Some of the following statements about a laser are true (T), while others are fa

Question

Some of the following statements about a laser are true (T), while others are false (F). In each case, explain why the statement is T or F.

a.A laser produces more energy than is supplied to it.

b.Lasers exist only in the visible region of the spectrum.

c. Stimulated emission is an essential aspect of laser operation.

d.The light beams from two different lasers are coherent, and thus can interfere, if their frequencies are the same.

e.When a photon is emitted from an atom due to stimulated emission, its radiation is coherent with that of the photon that caused the emission.

f.Metastability is important that the state responsible for the laser transition.

g.Einstein’s hypothesis explained Planck’s spectrum. What hypothesis?

Explanation / Answer

a.A laser produces more energy than is supplied to it. - True  

A laser consists of a gain medium, a mechanism to energize it, and something to provide optical feedback. For the gain medium to amplify light, it needs to be supplied with energy in a process called pumping.

b.Lasers exist only in the visible region of the spectrum   - False

It include the ultraviolet, visible, and infrared regions of the spectrum.

c. Stimulated emission is an essential aspect of laser operation - True

Lasers are designed to produce and amplify this stimulated form of light into intense and focused beams.

d.The light beams from two different lasers are coherent, and thus can interfere, if their frequencies are the same          - False - two wave sources are perfectly coherent if they have a constant phase difference and the same frequency.

e.When a photon is emitted from an atom due to stimulated emission, its radiation is coherent with that of the photon that caused the emission. - True   - The liberated energy transfers to the electromagnetic field, creating a new photon with identical phase, frequency, polarization, and direction of travel as the photons of the incident wave.

f.Metastability is important that the state responsible for the laser transition.   -   A laser works by using metastable states. First the lasing material is excited by an outside source, typically an electric current or a flash of light from another source. This excites the material, meaning that the electrons are boosted to a metastable higher energy state.

g.Einstein’s hypothesis explained Planck’s spectrum   -  

Planck postulated that the energy of light is proportional to the frequency, and the constant that relates them is known as Planck's constant (h). His work led to Albert Einstein determining that light exists in discrete quanta of energy, or photons.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.