Polarization of electromagnetic wave (EM) refers to the spatial trajectory of the endpoint of the electric field vector changing with time at a given spatial-point in the propagation space of the EM wave. For various planar EM waves, the spatial trajectory of the endpoint of the time-varying electric field vector at any spatial-point may be a straight line, a circle or an ellipse, therefore, the polarization of EM wave can be divided into three types: linear polarization (LP), circular polarization (CP) and elliptical polarization (EM). Different polarized EM waves have different propagation characteristics, appropriate polarizations should be chosen for EM waves propagating in various propagation environments, so it is of great significance to effectively modulate the polarization of EM wave.
The polarization converter is a functional device used to modulate the polarization of EM wave. The traditional polarization converters are almost all made of natural materials such as quartz or liquid crystal with birefringence effect , , so they usually have the disadvantages of large size, poor strength and narrow operating frequency band. In fact, the electromagnetic properties of natural materials depend on the composition and arrangement of their moleculars, similarly, for metamaterials, as a kind of artificial composite material composed of a periodic or quasi-periodic arrays of basic unit cells , , their equivalent permittivity and permeability can both be regulated by changing the structure and arrangement of their basic unit cells, therefore, metamaterials have many exotic electromagnetic properties that natural materials do not possess, , , , . Metasurfaces, as a two-dimensional planar metamaterials, have the advantages of simple structure, low loss, easy processing, etc., however, they also have a variety of strange electromagnetic properties, and can freely adjust the amplitude, , , phase, ,  and polarization of EM waves, so metasurfaces have been widely studied. In recent years, based on metasurfaces, considerable progress has been made in the work of polarization conversion, a large number of polarization conversion metasurfaces (PCMs) with different properties have been proposed successively, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , . However, the previously proposed PCMs all take LP or CP wave as the operating object, they can either make LP wave be converted to cross-polarized, , , , , , , , , , , , , ,  or CP one, , , , , , , , , , , , , , , , ,  after reflection or transmission, or make CP wave realize cross-polarized transmission, ,  or co-polarized reflection, , , , , or circular-to-linear polarization conversion, , , so far, there is still no relevant literature reporting on how to effectively modulate the polarization of EP waves.
In order to effectively modulate the polarization of any polarized wave, in this work, through detailed theoretical analysis, it is found that any polarized wave can be decomposed into two orthogonal LP components with equal amplitude, and its polarization can be effectively modulated by changing the phase difference between the two equal-amplitude orthogonal LP components. Based on this conclusion, a reflective PCM with an elliptical conductor patch as the unit cell is proposed in this work, and it can achieve arbitrary polarization conversion by changing the direction and size of the elliptical conductor patch in its unit cell.
For various EM waves, the most common polarization is EP. The polarization characteristics of an EP wave can be described quantitatively according to the geometric parameters of the elliptic spatial trajectory of the endpoint of the time-varying electric field vector in it. The major axis direction can indicate the polarization direction; the length ratio of the major axis to the minor axis, known as the axis ratio (AR), can indicate the roundness of the polarization, when the AR is equal to
Design and simulation
Based on the above theoretical analysis, a reflective PCM is proposed, its unit cell structure is composed of an elliptical conductor patch printed on the grounding dielectric substrate and covered by a dielectric layer, as shown in Fig.2. The period of the unit cell is mm, the grounding dielectric substrate and the top dielectric layer are both chosen as a PTFE with a relative permittivity of and a loss tangent of tan , but their thicknesses are = 3.40 mm and = 3.35
Finally, in order to experimentally verify the polarization conversion performance of the PCM, an experimental sample is fabricated and measured. The experimental sample is shown in Fig.5(a) when the top dielectric layer is not added, it contains 30×30 unit cells, and the total size is 240×240mm, the major axis of the elliptical conductor patch in each unit cell is in the -axis direction, and the lengths of the major and minor axes are 2 and 2, respectively. For the
In this work, to effectively modulate the polarization of any polarized wave, a detailed theoretical analysis is carried out; based on the theoretical analysis, a reflective PCM with an elliptical conductor patch as unit cell is proposed. Because the PCM is an orthogonal anisotropic structure symmetrical to the U- and V-axes, and the phase difference between and can be close to any constant in the frequency range of 7–23GHz by changing the direction and size of the elliptical
Declaration of Competing Interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Baoqin Lin reports was provided by Xijing University. Baoqin Lin reports a relationship with Xijing University that includes: employment.
This work was supported by the National Natural Science Foundation of China(Grant No. 62072378).
A multifunctional broadband polarization rotator based on reflective anisotropic metasurface
Physics Letters A, Volume 470, 2023, Article 128785
In this paper, both linear cross-polarization conversion (CPC) and linear-to-circular or circular-to-linear polarization conversion based on a single reflective anisotropic metasurface are realized and experimentally demonstrated. The multifunctional CPC metasurface in the frequency range of 5.9-6.4 GHz and 8.7-17.7 GHz has a fractional band of 68.2%, and the efficiency reaches almost 100% under plasma resonance. In addition, the metasurface acts as a high efficiency circular-polarizer in the range of 6.7–8.4 GHz. Moreover, the polarization transforming functionality of the structure is stable for the change of incident angle for both x-polarized or transverse-electric (TE) and y-polarized or transverse-magnetic (TM) illumination up to 45∘. It can be seen that the anticipated hypersurface has potential applications in reflector antenna, satellite communication and radar.
Absorption properties and mechanisms of metallic moth-eye structures
Optics Communications, Volume 540, 2023, Article 129487
The antireflection and absorption properties of non-metallic moth-eye structures have been intensively studied, however the research on those of metallic moth-eye structures, especially their absorption mechanisms, is far from enough. In this paper, the absorption properties and mechanisms of a metallic Au moth-eye structure are studied in detail. The results show that broadband perfect absorption covering the entire visible to the near infrared range with polarization independence and in a wide incident angle range can be easily realized using a single-layer single-material Au moth-eye structure. As for the absorption mechanism, in the short wavelength range of 300 nm–550nm, due to the high loss of the Au material, the antireflection effect plays a main role. While in the long wavelength range of 550 nm–1000nm, the widely accepted absorption mechanisms (the antireflection effect as well as the cascaded multiple plasmonic resonances, and even the combination of them) cannot completely account for the broadband perfect absorption. We found that the adiabatic nanofocusing effect of the plasmonic resonances enabled by the ultra-sharp air grooves plays a key role in the absorption. It is the nanofocusing effect that effectively increases the absorption to nearly 100% in a broad wavelength band. These findings provide a deeper insight into the absorption mechanisms of metallic moth-eye structures and offer an effective guide to explore demanded excellent absorption performance.
Multi-channel chaotic cross-correlation fiber loop ring down sensing
Optics Communications, Volume 540, 2023, Article 129502
A novel optical sensing of the multi-channel chaotic cross-correlation fiber loop ring down (FLRD) sensing is proposed and demonstrated experimentally. The proposed sensing system consist of the multiple FLRD sensors within a serial architecture. The chaotic laser was divided into reference signal and the detection signal by an optical coupler and measured the cross-correlation coefficient ring down time of chaotic signal to obtain the shorter response time. The three-channels FLRD chaotic signal are achieved by the cross correlation experimentally to verify the proposed concept. The simultaneous detection of temperature and refractive index is studied by the dual-channel experiment. The experimental results show that the high sensitivity of each channel can be achieved without interfering each other. We believe the proposed sensing system have great potential for short-distance and multi-point detection.
© 2023 Elsevier B.V. All rights reserved.
In general, an arbitrary polarization state α can be fully described by two parameters, namely, the main axis angle ψ and the ellipticity angle χ (Fig. 2a), which can be represented as a point with coordinates (2ψ, 2χ) on a Poincaré sphere (the red star in Fig.What is polarization conversion? ›
Polarization conversion of y-polarized field into x-polarized field, y-polarized electric field is resolved into two orthogonal components along u- and v-axis, u-component is reflected in phase while v-component is reflected out of phase resulting into reflected field along x-axis.How do you find the polarization direction of a wave? ›
The “handedness” of the polarization is observed by viewing the rotation of the wave vector as it travels. If your thumb points in the direction of propagation, your fingers should curl in the direction of polarization, hence the use of “hand” in the polarization description.What is polarization conversion efficiency? ›
The cross polarization conversion efficiency is defined as “Simulated polarization conversion efficiency as a function of wavelength. This efficiency is defined as the fraction of the incident circularly polarized optical power that is converted to transmitted optical power with opposite helicity.”What are the 2 types of polarization signal? ›
Linear polarization is the most common polarization.
Vertical polarization refers to the oscillation of an antenna's electrical field on the vertical plane, whereas horizontal polarization refers to the oscillation on the horizontal plane.
The metasurface has three plasmonic resonances with a polarization conversion ratio (PCR) of almost 100% in the lower two frequencies bands and 95% in the higher frequency band.How do you convert circular polarization to linear polarization? ›
Circularly polarized light can be converted into linearly polarized light by passing it through a quarter-waveplate. Passing linearly polarized light through a quarter-waveplate with its axes at 45° to its polarization axis will convert it to circular polarization.What are different polarization techniques? ›
The three basic ways to artificially polarize light are linear polarization, circular polarization, and elliptical polarization, with the latter two methods serving as extensions of linear polarization and not widely used in machine vision.
Polarization P in its quantitative meaning is the amount of dipole moment p per unit volume V of a polarized material, P = p/V.What is the formula of state of polarization? ›
An arbitrary polarization state can be represented by: | E 〉 = | E R 〉 〈 E R | E 〉 + | E L 〉 〈 E L | E 〉 . For example, for E = Ex we obtain: | E x 〉 = | E R 〉 〈 E R | E x 〉 + | E L 〉 〈 E L | E x 〉 .
Yes. Reason: Angle of polarisation iB=tan−1(n) and since refractive index varies as inverse of square of wavelength so angle of polarisation decreases with increase of wavelength.What are the advantages of polarization modulation? ›
The polarization modulation provides an additional degree of freedom for the modulation of the carrier waves. Furthermore, the polarization modulation is suitable to realize simple transceivers using RF signal processing. Antennas are the most important key parts of the polarization modulation systems.How do you calculate power conversion efficiency? ›
For an electrical power conversion process, efficiency is measured simply by dividing the output power in watts by the input power in watts and is expressed as a percentage.Why circular polarization is better than linear polarization in antenna? ›
Absorption: As stated above, radio signal can be absorbed depending on the material they come in contact with. Different materials absorb the signal from different planes. As a result, circular polarized antennas give you a higher probability of a successful link because it is transmitting on all planes.Which polarization is best? ›
In general, ground-wave propagation is better with a vertically polarized antenna, while sky-wave performance is better with horizontal polarization. Circular polarization is widely used with satellites as their orientation with respect to the ground station and other satellites is constantly changing.What is the biggest cause of polarization? ›
Causes. There are various causes of political polarization and these include political parties, redistricting, the public's political ideology, the mass media, and political context.What are the four mechanisms of polarization? ›
There are fundamentally four divisions of polarization mechanisms. They are Electronic polarization, dipolar or Orientation polarization, Ionic polarization and Interfacial polarization.What is the difference between S and P polarization? ›
P-polarized light (from the German word parallel) has its electric field polarized parallel to the plane of incidence. S-polarized light (from the German word senkrecht) is perpendicular to the plane of incidence.What is the difference between S polarization and P polarization? ›
S-polarization refers to the component perpendicular to the plane while P-polarization refers to the component in the plane. Examples of the depictions of linearly polarized light are illustrated in the remaining figures of the section.What is the difference between co polarization and cross polarization? ›
Co-polar means when the polarization of both the transmitting (test antenna) and receiving antenna (reference horn antenna) is the same and cross polarization means when the polarization of both the antennas are different.
In electromagnetic theory, metasurfaces modulate the behaviors of electromagnetic waves through specific boundary conditions rather than constitutive parameters in three-dimensional (3D) space, which is commonly exploited in natural materials and metamaterials.What is a metasurface used for? ›
Metasurfaces have unique abilities to block, absorb, concentrate, disperse or guide waves on the surface at a grazing incidence angle and in space at normal and oblique incidence, from microwave to visible frequencies.What is metasurface hologram for polarization measurement? ›
A reflective-type metasurface hologram is used to generate holographic images of graphene pattern. The ellipticity and helicity of the incident light are measured based on the intensities of the neighboring light spots, corresponding to two opposite circular polarization states.Which is better linear or circular polarization? ›
The short answer is that both Linear and Circular Polarizers do the same thing. The actual polarization effects such as reducing reflections on glass surfaces, increasing color saturation in foliage, darkening a blue sky are the same with both Linear and Circular polarizers.Is circular polarization better than linear? ›
If all the tags you need to read will be on the same plane and aligned with the plane of the antenna, then you should consider a linear polarized antenna. If your tag orientation is not something that will be reliable or consistent, then you will likely need to use a circular polarized antenna.What are the techniques to achieve circular polarization? ›
Circular polarization is generated by truncating two opposite edges from a circular patch antenna at 45° to the feed. The truncation splits the field into two orthogonal modes with equal magnitude and 90° phase shift.What is the most common technique for polarizing light? ›
The most common method of polarization involves the use of a Polaroid filter. Polaroid filters are made of a special material that is capable of blocking one of the two planes of vibration of an electromagnetic wave.What are the two methods of producing polarized light? ›
The phenomenon of confining the vibrations of the electric vector in a specific direction perpendicular to the direction of wave motion is called polarisation, The method of producing plane polarised light is reflection The other methods are by refraction, double refraction, scattering and selective absorption.What is the mathematical expression for linear polarization? ›
(0,1,0)(θ=π/2,ϕ=ϕ/2) corresponds to right circularly polarized light |R⟩, and (0,0,1) or θ=0 to linear polarization in the ˆx direction: |ˆx⟩.What is polarization directly proportional to? ›
Polarising power of the cation is directly proportional to the charge on a cation and inversely proportional to the size of the cation. In other words, the greater the charge, the higher the polarising power. The smaller the cation, the higher the polarising power.
This is because the spins of the ferromagnetic material align themselves parallel to the external magnetic field. Due to the magnetic polarization, the magnetic flux is considerably larger - the magnetic field becomes stronger.What factors affect polarization? ›
We need to know that the polarizability can be affected by many factors such as molecular size, number of electrons, molecular orientation and also the forces of dispersion. Polarization can be the interaction between non-polar atoms, molecules and electrically charged species.Is polarization a quantum effect? ›
The polarization of a photon is a two-state quantum-mechanical system. Just as the classical equivalent of a beam of light can be polarized into a coherent pattern of electromagnetic waves, on the quantum level, each individual photon, the smallest possible energy packet in that wave, can have a polarization state.What are the disadvantages of circular polarization? ›
Following are the drawbacks or disadvantages of Circular Polarization: ➨It makes cost of antenna system higher. ➨It offers slightly lower cross pol isolation. ➨It offers shorter read range for RFID reader compare to linear polarization.Why is circular polarization used? ›
use in radar
…are asymmetrical, the use of circular polarization can enhance the detection of aircraft in rain. With circular polarization, the electric field rotates at the radar frequency.
By using modulation to transmit the signals through space to long distances, we have removed the need for wires in communication systems. The technique of modulation helped humans to become wireless.What do you mean by ideal conversion efficiency? ›
Conversion Efficiency is the amount of energy produced as a percentage between the useful output of an energy conversion machine and the input.What is the formula for effectiveness? ›
Efficiency can be expressed as a ratio by using the following formula: Output ÷ Input. Output, or work output, is the total amount of useful work completed without accounting for any waste and spoilage. You can also express efficiency as a percentage by multiplying the ratio by 100.How do you calculate the efficiency of a PV module? ›
If a panel the same size instead produced 200W of power, then its efficiency is 200W/1000W x 100 = 20%. If we instead express this in kW then the equation becomes even simpler, as 0.2kW/1kW = 0.2 so the sun's power can be ignored in the calculation. The ratio is multiplied by 100 to give an answer in percentage.What are the disadvantages of linear polarization in antenna? ›
Drawbacks or disadvantages of Linear Polarization
➨Polarization adjustment required. ➨Polarization changes as per latitude and longitude of the place. ➨Greater chance of problems due to cross pol interference. ➨Linearly polarized waves are subjected to faraday rotation in the ionosphere layer.
Vertical polarisation: Antennas consisting of a single vertical element are widely used. The vertically polarised antenna provides a low angle of radiation which enables it to provide good long distance transmission and reception.Why does polarization only work with transverse waves? ›
Only transverse waves can be polarized. Longitudinal waves cannot be polarized. The reason behind this is that the transverse waves can vibrate in all directions perpendicular to the direction of propagation. It is therefore feasible to continue the vibration to a single plane.What is polarization example in psychology? ›
One example of informational influence within group polarization is jury verdicts. Multiple studies have shown that jury members in civil trials as a group often decided on punitive damage awards larger or smaller than they would have chosen individually.What does arbitrary mean in power? ›
having unlimited power; uncontrolled or unrestricted by law; despotic; tyrannical: an arbitrary government.What is the polarization process in psychology? ›
Polarization is defined as the process in which two entities (individuals or groups of people) move toward opposite extremes of a continuum of viewpoints or opinions.What is polarization in persuasion? ›
Persuasive Arguments Theory
If the group of arguments that the group members draw in favor of a more extreme position than the mean of the initial positions, then polarization is likely to occur (Friedkin, 1999).
- To differentiate between transverse and longitudinal waves.
- Used in sunglasses to cut of unwanted reflected light.
- Used to check chirality of organic compounds.
- They are used in 3D movies and 3D glasses.
One of the most common and practical applications of polarization is the liquid crystal display (LCD) used in numerous devices including wristwatches, computer screens, timers, clocks, and a host of others.What is polarization in simple words? ›
: division into two sharply distinct opposites. especially : a state in which the opinions, beliefs, or interests of a group or society no longer range along a continuum but become concentrated at opposing extremes.What is an example of arbitrary? ›
Something that's arbitrary seems like it's chosen at random instead of following a consistent rule. Team members would dislike their coach using a totally arbitrary method to pick starting players. Even though arbitrary comes from a word meaning "judge" (arbiter), that doesn't mean judges are always fair.
The doctrine of arbitrariness deals under Article 12 of the Constitution of India. Article 12 of the Constitution allows classifying the person for the application of law and not to differentiate their rational relationship to be achieved by law which otherwise leads to the violation.What are examples of something arbitrary? ›
- An arbitrary number has been assigned to each district.
- I don't know why I chose that one; it was a completely arbitrary decision.
- Although arbitrary arrests are illegal, they continue to occur in many parts of the country.
There are essentially four types of polarization mechanisms: (i) electronic, (ii) ionic, (iii) dipole and (iv) interfacial.What is the principle of polarization? ›
Polarization (also polarisation) is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave.What is polarization in the nervous system? ›
When the inside of the plasma membrane has a negative charge compared to the outside, the neuron is said to be polarized. Any change in membrane potential tending to make the inside even more negative is called hyperpolarization, while any change tending to make it less negative is called depolarization.How does group polarization affect behavior? ›
Group polarization is the idea that groups tend to make decisions that are more extreme compared to the original thoughts of individual group members. The change is influenced by the collective involvement of other members, which tends to amplify one's opinions and attitudes.How can a person avoid polarization? ›
All the skills of communication, conflict resolution, and collaboration are ways to prevent conflict from escalating into polarization which divides a community. However, it is important to pay attention for warning signs because polarization can be so damaging.