Development of optical nanoelectronics Essay

Nanotechnology has become more advanced in recent years. This made possible the development of optical nanoelectronics. Optical nanocircuits have been the focus of recent researches because of its superior advantages over the existing electronic circuits. They offer high-speed transmission of data, high bandwidth, and even miniaturization of circuit elements. But optical nanocircuits, operating in the optical frequencies, are not solely based on the existing circuit theory that has been the foundation of the existing Microwave circuits. Theory of Electromagnetics must be deeply analyzed and extended to understand how optical nanocircuits work. In microwave circuits, resistors, inductors and capacitors can be modeled using lumped elements. The changes in electromagnetic field inside the electronic components are quasi-static in nature. This idea also holds true for optical nanocircuits. In order to preserve the quasi-static nature of the elements, the dimensions of the components need to be tinier than the wavelength. This has been possible because of the advancement of nanotechnologies. But the problem in the optical frequencies is the behavior and response of the metallic and non-metallic components. At optical frequencies, metals tend to show plasmonic resonance, which causes the permittivity of the material to have a negative real part. Since metals don’t show the property of conduction at optical frequencies, Conduction current is not the main current flowing thru the metal. Displacement current is dominant current flowing thru the metals at optical frequencies. This displacement current is greatly affected by the permittivity of the material used. The characteristics of the permittivity of the material determine whether the material acts as a nanoinductor, a nanocapacitor, or a nanoresistor. If the real part of the permittivity of the material is positive, the material acts as a nanocapacitor. On the other hand, if the real part is negative, it acts as a nanoinductor. Materials have nanoresistance when the imaginary part of the permittivity of the material is not equal to zero. These nanoelements can also be used to realized nanofilters. Existing ideas using resistors, inductors, and capacitors to create lowpass, highpass, and bandpass filters can also be used to create nanofilters. Depending on the connections of the nanoelements, nanofilters can be constructed. Nanoinductors, nanocapacitors and nanoresistors can be connected in either series or parallel to produce the necessary nanofilter. A sample of optical nanocircuit is shown in the image below. Figure 1. Realization of optical nanocircuit. (Engheta, Science 2007. ) References: Alu, A. , Salandrino, A. , & Engheta, N. Parallel, Series, and Intermediate Interconnections of Optical Nanocircuit Elements, Part 2: Nanocircuit and Physical Interpretation. Universtiy of Pennsylvania, Philadelphia, PA, USA. Retrieved November 15, 2008 from http://arxiv.org/pdf/0707. 1003. pdf Engheta, N. , SAlandrino, A. , & Alu, A. (2004). Circuit Elements at Optical Frequencies : Nano-inductors, Nano-capacitors, and Nano-resistors. Universtiy of Pennsylvania, Philadelphia, PA, USA. Retrieved November 15, 2008 from http://arxiv. org/pdf/cond-mat/0411463. pdf Engheta, N. (2007). Circuits with Light at Nanoscales: Optical Nanocircuits Inspired by Metamaterials. Science. Shivanand, S. V. (2008). Optical Nanocircuits. Purdue University, Indiana, USA. Retrieved November 15, 2008 from http://cobweb. ecn. purdue. edu/~ece695s/Lectures/Lecture_20. pdf