One and two dimensional surface emitting distributed feedback lasers based on MEH-PPV

The focus of this dissertation is one and two-dimensional surface emitting distributed feedback lasers based on the organic polymer 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV). Theoretical models are developed, and experimental results are presented for both 1-D and 2-D structures. For the 2-D case the effects of pumping geometry on the laser performance and emission linewidth are studied.; Chapter II describes the basic theory of 1-D DFB laser using the couple mode theory and the Floquet's theorem. A complete solution of the couple equations including the second order or higher diffraction grating is presented. For generality, a semiconductor structure based on InGaAs was chosen for studying the influence of the grating shape in the coupling coefficient and to develop the theoretical formalism to be used in the study of the MEH-PPV based lasers in chapter 3.; Chapter III presents a more detailed description of the couple mode theory that includes evanescent and radiation modes into the coupled equations for the 1-D DFB. The theoretical analysis presented in this chapter is based on the same structure that was used for the experimental results in chapter IV. The decaying and radiating modes were calculated using finite differences and the threshold gain of the device was calculated for different laser lengths. We show that the an increase in the device length beyond a certain value will, in addition to increasing the feedback strength, will also increase the losses due to the decaying and radiating modes, which may cause the lasing threshold gain to increase.; Chapter IV describes the material and device fabrication and characterizations for the 1-D devices. Interferometric lithography was used for the grating fabrication and the optical properties of MEH-PPV were characterized using visible and UV spectroscopy. Lasing action is reported by photopumping the samples beyond amplified spontaneous emission (ASE).; Chapter V describes the experimental results obtained from the two-dimensional grating structure. The lasing instabilities associated with pumping geometries were demonstrated in the case of 2-D photonic crystal laser. As a result, the laser spectrum and threshold gain were found to be strongly dependent on the excitation geometry.