Examples of free-electron laser in the following topics:
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- A laser is a device that emits monochromatic light (electromagnetic radiation).
- Principles of laser operation are largely based on quantum mechanics.
- (One exception would be free-electron lasers, whose operation can be explained solely by classical electrodynamics. ) When an electron is excited from a lower-energy to a higher-energy level, it will not stay that way forever.
- An electron in an excited state may decay to an unoccupied lower-energy state according to a particular time constant characterizing that transition.
- Identify process that generates laser emission and the defining characteristics of laser light
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- A laser consists of a gain medium, a mechanism to supply energy to it, and something to provide optical feedback.
- When lasers were invented in 1960, they were called "a solution looking for a problem. " Nowadays, lasers are ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement, entertainment, and the military.
- Having examined stimulated emission and optical amplification process in the "Lasers, Applications of Quantum Mechanics" section, this atom looks at how lasers are built.
- There are many types of lasers depending on the gain media and mode of operation .
- Laser types with distinct laser lines are shown above the wavelength bar, while below are shown lasers that can emit in a wavelength range.
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- The electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.
- The electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.
- Electron configurations describe electrons as each moving independently in an orbital, in an average field created by all other orbitals.
- However, the electronic wave function is usually dominated by a very small number of configurations and therefore the notion of electronic configuration remains essential for multi-electron systems.
- In bulk materials this same idea helps explain the peculiar properties of lasers and semiconductors.
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- It involves the use of a laser, interference, diffraction, light intensity recording and suitable illumination of the recording.
- A hologram requires a laser as the sole light source.
- Laser is required as a light source to produce an interference pattern on the recording plate.
- Holography requires a specific exposure time, which can be controlled using a shutter, or by electronically timing the laser
- Process: When the two laser beams reach the recording medium, their light waves intersect and interfere with each other.
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- The behavior of the subatomic particles (electrons, protons, neutrons, photons, and others) that make up all forms of matter can often be satisfactorily described only using quantum mechanics.
- Examples include the laser , the transistor (and thus the microchip), the electron microscope, and magnetic resonance imaging (MRI).
- The study of semiconductors led to the invention of the diode and the transistor, which are indispensable parts of modern electronic systems and devices.
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- There are many types of microscopes: optical microscopes, transmission electron microscopes, scanning electron microscopes and scanning probe microscopes.
- Transmission Electron Microscope: The TEM passes electrons through the sample, and allows people to see objects that are normally not seen by the naked eye .
- Scanning Electron Microscopes: Referred to as SEM, these microscopes look at the surface of objects by scanning them with a fine electron beam .
- The electron beam of the microscope interacts with the electrons in the sample and produces signals that can be detected and have information about the topography and composition.
- The deflection of the tip is then measured using a laser spot that is reflected from the surface of the cantilever .
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- There are many variations of laser cooling, but they all use radiation pressure to remove energy from atomic gases (and therefore cool the sample).
- In laser cooling (sometimes called Doppler cooling), the frequency of light is tuned slightly below an electronic transition in the atom.
- Thus if one applies light from two opposite directions, the atoms will always scatter more photons from the laser beam pointing opposite to their direction of motion (typical setups applies three opposing pairs of laser beams as in ).
- Simple laser cooling setups can produce a cold sample of atomic gases at around 1mK (=10-3 K) starting from a room temperature gas.
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- In metals, the free charges are free electrons.
- Given an estimate of the density of free electrons in a conductor (the number of electrons per unit volume), it is possible to calculate the drift velocity for a given current.
- Free electrons moving in a conductor make many collisions with other electrons and atoms.
- The path of one electron is shown.
- The average velocity of the free charges is called the drift velocity and is in the direction opposite to the electric field for electrons.
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- All matter is composed of atoms made up of negatively-charged electrons and positively-charged protons.
- This is because electrons from one have transferred to the other, causing one to be positive and the other to be negative.
- Both pressure and heat increase the energy of a material and can cause electrons to break free and separate from their nuclei.
- Charge, meanwhile, can attract electrons to or repel them from a nucleus.
- For example, a nearby negative charge can "push" electrons away from the nucleus around which they typically orbit.
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- The Compton Effect is the phenomenon of the decrease in energy of photon when scattered by a free charged particle.
- Compton scattering is an inelastic scattering of a photon by a free charged particle (usually an electron).
- Part of the energy of the photon is transferred to the scattering electron.
- Still, the origin of the effect can be considered as an elastic collision between a photon and an electron.
- The Compton Effect is the name given to the scattering of a photon by an electron.