Detection of chemical species using ultraviolet microdisk lasers

We have utilized hybrid zinc oxide/silica microdisk lasers to sense volatile organic compounds, such as toluene and nitrobenzene. Nonspecific adsorption of these organic molecules onto the microdisk surface causes an increase in the disk refractive index, ultimately resulting in a redshift of the observed lasing wavelengths. The monitoring of these shifts provides the sensing modality. Microdisk lasers were found to respond rapidly and reversibly to the investigated chemicals demonstrating, in principal, the chemical and biological sensing capabilities of such devices. (C) 2004 American Institute of Physics.