Active microcavity and coupled cavities in one-dimensional photonic crystal

The propagation of light in one-dimensional SiO2-TiO2 coupled cavity photonic crystal is investigated. In particular the potential application in light amplification is proposed considering the small group velocity that characterizes the propagation at the edge of the resonance band due to the defects. Then, by means of a transfer-matrix method and a mode matching method code, an estimation of the photon lifetime and of the field intensity in a three-coupled cavity-photonic crystal is reported comparing it with those pertaining to a microcavity photonic crystal. This calculation allows us to underline the role of the light–matter interaction time with respect to that of the number of the active medium layers in the optical amplification

High sensitivity photonic crystal pressure sensor

A two-dimensional photonic crystal microcavity coupled with a waveguide is proposed to realise a high sensitive force sensor, designed on a GaAs membrane. A theoretical model is developed to evaluate the change of the refractive index induced by the application of the force onto a sensing surface. A linear calibration curve is obtained relating the resonant drop position to the applied force

Fabrication of force sensors based on two-dimensional photonic crystal technology

We propose the simulation and the fabrication of a photonic crystal (PhC) strain-sensitive structure, showing that the optical properties of photonic crystals can be used to realize sensing devices characterized by a high degree of compactness and good resolution. The force/pressure optical sensor has been realized by designing a bulk GaAs/AlGaAs photonic crystal microcavity operating in the wavelength range 1300-1400 nm. The simulations show that the resonant wavelength of the mode localized in the microcavity shifts its spectral position following a linear behaviour when a pressure ranging between 0.25 Gpa and 5 GPa is applied, thus allowing the possibility to achieve pressure resolution of 5.82 nm/GPa. High-resolution electron beam lithography technique followed by inductively coupled plasma process were used to transfer the designed geometry on the sample