The Laser Guidebook
Designed for ease of use and to explain the operation and characteristics of different types of lasers, this book is written to help end-users quickly and easily choose the laser best suited to their needs.
TABLE OF CONTENTS The Laser Guidebook
Chapter 23: Ruby Lasers
The ruby laser has proved surprisingly long-lived. Thirty years ago, it was the first laser demonstrated by Theodore H.Maiman (Maiman, 1960), who soon helped make the first commercial versions. Ruby lasers remain on the market today, although limited to a few applications, while most other types envisioned by laser pioneers are little more than laboratory curiosities.
Ruby emits pulses at 694.3 nanometers (nm) in the deep-red when pumped by a flashlamp. Continuous-wave operation has been demonstrated in the laboratory, but is difficult to achieve. Ruby was the first laser used for materials working, but has been replaced by other types except for a few special applications. It remains a valuable source of high-power red pulses for pulsed holography, interferometry, nondestructive testing, plasma measurements, and research.
Internal Workings
Ruby lasers are similar to the pulsed neodymium lasers described in Chap. 22, although repetition rates are much lower and ruby cannot be diode-pumped. In some cases, ruby lasers can operate in the same cavities as neodymium lasers, if suitable resonator optics are used.
Active Medium. Ruby laser rods are grown from sapphire (A1 2O 3) doped with about 0.01 to 0.5 percent chromium to from a synthetic ruby crystal colored red or pink with about 10 19 chromium atoms per cubic centimeter. Rods are up to 20 centimeters (cm) long and 3 to 25 millimeters (mm) in diameter. Ruby resists optical damage at normal power levels if its surface is clean, and conducts heat better than does...
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