ABSTRACT
This chapter discusses the details of what stimulated emission of radiation is, why it is the major physical phenomenon at the heart of the laser, and how it is exploited in ways to create laser light beams. It describes the Bohr model of the atom and how electrons can only make quantized leaps in energy levels from one atomic orbital or shell to the next. The chapter considers Pauli’s Exclusion Principle and singlet, doublet, and triplet states of the atom. It also describes the interaction of light with atoms through absorption, spontaneous emission, and stimulated emission. The chapter shows that the quantum mechanical harmonic oscillator and the ground state of the universe is a nonzero electromagnetic field and therefore is the trigger for spontaneous emission. It looks at the models for absorption, spontaneous and stimulated emission, and vibrational states.
