How powerful is a ruby laser?

Ruby Laser Power and Specifications

The ruby laser is a type of solid-state laser that was the first laser ever to be operated successfully. Invented by Theodore H. Maiman in 1960, it is made of a ruby crystal as its gain medium. The operation of ruby lasers involves the excitation of chromium ions in the crystal, which produce deep red light at a wavelength of 694.3 nanometers.

Power Output

Ruby lasers can be designed to emit either continuous-wave or pulsed laser beams. The power output of ruby lasers varies significantly depending on the design and application:

  • Pulsed operation - Typically, in the pulsed mode, ruby lasers can generate very high power output for short durations. Peak powers can reach several megawatts (MW), although the pulse durations are generally in the range of milliseconds to microseconds.
  • Continuous operation - Continuous wave (CW) ruby lasers are less common due to their lower efficiency and power output compared to other types of lasers. CW ruby lasers typically have power levels in the order of milliwatts (mW).

Applications

Despite their historic significance, the use of ruby lasers today is limited compared to other types of lasers. However, they are still employed in a few specialized applications, such as:

  • Holography
  • Pulsed laser deposition of thin films
  • Medical applications, particularly in dermatology for tattoo removal and treating pigmented lesions.

Comparison to Other Lasers

When compared to newer laser technologies (e.g., Nd:YAG, fiber lasers), ruby lasers have lower efficiency and a higher threshold for laser operation. This is partly because the active medium, chromium-doped corundum (ruby), has a relatively lower stimulated emission cross-section. Despite these limitations, the intense and short pulses achievable with pulsed ruby lasers make them uniquely suited for certain applications.

In summary, while ruby lasers might not be the most powerful or efficient type of laser available today, their ability to produce highly concentrated pulses of light continues to make them valuable for specific applications where short, intense pulses of light are required.

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