Laser operation in nondoped thin films made of a small-molecule organic red-emitter

Abstract

Stimulated emission in small-molecule organic films at a high dye concentration is generally hindered by fluorescence quenching, especially in the red region of the spectrum. Here we demonstrate the achievement of high net gains (up to 50 cm -1 ) around 640 nm in thermally evaporated non-doped films of 4-di(4'-tert-butylbiphenyl-4-yl)amino-4'-dicyanovinylbenzene, which makes this material suitable for green-light pumped single-mode organic lasers with low threshold and superior stability. Lasing effect is demonstrated in a Distributed Bragg Resonator configuration, as well as under the form of random lasing at high pump intensities.

Lasers organiques accordables dans l'UV (309–322 nm)

“…Nous proposons dans cet article un itinéraire alternatif pour atteindre le domaine UV avec un dispositif organique, tout en ne compromettant pas sa photostabilité : il s'agit d'utiliser une architecture laser originale démontrée par notre équipe [10] avec un milieu à gain émettant dans le rouge et de procéder à un doublement de fréquence intracavité. Alors que le doublement de fréquence a été couramment utilisé dans les lasers à colorants liquides, il est resté largement inexploré dans les lasers organiques à l'état solide, d'une part parce que les intensités disponibles sont souvent trop faibles, et d'autre part parce que les géométries standard planaires de type DFB ou DBR ne s'y prêtent pas [11]. Nous avons basé la conception de notre système laser organique doublé en fréquence sur deux principes de construction simples : 1) le faisceau laser à la longueur d'onde fondamentale doit avoir une densité de puissance élevée, à savoir une puissance crête importante et une qualité de faisceau élevée, et 2) le résonateur doit être ouvert pour permettre l'insertion d'un cristal non linéaire efficace à l'intérieur de la cavité.…”

Analytical study of vertical external-cavity surface-emitting organic lasers

“…via spin coating or thermal evaporation) which has led to sometimes compact, tunable and inexpensive solid-state laser sources with potential applications in different fields such as spectroscopy [4,5], bio/chemo sensing [6,7] and short-haul data telecommunications via plastic optical fibers [8]. There are numerous reports of such devices under optical pumping in different laser configurations such as distributed feedback resonators [9], vertical microcavities [10,11] and external-cavity resonators [12]. In the perspective of having compact organic laser sources which integrate the pump and the laser cavity in a small-volume device, there have been several achievements through indirect electrical pumping of organic solid-state lasers via Light Emitting Diodes [13] or nitride diode lasers [14,15] by means of somehow sophisticated electronic circuitry systems for the pump source to make it operate in a pulsed regime.…”

Highly efficient, diffraction-limited laser emission from a vertical external-cavity surface-emitting organic laser

“…Upon pumping by 7-ns pulses at 532 nm, a diffraction-limited beam (M²=1) was obtained, with a conversion efficiency of 43%; higher peak powers (2kW) could be attained when resorting to shorter (0.5 ns) pump pulses. [7,8] or microcavities [9,10]. In the meantime, less attention has been paid to the question of optimizing conversion efficiency, beam quality and power scaling capability.…”

“…They may find applications in the fields of, e.g., polymer optical fiber telecommunications [2], bio/chemo-sensing [3] or spectroscopy [4]. In the perspective of achieving direct [5] or indirect [6] electrical pumping of organic semiconductors, most of recent studies have been dealing with low-loss resonator structures such as distributed feedback resonators [7,8] or microcavities [9,10]. In the meantime, less attention has been paid to the question of optimizing conversion efficiency, beam quality and power scaling capability.…”