29 Questions
What does the acronym 'Laser' stand for?
Light Amplification by Stimulated Emission of Radiation
What is the main feature of a laser system?
Capacity to make atoms or molecules discharge light at set wavelengths and to amplify it into a narrow beam of radiation
What are the typical visible wavelengths emitted by lasers?
Infrared or ultra-violet
What are some materials from which laser beams can be made?
Crystals, gas, semi-conductors, glass, liquids, electron beams, and gelatin coated with favorable material
Why is it not possible to get beams from the strong and stimulated emissions of hot gases surrounding stars?
The clouds of gas do not have resonant cavities
What type of atoms are excited by an external light source within lasers of crystal and glass?
Dopants at low concentrations
What is the condition for the total light increase in a laser cavity?
The total light increase occurs when emission is triggered during every session between the two mirrors, equal to the amount of light that emerges within the beam added to the losses that occur in the optical resonator.
What is the result of combining a laser medium with a resonant cavity?
The result is the formation of a laser oscillator.
What is the condition for the laser to produce a continuous beam?
The laser must produce a beam that is continuous.
What would happen if no mirrors were used and there was no resonant cavity in a laser system?
The laser would not amount to anything more than just some optical amplifier.
Who demonstrated the original optical amplifier in 1961?
Elias Snitzer.
When was the original optical amplifier demonstrated?
In 1961.
When was the use of the original optical amplifier taken up in a serious way?
The use was not taken up in a serious way until fiber-optic communication became commonplace.
What are some of the properties of a laser dependent on?
Some of the properties of a laser are dependent on oscillation.
What is the condition for production of light by the laser system?
The production of light by the system occurs internally.
What elements are used to dope glasses for fiber optic lasers and amplifiers?
erbium, ytterbium, and neodymium
What type of laser was the first to gain widespread commercial use?
helium-neon laser
In the 1970s, how were ruby laser pulses utilized by eye surgeons?
to weld detached retinas without physical cutting
What are laser scanners widely used for in supermarkets?
product scanning
What are laser pointers widely used for by lecturers?
presentations
What type of lasers produce visible and ultraviolet light?
helium-neon and helium-neon-argon lasers
What are diode lasers popular for producing?
infrared and visible light
What are free-electron lasers capable of depending on the energy of the electron beam and changes in the magnetic field?
Free-electron lasers can be tuned across a wide wavelength range
What shapes laser emission in quantum mechanics?
Laws in quantum mechanics shape laser emission by restricting atoms and molecules to discrete energy levels
What happens when excited electrons move towards the outer orbit after absorbing energy?
When excited electrons move towards the outer orbit after absorbing energy, they emit surplus energy in the form of light
What is required to initiate inversion of population in a laser system?
Intense light or an electric current is required to selectively excite atoms or molecules for inversion of population
What are the most useful energy levels for a laser system?
The most useful energy levels for a laser system are three or four, with the meta-stable state being crucial for trapping and retaining excited energy
What type of lasers commonly rely on transparent crystals or semiconductors?
Solid-state lasers rely on transparent crystals or semiconductors with low concentration light discharging atoms
What state do 4-level lasers have that allows for continuous beam emission for several days?
4-level lasers have an additional state of transition between the meta-stable and ground state, allowing for continuous beam emission for several days
Study Notes
Understanding Lasers and Their Operation
- Some researchers question whether lasers with free electrons can be considered true lasers due to the failure of these electrons to transition between distinct energy levels
- Free-electron lasers can be tuned across a wide wavelength range, depending on the energy of the electron beam and changes in the magnetic field
- High-power lasers can be made using free-electron or chemical lasers
- In quantum mechanics, laws shape laser emission by restricting atoms and molecules to discrete energy levels
- Electrons in a ground state are wholly within an atom's closest orbit, while excited electrons move towards the outer orbit after absorbing energy
- Excited states of atoms are generally unstable, and when electrons drop from high energy levels to lower levels, they emit surplus energy in the form of light
- Emission of energy can occur naturally with no outside support, or a photon in motion can trigger an atom or molecule to discharge light if the photon's energy matches the energy the electron can emit
- The energy configuration ratios of low to high determine the prevailing process, with low-level energy configurations being more probable
- Inversion of population occurs when higher energy configurations predominate, leading to the cascading of photons
- Heat alone cannot initiate inversion of population; intense light or an electric current is required to selectively excite atoms or molecules
- The most useful energy levels for a laser system are three or four, with the meta-stable state being crucial for trapping and retaining excited energy
- 4-level lasers have an additional state of transition between the meta-stable and ground state, allowing for continuous beam emission for several days
- Laser media are commonly gaseous or solid, with gaseous lasers excited by electric current or external light, while solid-state lasers rely on transparent crystals or semiconductors with low concentration light discharging atoms
Test your knowledge of laser operation and principles with this quiz! Explore topics such as energy levels, electron transitions, laser media, and the functioning of free-electron and chemical lasers.
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