We present a theoretical study of the sensing properties of silica microtube resonator sensors. By solving the Maxwell’s equations to obtain the electric field distribution in a cylindrical coordinate system and by using the perturbation method, we have analyzed in detail the sensing properties of silica microtube resonator sensors, which include the bulk refractive index, surface, and absorption sensing sensitivities with different radial order resonant modes. We found that a type of resonant mode, different from the evanescent modes commonly employed in previous investigations, is very promising for sensing changes of the refractive index. Furthermore, the resonant mode with high electric field at the inner boundary of the microtube is ideal for surface sensing applications. The high Q factor resonant mode is useful for the absorption sensing application. These sensing properties analyzed by using the perturbation method match very well with the results from the Mie scattering method. Finally, the limitation of the perturbation method is discussed.
© 2009 Optical Society of America
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