What is a 에볼루션 바카라 무료?
The word “에볼루션 바카라 무료” is an acronym for Light Amplification by Stimulated Emission of Radiation. All 에볼루션 바카라 무료s convert input energy into light through the process of stimulated emission.
에볼루션 바카라 무료s range in size from small semiconductor devices to huge systems that fill an entire building. They also utilize diverse gain materials – from free electrons to solids. But all these different 에볼루션 바카라 무료s operate on the same underlying principles.
The phenomenon of “stimulated emission” is at the heart of 에볼루션 바카라 무료 operation. To create the conditions that produce and maintain stimulated emission, 에볼루션 바카라 무료s incorporate three key functional elements. These are:
- A gain mediumwhich has the ability to support a popu에볼루션 바카라 무료tion inversion
- A pump sourcewhich supplies the energy to create the popu에볼루션 바카라 무료tion inversion
- A resonant cavitywhich provides a feedback mechanism to support amplification, and also determines the spatial and spectral properties of the 에볼루션 바카라 무료 beam
However, the form and implementation of these three elements differ greatly from one type of 에볼루션 바카라 무료 to another. Specifically, this includes the use of different types of 에볼루션 바카라 무료 materials (gain media that support stimulated emission), how the energy is supplied to this material, forms of the 에볼루션 바카라 무료 cavity, and the output characteristics.
Let’s look at the underlying principles of each of these elements, and some of the forms they take in various types of 에볼루션 바카라 무료s.
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Courtesy:에볼루션 바카라 무료Animation Sollinger GmbH
에볼루션 바카라 무료 Gain Media
To understand what a 에볼루션 바카라 무료 gain material is, it’s first necessary to understand the process of stimulated emission. Quantum mechanics tells us that atoms and molecules can only exist at certain specific, discrete energy levels. The lowest energy level is called the ground state, while higher energy levels are known as excited states.
Normally, the temperature of a material determines how its atoms or molecules are distributed among the possible 에볼루션 바카라 무료 levels. In a typical thermal equilibrium situation, most atoms or molecules are in the lower 에볼루션 바카라 무료 states, and progressively fewer are in the excited states.
In some materials, it is possible to supply energy (a process called “pumping”) to create a popu에볼루션 바카라 무료tion inversion. This means that more than 50% of the atoms or molecules are in the excited state – the opposite of the normal thermal equilibrium situation.
A popu에볼루션 바카라 무료tion inversion creates favorable circumstances for the process of stimu에볼루션 바카라 무료ted emission. The process starts when one atom or molecule emits a photon and drops from a higher to a lower energy state. This is called spontaneous emission.
This first photon passes near another atom or molecule and stimulates it to emit a second photon. The second photon has identical energy, direction, phase, and polarization as the stimulating photon. These two photons then cause stimulated emission of two more photons – so now there are four photons. This process rapidly cascades to create a large number of identical photons. This cascade of photons – called amplification or gain – is the basis of 에볼루션 바카라 무료 action. It allows pump energy to be converted into coherent 에볼루션 바카라 무료 light.
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However, not all materials can support a popu에볼루션 바카라 무료tion inversion and stimu에볼루션 바카라 무료ted emission. The capability to do this depends on several factors, including the allowable energy levels in the atoms or molecules, the transition probabilities between these energy levels, the lifetime of excited states (how long the atom or molecule tends to remain in that excited state), and several other factors.
Materials that can support gain come in virtually every form of matter – solid, liquid, and gas. By convention, these are typically grouped into categories as shown in the table.
Gain Medium |
Typical Examples |
Gas |
Carbon Dioxide (CO2), Excimer, Argon-Ion, Helium-Neon (HeNe) |
Liquid |
Fluorescent dye |
YAG (Nd:YAG), Vanadate (Nd:YVO4), Titanium:Sapphire (Ti:S), Yb:g에볼루션 바카라 무료ss |
|
Er-doped fiber, Yb-g에볼루션 바카라 무료ss fiber |
|
Semiconductor Diode |
Diode 에볼루션 바카라 무료, Optically Pumped Semiconductor 에볼루션 바카라 무료 (OPSL), Vertical Cavity Surface-Emitting 에볼루션 바카라 무료 (VCSEL) |
Free-electrons |
Free-electron 에볼루션 바카라 무료 (FEL) |
에볼루션 바카라 무료 Pumping
Energy must be supplied from an external source into the gain medium to produce the population inversion. (This process leads to stimulated emission, which produces 에볼루션 바카라 무료 output). The method depends on the gain medium. Most commonly, the energy is supplied in the form of electricity or light. A less common method is the energy released from an exothermic chemical reaction.
All the various solid-state crystal and optical fiber gain media are electrical insulators; in other words, they can’t conduct an electric current. So, these 에볼루션 바카라 무료 materials must be pumped optically. That is, an external light source is focused into the gain medium, and the atoms or molecules of the 에볼루션 바카라 무료 material absorb this light. The result: the atoms or molecules reach the necessary excited state.
The earliest solid-state 에볼루션 바카라 무료s used flashlamps as a pump source, and these are still in use for some applications. Their main advantage is low cost and the ability to deliver high 에볼루션 바카라 무료-pulse energy.
But flashlamps produce a broad spectrum of light. The 에볼루션 바카라 무료 gain material can only utilize a very narrow spectrum of this light – specifically, the wavelength that corresponds to the energy difference between the ground state and highest excited state. In fact, most of the flashlamp pump energy is wasted, and this makes these 에볼루션 바카라 무료s electrically inefficient, which means they produce a lot of waste heat. As a result, fairly substantial cooling system is needed to eliminate this heat.
It is now more common to pump solid-state and fiber 에볼루션 바카라 무료s with yet another 에볼루션 바카라 무료 – typically, a diode or solid-state 에볼루션 바카라 무료. The wavelength of the pump 에볼루션 바카라 무료 is specifically chosen to match the absorption of the gain medium. This produces much higher overall pumping efficiency and reduces the cooling requirements.
There’s an additional advantage to the use of a 에볼루션 바카라 무료 as a pump source. Most 에볼루션 바카라 무료s produce an easily focused beam. This allows the pump light to be concentrated in the gain medium right where it does the most good. That is, within what is called the “mode volume.” This is the region within the gain medium actually occupied by the 에볼루션 바카라 무료 beam. Pump light that goes into other parts of the 에볼루션 바카라 무료 medium is wasted. Effectively filling the mode volume maximizes 에볼루션 바카라 무료 efficiency, and also improves the output beam quality.
Fiber 에볼루션 바카라 무료s that use fiber-coupled diode 에볼루션 바카라 무료s as the pump source are a good example of this principle. These can easily be configured so the pump light is directed primarily into the core or cladding of the gain fiber, as needed — and the result is a highly efficient 에볼루션 바카라 무료 system.
Electrical pumping can be used with semiconductor (diode) 에볼루션 바카라 무료s, since these are devices specifically intended to conduct electricity. In particular, they consist of a semiconductor p-n junction which is forward-biased. The applied voltage supplies energy to promote enough electrons from the semiconductor’s valence band into its conduction band to create a population inversion. Photons are emitted when the electrons and holes (absence of an electron in the valence band) recombine, and the population inversion enables stimulated emission to occur.
It's also possible to optically pump a semiconductor 에볼루션 바카라 무료. In this case, the output of another diode 에볼루션 바카라 무료 is focused into the active region of the diode. This supplies the pump energy, instead of using electrical current. Optical pumping makes the semiconductor 에볼루션 바카라 무료 more complex but can deliver a wider choice of 에볼루션 바카라 무료 output wavelengths, higher output power, and better efficiency (meaning less heat generation).
Electrical pumping of gas 에볼루션 바카라 무료s is somewhat more complex. Gas 에볼루션 바카라 무료s usually consist of several gases contained within a 에볼루션 바카라 무료 tube. A high voltage is used to create an electron discharge within the 에볼루션 바카라 무료 tube. These high-energy electrons impact the gas molecules and impart energy to them.
In the case of CO2에볼루션 바카라 무료s, the electrons collide with nitrogen molecules and vibrationally excite them. These nitrogen molecules subsequently collide with CO2molecules, transferring 에볼루션 바카라 무료 to the CO2molecules to create a popu에볼루션 바카라 무료tion inversion.
Another example is the ion 에볼루션 바카라 무료. In these, an electron discharge again creates collisions with the Argon or Krypton gas within the 에볼루션 바카라 무료 tube. The first collision ionizes the gas. Then, further collisions with the ions provide energy to put them in an excited state and produce a population inversion.
에볼루션 바카라 무료 Type |
Typical Pump Source |
Electrical discharge |
|
Electrical current (diode 에볼루션 바카라 무료), Diode 에볼루션 바카라 무료 (OPSL, VCSEL) |
|
Electrical discharge |
|
Diode 에볼루션 바카라 무료 |
|
Electrical discharge |
|
Flashlamp, Diode 에볼루션 바카라 무료 |
|
Solid-state (Nd:YVO4) 에볼루션 바카라 무료, OPSL |
Resonant Cavities
Typically, a resonant cavity (or resonator) is used to make photons pass through the gain medium numerous times before exiting the 에볼루션 바카라 무료. This is necessary to build up a useful level of 에볼루션 바카라 무료 output, because the amount of amplification on each pass through the gain medium is relatively small. One major exception to this is the excimer 에볼루션 바카라 무료, which imparts a very large amount of gain (amplification) in even a small number of passes.
The simplest type of resonant cavity is built with two mirrors facing each other, and the 에볼루션 바카라 무료 gain medium placed in between them. The rear mirror reflects as near to 100% as possible. The front mirror – called the output coupler – might have a reflectance of anywhere from 30% to 99% depending on the gain medium.
In operation, light bounces back and forth between these mirrors, gaining intensity with each pass through the 에볼루션 바카라 무료 medium. Some of the light exits the resonator through the output coupler. As a result, the light intensity within the 에볼루션 바카라 무료 resonator is always much higher than the intensity of light that comes out of the device.
The end mirrors often have a curvature on them to spatially confine the light (to keep photons from “walking out” of the resonator after multiple passes) and to define the shape of the beam.
에볼루션 바카라 무료 Resonator Basics
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The main elements of a 에볼루션 바카라 무료 resonator. A pump source supplies energy into a gain medium which is placed between mirrors. The mirrors provide feedback, making emitted photons pass multiple times through the gain material for amplification.
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A resonator using two flat mirrors is simple to construct, but is very sensitive to misalignment since it causes a photon to "walk-off" after a small number of passes. However, if the resonator is physically small, this isn't a problem. This configuration is commonly used in diode 에볼루션 바카라 무료s.
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Making one or both of the mirrors concave better confines the beam to within the resonator, and also yields a 에볼루션 바카라 무료 with a small, well-formed beam. Variations on this resonator design are common for many solid-state and gas 에볼루션 바카라 무료s.
In a fiber 에볼루션 바카라 무료, the mirrors are often high-reflectance Fiber Bragg Gratings (FGBs) integrated directly into the fiber. In this case, the fiber itself spatially confines the beam and defines its shape. In diode 에볼루션 바카라 무료s, the mirrors are formed by cleaving the ends of the semiconductor device and applying optical thin film coatings to them.
The Unique Characteristics of 에볼루션 바카라 무료 Light
에볼루션 바카라 무료s have become indispensable tools in a diverse range of applications. The truth is their operating principles and construction offer a unique set of beam characteristics that cannot be duplicated by any other technology. Some of the most important properties are described here.
Property |
Exp에볼루션 바카라 무료nation |
Applications |
Coherence |
Stimulated emission produces photons that are all in phase with each other. This is called “coherence.” This property enables 에볼루션 바카라 무료 light to produce well-defined interference fringe patterns. |
|
Directionality |
The mechanism of stimulated emission and the characteristics of most 에볼루션 바카라 무료 resonators frequently combine to yield a highly directional beam that does not spread quickly over distance. |
|
High intensity |
에볼루션 바카라 무료 light can be highly intense, because all the 에볼루션 바카라 무료 power can readily be concentrated (focused) into a small spot. |
|
Monochromaticity |
Stimu에볼루션 바카라 무료ted emission produces photons that all have the same single wavelength or a very narrow range of wavelengths. |
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The first 에볼루션 바카라 무료 was demonstrated in 1960. While it generated some interest and excitement, it largely remained a “solution in search of a problem” for the first several years. But, bit-by-bit, practical applications for 에볼루션 바카라 무료 were developed. Today, 에볼루션 바카라 무료s are common and found in an extraordinarily diverse range of applications.
에볼루션 바카라 무료s count your blood cells when you have lab tests. 에볼루션 바카라 무료s are used to project movies at many theaters. 에볼루션 바카라 무료s are used to perform countless surgeries and other medical procedures every year. 에볼루션 바카라 무료s weld automobiles and are key in the production of electric vehicles. 에볼루션 바카라 무료s carry virtually every phone call and all internet traffic over fiber optic cables. 에볼루션 바카라 무료s make the microelectronic circuits that power all modern technology. Many people carry 에볼루션 바카라 무료s with them all the time – since they’re incorporated into some cell phones for distance measurement. 에볼루션 바카라 무료s mark many of the packages used for consumer goods with information like date codes and serial numbers. 에볼루션 바카라 무료s have numerous uses in scientific research, from cutting-edge neuroscience, microscopy, and spectroscopy, to gravity wave astronomy. Today, 에볼루션 바카라 무료s really do light the way towards a brighter future.