Room-temperature lasing from fluorene thin-film crystals densely doped with anthracene.
The potential for room-temperature lasing in densely doped organic crystals has been examined using (fluorene)0.8-(anthracene)0.2 thin crystals fabricated in a narrow gap between two quartz plates. An excitation-intensity dependence study confirms that the system shows spectral line narrowing, a super linear increase of the narrow line above threshold excitation intensity, and laser cavity modes. These results indicate that lasing has been observed in the densely doped organic crystal, which contains in-plane cavities with a length of approximately 100 μm.
Organic Single Crystal Lasers: A Materials View
Materials design has become a vigorous aspect for organic solid‐state lasing, which often lacks a fundamental understanding of structure–property relationships. The development of such an understanding is undertaken in this progress report, which systematically explores the now‐available libraries of organic single crystals exhibiting light amplification under optical pumping. By doing so, intra‐ and intermolecular contributions are disentangled for the non‐/occurrence, type, threshold, wavelength, and polarization of the light amplification processes, opening the path to targeted materials design.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.