Physics Unit-4: Laser Basics

What is the acronym for laser stands for?

Light Amplification by Stimulated Emission of Radiation

Who developed the first laser device?

T.H.Maiman

What is the wavelength of light emitted by the Ruby Laser?

694.3 nm

What is the wavelength of light emitted by the Helium-Neon laser?

632.8 nm Signup and view all the answers

In which year was the theoretical basis for the development of laser provided?

1917 Signup and view all the answers

What was the historical precursor to the laser?

Maser Signup and view all the answers

What is the probability of spontaneous emission given by?

A21 Signup and view all the answers

What is the coefficient of stimulated emission?

B21 Signup and view all the answers

What is the Boltzmann distribution law?

The states with lower energy have a higher probability of being occupied. Signup and view all the answers

How does the frequency of radiation affect the value of B21?

Higher frequencies result in a lower value of B21. Signup and view all the answers

What is the total probability of emission of a photon given by?

P21 = A21 + B21.u(ν) Signup and view all the answers

What happens to the population of the higher energy state when temperature increases?

It increases Signup and view all the answers

What is the minimum number of energy states required to achieve population inversion?

3 Signup and view all the answers

What is the characteristic of a metastable state?

Long lifetime Signup and view all the answers

What happens when the population of the higher energy state exceeds that of the lower energy state?

No optical gain occurs Signup and view all the answers

What is the purpose of a metastable state in a laser?

To retain the state of population inversion Signup and view all the answers

What is the condition for achieving optical gain?

N1 < N2 Signup and view all the answers

What is the condition required for population inversion to be achieved?

Ratio N2/N1 must be high Signup and view all the answers

What is the function of the optical resonator?

To increase the intensity of the laser beam Signup and view all the answers

What type of lasers can be formed depending on the active medium?

Solid state lasers, liquid lasers, and gas lasers Signup and view all the answers

What happens to the spontaneous emission from E3 to a metastable state?

It is nonradiative Signup and view all the answers

What is the purpose of the energy source?

To raise the system to an excited state Signup and view all the answers

What is the function of one of the mirrors in the optical resonator?

It is partially transparent Signup and view all the answers

What is the duration of the flash lamp's bright flash of light?

A thousandth of a second Signup and view all the answers

Why is the rod's length made precisely an integral number of half wavelengths long?

To form an optical standing wave Signup and view all the answers

What is the effect of the flash lamp stopping its operation?

The population of the upper level is depleted very rapidly Signup and view all the answers