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30.5 Applications of Atomic Excitations and De-Excitations
30.5 Applications of Atomic Excitations and De-Excitations
- The double-helix structure of DNA was discovered in 1953 by an international team of scientists working at the Cavendish Laboratory.
- They were the first to discern the structure of DNA using x-ray data.
- The 1962 Nobel Prize in Physiology or Medicine was awarded to Crick, Wilkins, and Watson.
- There is a lot of debate over whether or not Rosalind Franklin was included in the prize.
- The figure shows a pattern of x rays in a crystal.
- x-ray crystallography is a process that gives information about crystal structure, and it was the type of data that Rosalind Franklin supplied to Crick for DNA.
- x rays give information on the atomic arrangements in materials and confirm the size and shape of atoms.
- Current research in high-temperature superconductors involves complex materials whose lattice arrangements are crucial to obtaining a superconducting material.
- x-ray crystallography can be used to study these.
- The interference pattern was created by the X-ray diffraction from the hen egg lysozyme.
- The German Max von Laue convinced two of his colleagues to scatter x rays from crystals after he discovered x rays in 1895.
- If a pattern of waves is obtained, the x rays could be determined.
- Von Laue was awarded the 1914 Nobel Prize in physics for suggesting that x rays are waves.
- The father and son team of Sir William Henry Bragg and his son Sir William Lawrence Bragg were awarded a joint Nobel Prize in 1915 for inventing the x-ray analyzer.
- After graduating from mathematics, the elder Bragg moved to Australia.
- He studied physics and chemistry at the University of Adelaide.
- The younger Bragg was born in Australia but went back to England to work in x-ray and neutron crystallography, and he supported the work of James Crick and Max Perutz for their work on unraveling the mysteries of DNA.
- This time, we see the enabling nature of physics--establishing instruments and designing experiments as well as solving mysteries in the biomedical sciences.
- Other uses for x rays will be studied later in the chapter.
- X rays have an effect on cell reproduction and are useful in the treatment of cancer.
- X rays from outer space can be used to determine the nature of their sources, such as black holes.
- x rays can be used to detect atmospheric tests of nuclear weapons.
- X rays can cause the fluoresce of atoms, which makes them a valuable analytical tool in a range of fields from art to archaeology.
- The properties of matter and phenomena in nature are related to atomic energy levels.
- The transparency of air, the color of a rose, and the output of a laser are a few examples.
- It may not seem like they have much in common, but glow-in-the-dark pajamas and lasers are different applications of atomic de-excitations.
- Light from a laser is based on atomic de-excitation.
- The color of a material is determined by the ability of its atoms to absorb certain wavelengths.
- The levels of the lycopene's atoms are separated by a variety of energies, which correspond to all visible photon energies except red.
- Another example is air.
- It is transparent because there are few energy levels visible to the naked eye.
- The light cannot be absorbed.
- The visible light is scattered weakly by the air because the visible wavelength is larger than the air atoms.
- To cause red sunsets and blue skies, light must pass through kilometers of air.
- The atomic energy levels of a material are related to its ability to emit light.
- Some rocks glow in black light because of their mineral composition.
- Posters with black lights make them glow.
- When illuminated by a black light, objects glow in the visible spectrum.
- Emissions are related to the mineral's energy levels.
- In the case of scorpions, the blue glow is due to the presence of proteins near the surface of their skin.
- This is a colorful example of fluorescent activity in which de-excitation occurs in the form of visible light.
- An atom is excited to a level several steps above its ground state by the absorption of a relatively high-energy UV photon.
- One way the atom can de-excite is to re-emit a photon of the same energy as excited it, a single step back to the ground state.
- Smaller steps in which lower-energy (longer wavelength) photons are emitted are all other paths of de-excitation.
- There are many types of energy input.
- The use of fluorescent paint, dyes, and soap in clothes makes the colors look brighter in the sun.
- X rays can be used to make visible images.
- Neon lights and gasdischarge tubes that produce atomic and molecular spectrum can be caused by electric discharges.
- Atomic emissions from mercury atoms are caused by an electric discharge in mercury vapor.
- The inside of a fluorescent light is coated with a fluorescent material that emits visible light over a broad spectrum of wavelength.
- The fluorescent lights are four times more efficient in converting electrical energy into visible light than the incandescent lights are.
- The atom is excited by the UV photon.
- It can de-excite in a single step, re-emitting a photon of the same energy, or in several steps.
- If the atom de-excites in smaller steps, it will emit different energy than if it excited it.
- UV, x-rays, and electrical discharge are some of the energy inputs that can causeescence.
- glow-worms can be found in the Waitomo caves on New Zealand's North Island.
- The glow-worms hang up to 70 silk threads each to catch prey that fly towards them in the dark.
- The process of turning energy into light is very efficient.
- There are many uses for florescence.
- It is used to follow a molecule in a cell.
- One can study the structure of genes.
- The emission of visible light is observed when the molecule is illuminated with UV light and tagged with fluorescent dyes.
- Identification of elements within a sample can be done this way.
- The fluorescent dye shown in Figure 30.32 is called fluorescein.
- Figure 30.33 shows the dispersion of a fluorescent dye in water.
- The dye is used in the laboratory.
- A beaker of water has fluorescent powder added to it.
- Under ultraviolet light, the mixture gives off a bright glow.
- These are small single-crystal molecules.
- The indicators are small and provide improved brightness.
- All colors can be excited with the same wavelength.
- Conventional phosphors have a longer lifetime than organic dyes.
- They are an excellent tool for long-term studies of cells.
- Chicken cells are being imaged using a fluorescent dye.
- Cell nuclei are blue while neurofilaments are green.
- Spontaneous de-excitation has a very short lifetime.
- Some levels have lifetimes of up to minutes or even hours.
- The energy levels are slow in de-exciting because their quantum numbers are different from the lower levels.
- phosphorescent substances are used to make glow-in-the-dark materials, such as Luminous dial on some watches and clocks and on children's toys and pajamas.
- The stored energy is released partially as visible light when the atoms or molecules decay slowly.
- After the ceramic has cooled from its firing, atomic energy can be frozen in.
- Since the release is slow, thermoluminescence can be used to date antiquities.
- The older the ceramic, the less light it emits.
- The Chinese ceramic figure can be stimulated to de-excite and emit radiation by heating a sample of the ceramic, a process called thermoluminescence.
- Since the slowly states de-excite over centuries, the amount of thermoluminescence decreases with age, making it possible to use this effect to date and authenticate antiquities.
- The figure is from the 11th century.
- Today's lasers are commonplace.
- Lasers are used to read bar codes at stores and libraries, laser shows are staged for entertainment, laser printers produce high-quality images at a relatively low cost, and lasers send large numbers of telephone messages through optical fibers.
- Lasers are used in a number of things, including surveying, weapons guidance, tumor eradication, and for reading music CDs and computer CD-ROMs.
- The answer is that lasers emit single-wavelength EM radiation that is very coherent.
- Laser output can be more precisely manipulated than other sources.
- Laser output is so pure and coherent because of how it is produced, which depends on a metastable state in the lasing material.
- electrons are raised to all possible levels when energy is put into a large collection of atoms The electrons that originally excited the metastable state and those that fell into it from above are included.
- A population inversion has been achieved if a majority of electrons are in the metastable state.
- An electron falls from the metastable state.
- A second photon of the same wavelength and phase with the first is emitted when this photon finds another atom in the metastable state.
- An excited atom with an electron in an energy orbit higher than normal releases a photon of a specific Frequency when the electron drops back to a lower energy orbit.
- If this photon strikes another electron in the same high-energy space, another photon of the same frequency is released.
- The emitted and triggering photons are both in the same phase and travel in the same direction.
- A majority of atoms must be in the metastable state to produce energy because the probability of absorption of a photon is the same as the probability of stimulated emission.
- Einstein was the first to realize that stimulated emission and absorption are equally probable.
- The laser acts as a temporary energy storage device that produces a massive energy output.
- One atom in the metastable state spontaneously decays to a lower level, producing a photon that stimulates another atom to de-excite.
- The second photon is in phase with the first and has the same energy and wavelength.
- The emission of other photons is stimulated by both of them.
- A net production is necessary for there to be a net absorption.
- The process was developed after advances in quantum physics.
- The development of lasers was one of the reasons why the Soviet Union and the United States won a joint Nobel Prize in 1964.
- Arthur Schawlow won the 1981 Nobel Prize for his work in laser applications.
- The devices were called masers because they produced microwaves.
- T. Maiman created the first working laser in 1960.
- The red light was produced by using a flash lamp and a rod.
- The name laser is used for all of the devices that produce a variety of wavelengths.
- In a process called optical pumping, energy input can come from a flash tube, electrical discharge, or other source.
- A large percentage of the original pumping energy is dissipated in other forms.
- Mirrors can be used to enhance stimulated emission by multiple passes of the radiation back and forth.
- Some of the light can be seen through one of the mirrors.
- A laser's output is 1% of the light passing back and forth in a laser.
- Laser construction uses a method of pumping energy into the lasing material.
- Many types of lasing materials are used to make lasers.
- The existence of a metastable state or phosphorescent material is what determines lasers.
- Some lasers produce continuous output while others are short-lived.
- The more common lasers produce something on the order of.
- The red light that comes from the laser is very common.
- The number of atoms of helium is ten times greater than the number of neon atoms.
- The first excited state of helium stores energy.
- Neon atoms have an excited state that is nearly the same as that in helium, which makes it easy to transfer this energy.
- The neon state that produces the laser output is also metastable.
- There are so many more helium atoms in neon that it can produce a population inversion.
- The population can be maintained even while lasing occurs because helium-neon lasers have continuous output.
- The most common lasers in use today are made of Silicon.
- The energy is pumped into the material by passing a current into the device.
- Light bounces back and forth and a tiny fraction emerges as laser light thanks to special coating on the ends and fine cleavings of the material.
- The lasers can produce outputs in the range of a few hundredths of a watt.
- The gas mixture has more neon atoms than helium.
- In a collision, excited helium atoms can de-excite by transferring energy to neon.
- Neon allows lasing by the neon to occur.
- There are many uses of lasers.
- Lasers can focus on a small spot.
- They have a wavelength that is defined.
- There are many types of lasers that provide the same wavelength of light.
- One needs to be able to pick a wavelength that will be preferentially absorbed by the material of interest.
- The objects appear a certain color because they absorb all other colors.
- The wavelength absorbed depends on the energy spacing between the electrons in the molecule.
- Unlike the hydrogen atom, biologicalmolecules are complex and have a variety of absorption lines.
- In the selection of a laser with the appropriate wavelength, these can be determined.
- Water absorbs light in the UV and IR regions.
- hemoglobin absorbs most of the UV light.
- Laser surgery uses a wavelength that is absorbed by the tissue it is focused upon.
- Total loss of vision can be caused by a detached retina.
- scar tissue that can hold the retina in place, salvaged the patient's vision after Burns made by a laser focused to a small spot on the retina.
- Refractive dispersion of different wavelength light sources can't be focused as precisely as a laser.
- Laser surgery in the form of cutting or burning away tissue is more accurate because the laser output can be very precisely focused and is preferentially absorbed.
- Depending on what part of the eye needs repair, the appropriate type of laser can be selected.
- The repair of tears in the eye can be done with a green laser.
- The light absorbed by tissues containing blood can be used to "weld" the tear.
- A laser is used to focus on a small spot on the retina, causing scar tissue to hold it in place.
- The light is focused by the lens of the eye and the laser is brought to the eye.
- Lasers are being used in dentistry.
- The soft tissue of the mouth is the most common place where lasers are used.
- They can be used to heal wounds.
- The erbium YAG laser is used to cut into bones and teeth.
- Since lasers can produce very high power in short bursts, they can be used to focus a lot of energy on a small glass sphere.
- The incident energy increases the fuel temperature so that fusion can occur and it also increases the density of the fuel.
- The implosion is caused by the impinging laser.
- Nuclear fusion can be achieved using a system of lasers.
- A burst of energy is focused on a small fuel pellet, which is imploded to the high density and temperature needed to make the fusion reaction proceed.
- CDs and DVDs have larger storage capacities than vinyl records.
- The encyclopedia can be stored on a single CD.
- The CD can be used to record digital information because the pits are very small.
- They are read by having a cheap solid-state laser beam scatter from pits as the CD spins, revealing their digital pattern and the information on them.
- Laser-created pits on a CD's surface hold digital information.
- The laser light scattered from the pit can be read.
- The precision of the laser makes it possible for large information capacity.
- holograms are used for amusement, decoration on novelty items and magazine covers, security on credit cards and driver's licenses, and for serious three-dimensional information storage.
- When viewed from different angles, a hologram is a true three-dimensional image.
- Holography uses light interference, whereas normal photography uses wave optics.
- The light from a laser is split into two parts by a mirror.
- The reference beam shines on a piece of film.
- Light from the object is interfering with the reference beam.
- The exposed film looks foggy, but close examination shows a complicated interference pattern on it.
- The film is darkened where the interference was constructive.
- Holography uses the wave characteristics of light as compared to normal photography, which requires a lens.
- A piece of film is interfered with by a single wavelength coherent light from a laser.
- A partially silvered mirror splits the laser beam into two parts, one illuminating an object and the other shining directly on the film.
- Light falling on a hologram can create a three-dimensional image.
- The film's exposed regions are dark and block the light, while less exposed regions allow light to pass.
- The film acts like a collection of gratings.
- Light passing through the hologram is diffracted in various directions, producing both real and virtual images of the object used to expose the film.
- The interference pattern is the same as the object.
- The interference pattern gives you different perspectives when you move your eye to different places.
- The image is three-dimensional like the object.
30.5 Applications of Atomic Excitations and De-Excitations
- The double-helix structure of DNA was discovered in 1953 by an international team of scientists working at the Cavendish Laboratory.
- They were the first to discern the structure of DNA using x-ray data.
- The 1962 Nobel Prize in Physiology or Medicine was awarded to Crick, Wilkins, and Watson.
- There is a lot of debate over whether or not Rosalind Franklin was included in the prize.
- The figure shows a pattern of x rays in a crystal.
- x-ray crystallography is a process that gives information about crystal structure, and it was the type of data that Rosalind Franklin supplied to Crick for DNA.
- x rays give information on the atomic arrangements in materials and confirm the size and shape of atoms.
- Current research in high-temperature superconductors involves complex materials whose lattice arrangements are crucial to obtaining a superconducting material.
- x-ray crystallography can be used to study these.
- The interference pattern was created by the X-ray diffraction from the hen egg lysozyme.
- The German Max von Laue convinced two of his colleagues to scatter x rays from crystals after he discovered x rays in 1895.
- If a pattern of waves is obtained, the x rays could be determined.
- Von Laue was awarded the 1914 Nobel Prize in physics for suggesting that x rays are waves.
- The father and son team of Sir William Henry Bragg and his son Sir William Lawrence Bragg were awarded a joint Nobel Prize in 1915 for inventing the x-ray analyzer.
- After graduating from mathematics, the elder Bragg moved to Australia.
- He studied physics and chemistry at the University of Adelaide.
- The younger Bragg was born in Australia but went back to England to work in x-ray and neutron crystallography, and he supported the work of James Crick and Max Perutz for their work on unraveling the mysteries of DNA.
- This time, we see the enabling nature of physics--establishing instruments and designing experiments as well as solving mysteries in the biomedical sciences.
- Other uses for x rays will be studied later in the chapter.
- X rays have an effect on cell reproduction and are useful in the treatment of cancer.
- X rays from outer space can be used to determine the nature of their sources, such as black holes.
- x rays can be used to detect atmospheric tests of nuclear weapons.
- X rays can cause the fluoresce of atoms, which makes them a valuable analytical tool in a range of fields from art to archaeology.
- The properties of matter and phenomena in nature are related to atomic energy levels.
- The transparency of air, the color of a rose, and the output of a laser are a few examples.
- It may not seem like they have much in common, but glow-in-the-dark pajamas and lasers are different applications of atomic de-excitations.
- Light from a laser is based on atomic de-excitation.
- The color of a material is determined by the ability of its atoms to absorb certain wavelengths.
- The levels of the lycopene's atoms are separated by a variety of energies, which correspond to all visible photon energies except red.
- Another example is air.
- It is transparent because there are few energy levels visible to the naked eye.
- The light cannot be absorbed.
- The visible light is scattered weakly by the air because the visible wavelength is larger than the air atoms.
- To cause red sunsets and blue skies, light must pass through kilometers of air.
- The atomic energy levels of a material are related to its ability to emit light.
- Some rocks glow in black light because of their mineral composition.
- Posters with black lights make them glow.
- When illuminated by a black light, objects glow in the visible spectrum.
- Emissions are related to the mineral's energy levels.
- In the case of scorpions, the blue glow is due to the presence of proteins near the surface of their skin.
- This is a colorful example of fluorescent activity in which de-excitation occurs in the form of visible light.
- An atom is excited to a level several steps above its ground state by the absorption of a relatively high-energy UV photon.
- One way the atom can de-excite is to re-emit a photon of the same energy as excited it, a single step back to the ground state.
- Smaller steps in which lower-energy (longer wavelength) photons are emitted are all other paths of de-excitation.
- There are many types of energy input.
- The use of fluorescent paint, dyes, and soap in clothes makes the colors look brighter in the sun.
- X rays can be used to make visible images.
- Neon lights and gasdischarge tubes that produce atomic and molecular spectrum can be caused by electric discharges.
- Atomic emissions from mercury atoms are caused by an electric discharge in mercury vapor.
- The inside of a fluorescent light is coated with a fluorescent material that emits visible light over a broad spectrum of wavelength.
- The fluorescent lights are four times more efficient in converting electrical energy into visible light than the incandescent lights are.
- The atom is excited by the UV photon.
- It can de-excite in a single step, re-emitting a photon of the same energy, or in several steps.
- If the atom de-excites in smaller steps, it will emit different energy than if it excited it.
- UV, x-rays, and electrical discharge are some of the energy inputs that can causeescence.
- glow-worms can be found in the Waitomo caves on New Zealand's North Island.
- The glow-worms hang up to 70 silk threads each to catch prey that fly towards them in the dark.
- The process of turning energy into light is very efficient.
- There are many uses for florescence.
- It is used to follow a molecule in a cell.
- One can study the structure of genes.
- The emission of visible light is observed when the molecule is illuminated with UV light and tagged with fluorescent dyes.
- Identification of elements within a sample can be done this way.
- The fluorescent dye shown in Figure 30.32 is called fluorescein.
- Figure 30.33 shows the dispersion of a fluorescent dye in water.
- The dye is used in the laboratory.
- A beaker of water has fluorescent powder added to it.
- Under ultraviolet light, the mixture gives off a bright glow.
- These are small single-crystal molecules.
- The indicators are small and provide improved brightness.
- All colors can be excited with the same wavelength.
- Conventional phosphors have a longer lifetime than organic dyes.
- They are an excellent tool for long-term studies of cells.
- Chicken cells are being imaged using a fluorescent dye.
- Cell nuclei are blue while neurofilaments are green.
- Spontaneous de-excitation has a very short lifetime.
- Some levels have lifetimes of up to minutes or even hours.
- The energy levels are slow in de-exciting because their quantum numbers are different from the lower levels.
- phosphorescent substances are used to make glow-in-the-dark materials, such as Luminous dial on some watches and clocks and on children's toys and pajamas.
- The stored energy is released partially as visible light when the atoms or molecules decay slowly.
- After the ceramic has cooled from its firing, atomic energy can be frozen in.
- Since the release is slow, thermoluminescence can be used to date antiquities.
- The older the ceramic, the less light it emits.
- The Chinese ceramic figure can be stimulated to de-excite and emit radiation by heating a sample of the ceramic, a process called thermoluminescence.
- Since the slowly states de-excite over centuries, the amount of thermoluminescence decreases with age, making it possible to use this effect to date and authenticate antiquities.
- The figure is from the 11th century.
- Today's lasers are commonplace.
- Lasers are used to read bar codes at stores and libraries, laser shows are staged for entertainment, laser printers produce high-quality images at a relatively low cost, and lasers send large numbers of telephone messages through optical fibers.
- Lasers are used in a number of things, including surveying, weapons guidance, tumor eradication, and for reading music CDs and computer CD-ROMs.
- The answer is that lasers emit single-wavelength EM radiation that is very coherent.
- Laser output can be more precisely manipulated than other sources.
- Laser output is so pure and coherent because of how it is produced, which depends on a metastable state in the lasing material.
- electrons are raised to all possible levels when energy is put into a large collection of atoms The electrons that originally excited the metastable state and those that fell into it from above are included.
- A population inversion has been achieved if a majority of electrons are in the metastable state.
- An electron falls from the metastable state.
- A second photon of the same wavelength and phase with the first is emitted when this photon finds another atom in the metastable state.
- An excited atom with an electron in an energy orbit higher than normal releases a photon of a specific Frequency when the electron drops back to a lower energy orbit.
- If this photon strikes another electron in the same high-energy space, another photon of the same frequency is released.
- The emitted and triggering photons are both in the same phase and travel in the same direction.
- A majority of atoms must be in the metastable state to produce energy because the probability of absorption of a photon is the same as the probability of stimulated emission.
- Einstein was the first to realize that stimulated emission and absorption are equally probable.
- The laser acts as a temporary energy storage device that produces a massive energy output.
- One atom in the metastable state spontaneously decays to a lower level, producing a photon that stimulates another atom to de-excite.
- The second photon is in phase with the first and has the same energy and wavelength.
- The emission of other photons is stimulated by both of them.
- A net production is necessary for there to be a net absorption.
- The process was developed after advances in quantum physics.
- The development of lasers was one of the reasons why the Soviet Union and the United States won a joint Nobel Prize in 1964.
- Arthur Schawlow won the 1981 Nobel Prize for his work in laser applications.
- The devices were called masers because they produced microwaves.
- T. Maiman created the first working laser in 1960.
- The red light was produced by using a flash lamp and a rod.
- The name laser is used for all of the devices that produce a variety of wavelengths.
- In a process called optical pumping, energy input can come from a flash tube, electrical discharge, or other source.
- A large percentage of the original pumping energy is dissipated in other forms.
- Mirrors can be used to enhance stimulated emission by multiple passes of the radiation back and forth.
- Some of the light can be seen through one of the mirrors.
- A laser's output is 1% of the light passing back and forth in a laser.
- Laser construction uses a method of pumping energy into the lasing material.
- Many types of lasing materials are used to make lasers.
- The existence of a metastable state or phosphorescent material is what determines lasers.
- Some lasers produce continuous output while others are short-lived.
- The more common lasers produce something on the order of.
- The red light that comes from the laser is very common.
- The number of atoms of helium is ten times greater than the number of neon atoms.
- The first excited state of helium stores energy.
- Neon atoms have an excited state that is nearly the same as that in helium, which makes it easy to transfer this energy.
- The neon state that produces the laser output is also metastable.
- There are so many more helium atoms in neon that it can produce a population inversion.
- The population can be maintained even while lasing occurs because helium-neon lasers have continuous output.
- The most common lasers in use today are made of Silicon.
- The energy is pumped into the material by passing a current into the device.
- Light bounces back and forth and a tiny fraction emerges as laser light thanks to special coating on the ends and fine cleavings of the material.
- The lasers can produce outputs in the range of a few hundredths of a watt.
- The gas mixture has more neon atoms than helium.
- In a collision, excited helium atoms can de-excite by transferring energy to neon.
- Neon allows lasing by the neon to occur.
- There are many uses of lasers.
- Lasers can focus on a small spot.
- They have a wavelength that is defined.
- There are many types of lasers that provide the same wavelength of light.
- One needs to be able to pick a wavelength that will be preferentially absorbed by the material of interest.
- The objects appear a certain color because they absorb all other colors.
- The wavelength absorbed depends on the energy spacing between the electrons in the molecule.
- Unlike the hydrogen atom, biologicalmolecules are complex and have a variety of absorption lines.
- In the selection of a laser with the appropriate wavelength, these can be determined.
- Water absorbs light in the UV and IR regions.
- hemoglobin absorbs most of the UV light.
- Laser surgery uses a wavelength that is absorbed by the tissue it is focused upon.
- Total loss of vision can be caused by a detached retina.
- scar tissue that can hold the retina in place, salvaged the patient's vision after Burns made by a laser focused to a small spot on the retina.
- Refractive dispersion of different wavelength light sources can't be focused as precisely as a laser.
- Laser surgery in the form of cutting or burning away tissue is more accurate because the laser output can be very precisely focused and is preferentially absorbed.
- Depending on what part of the eye needs repair, the appropriate type of laser can be selected.
- The repair of tears in the eye can be done with a green laser.
- The light absorbed by tissues containing blood can be used to "weld" the tear.
- A laser is used to focus on a small spot on the retina, causing scar tissue to hold it in place.
- The light is focused by the lens of the eye and the laser is brought to the eye.
- Lasers are being used in dentistry.
- The soft tissue of the mouth is the most common place where lasers are used.
- They can be used to heal wounds.
- The erbium YAG laser is used to cut into bones and teeth.
- Since lasers can produce very high power in short bursts, they can be used to focus a lot of energy on a small glass sphere.
- The incident energy increases the fuel temperature so that fusion can occur and it also increases the density of the fuel.
- The implosion is caused by the impinging laser.
- Nuclear fusion can be achieved using a system of lasers.
- A burst of energy is focused on a small fuel pellet, which is imploded to the high density and temperature needed to make the fusion reaction proceed.
- CDs and DVDs have larger storage capacities than vinyl records.
- The encyclopedia can be stored on a single CD.
- The CD can be used to record digital information because the pits are very small.
- They are read by having a cheap solid-state laser beam scatter from pits as the CD spins, revealing their digital pattern and the information on them.
- Laser-created pits on a CD's surface hold digital information.
- The laser light scattered from the pit can be read.
- The precision of the laser makes it possible for large information capacity.
- holograms are used for amusement, decoration on novelty items and magazine covers, security on credit cards and driver's licenses, and for serious three-dimensional information storage.
- When viewed from different angles, a hologram is a true three-dimensional image.
- Holography uses light interference, whereas normal photography uses wave optics.
- The light from a laser is split into two parts by a mirror.
- The reference beam shines on a piece of film.
- Light from the object is interfering with the reference beam.
- The exposed film looks foggy, but close examination shows a complicated interference pattern on it.
- The film is darkened where the interference was constructive.
- Holography uses the wave characteristics of light as compared to normal photography, which requires a lens.
- A piece of film is interfered with by a single wavelength coherent light from a laser.
- A partially silvered mirror splits the laser beam into two parts, one illuminating an object and the other shining directly on the film.
- Light falling on a hologram can create a three-dimensional image.
- The film's exposed regions are dark and block the light, while less exposed regions allow light to pass.
- The film acts like a collection of gratings.
- Light passing through the hologram is diffracted in various directions, producing both real and virtual images of the object used to expose the film.
- The interference pattern is the same as the object.
- The interference pattern gives you different perspectives when you move your eye to different places.
- The image is three-dimensional like the object.