Types of Microcavities

FIGURE 4.1. Structures of two types of microcavities (a) planar microcavity and (b) microdisk. 

For the formation of microcavities, it is necessary that a complete two-dimensional PBG exists at least for one polarization (TE or TM) and ideally for both polarizations. This involves careful design and requires that there be a sufficient index difference between the two materials. The photonic band structure of a triangular lattice of air holes in a membrane of SiCF coated with a thin layer of organic semiconductor has been described in Ref 24. Such a structure has been shown to possess a complete bandgap for TE polarized light. In a photonic lattice which possesses a complete bangap, it is possible to create a microcavity 

FIGURE 4.2. Illustration of a two-dimensional photonic bandgap structure in which the white regions possess a high refractive index and the black regions represent air holes. Such structures can have a complete photonic bandgap under appropriate conditions. When a defect is introduced in the perfectly periodic lattice, a microcavity can be created. 

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Other types of optical microcavities employing the DBR mechanism of light confinement include planar annular Bragg resonators (Scheuer, 2005), based on a radial defect surrounded by Bragg reflectors, and their 3-D equivalent, spherical Bragg onion resonators (Liang, 2004). 

Fig. 1 Types of PSi sensors, (a) single-layer (b) Bragg filter (c) Thue-Morse filter (d) Microcavity...

It has been shown that the hexagonal columnar phase forms honeycombed network and has the microcavity with diameter of ca. 3 nm (Figure 7-6) [30]. It is the first type of aromatic polyester with flexible side chains. Further, it is expected that existence of the microcavity in the hexagonal columnar phase leads to possibility to be used as soft materials with anisotropic field and so may be applied to smart membranes. For this, stmctural and dynamic behavior of the polymers must be characterized with high precision. 

The intriguing properties of devices made by the combination of a film-forming dye and an optical microstructure turn up in the discovery of strong coupling between excited states and photon modes in microcavities, creating Rabi-splitted polariton modes [211]. They occur in materials with narrow absorption bands (e.g., porphyrins and cyanine dyes) and may pave the way to new laser types and fundamental insights into the interaction of matter and light. 

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