Introduction to Laser Components
Although lasers and laser systems exist in a multitude of operating capabilities, most all share a common thread of physical conformity. Their overlap includes three basic properties in common, namely:
- An energy source to initiate the lasing process (sometimes referred to as a pump source)
- A gain medium which is excited by the pump source to induce a population inversion which initiates stimulated emission of photons at discrete wavelength(s) outputs
- An enclosed optical cavity (sometimes referred to as an optical resonator) to amplify the production of laser light emission for discharge outside the optical cavity/resonator
Taken individually, these three elements are comprised of the following laser componentry:
- Pump source examples may include:
- Flashlamps
- Arc lamps
- Electric discharge
- Chemical reactions
- Gain mediums are comprised of:
- Dye laser liquids (e.g., mixtures of chemical organic solvents – ethylene glycol, methanol, etc. – added to chemical dyes – Coumarin, Rhodamine 6G, etc.)
- Gasses (e.g., CO2, HeNe, argon, etc.)
- Solid state materials in the form of crystals and glasses (e.g., chromium, erbium, neodymium, etc.)
- Semiconductors
- Optical cavities or optical resonators:
- In its most basic form: two parallel mirrors placed within the gain medium to provide an optical feedback loop with reflective optical coatings having one of the mirrors (sometimes termed the output coupler) possessing partially transmissive properties – thereby allowing laser emission outside of the optical cavity/optical resonator
- Other optical devices (e.g., custom optics, spinning mirrors, protection filters, beam splitters, etc.) are commonly used to modify the optical properties of the laser output