What does laser mean?

Who built the first working laser?

• Charles Townes

• Theodore Maiman

• Gordon Gould

What is the main component of a laser system?

• Active medium

• Pumping source

• Optical Resonator

What is population inversion?

What does the Boltzmann equation determine?

What is the effect of greater population inversion?

What are the three important effects in optical physics?

• Stimulated emission

• Spontaneous emission

• Absorption

Calculate the value of the stimulated emission rate to the spontaneous emission for an incandescent lamp operating at a temperature of 1000 K. It may be assumed that the average operating wavelength is 0.5 μm.

Calculate the stimulated emission rate B21 for a transition at 632.8 nm, an average index of refraction of 1, and spontaneous lifetime tspont = 0.3 μs.

Consider two energy states, E2 = 2.1 eV and E1 = 1 eV. Assume that there are 1*10^16 electron/cm^3 in E1. At a temperature of 1000 K, how many electrons are in state 2?