Final answer:
Laser sources generate light through the process of stimulated emission, involving energy input, population inversion, and mirrors to enhance photon emission. The first laser was developed in 1960, and modern lasers can emit light in a range of wavelengths.
Step-by-step explanation:
Laser sources generate light through a process called stimulated emission of radiation. This process leads to the production of coherent and monochromatic light, where the photons are in-phase, and all have a single frequency or color. A laser creates a beam of light through the stimulation of electrons to release photons in a controlled manner. To achieve this, an energy source, such as a flash tube or electrical discharge, pumps energy into the lasing material, a process often referred to as optical pumping. This leads to a condition known as population inversion where more electrons are in an excited state than in their ground state. The presence of mirrors in the construction of a laser enhances stimulated emission by allowing photons to pass multiple times through the lasing material, with one mirror being partly transparent to release the laser light.
The first working laser was developed in 1960 and used a ruby rod to produce red light. Today, lasers can produce a variety of wavelengths including microwave, infrared, visible, and ultraviolet radiation. The efficiency of converting pumping energy to laser output is typically low, with only about 1% of light being emitted as laser output compared to the light that actually passes back and forth within the laser.