31:16

Transverse Modes of LASER cavity

27:57

Components of LASERs

30:30

Properties of Laser: Directionality and Intensity

33:24

Mode Locking

38:33

Properties of Laser: Coherence and Monochromaticity

32:43

Continuous and Pulsed Lasers

28:28

Population inversion, 2-level system and 3-level system

34:36

3-level System and 4-level system