We have fabricated and studied mechanically tunable elastomer dye lasers constructed in large area sheets by a single-step layer-multiplying co-extrusion process. The laser films consist of a central dye-doped (Rhodamine-6G) elastomer layer between two 128-layer distributed Bragg reflector (DBR) films comprised of alternating elastomer layers with different refractive indices. The central gain layer is formed by folding the coextruded DBR film to enclose a dye-doped skin layer. By mechanically stretching the elastomer laser film from 0% to 19%, a tunable miniature laser source was obtained with ~50 nm continuous tunability from red to green. Optically pumped by a frequency-doubled Nd:YAG laser, the elastomer laser showed a lasing threshold of 0.9 mJ/cm 2 at 600 nm.

The synthesis of several new truxenones and one tris(dicyanomethylene) derivative substituted by different amines at positions 4, 9, and 14 is reported. A complete characterization of the NLO properties of representative derivatives was carried out by hyper-Rayleigh scattering; the major electronic effects and the influence of the structural modifications on the NLO properties have been examined. Because of their C 3 symmetry and their large first hyperpolarizability, the chiral versions of the tris(dicyanomethylene) truxene derivatives are of interest for second-order nonlinear optics in uniaxially aligned chiral media.

We report on improved gain and spectral control in co-extruded all-polymer multilayer distributed feedback (DFB) lasers achieved by folding and deliberate modification of the center "defect" layer. Because DFB laser gain is greater at spectral defects inside the reflection band than at the band edges, manipulation of structural defects can be used to alter spectral defects and thereby tune the output wavelength and improve laser efficiency. By experimentally terracing the layer that becomes the center of the fold, we tuned the lasing wavelength across the reflection stop-band (∼25 nm) in controllable, discrete steps. The increased density of states associated with the defect resulted in a lower lasing threshold and, typically, a 3- to 6-fold increase in lasing efficiency over non-folded samples.

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