Tunable Lasers Tutorial

Understanding lasers in simple words

F. J. Duarte

Key words: beam divergence, coherence, coherent, course, courses, Dirac's notation, lasers, electrical pumping, electrical excitation, grating, interferometric, introduction, instruction, laser, laser-cavity, lecture, linewidth, multiple prism, optical excitation, oscillator, prism, quantum, resonator, spatial coherence, spectral coherence, teaching, tunable, tuning, uncertainty principle, university, university degree.

This brief introduction is a companion article to tunable lasers tutorial, and understanding tunable lasers. The intention is to provide a very brief explanation of what a laser is in simple and clear language.

The concept essential to a laser is the emission of light which is spatially coherent and spectrally coherent :

The radiation described above is emitted by a laser. A laser can be a macroscopic, or classical, device that emits quantum mechanical radiation. A laser uses two basic components, the gain medium, and the laser cavity:

This is an optimized tunable laser oscillator yielding extremely pure emission. The schematics show a gain medium, a tuning grating, a multiple-prism beam expander, and an output mirror which is also a polarizer. For this particular laser (Duarte, 1999 ) the emission is tunable in the visible spectrum in the 550-603 nm range (that is, mainly in the yellow-orange portion of the spectrum). The linewith of this high-power laser oscillator, Δλ ≈ 0.0004 nm, is only limited by Heisenberg's uncertainty principle.

With these basic ideas in mind the initial reader should now be more familiar with the concepts described in our laser tutorial. Tunable Laser Optics explains and explores further these exciting ideas and provides a simple introduction to the quantum physics behind the laser. Tunable lasers are very widely applied (from astronomy to medicine) and, for those interested, Tunable Laser Applications provides an ample authoritative survey also suitable for professionals and university students.


Prism Compressors: Tutorial

Tunable Laser Tutorial

Understanding Tunable Lasers

First published on the 16th of April, 2010.

Updated on the 7th of April, 2022.