Recently, several applications of layered structures with conducting interfaces including integrated optical modulator [1-3], integrated optical memory, optical transistor [4], and programmable diffractive element [5] have been reported. In these structures, a two-dimensional free interface charge layer is generated at the dielectric interfaces by a transverse voltage.
In general, a conducting interface can be realized through all or some of the following effects [6]:
-the inversion layers in Metal-Oxide-Semiconductor (MOS) structures,
-the electron (hole) gas at the edges of conduction (valence) bands,
-the depletion layer charge resulting from the initial imbalance between the Fermi levels of the adjacent dielectrics,
-the trapped charge in interface states.
Experimental verification of transport effects associated with the latter type interfaces has been recently reported in [6] and also, the coupling between waveguides with conducting interfaces has been proposed for implementing programmable gratings in [5,7]. Propagation of surface electromagnetic waves at the conducting interfaces and its promising applications in construction of novel optical devices have been reported [8], the possibility of optical slow wave propagation is explored in [9], and new type of optical band structures are introduced in [10].
The basic idea behind all these effects lies in the fact that continuity of tangential electromagnetic fields is influenced by the presence of surface charge layers. Surface charge and surface currents negate conventional boundary condition. This point of view raises a new question: " How much thin the surface charge layer should be to support all those new optical modes? "
As per our simulations, such a criterion depends a good deal on the polarization of optical modes propagating in such devices.
This page is still under construction!
1. Khorasani, S., and Rashidian, B., J. Opt. A: Pure Appl. Opt., 3, 380-386 (2001).
2. Darabi, E., Khorasani, S., and Rashidian, B., Semicond. Sci. Technol., 18, 60-67 (2003).
3. Khorasani, S., Nojeh, A., and Rashidian, B., Fiber Int. Opt., 21, 173-191 (2002).
4. Khorasani, S., Nojeh, A., and Rashidian, B., Proc. SPIE, 4277, 311-314 (2001).
5. Rashidian, B., and Khorasani, S., Proc. SPIE, 4277, 428-434 (2001).
6. Khorasani, S., Motieifar, A., and Rashidian, B., Semicond. Sci. Technol., 17, 421-426 (2003).
7. Rashidian, B., and Khorasani, S., Proc. SPIE, 4598, 175-185 (2001).
8. Mehrany, K., Khorasani, S., and Rashidian, B., Semicond. Sci. Technol., 18, 582-588 (2003).
9. Mehrany, K., and Rashidian, B., Semicond. Sci. Technol., 19, 890-896 (2003).
10. Mehrany, K., and Rashidian, B., Journal of Optics A., 6, 937-942 (2004).