Mineralogy geophysics-optical-min-1
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This document discusses the use of a petrographic microscope for mineral identification. It begins by explaining why microscopes are used, such as for identifying minerals without guessing, determining rock and crystallization sequences, and documenting deformation history. It then describes how plane polarized light and crossed nicols work to reveal properties of isotropic and anisotropic minerals. Key mineral identification properties discussed include color, pleochrism, refractive index and relief. Birefringence is also introduced as a property seen under crossed polars related to the refractive index difference along crystallographic axes.
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Copy of nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity.
The index of refraction and relief of minerals can be used to identify them. Index of refraction refers to how much light is refracted when passing from one substance to another. It varies based on crystallographic orientation in anisotropic minerals. Relief and birefringence are properties related to the index of refraction.
Nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity. Minerals can be characterized by their index of refraction (n), which is a measure of how much light is bent when passing into the mineral. It determines properties like relief and birefringence. Some minerals like calcite have the property of double refraction, where a single ray of light enters and splits into two rays.
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This document discusses isotropic and anisotropic minerals and the optical phenomenon of double refraction. It begins by explaining that anisotropic crystals split light into two polarized rays with different velocities and refractive indices, called the ordinary and extraordinary rays. Double refraction, where two images are seen, is characteristic of anisotropic minerals like calcite. Isotropic minerals like those in the cubic crystal system do not exhibit double refraction and appear black under crossed polarized light. The document provides examples and explanations of these optical properties.
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This document discusses polarization of light. There are three types of polarized light: plane polarized light, circularly polarized light, and elliptically polarized light. Plane polarized light has vibrations confined to a definite plane. Circularly polarized light results from the superposition of two plane polarized light waves with a phase difference of π/2, giving a constant magnitude vector that varies in orientation. Elliptically polarized light results from two plane polarized waves with different amplitudes and a phase difference of π/2, giving a varying magnitude and orientation vector. Polarized light can be produced through reflection, refraction, selective absorption, scattering, and double refraction. Polarizers, quarter wave plates, and half wave plates are used
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polarization of light & its application.
PRESENTATION LAYOUT
Concept of Polarization
Types of Polarization
Methods of achieving Polarization
Applications of Polarization
POLARIZATION
Transforming unpolarized light into polarized light
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For Further Reading
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This document discusses reflection of light. It describes two types of reflection: regular reflection, which occurs on smooth surfaces like mirrors and reflects light regularly; and diffuse reflection, which occurs on rough surfaces and reflects light irregularly in different directions. The document also lists activities that involve identifying materials that reflect light and demonstrating the path of light rays using a medium like dust or smoke.
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Light is part of the electromagnetic spectrum that is visible to the human eye. It travels in straight lines called rays. Reflection is when light bounces off a surface, following the laws that the angle of incidence equals the angle of reflection and that the incident, normal, and reflected rays lie in the same plane. Refraction is when light changes speed and direction as it passes from one medium to another due to the different refractive indices, following Snell's law. Total internal reflection occurs when light cannot pass from an optically denser medium to a less dense one if the angle of incidence exceeds the critical angle.
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Copy of nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity.
The index of refraction and relief of minerals can be used to identify them. Index of refraction refers to how much light is refracted when passing from one substance to another. It varies based on crystallographic orientation in anisotropic minerals. Relief and birefringence are properties related to the index of refraction.
Nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity. Minerals can be characterized by their index of refraction (n), which is a measure of how much light is bent when passing into the mineral. It determines properties like relief and birefringence. Some minerals like calcite have the property of double refraction, where a single ray of light enters and splits into two rays.
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This document discusses isotropic and anisotropic minerals and the optical phenomenon of double refraction. It begins by explaining that anisotropic crystals split light into two polarized rays with different velocities and refractive indices, called the ordinary and extraordinary rays. Double refraction, where two images are seen, is characteristic of anisotropic minerals like calcite. Isotropic minerals like those in the cubic crystal system do not exhibit double refraction and appear black under crossed polarized light. The document provides examples and explanations of these optical properties.
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This document discusses polarization of light. There are three types of polarized light: plane polarized light, circularly polarized light, and elliptically polarized light. Plane polarized light has vibrations confined to a definite plane. Circularly polarized light results from the superposition of two plane polarized light waves with a phase difference of π/2, giving a constant magnitude vector that varies in orientation. Elliptically polarized light results from two plane polarized waves with different amplitudes and a phase difference of π/2, giving a varying magnitude and orientation vector. Polarized light can be produced through reflection, refraction, selective absorption, scattering, and double refraction. Polarizers, quarter wave plates, and half wave plates are used
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Download link ❤❤https://healthkura.com/eye-ppt/29/❤❤
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polarization of light & its application.
PRESENTATION LAYOUT
Concept of Polarization
Types of Polarization
Methods of achieving Polarization
Applications of Polarization
POLARIZATION
Transforming unpolarized light into polarized light
Restriction of electric field vector E in a particular plane so that vibration occurs in a single plane
Characteristic of transverse wave
Longitudinal waves can’t be polarized; direction of their oscillation is along the direction of propagation.............
For Further Reading
•Optics by Tunnacliffe
•Optics and Refraction by A.K. Khurana
•Principle of Physics, Ayam Publication
•Internet
Polarization
Polarization is a property of transverse waves where the oscillations occur in one direction rather than randomly in all directions perpendicular to the propagation direction. Unpolarized waves have oscillations in any direction, while linearly polarized waves oscillate in only one direction. Polarization of electromagnetic waves is defined by the electric field. Polarization can occur through selective absorption by materials that preferentially absorb certain oscillation directions, such as Polaroid which absorbs oscillations parallel to its long molecular chains. Many applications rely on polarization, including Polaroid sunglasses, LCD displays, and antennas.
Types of reflection
This document discusses reflection of light. It describes two types of reflection: regular reflection, which occurs on smooth surfaces like mirrors and reflects light regularly; and diffuse reflection, which occurs on rough surfaces and reflects light irregularly in different directions. The document also lists activities that involve identifying materials that reflect light and demonstrating the path of light rays using a medium like dust or smoke.
Reflection and Refraction
Light is part of the electromagnetic spectrum that is visible to the human eye. It travels in straight lines called rays. Reflection is when light bounces off a surface, following the laws that the angle of incidence equals the angle of reflection and that the incident, normal, and reflected rays lie in the same plane. Refraction is when light changes speed and direction as it passes from one medium to another due to the different refractive indices, following Snell's law. Total internal reflection occurs when light cannot pass from an optically denser medium to a less dense one if the angle of incidence exceeds the critical angle.
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There are three main types of polarization: plane, circular, and elliptical. Plane polarization occurs when light vibrates in a single plane, and can be produced through reflection, refraction, double refraction, scattering, or selective absorption. Circular polarization results from two plane waves that are 90 degrees out of phase. Elliptical polarization is when the electric field vector traces out an ellipse as the light propagates.
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Refraction is the bending of light when passing from one medium to another. It occurs because the speed of light is decreased in denser mediums, causing the light's path to bend toward the normal. Snell's law describes the mathematical relationship between the angle of incidence and angle of refraction, stating that for two mediums, the ratio of sines of the incidence and refraction angles is equal to the ratio of the indexes of refraction. The index of refraction is a number that represents how much a medium slows light down relative to a vacuum.
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This document summarizes key concepts about reflection and refraction of light. Reflection occurs when light hits a boundary and bounces off, following the law of reflection where the angle of incidence equals the angle of reflection. Refraction occurs when light crosses boundaries between materials with different optical densities, causing the light to change direction due to a change in speed. Snell's law describes the relationship between angles of incidence and refraction. Total internal reflection can occur when traveling from high to low density materials above the critical angle. Dispersion is the separation of white light into colors due to differing refractive indices.
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What is Polarization?
Types of polarized light
Few related terms
Few laws related to polarization
Applications
FOR MORE VISIT: https://tariqalfayad.blogspot.com/
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This document discusses various optical phenomena that involve the reflection and refraction of light, including:
- Light pillars, which are vertical bands of light formed by the reflection of light from ice crystals in cold climates.
- Total internal reflection, which occurs when light passes from a dense to rare medium at an angle greater than the critical angle.
- Mirages, which create optical illusions of water or other objects due to the refraction of light in air layers of different temperatures.
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SIMPLE AND ACCESSIBLE SLIDES ON POLARIZATION. IT INCLUDES SLIDES ON DOUBLE REFRACTION , CALCITE CRYSTALS, HUYGEN'S THEORY , NEGATIVE AND POSITIVE CRYSTALS,...
POLARIZATION OF LIGHT - BIREFRINGENCE AND HUYGEN'S THEORY OF DOUBLE REFRACTION
Huygen's theory of double refraction explains the phenomenon of birefringence in crystals like calcite. According to the theory:
- Each point in a birefringent crystal produces two types of wavefronts - a spherical wavefront for the ordinary ray and an ellipsoidal wavefront for the extraordinary ray.
- The shape of the wavefronts depends on whether the crystal is negative or positive. In negative crystals like calcite, the extraordinary wavefront is outside the ordinary wavefront, while in positive crystals it is inside.
- Huygen's principle treats each point on a wavefront as a secondary source of spherical wavelets, and the envelope of these wavelets makes up the
L 10 onwards Optical Mineralogy 3.pptx
This document provides an overview of optical mineral properties that can be observed using a petrographic microscope. It discusses properties that are visible with plane polarized light (PPL) alone or with cross polarized light (XPL), including birefringence, extinction angle, and whether minerals are isotropic or anisotropic. It introduces the concept of the optical indicatrix to explain the behavior of light in isotropic, uniaxial, and biaxial minerals. Interference figures are described as a way to determine optical properties like sign and 2V for biaxial minerals. The document aims to build optical mineralogy skills through examples and diagrams of how light interacts with different crystal structures.
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This document discusses polarization, interference, and optical activity of light waves. It defines longitudinal and transverse waves, and explains that polarization is a property specific to transverse waves where there is a preferential direction of oscillation perpendicular to the propagation direction. Optical activity is described as the ability of certain materials to rotate the plane of polarization of polarized light passing through them. A Laurent's half-shade polarimeter is summarized as a common instrument used to measure the angle of optical rotation and determine the specific rotation of optically active solutions.
Birefringence
Birefringence is the phenomenon of double refraction that occurs when light passes through anisotropic crystals. Anisotropic crystals have non-equivalent crystallographic axes and therefore interact with light differently depending on the crystal's orientation. This causes light to refract into two rays with perpendicular vibration directions traveling at different velocities, known as ordinary and extraordinary rays. Crystals are classified as either isotropic, where all axes interact with light the same, or anisotropic. Common anisotropic crystals that exhibit birefringence include quartz, calcite, and tourmaline.
COLOR_OF_LIGHTS.ppt
Electromagnetic waves interact with materials in several ways that determine the color perceived. Color arises from emission, reflection, transmission, interference, dispersion, and scattering of light waves interacting with objects. The primary colors of light are red, green and blue, which combine to make white light. The primary colors of pigment are cyan, yellow and magenta, which combine to make black. Reflection, refraction, polarization, and interference cause the wide variety of colors observed from different materials due to the interaction of light waves.
Extinction angle and Types of Extinction in Minerals.pdf
Extinction refers to the dimming of light when viewed through a mineral under cross-polarized light in a petrographic microscope. There are four main types of extinction: parallel extinction occurs when the mineral's long axis or cleavage plane is parallel to the vibration direction of light; inclined extinction occurs when these are not parallel in monoclinic and triclinic minerals; symmetrical extinction occurs when the vibration direction bisects two cleavage planes; and some minerals lack distinct cleavage planes and therefore have no measurable extinction angle. The extinction angle is the amount of rotation required for a mineral to become extinct and is a diagnostic characteristic.
10 properties of light
The document discusses several key properties of light, including:
- Reflection - Light bounces off surfaces at the same angle it hits.
- Refraction - Light bends as it passes from one medium to another, changing speed. The degree of bending depends on the medium's index of refraction.
- Interference - When two light waves meet, they can constructively or destructively interfere based on how their crests and troughs align.
It explores light's dual nature as both a wave and particle, demonstrated through experiments like Young's double-slit experiment showing light's wave-like interference patterns, and the photoelectric effect showing its particulate properties.
Polarization of light (1) (1).pptx
Polarization occurs when light vibrates in only one direction, rather than in all planes. There are several methods to polarize unpolarized light, which vibrates in all directions, including selective absorption using polarizing materials like Polaroid. Polarization experiments showed that light waves are transverse, not longitudinal, with electric and magnetic fields oscillating perpendicular to the direction of propagation. Polarized light has many applications like 3D movies, sunglasses, and improving contrast in microscopes.
10propertiesoflight-140123181500-phpapp02.pdf
The document discusses various properties of light, including:
- Reflection - Light bounces off surfaces at the same angle it hits the surface.
- Refraction - Light bends as it passes from one medium to another of different density, bending more in denser materials.
- Interference - When two light waves meet, they can constructively or destructively interfere based on crest and trough alignment.
- Diffraction - Light bends around obstacles, spreading out as it passes through small openings.
So in summary, the document covers key properties of light such as reflection, refraction, interference, and diffraction.
POLARIZATION.pptx
Polarization refers to the orientation of oscillations in light waves. Light can be linearly polarized, circularly polarized, or elliptically polarized depending on the orientation. Polarization occurs through reflection, refraction, and double refraction in anisotropic materials. Polarizers and waveplates can be used to alter the polarization state. Some materials exhibit optical activity and can rotate the plane of polarized light through either dextrorotation or levorotation. Specific rotation is a measure of the degree of optical activity for a substance.
OPTOMETRY - Part V POLARIZATION OF LIGHT
This article describes the principle and phenomenon of polarization of light. This article also illustrates on Birefringence, Dichroism and crossed polarizers.
Malu's Law is elaborated here as prerequisite to understand Polarization along with Brewster's Angle. Polarization by reflection and polarization by refraction are also discussed here for quick comprehension of the readers.
Polarization 1, polarization of light, physical optics
Light can be polarized, meaning it vibrates in only one direction rather than randomly. Unpolarized light becomes polarized when it interacts with filters, surfaces like water, or crystals. Polarized light has many applications including polarized sunglasses, LCD screens, and microscopy. It is detected using polarizing filters, where intensity is reduced based on the relative angle between the light's polarization direction and the filter's axis according to Malus' law.
Polarization and it's application in Ophthalmology
Polarization, types of polarization, mechanisms to produce polarization, Applications of polarization, precautions with polarizing sunglasses, ophthalmic uses of polarization
Presentation on lights [ gamma team ]
Light is electromagnetic radiation that allows for vision. It is produced by the sun and bounces off objects into our eyes, enabling sight. Light exhibits properties of both waves and particles. As a wave, light displays phenomena like reflection, refraction, interference and diffraction. Reflection causes light to bounce off surfaces, while refraction bends light when it passes from one medium to another. Interference and diffraction are results of light behaving as a wave. The photoelectric effect provided evidence that light also behaves as a particle. Polarization demonstrated that light waves oscillate transversely. Polarizing filters allow only certain transverse oscillations to pass through. Malus's law describes how light intensity is reduced when passing through multiple polarizing filters based on
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Mineralogy geophysics-optical-min-1
- 1. Mineral Optik Pemakaian mikroskop petrografi Untuk identifikasi mineral I Wayan Warmada
- 2. Mengapa memakai mikroskop? • Identifikasi mineral (no guessing!) • Menentukan tipe batuan • Menentukan sekuen kristalisasi • Mendokumentasi sejarah deformasi • Mencata pelapukan/alterasi • Fun, powerful, and cheap!
- 3. Mikroskop petrografi Juga disebut sebagai mikros- kop polarisasi (PLM, polariz- ing light mi- croscope)
- 4. Apa yang terjadi jika cahaya melalui “scope”? sumber cahaya mata anda sinar cahaya gelombang berjalan dari sumber ke mata panjang gel, amplitude, A sinar berja- lan sebagai gelombang
- 5. Microscope light is white light, i.e. it’s made up of lots of different wavelengths; Each wavelength of light corresponds to a different color Can prove this with a prism, which separates white light into its constituent wavelengths/colors Apa yang terjadi jika cahaya melalui “scope”?
- 6. light vibrates in all planes that contain the light ray (i.e., all planes perpendicular to the propagation direction plane of vibration vibration direction propagation direction Apa yang terjadi jika cahaya melalui “scope”?
- 7. 1) Cahaya lewat pada polarizer bagian bawah west (left) east (right) Plane polarized light PPL=plane polarized light Unpolarized light Only the component of light vibrating in E-W direction can pass through lower polarizer – light intensity decreases
- 8. 2) Gunakan polarizer bagian atas west (left) east (right) Now what happens? What reaches your eye? Why would anyone design a microscope that prevents light from reaching your eye??? XPL=crossed nicols (crossed polars) south (front) north (back) Black!!
- 9. 3) Sekarang masukkan asahan tipis suatu batuan west (left) east (right) Light vibrating E-W Light vibrating in many planes and with many wavelengths How does this work?? Unpolarized light Light and colors reach eye!
- 10. Conclusion has to be that minerals somehow reorient the planes in which light is vibrating; some light passes through the upper polarizer But, note that some minerals are better magicians than others (i.e., some grains stay dark and thus can’t be reorienting light) Minerals act as magicians!!
- 11. • Isotropic minerals: light does not get rotated or split; propagates with same velocity in all directions • Anisotropic minerals: • Uniaxial - light entering in all but one special direction is resolved into 2 plane polarized components that vibrate perpendicular to one another and travel with different speeds • Biaxial - light entering in all but two special directions is resolved into 2 plane polarized components… • Along the special directions (“optic axes”), the mineral thinks that it is isotropic - i.e., no splitting occurs • Uniaxial and biaxial minerals can be further subdivided into optically positive and optically negative, depending on orientation of fast and slow rays relative to xtl axes A brief review…
- 12. Isotropic Uniaxial Biaxial How light behaves depends on crystal structure (there is a reason you took mineralogy!) Isometric • All crystallographic axes are equal Orthorhombic, monoclinic, triclinic • All axes are unequal Hexagonal, trigonal, tetragonal • All axes c are equal but c is unique Let’s use all of this information to help us identify minerals
- 13. Sifat-sifat mineral: warna & pleokrisme • Color is observed only in PPL • Not an inherent property - changes with light type/intensity • Results from selective absorption of certain of light • Pleochroism results when different are absorbed differently by different crystallographic directions - rotate stage to observe plag hbl plag hbl -Plagioclase is colorless -Hornblende is pleochroic in olive greens Now do question 2
- 14. Sifat-sifat mineral: Indeks refraksi (R.I. or n) Light is refracted when it passes from one substance to another; refraction is accompanied by a change in velocity n1 n1n2 n2 n2>n1 n2<n1 n = velocity in air velocity in mineral • n is a function of crystallographic orientation in anisotropic minerals isotropic minerals: characterized by one RI uniaxial minerals: characterized by two RI biaxial minerals: characterized by three RI • n gives rise to 2 easily measured parameters: relief & birefringence
- 15. Sifat-sifat mineral: relief • Relief is a measure of the relative difference in n between a mineral grain and its surroundings • Relief is determined visually, in PPL • Relief is used to estimate n olivine plag olivine: n=1.64-1.88 plag: n=1.53-1.57 epoxy: n=1.54 - Olivine has high relief - Plag has low relief
- 16. Apa yang menyebabkan relief? nxtl > nepoxy nxtl < nepoxynxtl = nepoxy Hi relief (+) Lo relief (+) Hi relief (-) Difference in speed of light (n) in different materials causes refraction of light rays, which can lead to focusing or defocusing of grain edges relative to their surroundings Now do question 3
- 17. Sifat-sifat mineral: warna interferensi/birefringence • Colors one observes when polars are crossed (XPL) • Color can be quantified numerically: = nhigh - nlow More on this next week… Now do question 4