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19-653: Shtora-1 is an electro-optical jammer that disrupts semiautomatic command to line of sight ( SACLOS ) ATGMs, laser rangefinders and target designators . Shtora-1 is a soft kill countermeasure system . The system was shown fitted to a Russian main battle tank during the International Defense Exposition, held in Abu Dhabi in 1995. The first known application of the system is the Russian T-90 main battle tank, which entered service in

38-420: A chlorin -type ring in the case of chlorophyll. The highly conjugated pi-bonding system of the macrocycle ring absorbs visible light. The nature of the central metal can also influence the absorption spectrum of the metal-macrocycle complex or properties such as excited state lifetime. The tetrapyrrole moiety in organic compounds which is not macrocyclic but still has a conjugated pi-bond system still acts as

57-479: A pi-bond , three or more adjacent p-orbitals in a molecule can form a conjugated pi-system . In a conjugated pi-system, electrons are able to capture certain photons as the electrons resonate along a certain distance of p-orbitals - similar to how a radio antenna detects photons along its length. Typically, the more conjugated (longer) the pi-system is, the longer the wavelength of photon can be captured. In other words, with every added adjacent double bond we see in

76-640: A change in the birefringence , and not simply the refractive index of the medium. In a Kerr cell , the change in birefringence is proportional to the square of the electric field, and the material is usually a liquid. In a Pockels cell , the change in birefringence varies linearly with the electric field, and the material is usually a crystal. Non-crystalline, solid electro-optical materials have generated interest because of their low cost of production. These organic, polymer-based materials are also known as organic EO material, plastic EO material, or polymer EO material. They consist of nonlinear optical chromophores in

95-478: A chromophore. Examples of such compounds include bilirubin and urobilin , which exhibit a yellow color. An auxochrome is a functional group of atoms attached to the chromophore which modifies the ability of the chromophore to absorb light, altering the wavelength or intensity of the absorption. Halochromism occurs when a substance changes color as the pH changes. This is a property of pH indicators , whose molecular structure changes upon certain changes in

114-406: A metal in a coordination complex with ligands. Examples are chlorophyll , which is used by plants for photosynthesis and hemoglobin , the oxygen transporter in the blood of vertebrate animals. In these two examples, a metal is complexed at the center of a tetrapyrrole macrocycle ring: the metal being iron in the heme group (iron in a porphyrin ring) of hemoglobin, or magnesium complexed in

133-427: A molecule diagram, we can predict the system will be progressively more likely to appear yellow to our eyes as it is less likely to absorb yellow light and more likely to absorb red light. ("Conjugated systems of fewer than eight conjugated double bonds absorb only in the ultraviolet region and are colorless to the human eye", "Compounds that are blue or green typically do not rely on conjugated double bonds alone.") In

152-508: A polymer lattice. The nonlinear optical chromophores can produce Pockels effect . Chromophores A chromophore is a molecule which absorbs light at a particular wavelength and reflects color as a result. Chromophores are commonly referred to as colored molecules for this reason. The word is derived from Ancient Greek χρῶμᾰ (chroma)  'color' and -φόρος (phoros)  'carrier of'. Many molecules in nature are chromophores, including chlorophyll ,

171-414: A spectrum the chromophore will absorb. Lengthening or extending a conjugated system with more unsaturated (multiple) bonds in a molecule will tend to shift absorption to longer wavelengths. Woodward–Fieser rules can be used to approximate ultraviolet -visible maximum absorption wavelength in organic compounds with conjugated pi-bond systems. Some of these are metal complex chromophores, which contain

190-494: Is closely related to photonics , the branch of optics that involves the application of the generation of photons . It is not only concerned with the " electro–optic effect ", since it deals with the interaction between the electromagnetic ( optical ) and the electrical ( electronic ) states of materials. The electro-optic effect is a change in the optical properties of an optically active material in response to changes in an electric field. This interaction usually results in

209-694: The Copperhead and some variants of the Maverick and Hellfire . Newer missiles such as the TOW 2 (which encodes the tracking beacon signals to reject interference) and imaging infrared guided missiles such as the Javelin are unaffected by it. This has resulted in a number of Shtora-1 protected T-90s being lost to such weapons in Syria and Ukraine. The jammers have been removed from many currently serving T-90s and

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228-454: The conjugated chromophores, the electrons jump between energy levels that are extended pi orbitals , created by electron clouds like those in aromatic systems. Common examples include retinal (used in the eye to detect light), various food colorings , fabric dyes ( azo compounds ), pH indicators , lycopene , β-carotene , and anthocyanins . Various factors in a chromophore's structure go into determining at what wavelength region in

247-661: The Russian Army in 1993. It is also available on the BMP-3M infantry fighting vehicle. The Shtora-1 has four key components: two electro-optical/infrared (EO/IR) " dazzlers " mounted on both turret cheeks, an infrared jammer , a modulator , and a control panel in the fighting compartment. Shtora-1 has twelve smoke grenade launchers and weighs 400 kg. It can lay a 15 meter high and 20 meter wide smoke screen in three seconds that lasts about twenty seconds at ranges from 50 to 70 meters. The Shtora-1 can also automatically slew

266-497: The aromatic rings conjugate. Because of their limited extent, the aromatic rings only absorb light in the ultraviolet region, and so the compound appears colorless in the 0-8 pH range. However, as the pH increases beyond 8.2, that central carbon becomes part of a double bond becoming sp hybridized and leaving a p orbital to overlap with the π-bonding in the rings. This makes the three rings conjugate together to form an extended chromophore absorbing longer wavelength visible light to show

285-454: The main gun towards a detected threat, so that the tank crew can return fire and so that the stronger frontal turret armour is facing it. Shtora-1 can operate in fully automatic or semi-automatic modes, continuously for six hours against ATGM attack. The Shtora-1 can effectively jam obsolete SACLOS missiles such as the TOW , HOT , MILAN , Dragon , and Malyutka and laser guided weapons such as

304-407: The molecule responsible for the green colors of leaves . The color that is seen by our eyes is that of the light not absorbed by the reflecting object within a certain wavelength spectrum of visible light . The chromophore indicates a region in the molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum (or in informal contexts,

323-408: The more modern S and M variants did not include them. Electro-optical Electro–optics is a branch of electrical engineering , electronic engineering , materials science , and material physics involving components, electronic devices such as lasers , laser diodes , LEDs , waveguides , etc. which operate by the propagation and interaction of light with various tailored materials. It

342-404: The spectrum under scrutiny). Visible light that hits the chromophore can thus be absorbed by exciting an electron from its ground state into an excited state . In biological molecules that serve to capture or detect light energy, the chromophore is the moiety that causes a conformational change in the molecule when hit by light. Just like how two adjacent p-orbitals in a molecule will form

361-400: The surrounding pH. This change in structure affects a chromophore in the pH indicator molecule. For example, phenolphthalein is a pH indicator whose structure changes as pH changes as shown in the following table: In a pH range of about 0-8, the molecule has three aromatic rings all bonded to a tetrahedral sp hybridized carbon atom in the middle which does not make the π-bonding in

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