Volume 99, Issue 1, 01 January 2006
Index of content:
- LASERS, OPTICS, AND OPTOELECTRONICS
Low gain threshold of the cavity mode close to the cutoff wavelength in a three-slab asymmetric conjugated polymer-based waveguide structure99(2006); http://dx.doi.org/10.1063/1.2160715View Description Hide Description
The emission mode close to the cutoff wavelength in a three-slab asymmetric (glass/polymer/air) conjugated polymer-based waveguide structure is characterized and found to be largely affected by microcavity effects. The spectral profiles of the emission as a function of viewing angle suggest that the peak emission is due to a cavity effect between the fully reflecting polymer-air interface and the highly reflecting polymer-glass interface. A low gain threshold is found using conjugated benzothiadiazole-arylamine copolymer as the gain medium. The exceptionally low threshold is attributed to cavity enhancement effects.
99(2006); http://dx.doi.org/10.1063/1.2159072View Description Hide Description
Limitations are discussed on the use in quantum dot(QD) lasers of the conventional method of determining internal loss coefficient and internal quantum efficiency from a measured plot of the reciprocal slope efficiency versus the cavity length . The limitations are imposed by the -dependence of and themselves. The effect of internal loss is quantitatively analyzed, which originates from the dependence of on the carrier density, with the latter being -dependent. In short cavities, a plot of the reciprocal slope efficiency versus can significantly deviate from a straight line, thus limiting the practicality of the standard procedure. For longer than several hundred , the limitations are strong in a single-QD-layer laser and moderate in a multiple-QD-layer laser.