Type Of Polarization And Their Principle Of Electron Magnetic Wave Pdf


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Electric polarization , slight relative shift of positive and negative electric charge in opposite directions within an insulator , or dielectric , induced by an external electric field.

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Polarization state is an important characteristic of electromagnetic waves. The arbitrary control of the polarization state of such wave has attracted great interest in the scientific community because of the wide range of modern optical applications that such control can afford. Recent advances in metamaterials provide an alternative method of realizing arbitrary manipulation of polarization state of electromagnetic waves in nanoscale via ultrathin, miniaturized, and easily integrable designs.

In this chapter, we give a review of recent developments on polarization state manipulation of electromagnetic waves in metamaterials and discuss their applications in nanophotonics, such as polarization converter, wavefront controller, information coding, and so on. Metamaterials - Devices and Applications. Harnessing electromagnetic waves for modern nanophotonics applications often involves the control and manipulation of polarization state.

The ability to manipulate the polarization state of electromagnetic waves can enable us to control electromagnetic waves for a wide range of applications such as polarization manipulation, wavefront controlling, and optical communication [ 1 — 4 ]. Conventional approaches to manipulate the polarization state of electromagnetic waves employ bulky wave-plates, which are made of birefringent materials composed of crystalline solids and liquid crystals.

However, the inherent disadvantages in the size, collimation, and bandwidth of these configurations prevent optical system miniaturization and integration. Thus, realizing polarization state manipulation of electromagnetic waves in nanoscale has become one of the key problems for the development of modern optics and nanophotonics. Metamaterials are generally composed of subwavelength artificial nanostructures, which can overcome the physical limitations imposed by natural materials and provide exceptional capabilities for manipulating waves with greater precision.

Over the past decade, numerous novel optical properties have been demonstrated in this area, such as negative refractive index, super-lenses, cloaking, etc. The soul of metamaterials is the ability to realizing arbitrary manipulation of the electromagnetic waves in multiple parameters frequency, amplitude, phase, and polarization with multiple degrees of freedom, which make it possible for people to design devices with optical properties on demand.

Recently, metamaterials have been reported to provide a promising pathway toward the realizing of efficient manipulation of polarization state of electromagnetic waves via ultrathin, miniaturized, and easily integrable designs, which open up intriguing possibilities toward the realization of polarization state manipulation of electromagnetic waves in nanoscale and show infinite prospection in nanophotonics applications [ 4 , 5 , 15 — 17 ].

In this chapter, we will review the development of metamaterials in polarization state manipulation of electromagnetic waves and discuss its applications in nanophotonics, which will provide a guidance for its further designs and applications. The chapter is organized as follows:. In the second section, we begin with a brief introduction of polarization state of electromagnetic waves and give a review of the development process of metamaterials for polarization state manipulation.

In the third section, the fundamental applications of metamaterials in nanophotonics, such as wave plates, polarization converter, opt-isolator, arbitrary generation of vector beam, polarization-based wavefront-control, and so on will be discussed in detail.

In the fourth section, the polarization integrated metamaterials devices, such as tunable polarization controlling devices, photonic spin Hall effect, information coding and optical communication, and polarization-switchable phase holograms, will be discussed in detail.

In the fifth section, we will overlook the whole area of metamaterials-based polarization devices, summarize the main difficulties, possible solutions, and further applications in future. The polarization state of electromagnetic waves, which cannot be detected by human eyes, forms an important characteristic of such waves. The trajectory of Eq. For the plane wave whose wavefront is parallel transverse plane, the elliptical trajectory stays the same. Thus, the polarization state of plane wave can be described by a single ellipse.

Moreover, such polarization ellipse can be determined by its orientation and shape which can be characterized by two angles:. For other condition, the polarization state of electromagnetic waves is said to be elliptically polarized. Thus, the polarization state manipulation with metamaterials always involves the tailoring of the wave interference at the subwavelength scale by introducing the anisotropic optical resonance mode to effectively manipulate the magnitude and phase of electric components in two orthogonal directions.

Thus, the polarization state manipulation of electromagnetic waves in metamaterials always involves structures with two orthogonal resonance including elliptical nanoholes, L-shaped nanoparticles, crossed nanodipoles, nanoslits, and nanorods, as shown in Figure 1 [ 19 — 24 ]. Reprinted by permission from [19] copyright American Physical Society. Reprinted by permission from [20] copyright American Chemical Society.

Reprinted by permission from [22] copyright American Chemical Society. Reprinted by permission from [23] copyright American Chemical Society.

Reprinted by permission from [24] copyright Optical Society of America. However, the polarization state manipulative ability of initial complanate metamaterials with the above-mentioned structures is limited because of the limited interaction between electromagnetic waves and structures, thus the efficiency and bandwidth are lower than that required for practical applications.

Over the past decade, many efforts have been made in the scientific community to overcome the drawbacks of complanate metamaterials and improve the polarization state manipulation of electromagnetic waves in nanoscale with new types of metamaterials [ 25 , 26 ]. As one of the solutions, sandwich-like metamaterials constructed with anisotropic resonators, dielectric layer, and highly reflective metallic film have been proposed to provide an alternate way to realize effective polarization state manipulation in reflection mode as shown in Figure 2a and b [ 27 , 28 ].

The near-field interference in this type of designs improves the interaction between electromagnetic waves and metamaterials effectively, thus realizing effective polarization state manipulation of electromagnetic waves in reflection mode.

On the other hand, applications in modern nanophotonics always require nanoscale polarization state manipulation in transmission mode. Thus, sandwich-like metamaterials is out of work in this situation. Recently, the proposition of few-layer metamaterials makes it possible to realize effective polarization state manipulation in transmission mode as shown in Figure 2c and d [ 29 , 30 ].

The interference and near-field coupling between layers in few-layer metamaterials ensure that the energy of electromagnetic waves can be strongly redistributed and can effectively interact with the structures, resulting in polarization state manipulation with high efficiency and broadband in transmission mode. However, the above-mentioned metamaterials are all based on metallic structures, and thus the electromagnetic waves absorption and subsequent heat conversion in sandwich-like and few-layer metamaterials inevitably increase which impeded the applications of metallic structure-based metamaterials for polarization state manipulation of electromagnetic waves.

Recently, a different approach has emerged. The Mie resonance in high-index dielectric structures provides a novel way to realize anisotropic optical resonance [ 31 , 32 ].

Metamaterials based on all-dielectric nanoparticles as shown in Figure 2e and f overcome the energy loss of electromagnetic waves in metallic structure-based metamaterials and become an ideal selection for polarization state manipulation of electromagnetic waves. Reprinted by permission from Macmillan Publishers Ltd [28], Scientific reports copyright Reprinted by permission from [31] copyright Optical Society of America. In summary, metamaterials with the development of it can realize the effective controlling of amplitude and phase of electromagnetic waves in two orthogonal directions, which provide infinite possibilities for arbitrary manipulation of polarization state of electromagnetic waves in nanoscale.

Thus, the role of metamaterials for polarization manipulation devices in nanophotonics is no substitute. With the improvement of the relative research, metamaterial-based polarization manipulation devices have been widely proposed in recent years which will be discussed in detail in the next section.

As mentioned above, polarization state is one of the intrinsic properties of electromagnetic waves, which can always be resolved into different orthogonal basis, such as x -polarized and y -polarized, left-handed and right-handed waves. It is worth mentioning that the left-right-handed polarization corresponds to the spin of photons, which enables metamaterials with great abilities of polarization conversion to be a possible quantum candidate in large scale.

In modern optics and photonic applications, polarization conversion is often utilized in advanced communication, sensing, displayer, noise reduction, and so on. However, most of these applications come down to three categories: conversion of polarization and generation of vector beams, wave plates, and asymmetric transmission. In this section, we aim at providing an overall view on the applications and evaluating the possibilities of commercial utilization of metamaterials.

Metamaterials have shown to the world their unique design flexibility, compactness, and highly novel characteristics at its very first birth. Unlike the traditional method, in which polarization is often controlled with polarized molecules such as liquid crystals [ 33 ], birefringent crystals [ 18 ], or magneto-optic phenomenon Faraday Effect [ 34 ], metamaterials can directly manipulate strength and phase of electromagnetic waves at subwavelength scale.

Throughout the recent works, there are two kinds of metamaterials polarization converters that have shown their powerful ability to handle polarization. One is as shown in Figure 3a , which is an enhanced optical rotator of the zero-order transmitted electromagnetic waves through a silver film with an array of perforated S -shaped holes [ 36 ]. The fundamental mechanisms of these kinds of polarization rotators are as follows: the incident wave interacts with the subwavelength structure and creates orthogonal polarized component due to the surface plasmon polaritons SPPs , or localized surface plasmons LSPs , or both.

With elaborate design, the original polarized electric component can be cancelled due to near-field interference, and the orthogonal one is left over, thus a cross-polarization converter is achieved. Other states of polarization can also be accomplished with similar method because the complete orthogonal basis has been acquired.

The transmitted polarization depends on the thickness of the device, as shown in Figure 3b , which exhibits a tiny ellipticity, indicating the transmission can be roughly treated as a linearly polarized one [ 21 , 31 , 37 ].

Recently another design almost dominates the area of polarization conversion with metamaterials, as shown in Figure 3 c to 3 f. This kind of designs simultaneously manipulate the amplitude and phase of electric-magnetic components [ 35 ], [ 38 ]—[ 41 ], resulting in much higher degree of freedom for polarization conversion.

In Figure 3 c , the incident linearly polarized LP wave can be converted into left-circularly polarized LCP and right-circularly polarized RCP beams at sub-wavelength scale [ 38 ]. The difference of phase retardation between the LCP and RCP beams can be easily modified by varying the geometrical parameters of the nano-apertures, leading to continuously controllable optical activity.

Circularly to linearly polarized wave can also be achieved in [ 39 ], as shown in Figure 3 e and 3 f. The inset in Figure 3 f depicts the artistic rendering of the design. As amplitude ratio varies throughout the working waveband, indicating different orientation of transmitted wave when differing the incident wavelength, this device can hardly called a broadband quarter-wave plate. However, it is still a novel polarization converter, and may be utilized in a metasurface displayer to distinguish different colors.

Since this design is a time reversal symmetric system taking no account of the thermal loss , it can also be applied to convert linearly polarized wave to circularly polarized one.

In the experiment, the incident wave remains linearly polarized along the x axis. Reprinted by permission from [36] copyright American Physical Society. The insets show the polarization states and the corresponding degree of linear polarization DoLP for four metasurfaces.

Inset: artistic rendering of the circular-to-linear CTL polarization converter. Reprinted by permission from Macmillan Publishers Ltd [39], Scientific reports, copyright As mentioned above, the subwavelength characteristics of metamaterials enable people to modify polarization of electromagnetic waves pixel by pixel unit cell of the design , and to generate wave with different polarization in each cross-section of the outputs. As shown in Figure 4a , a radially polarized beam is generated by appropriately arranging the nano-apertures [ 14 ].

A far-field intensity profile of the radially polarized beam is shown in Figure 4b. Furthermore, with the in-plane field of SPPs combined, all types of polarization states can be achieved simultaneously [ 42 ], as shown in Figure 4c — e. This remarkable consequence results from that the in-plane field of SPPs with proper polarization states and phases can be selectively scattered out to the desired electromagnetic wave beams.

This design offers a novel route to achieve the full control of optical polarizations. However, all these devices are plasmonic based and the efficiency is limited by the intrinsic absorption loss. Although many researchers struggled to overcome this limitation by introducing multilayered structures or performing at reflectance mode [ 24 , 27 ], and so on, it can hardly be solved thoroughly due to the high conductivity of metals.

In recent years, high-contrast dielectric designs have been developed to enlarge the working efficiency and practicability of metamaterials [ 26 ]. The complete and simultaneous control over the polarization and phase profiles of electromagnetic waves offered by the proposed platform and the design technique enables the realization of integrated nano-optic devices, which is one of the greatest steps in modern optics and photonics.

Each region of the plasmonic metasurface is filled with one type of nano-aperture pairs marked by the number. Reprinted by permission from [14] copyright by John Wiley and Sons. The two different points can be chosen at will.

Reprinted by permission from Macmillan Publishers Ltd [35], Nature nanotechnology copyright Although full control of polarization is the primary issue with respect to polarization, wave plates are still worth discussing due to their wide applications in applied optics.

Normally wave plates are manufactured from birefringent crystals, which are really successful due to their high efficiency and accuracy.

In contrast, metamaterials once again provide a promising pathway toward the perfect wave plates with thickness less than a micrometer. As shown in Figure 5a , a broadband half-wave plate is accomplished by a nanorod layer and a metallic reflective ground plane sandwiched by a dielectric layer [ 28 ]. This phenomenon results from the asymmetric length of the long and short sides of the nanorod, which responds to the incident beams with different phase delay and radiative intensity.

Similarly, a quarter-wave plate can also be obtained with careful adjustment of dimensions of the structure. As shown in Figure 5c , the calculated results are in good agreement with the experimental ones. Although the designed wave plates are broadband and wide-angled, especially with high efficiency, a critical drawback still exists that they work in reflectance mode, compared to which transmission mode is often preferable because of its intrinsic convenience for experimental and commercial utilization.

Electric polarization

Birefringence is formally defined as the double refraction of light in a transparent, molecularly ordered material, which is manifested by the existence of orientation-dependent differences in refractive index. Many transparent solids are optically isotropic, meaning that the index of refraction is equal in all directions throughout the crystalline lattice. Examples of isotropic solids are glass, table salt sodium chloride, illustrated in Figure 1 a , many polymers, and a wide variety of both organic and inorganic compounds. The simplest crystalline lattice structure is cubic, as illustrated by the molecular model of sodium chloride in Figure 1 a , an arrangement where all of the sodium and chloride ions are ordered with uniform spacing along three mutually perpendicular axes. Each chloride ion is surrounded by and electrostatically bonded to six individual sodium ions and vice versa for the sodium ions. The lattice structure illustrated in Figure 1 b represents the mineral calcite calcium carbonate , which consists of a rather complex, but highly ordered three-dimensional array of calcium and carbonate ions. Calcite has an anisotropic crystalline lattice structure that interacts with light in a totally different manner than isotropic crystals.

We can get a good understanding of electromagnetic waves EM by considering how they are produced. Whenever a current varies, associated electric and magnetic fields vary, moving out from the source like waves. Perhaps the easiest situation to visualize is a varying current in a long straight wire, produced by an AC generator at its center, as illustrated in Figure 1. Figure 1. This long straight gray wire with an AC generator at its center becomes a broadcast antenna for electromagnetic waves. Shown here are the charge distributions at four different times.

The recorded biological effects range from alterations in the synthesis rates and intracellular concentrations of different biomolecules, to DNA and protein damage, which may result in cell death, reproductive declines, or even cancer 1 , 2 , 3 , 4 , 5 , 6 , 7. The intensities of radiation and durations of exposure in all these studies were significantly smaller than those of corresponding exposures from natural EMFs in the terrestrial environment. Moreover, the field intensities applied in the studies were several orders of magnitude smaller than physiological fields in cell membranes, or fields generated by nerve and muscle excitations 10 , Similarly, terrestrial electric and magnetic fields, or infrared radiation from every human body at normal temperature, have significantly larger incident intensities and exposure durations on any human than most artificial EMF sources 14 , 15 , Why is then the first beneficial while the latter seem to be detrimental? In the present study we shall attempt to explain theoretically that the increased adverse biological action of man-made EMFs is due to the fact that they are polarized in contrast to the natural ones.


the wave equation for electromagnetic waves follows from Maxwell's equations carry both.1 In Section we discuss polarization, which deals with the relative phases their present form in terms of discrete quantities, and then take the continuum limit (see what is the relation between the frequency and wavenumber?


Polarization (waves)

Electromagnetic radiation, as the name implies, involves the propagation of both electric and magnetic forces. At each point in an ordinary light beam, there is a component electric field and a component magnetic field, which are perpendicular to each other and oscillate in all directions perpendicular to the direction in which the beam propagates. In plane-polarized light the component electric field oscillates as in ordinary light, except that the direction of oscillation is contained within a single plane. Likewise, the component magnetic field oscillates within a plane, the planes in question being perpendicular to each other.

Polarization state is an important characteristic of electromagnetic waves. The arbitrary control of the polarization state of such wave has attracted great interest in the scientific community because of the wide range of modern optical applications that such control can afford. Recent advances in metamaterials provide an alternative method of realizing arbitrary manipulation of polarization state of electromagnetic waves in nanoscale via ultrathin, miniaturized, and easily integrable designs.

Polarization also polarisation is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves , such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves , gravitational waves , [6] and transverse sound waves shear waves in solids.

Named after esteemed physicist James Clerk Maxwell, the equations describe the creation and propagation of electric and magnetic fields.

19.1: Plane-Polarized Light and the Origin of Optical Rotation

A light wave is an electromagnetic wave that travels through the vacuum of outer space. Light waves are produced by vibrating electric charges. The nature of such electromagnetic waves is beyond the scope of The Physics Classroom Tutorial. For our purposes, it is sufficient to merely say that an electromagnetic wave is a transverse wave that has both an electric and a magnetic component. The transverse nature of an electromagnetic wave is quite different from any other type of wave that has been discussed in The Physics Classroom Tutorial.

 Работайте, - поторопил Фонтейн. На ВР последняя стена стала уже тоньше яичной скорлупы. Джабба поднял брови. - Хорошо, это ничего не дает. Начнем вычитание. Я беру на себя верхнюю четверть пунктов, вы, Сьюзан, среднюю.

Если мы - охранники общества, то кто будет следить за нами, чтобы мы не стали угрозой обществу. Сьюзан покачала головой, не зная, что на это возразить. Хейл улыбнулся: - Так заканчивал Танкадо все свои письма ко. Это было его любимое изречение. ГЛАВА 32 Дэвид Беккер остановился в коридоре у номера 301. Он знал, что где-то за этой витиеватой резной дверью находится кольцо. Вопрос национальной безопасности.


not emerge, and there would be no electromagnetic theory of light. The two circularly polarized waves () form an equally acceptable set of basic fields for​.


Polarization

 На этой машине нет автоматического определителя номера, сэр. Я позвоню в телефонную компанию. Я уверена, что они смогут сказать.

 Я же сказал. Я прочитал все, что вы доверили компьютеру. - Это невозможно.

Беккер кивнул, плохо соображая, какая тут связь. - Такая прическа была у Табу в день гибели.  - Парень снова сплюнул.  - Поэтому все его последователи, достойные этого названия, соорудили себе точно такие .

Перечень этой бесценной информации был нескончаем. Всяческие вторжения, способные повредить американской разведке, абсолютно исключались. Конечно, офицеры АНБ прекрасно понимали, что вся информация имеет смысл только в том случае, если она используется тем, кто испытывает в ней необходимость по роду работы.

 Твое сокровище в беде, коммандер, - пробормотал .

Командный центр главного банка данных располагался на глубине шестидесяти с лишним метров от земной поверхности, что обеспечивало его неуязвимость даже в случае падения вакуумной или водородной бомбы. На высокой рабочей платформе-подиуме в центре комнаты возвышался Джабба, как король, отдающий распоряжения своим подданным. На экране за его спиной светилось сообщение, уже хорошо знакомое Сьюзан. Текст, набранный крупным шрифтом, точно на афише, зловеще взывал прямо над его головой: ТЕПЕРЬ ВАС МОЖЕТ СПАСТИ ТОЛЬКО ПРАВДА ВВЕДИТЕ КЛЮЧ_____ Словно в кошмарном сне Сьюзан шла вслед за Фонтейном к подиуму.

Сначала она едва заметно вздрогнула, словно от озноба, и тут же ее захлестнула волна отчаяния. Приоткрыв дрожащие губы, она попыталась что-то сказать, но слов не последовало. Не спуская со Стратмора ледяного взгляда, Сьюзан сделала шаг вперед и протянула к нему руку с зажатым в ней предметом. Стратмор был почти уверен, что в руке Сьюзан сжимала беретту, нацеленную ему в живот, но пистолет лежал на полу, стиснутый в пальцах Хейла.

 - С руки Танкадо исчезло кольцо. - Да. К счастью, Дэвид это обнаружил.

Но решил, что хочет от этого парня слишком многого. - Мне нужна кое-какая информация, - сказал. - Проваливал бы ты отсюда. - Я ищу одного человека.

Спереди на него быстро надвигалась стена.

2 Comments

Jim D.
03.05.2021 at 13:36 - Reply

This relation implies that electromagnetic waves are disper- the form. E = E0eiω(z c −t). (5) which moves in the z direction at the speed of light. We say a plane wave is linearly polarized if there is no phase difference between Ex and Ey. Now that we understand the mathematics of polarizations, what is the physics?

Qrios
07.05.2021 at 10:07 - Reply

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