An acoustic model for microresonator in on-beam quartz-enhanced photoacoustic spectroscopy

The effect of air impurity layer on the reflection spectrum of one-dimensional holographic photonic crystals was investigated in two forms. One form is the band-edge oscillation phenomenon when the air impurity layer is near the surface of the structure; the other form is the defect mode appearing in the band gap when the air impurity layer is near the center of the structure. For the defect mode, its central wavelength will nonlinearly change with some repeatability with the defect size, not as the result of the step-index photonic crystal. Moreover, the depth of the defect mode in the band gap can be modulated by the intensity ratio of the two construction beams. And the reflectance at the central wavelength of the defect mode can be almost zero with appropriate optical intensity ratio. The corresponding experimental results were also demonstrated.