The Study Behind the Components of Modern Technology, Essay Example
Introduction
In a world governed by modern technology, the creation of new ways of defining technological advancements has become a common source of innovative competence. Plasmonics, the emerging utilization of metal-reflection technology, is one of the most common and most effective patterns of data transfer used at present that makes wired connections more effective and definitive especially in dedication to the creation of new age technological advancements[1]. There are however some conditions of development that often redefine the proper utilization of plasmonics especially in mandating further progressions in technology that increases the competence of gadgets to be more effective in mandating a better sense of advancement especially in terms of determining what is assumed of the future of computer and communications technology[2]. In the discussion that follows, plasmonics would be considered as the primary focus of distinct indication on how modern communication technology advances fully based on the policies and requisites of using metal reflection into the actual processing of data from one particular portal of network towards another.
Plasmonics
Plasmonics is a study that is founded in the general field of nanophotonics, which focuses on the confinement of electromagnetic fields over dimensions smaller than the wavelengths or those of the order[3]. This stems from the interaction process between the conduction electrons in small metallic nanostructures, or at metallic interfaces and electromagnetic radiation. The interaction between an electromagnetic field and conductive electrons in metallic nanostructures or interface results in the enhancement of any optical near field of sub-wavelength.
A plasmon is a quantum of plasma oscillation. It is fundamentally the result of longitudinal excitation of a given metal’s conductive electron, collectively quantized. In order for a plasmon to be excited, an electron or photon is reflected from the metallic film or passing an electron through a thin metal. The scheme below highlights the interaction between a thin metal film and an incident electron. This resulted in one or more plasmons and a scattered electron[4].
Electron incident energy:~1-10 KeV
Plasmon energy:~10 eV
Through the point of scattering the electrons, plasmonics allow for the determination of how data is defined and transported through reflection through mandating an easier pattern of data distribution. Through this manner, electronic data transfer is manipulated through directed insistence on how modern computer technology works towards implicating a better sense of what is thought as interactive technology[5]. To further improve the ways by which the concept of plasmonics is understood and applied, it is important to take note of how metals and electromagnetic fields interact with each other.
Maxwell’s equations can be used to understand the interaction between metals and electromagnetic fields. The thermal excitation () is much higher than the spacing that is between the energy levels of the electrons[6]. This results from the fact that the collective density of the carriers is considerably large.
This model developed in the early 1900s applies the kinetic theory of gases to a metal[7]. This theory assumes that gas molecules are identical spheres which have a straight linear motion until they face collision with another molecule. Metals usually have two types of particles. In order for the metal to remain electrically neutral, the valence electrons have to be replaced by a general positive charge[8]. Drude postulated that this positive charge was attached to the immobile particles of the metal[9]. These particles were also considerably heavier than the others.
The Drude theory is fundamentally based on the assumption that in the event where forming a metal from the atoms of other metallic elements, the positive metallic ions remain immobile while the valence electrons move freely throughout the metal.
As the image depicts, the ion core and the nucleus of any given metal retain the original configuration as in a single free atom. However, the valence electrons are not present as they all move together to form the electron gas.
Isolated Atoms have the following configuration:
Nucleus charge | |
Atomic Number | |
Electronic charge magnitude | |
Relatively weakly bound valence electrons | |
Total charge surrounding nucleus | |
Core electrons (Tightly bound electrons) |
Table 1: Atom Configuration Data
Conduction electrons result during the formation of a metal from the condensation of the isolated atoms. As the core electrons form the metallic ions by binding to the nucleus, some electrons are left free to move around the parent atom. Through calculation of the density of the electrons, one finds that the value far superceeds theose of conventional gas at standard or room temeperature. The Drude model ignores this fact and applies the kinetic thoery of neutral diluted gas in the treatment of the much denser metallic electrons[10].
Theoretical consideration plasmonics
Drude Model
Introduced by Paul Drude, this model of the movement of electrons provides a definitive indication on how data electrons are passed on or reflected through metal reference points. The Drude model is founded on four basic assumptions[11]
- A standard probability per unit time, , defines the collsion of an electron. is the mean free time or relaxation time. describes the chances an electron will experience a collision in time interval . is assumed to be independent of the velocity and position of an electronEvery electron moves in a straight line in the basence of externally applied fields. As such, the interaction between the electron and the ion as well as other electrons is disregarded. However, in the preseance of an applied field, the electron will adhere to Netwon’s Law. While this is done, the additional fields that emerge from the other ions and electrons are disregarded.
- Through collision, electrons realize thermal equilibrium with their surrounding.
- Every electron moves in a straight line in the basence of externally applied fields. As such, the interaction between the electron and the ion as well as other electrons is disregarded. However, in the preseance of an applied field, the electron will adhere to Netwon’s Law. While this is done, the additional fields that emerge from the other ions and electrons are disregarded.
- Drude’s model applies the same concept of collsion as in the Kinetic throey; instant and sudden events that causes changes to the velocity of a given electron. The figure below depicts the trajectory of conduction electrons in collision with the ions;
Applications of Drude’s Model
Drude’s model has been foud to be effective In the following ways[12];
- DC (direct current) electrical conductivity of metal
- General equations of motions for the electrons under force
- Hall effect and magenotresistance
- AC conductitivity of metal
- Preparation of electromagenetic waves in metal
Plasmon
In water, ripples that appear on the surface of the water are a collective mode of its molecules. In a similar way, a Plasmon is the resultant sum excitation of a metals electronic fluid that is made up of the metal’s conductive electrons. Electronic fluid has similar behavior to that of water; when pushed down on the surface of the electronic fluid, there is some point beyond which its density does not change[13]. Instead, electronic fluid that is elsewhere is displaced. This is because the metal molecules possess a finite volume and therefore displace each other. This behavior that is similar to water is as a result of the Pauli Exclusion Principle that keeps an electron out of the way of another electron and is not as a result of Coulomb repulsion between the electrons and/or because of the finite size. The electronic ripples that originate from this process sometimes have a distinct wavelength which is usually related to their momentum in quantum mechanics. The frequencies of plasmons originate from the displacement of electrons which result in an attractive force that is exerted by the overall positive charge that the process of displacement leaves behind[14]. This attractive force attempts to bring the electrons back creating an oscillating movement upon excitement of the electrons. The coulomb interactions require energy to instigate[15]. As such, in order to excite plasmons, energy has to be spent. There is a general positive charge in the background of this coulomb interactions. Certain boundary conditions are created at the ends of the host metal where there is a background positive charge.
The interactions between the background positive charge and the coulomb obey these boundary conditions. This results in nanoparticles with plasmodia modes that are considerably influenced by shape. However larger structures such as thin metals may have numerous propagating plasmon modes that exist over a broad wavelength range. Plasmons only flow along the boundary between the dielectric and the host metal. They usually decay into excitations that are characterized by disjointed electron-hole pairs. During the process of decay, the plasmons gradually stop the smooth oscillating motion and instead adopt a random sloshing movement as energy dissipates. As this happens, the electric dipoles and other multipoles radiate. The usual plasmon frequencies are quite similar to light and as such, both can be compared ().
The optical properties of metals are influenced by plasmons. The electric field of light from a light source with a frequency that is lower than that of plasma is reflected as a result of the electrons screening the electric field of light. However, any light with frequencies higher than plasma is transmitted through the medium because the light oscillates at a rate too fast for the electrons to screen. Most metals have a plasma frequency that lie within the ultraviolet range, giving them a reflective or shinny look in the visible range. However, some metals (such as gold and copper) have unique visual properties that result from interband transitions found within the visible range[16]. Specific colors are absorbed giving a unique color that is a combination of the band transitions. Semiconductors are reflective as a result of the plasma frequency of the valence electron existing within the deep ultraviolet range.
There has been increasing research into plasmons in the recent past owing to their potential benefits and applications. One of the most prominent is the use of optics to shuttle information on computer chips that have a natural optics interface. Optical trapping and spectroscopies make use of large local electric fields on the surfaces of metals that are associated with plasmons[17]. Plasmon properties of properly designed materials can be manipulated to fine tune the overall optical response of any conducting system. For this reason, perfect lenses and invisibility cloaks have been postulated to be possible with progress in the study of plasmonics.
Surface Plasmon
At the interface between two materials (a conductor and a dielectric), there exist coherent delocalized electron oscillations that are confined perpendicularly[18]. This specifically occurs at the planar interface where the sign changes across the interface as a result of the dielectric function. The alternating motion of the charge across the interface results from the oscillations of electron plasma of the conductor. This causes electromagnetic fields to form on both sides of the interface, i.e. both outside and inside the material as depicted in the figure below;
These surface Plasmon polarizations are triggered by photons as well as electrons. When electrons or photons are propelled towards the bulk of a metal, the collision causes the electrons to scatter and energy is transferred into the metal’s bulk plasma. This is the origin of excitement that causes the surface plasmon polarization. Photons cannot trigger a surface plasmon polarization at the interface between the metal and air. This arises from the inherent differences in in-plane wave vectors which is caused by the surface plasmon polarization and the photon having the same frequency[19]. When the dielectric is uniform, a surface plasmon polarization cannot lose energy as a result of the dielectric receiving radiation. However there are two techniques through which photons can be coupled into surface plasmon polarizations;
- Coupling medium; using the Kretschmann configuration, a prism is placed against a metal surface. Alternatively, the Otto configuration can be used with the prism being placed considerably close to the surface of the metal. This is shown in figure (b) below.
- Grating; this is matching the surface plasmon wave vectors to the photon wave vectors. This is achieved by selecting an amount that is related to the grating period and increasing the parallel wave vector by this amount, figure (a). This highlights the importance of the aspect of the roughness of the surface and it effect on surface plasmons as depicted in figure (c)
Localized surface plasmons resonances
Localization of surface particle resonance originates from confining surface plasmon in a nanoparticle that is either smaller than or equal to the frequency of the wavelength of light that caused excitement. At the resonance wavelength, the plasmon depicts considerably high levels of near-field amplitude. The resonance increases the rate at which the particle causes far-field scattering. The intensity of light determines the spatial resolution of localized surface plasmon resonances. However, the size of the nanoparticles limits the aspect of spatial resolution. Localized surface plasmon resonance results in the nanoparticles developing a considerably enhanced electromagnetic field around. The resonant wavelength will also be responsive to any deviations in the local dielectric environment.
Plasmonic Properties in Metal nanostructures
Nanofabrication and chemical synthesis has resulted in the formulation of a number of metal nanostructures that have unique properties with numerous possible applications. Concentrating electromagnetic energy into sub wavelength volume increases the local electrical field of metal structures[20]. Most of the metal nanostructures have one interesting plasmonic optical property; their strong absorption of the region within the spectrum rich in colors[21]. The absorption attributes results from the collective oscillation of the conduction band electron relative to the electrical field generated by the electromagnetic light radiation.
The shape of the nanostructures considerably influences the surface plasmon and color absorption. However, the size of the spherical nanostructures plays an important limiting role. Controlling the shape of the nanostructures allows for one to produce any absorption or color that lies in any section of the visible spectrum[22]. Some of the well-known nonshperical nanostructures include; nanoprisms, nancages, nanowires, nanosheets and nanorods[23]. Nanostructures with different shapes depict different colors or absorption.
Conclusion
The overall presentation of details on how plasmonic operation happen provide a definite foundation on how data networks are established for the sake of developing computer-defined communication options open for the public at present. Making use of refraction rule and policy for metal directed oscillation, the plasmonic operations definitely insist on how modern technologies are developed especially for the sake of improving gadget-innovation offered in the market at present.
The assumption of the overall role of plasmonic operations on the creation of new and innovative gadgets have definitely changed the way humans identify with the need to establish distinct connections with each other. Relatively, it could be observed that the current developments with regards plasmonic studies provide a distinct foundation on how extensive electron distribution could be used to further progressive points that could identify the concept of improved network-data sharing through electron conduction[24].
The emergence of nanotechnology even furthers the improvement by which plasmonic technology becomes highly useful for the society. The desire of making easy-to-carry gadgets and other mobilized innovations that could provide the demands of the new market being served by the tech-industries insist on further developments that are supposed to be embraced by the organizations enjoined within the industry. Practical options of developments that are able to fit with the demands of the market makes such technology even more valid and interesting to study. With the new age system of developments, it could not be denied that plasmonic developments will certainly make a mark on how the society embraces technological innovations that would directly impact the way they connect with each other and make a massive insistence on how the concept of internet and computer technology does provide a definite pattern of growth for the industry, the society and the way these two elements interact with each other to create a progressive system of high-tech improvement.
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[1]Kyzer, Lindy OCPA – Media Relations Division (Aug 21, 2008). “Army research on invisibility not science fiction”. U.S. Army.
[2]Smolyaninov, Igor I (2011). “Metamaterial ‘multiverse'”. Journal of Optics 13 (2): 024004.
[3]Zeng, Shuwen; Yu, Xia; Law, Wing-Cheung; Zhang, Yating; Hu, Rui; Dinh, Xuan-Quyen; Ho, Ho-Pui; Yong, Ken-Tye (2013). “Size dependence of Au NP-enhanced surface plasmon resonance based on differential phase measurement”. Sensors and Actuators B: Chemical 176: 1128.
[4]Strategic Technology Office (February 1, 2010). “Manufacturable Gradient Index Optics (M-GRIN)”. DARPA.
[5]Zeng, Shuwen; Yu, Xia; Law, Wing-Cheung; Zhang, Yating; Hu, Rui; Dinh, Xuan-Quyen; Ho, Ho-Pui; Yong, Ken-Tye (2013). “Size dependence of Au NP-enhanced surface plasmon resonance based on differential phase measurement”. Sensors and Actuators B: Chemical 176: 1128.
[6]Matson, John (2009-10-29). “Researchers Create an Electromagnetic “Black Hole” the Size of a Salad Plate”. Scientific American. Retrieved 2009-04-20.
[7]Narimanov, E. E., Kildishev, A. V. (2009). “Optical black hole: Broadband omnidirectional light absorber”. Applied Physics Letters 95 (4): 041106.
[8]Matson, John (2009-10-29). “Researchers Create an Electromagnetic “Black Hole” the Size of a Salad Plate”. Scientific American.
[9]Ward, A. J.; Pendry, J. B. (1996). “Refraction and geometry in Maxwell’s equations”. Journal of Modern Optics 43 (4): 773.
[10]Ward, A. J.; Pendry, J. B. (1996). “Refraction and geometry in Maxwell’s equations”. Journal of Modern Optics 43 (4): 773.
[11]Schurig, David; David Smith and Steve Cummer (2008). “Transformation Optics and Cloaking”. Center for Metamaterials & Integrated Plasmonics.
[12]Yarris, Lynn; Xiang Zhang (July 20, 2009). “Testing Relativity, Black Holes, and Strange attractors in the Laboratory”. Lawrence Berkeley National Laboratory.
[13]Ward, A. J.; Pendry, J. B. (1996). “Refraction and geometry in Maxwell’s equations”. Journal of Modern Optics 43 (4): 773.
[14]Leonhardt, Ulf; Philbin, Thomas G (2006). “General relativity in electrical engineering”. New Journal of Physics 8 (10): 247.
[15]Andreev, A. A. (2000), An Introduction to Hot Laser Plasma Physics, Huntington, New York: Nova Science Publishers, Inc.
[16]Andreev, A. A. (2000), An Introduction to Hot Laser Plasma Physics, Huntington, New York: Nova Science Publishers, Inc.
[17]Burke, P. J.; I. B. Spielman, J. P. Eisenstein, L. N. Pfeiffer, K. W. West (2000). “High frequency conductivity of the high-mobility two-dimensional electron gas”. Appl. Phys. Lett. 76 (6): 745–747.
[18]Matson, John (2009-10-29). “Researchers Create an Electromagnetic “Black Hole” the Size of a Salad Plate”. Scientific American.
[19]Burke, P. J.; I. B. Spielman, J. P. Eisenstein, L. N. Pfeiffer, K. W. West (2000). “High frequency conductivity of the high-mobility two-dimensional electron gas”. Appl. Phys. Lett. 76 (6): 745–747.
[20]Genov, Dentcho A.; Zhang, Shuang; Zhang, Xiang (2009-07-20). “Mimicking celestial mechanics in metamaterials”. Nature Physics 5 (9): 687–692.
[21]Brongersma, Mark; Shalaev, Vladimir (2010). “The case for plasmonics”. Science 328: 440–441. Bibcode:2010Sci…328..440B
[22]Zeng, Shuwen; Yu, Xia; Law, Wing-Cheung; Zhang, Yating; Hu, Rui; Dinh, Xuan-Quyen; Ho, Ho-Pui; Yong, Ken-Tye (2013). “Size dependence of Au NP-enhanced surface plasmon resonance based on differential phase measurement”. Sensors and Actuators B: Chemical 176: 1128.
[23]Schuller, Jon; Barnard, Edward; Cai, Wenshan; Jun, Young Chul et al. (2010). “Plasmonics for Extreme Light Concentration and Manipulation”. Nature Materials 9 (3): 193–204. Bibcode:2010NatMa…9..193S. doi:10.1038/nmat2630.
[24]Leonhardt, Ulf; Philbin, Thomas G. (2009). “Chapter 2 Transformation Optics and the Geometry of Light”. Progress in Optics. Progress in Optics 53: 69.
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