide (KPB), a moisture-insensitive low-energy phonon laser host, were synthesized and purified. High-quality undoped and Tb3+-doped (nominal doping concentration was 5mol% TbBr3) KPb2Br5 were grown by the vertical Bridgman technique. X-ray diffraction measurements indicated that, at room temperature, the material was monoclinic with space group P21∕c, while at a high temperature the phase transformed to orthorhombic form. A reversible phase transition was observed around 256°C upon the heating and cooling cycle from differential scanning calorimetric measurements. The material was found to be transparent in the broad range from ∼0.4μmto25μm and above. The transmission spectrum of a Tb3+-doped crystal showed different absorption bands of Tb3+ at 4.5μm, 3μm, 2.3μm, and 2μm corresponding to F67–Fα7 transitions, for α=2–5. The maximum phonon energy of undoped KPb2Br5 at room temperature was determined to be 134cm−1 from Raman scattering spectrum.

Contribution of Energy Transfer from the Singlet State to the Sensitization of Eu3+ and Tb3+ Luminescence by Sulfonylamidophosphates

“…Our motivation for this approacha re the curiously long 7 F 5 lifetimes (from 2.8 to 22 ms), measured in glass and crystalline materials. [53,54] This level cannotb et hermally populated (lying at 2185 cm À1 above the ground 7 F 6 level). The value of W ETS1 ,w hen the population of 7 F 5 is taken into account,i ncreases from 4.39 10 6 to 7.53 10 6 s À1 for 1Tb.T he energy transfer rate from T 1L1 to 5 D 4 level of Tb 3 + in 1Tb involving 7 F 5 (exchange mechanism)i sa bout 100 times larger than involving the 7 F 6 level (direct Coulomb interaction), and additionally the following new energy transfer paths become possible:f rom S 1 to 5 I 5 (DE = 1320 cm À1 ), 5 I 4 (DE = 1698cm À1 ), 5 I 6 (DE = 1708 cm À1 ), 5 F 4 (DE = 3932 cm À1 ), 5 H 4 (DE = 4967cm À1 ).…”

Tl3PbBr5: A possible crystal candidate for middle infrared nonlinear optics

“…The task of the chemists has consisted in finding, synthesizing and growing large single crystals of possibly new and non hygroscopic halides, likely to incorporate rare earth ions and exhibiting sufficiently satisfactory thermomechanical properties for resisting the electromagnetic and heat fluxes inherent to the laser cavity [4,5]. In the course of our research activity related to these compounds, we became particularly interested in Tl 3 PbBr 5 , a well-defined phase of the pseudo-binary system TlBr-PbBr 2 (which melts congruently at T melt ¼ 392 1C [6]).…”

Optical Transition, Excitation State Absorption, and Energy Transfer Study of Er3+, Nd3+ Single-Doped, and Er3+/Nd3+ Codoped Tellurite Glasses for Mid-Infrared Laser Applications

“…In contrast, rare earth-doped glass or crystal lasers pumped by near infrared laser diode (LD) are more attractive in the studies of mid-infrared lasers, because some trivalent rare earth ions can emit mid-infrared lights, for example, 3.0 mm from Er 31 ( 4 I 11/2 -4 I 13/2 ), 3.9 mm from Ho 31 ( 5 I 5 -5 I 6 ), 3.4 mm from Pr 31 ( 3 H 5 -3 H 4 ), 4.3 mm from Dy 31 ( 6 H 11/2 -6 H 13/2 ), and 4.8 mm from Tb 31 ( 7 F 5 -7 F 6 ). [9][10][11][12] Three micrometer lasers based on Er 31 -doped gain media have attracted increasing attention because they match the strong OH optical absorption of high water-containing biologic tissues; thus, this wavelength laser can be used as surgical bistoury for precise ablation of tumors. 13 In order to obtain highly efficient laser operation, gain media with low phonon energy is needed because the energy gap between 4 I 11/2 and 4 I 13/2 is narrow.…”