Amplified spontaneous emission in the cyano-substituted oligo(p-phenylenevinylene) organic crystals: Effect of excitation wavelength

Abstract

We report an unusual phenomenon in amplified spontaneous emission ͑ASE͒ from cyano-substituted oligo͑p-pheny lenevinylene͒ ͑CNDPASDB͒ single crystals, i.e., the ASE peak wavelength, exhibits varied dependence on the pumping wavelength ex. The former is basically kept a constant when ex Ͻ 505 nm, while a rapid redshift from 560 to 572 nm occurs when ex Ͼ 505 nm. The observation is different from stimulated Raman resonant scattering ͑SRRS͒ in two following aspects: the nonconstant Stokes shift and a much broader emission linewidth. A model describing competition between the stimulated emission and vibration relaxations has been proposed to interpret the underlying mechanism.

Organic Single Crystal Lasers: A Materials View

“…Finally, a further line‐narrowing process in organic crystals is stimulated resonance Raman scattering (SRRS), which gives rise to narrow lines with a full‐width‐at‐half‐maximum (FWHM) of a few tenths of a nanometer and can be tuned through the excitation laser source. SRRS was first observed in anthracene and, since then, observed in a number of thiophene‐phenylene‐, and DSB‐based materials . From the Raman‐active modes, the one with the highest Raman activity modes that couple to the TDM is especially enhanced under resonant excitation conditions due to the presence of coherent vibrationally dressed excitons, explaining the strong enhancement in J‐type aggregates like DBADCS .…”

Functional organic single crystals for solid-state laser applications

“…Since then, ASE have been confirmed in many organic crystals . Up to now, several classes of molecular crystalline materials have been demonstrated to exhibit ASE phenomena, such as oligothiophenes , oligo(p‐phenylene) , thiophene/phenylene co‐oligomers , fluorene/phenylene co‐oligomers , bis‐Styrylbenzene derivatives , cyano derivatives . In this section, we will introduce some typical organic laser crystals.…”

Large and Emissive Crystals from Carbon Quantum Dots onto Interfacial Organized Templates

“…This result can be explained by the competition between the stimulated emission and vibration relaxations of the highly ordered anisotropic arrangement of CQDs in the crystal. [39] Additionally,t he layered ordering of the CQDs contributes to good mechanical stability allowing then to sustain their shape in free-standing form without the support from substrate.T he microcrystal surfaces show uniform distribution of elastic modulus with the high average value of 5.4 AE 0.5 GPa across the whole crystal (Supporting Information, Figure S16). Finally,a sp rospective application of these crystals,w es howed that the CQDs crystals demonstrate superior catalytic application in the photodegradation of dye with multiple reversible cycles due to the N-doping chemical structure and unique anisotropic organization of the CQDs crystals (Supporting Information, Figure S17).…”