by S Berthier · 2014 · Cited by 18 — Numerous other organisms that produce circularly polarized light by reflection, mainly beetles of the Scarabaeidae family, have also been identified and ...

where n is the refractive index of the medium, q(i) is the angle of incidence, and q(r) is the angle of refraction. When incident light is polarized in this way, it is often referred to as glare. On unusually bright days, the glare caused by sunlight on a roadway or a field of snow, may be almost blinding to the human eye.

Linearly polarized light

Pigment for paints, oilcloths, linoleum, leather, dental rubber, etc., especially in the form of lithopone; mixed with ZnO as "mineral white." Anhydrous zinc sulfide is used in x-ray screens and with a trace of a radium or mesothorium salt in luminous dials of watches; also television screens.

zinc sulphide: A yellow-whitewater-soluble solid, ZnS. It occursnaturally as sphalerite (see also zincblende) and wurtzite. The compoundsublimes at 1180°C. It is used as apigment and phosphor.

Zinc sulfide is well known as an optical coating material for its high refractive index (~2.35 at 500 nm) and very broad transmittance range from 400 nm up to 14 µm. It allows for coatings in the IR and VIS range with good environmental durability, and can be evaporated rapidly from e-beam and resistance heated sources. It is used as a semiconductor and in photo optic applications. Copperactivated zinc sulfides are the most widely used phosphors for safety purposes. Zinc sulfide and white lead are sometimes used in coating materials because of their fungicidal properties and to neutralize acid to protect against corrosion.

Circularly polarized light

May 6, 2014 — Depth of focus in optics is a measure of the tolerance of placement of the image plane with respect to the lens. In photography, depth of ...

Furthermore, laser light is monochromatic and coherent. White light is a jumble of colored light waves. Each color has a different wavelength. If all the wavelengths but one are filtered out, the remaining light is monochromatic. If these waves are all parallel to one another, they are also coherent: the waves travel in a definite phase relationship with one another. In the case of laser light, the wave crests coincide and the troughs coincide. The waves all reinforce one another. It is the monochromaticity and coherency of laser light that makes it ideal for recording data on optical media such as a CD as well as use as a light source for long haul fiber-optic communications.

Inhalation of material may be harmful. Contact may cause burns to skin and eyes. Inhalation of Asbestos dust may have a damaging effect on the lungs. Fire may produce irritating, corrosive and/or toxic gases. Some liquids produce vapors that may cause dizziness or suffocation. Runoff from fire control may cause pollution.

P-polarized light

Physicist Gordon Gould invented the laser in 1958. The first working model was built in 1960 by T.H. Maiman. It contained a synthetic, cylindrical ruby with a completely reflecting silver layer on one end and a partially reflecting silver layer on the other. Ruby is composed of aluminum oxide with chromium impurities. The chromium atoms absorb blue light and become excited; they then drop first to a metastable level and finally to the ground (unexcited) state, giving off red light. Light from a flash lamp enters the ruby and excites most of the chromium atoms, many of which fall quickly to the metastable level. Some atoms then emit red light and return to the ground state. The light waves strike other excited chromium atoms, stimulating them to emit more red light. The beam bounces back and forth between the silvered ends until it gains enough energy to burst through the partially silvered end as laser light. When most of the chromium atoms are back in the ground state, they absorb light, and the lasing action stops. In continuous-wave lasers, such as the helium-neon laser, electrons emit light by jumping to a lower excited state, forming a new atomic population that does not absorb laser light, rather than to the ground state.

Laser light has several features that are significantly different from white light. To begin with, light from most sources spreads out as it travels, so that much less light hits a given area as the distance from the light source increases. Laser light travels as a parallel beam and spreads very little.

The laser uses a process called stimulated emission to amplify light waves. (One method of amplification of an electromagnetic beam is to produce additional waves that travel in step with that beam.) A substance normally gives off light by spontaneous emission. One of the electrons of an atom absorbs energy. While it possesses this energy, the atom is in an excited state. If the electron gives off this excess energy (in the form of electromagnetic radiation such as light) with no outside impetus, spontaneous emission has occurred.

Unpolarizedlaser

A yellowish-white powder in a liquid. Insoluble in water and denser than water. Primary hazard is to the environment. Immediate steps should be taken to limit spread to the environment. Easily penetrates the soil to contaminate groundwater and nearby waterways.

This nomenclature arises from the fact that the tip of the electric field vector traces out an ellipse in the plane normal to the direction of wave propagation.

Production is similar to that of lithopone. A Na2S solution is mixed with a zinc salt solution under precisely controlled conditions. The resulting zinc sulfide precipitate is calcined and processed to give the finished product. Na2S + ZnSO4 →ZnS + Na2SO4.

S-polarization vs p-polarization

The reflector directs most of the light towards the Fresnel lens, which then corrals the illumination into a beam. Encasing all of this is a housing that ...

Zinc sulfide(Sachtolith) is mainly used in plastics. Functional properties such as lightening and hiding power are criteria for the use of Sachtolith. It has proved to be very useful for coloring many thermoplasts. During the dispersion process it does not cause abrasion of metallic production machinery or adversely effect the polymer, even at high operating temperatures or during multistage processing. Even ultrahigh molecular mass thermoplasts can be colored without problems. In glass-fiber-reinforced plastics, the soft texture of Sachtolith prevents mechanical fiber damage during extrusion. Sachtolith is also used as a dry lubricant during the fabrication of these materials. The low abrasiveness of Sachtolith prolongs the operating life of stamping tools used in the manufacture of industrial rubber articles. The lightfastness and ageing resistance of many elastomers are improved by using Sachtolith. It is also used as a dry lubricant for roller and plain bearings, and as a white pigment for greases and oils.

Another interesting use of light polarization is the liquid crystal display (LCD) utilized in applications such as wristwatches, computer screens, timers, and clocks. These devices are based upon the interaction of rod-like liquid crystalline molecules with an electric field and polarized light waves. The liquid crystalline phase exists in a ground state that is termed cholesteric, in which the molecules are oriented in layers and each successive layer is slightly twisted, forming a spiral pattern. When a polarized light wave interacts with the liquid crystalline phase, the wave is twisted by an angle of approximately 90 degrees with respect to the incident wave. This angle is a function of the helical pitch of the cholesteric liquid crystalline phase, which is dependent upon the chemical composition of the molecules. However, the helical pitch may be fine-tuned if small changes are made to the molecules.

Zinc sulfide is well known as an optical coating material for its high refractive index (~2.35 at 500 nm) and very broad transmittance range from 400 nm up to 14 µm. It allows for coatings in the IR and VIS range with good environmental durability, and can be evaporated rapidly from e-beam and resistance heated sources. It is used as a semiconductor and in photo optic applications. Copperactivated zinc sulfides are the most widely used phosphors for safety purposes. Zinc sulfide and white lead are sometimes used in coating materials because of their fungicidal properties and to neutralize acid to protect against corrosion.

Edmund Optics has been a leading producer of ... by EDMUND OPTICAL FILTERS by ... BG3 BG36 BG38 BG39 BG40 BG42 BG50 BG55 BG60 BG61 BG62 BG63 BG64 BG7 ...

When current is applied to the electrodes, however, the liquid crystalline phase aligns with the current and loses the cholesteric spiral pattern. Therefore, light passing through a charged electrode is not twisted and is blocked by Polarizer 2. By coordinating the voltage on the seven positive and negative electrodes, the display is capable of rendering the numbers 0 through 9. In this example, the upper right and lower left electrodes are charged and, consequently, block light from passing through them, which results in the formation of the number "2".

If a wave emitted by one excited atom strikes another, it stimulates the second atom to emit energy in the form of a second wave that travels parallel to and in step with the first wave. This stimulated emission results in amplification of the first wave. If the two waves strike other excited atoms, a large coherent beam builds up. But if they strike unexcited atoms, they are simply absorbed, and the amplification is then lost. In the case of normal matter on Earth, the great majority of atoms are not excited. As more than the usual number of atoms become excited, the probability increases that stimulated emission rather than absorption will take place.

Polarization of laser beamexperiment

Obstacles with a large number of slits (more than, say, 20 to the millimetre) are called diffraction gratings. These were first developed by Fraunhofer in the ...

Acktar™ offers Fractal Black™, a low reflectance, high emissivity coating for straylight suppression from the UV through LWIR.

Zinc sulfide (ZnS) is used as a pigment and to make white glass, rubber, and plastics. It is an ingredient in pesticides, luminous paints, and X-ray and television screens.

Lens Mounts & Lens Descriptions · EF. Lenses designed for full-frame Canon DSLRs, such as the 5D, 6D, and 1D families. · FX. These lenses are designed for full- ...

Yellowish-white powder. ZnS exists in two crystalline forms, α (wurtzite) and β (sphalerite). Stable if kept dry. α: d 3.98. β: d 4.102, changes to α form at 1020C. Sublimes at 1180C. Soluble in acids; insoluble in water.

Linearpolarization

The basic concept of polarization is illustrated above in Figure 1. In this example, the electric field vectors of the incident light are vibrating perpendicular to the direction of propagation in an equal distribution of all planes before encountering the first polarizer, a filter containing long-chain polymer molecules that are oriented in a single direction. Only the incident light that is vibrating parallel to the polarization direction is allowed to continue propagating unimpeded. Therefore, since Polarizer 1 is oriented vertically, it only permits the vertical waves in the incident beam to pass. However, the waves that pass through Polarizer 1 are subsequently blocked by Polarizer 2 because it is oriented horizontally and absorbs all of the waves that reach it due to their vertical orientation. The act of using two polarizers oriented at right angles with respect to each other is commonly termed crossed polarization and is fundamental to the practice of polarized light microscopy.

The use of zinc sulfide and barium sulfate in contact with foods is permitted by the FDA (United States) and in most European countries. Some restrictions apply in France, Italy, the United Kingdom, and Czechoslovakia. Soluble zinc is toxic in large amounts, but the human body requires small quantities (10–15 mg d−1) for metabolism. Zinc sulfide is harmless in the human due to its low solubility. The acid concentration in the stomach and the rate of dissolution following ingestion are not sufficient to produce physiologically significant quantities of soluble zinc. LD50 values in the rat exceed 15 g kg−1. No cases of poisoning or chronic damage to health have been observed in the manufacture of zinc sulfide pigments.

Oct 12, 2018 — If you just bought a laser collimator, please make sure it is collimated! You can do that by placing it on a table not too far from a bright ...

What is a retarder that is used on semi-trucks? First of all some information for clarification: Retarders are not engine brakes, they only ...

The hazard of driving, or performing other daily activities, with a large amount of glare in one's eyes has resulted in the development of polarized sunglasses. The lenses of such sunglasses contain polarizing filters that are oriented vertically with respect to the frames. Below, Figure 2 demonstrates how polarized sunglasses eliminate the glare from the surface of a highway. As illustrated, the electric field vectors of the blue light waves are oriented in the same direction as the polarizing lenses and, therefore, are passed through. In contrast, the red light wave represents glare, which is parallel to the surface of the highway. Since the red wave is perpendicular to the filters in the lenses, it is successfully blocked by the lenses.

Linearpolarizationvs circularpolarization

From http://micro.magnet.fsu.edu/optics/lightandcolor/polarization.html �by Mortimer Abramowitz, Shannon Neaves and Michael Davidson and http://technology.niagarac.on.ca/courses/tech238g/Lasers.html by Mark Csele

Zinc sulfide is mined from natural deposits and concentrated by various processes. Also, zinc sulfide may be prepared in the laboratory by passing hydrogen sulfide through an aqueous solution of a soluble zinc salt, such as zinc chloride or zinc nitrate. The precipitate is filtered, washed, and dried.

Zinc Sulfide is used as a friction material to carry sulfur, which hardens rotor surfaces and thereby reduces wear. Also in printing inks, UV-hardened systems, powder coatings, adhesives, insulating & sealing compounds, thermoplastic pigmentation, thermosets, flame resistant plastics, glass-fiber reinforced plastics, pigment concentrates, elastomers,. textile fibers, paper, mastics, lubricants, electroluminescent lamps, infrared windows, domes and optical elements.

Zinc sulfide is white to gray-white or pale yellow powder. It exists in two crystalline forms, an alpha (wurtzite) and a beta (sphalerite). The wurtzite form has hexagonal crystal structure; refractive index 2.356; density 3.98 g/cm3; melts at 1,700°C; practically insoluble in water, about 6.9 mg/L; insoluble in alkalis; soluble in mineral acids. The sphalerite form arranges in cubic crystalline state; refractive index 2.368; density 4.102 g/cm3; changes to alpha form at 1,020°C; practically insoluble in water, 6.5 mg/L; soluble in mineral acids, insoluble in alkalis. When zinc sulfide contains water, it slowly oxidizes to sulfate on exposure to air.

Natural sunlight and most forms of artificial illumination transmit light waves whose electric field vectors vibrate equally in all planes perpendicular to the direction of propagation. When their electric field vectors are restricted to a single plane by filtration, however, then the light is polarized with respect to the direction of propagation.

A prime example of the basic application of liquid crystals in display devices is the seven-segment LCD numerical display illustrated in Figure 3. Here, the liquid crystalline phase is sandwiched between two glass plates that have seven electrodes, which can be individually charged, attached to them. Although the electrodes appear black in this example, they are transparent to light in real devices. As demonstrated in Figure 3, light passing through Polarizer 1 is polarized in the vertical direction and, when no current is applied to the electrodes, the liquid crystalline phase induces a 90 degree twist of the light and it can pass through Polarizer 2, which is polarized horizontally. This light can then form one of the seven segments on the display.

Polarization of light is also very useful in many aspects of optical microscopy. Microscopes may be configured to use crossed polarizers, in which case the first polarizer, described as the polarizer, is placed below the sample in the light path and the second polarizer, known as the analyzer, is placed above the sample, between the objective and the eyepieces. If the microscope stage is left empty, the analyzer blocks the light polarized by the polarizer and no light is visible. However, when a birefringent, or doubly refracting, sample is placed on the stage between the crossed polarizers, the microscopist can visualize various aspects of the sample. This is because the birefringent sample rotates the light, allowing it to successfully pass through the analyzer.

Even unpolarized incident light, such as natural sunlight, is polarized to a certain degree when it is reflected from an insulating surface like water or a highway. In such cases, the electric field vectors of light parallel to the insulating surface are reflected to a greater degree than vectors with different orientations. However, the optical properties of the surface primarily determine how much of the reflected light is polarized. For instance, the properties of mirrors make them very poor polarizers, while many transparent materials are excellent polarizers if the angle of incident light is within certain limits. The particular angle inducing maximum polarization is known as the Brewster angle and is expressed by the equation:

Zinc sulfide occurs in nature in two crystalline forms, the minerals, wurtzite, and sphalerite. Sulfide ore is the principal zinc mineral. The most important use of Zinc sulfide is as a pigment. As lithopone, a mixture with barium sulfate, it forms a low gloss interior house paint. The pigment, “mineral white” is made by combining zinc sulfide with zinc oxide. Zinc sulfide is incorporated into phosphors to produce luminescence when irradiated with light. It is used in making luminous dials, x-ray and television screens, and fluorescent lights. Also, it is used in making white and opaque glass and as a base for color lakes (which consist of an organic pigment with an inorganic carrier).