Continuously tunable organic solid-state DFB laser utilizing molecular reorientation in molecular glasses

Abstract

We report a facile way for continuously tuning the lasing wavelength of an organic thin-film distributed feedback (DFB) laser after device fabrication by varying the effective refractive index seen by the one-dimension DFB laser structure. Varying the effective refractive indices of the organic gain medium and thus the effective refractive index of a one-dimension DFB laser structure after device fabrication is made possible with reorientation of molecules in a molecular glass at elevated temperatures. Distributions of molecular orientations can be fine controlled by annealing temperatures and times, permitting continuous tuning of optical properties and lasing wavelengths. Molecular reorientation can be conducted after devices are made, thus giving one the freedom to set or tune the lasing wavelength to meet a particular purpose with a common structure.