The Study on the Holmium YAG Laser

Abstract

A solid state laser known as a holmium YAG laser is created by doping YAG (Yttrium Aluminum Garnet) crystals with rare-earth holmium ions (Ho3+). The YAG laser was originally doped with holmium in tests conducted in the 1960s. These experiments produced a laser emission with a wavelength of 2.1 µm. [22] A high-power, solid-state, near-infrared source that can be provided by fiber is the Ho:YAG (or holmium) laser. As a result, it is widely used in urology, orthopedics, gynecology, dentistry, and other surgical specialties. [23]

Introduction

A laser (Light Amplification by Stimulated Emission of Radiation) is a device that produces coherent light through optical amplification based on stimulated emission. Theodore Maiman built the first laser in 1960, based on theoretical work by Charles Townes and Arthur Schawlow. Lasers emit highly focused, narrow-spectrum light with applications in cutting, welding, communications, medical procedures, entertainment, and military uses. Unlike LEDs, lasers can produce intense, precise beams with small emitting areas. Devices operating at microwave frequencies are called masers, while those above microwaves are lasers. A laser is “lasing” when actively emitting coherent light.

Historical Background:
Einstein proposed stimulated emission in 1916. Rudolf Ladenburg first observed it in 1928. Charles Townes developed the maser in the early 1950s, later inspiring attempts to create optical lasers with Schawlow and Gould. Theodore Maiman achieved the first working laser using a ruby crystal in 1960. Subsequent developments included helium-neon gas lasers and semiconductor lasers. Early applications ranged from holography to laser surgery and supermarket scanners.

Principle of Operation:
Lasers operate based on quantum mechanics: electrons in atoms transition between energy states, emitting photons spontaneously or via stimulated emission. Population inversion—where more atoms occupy higher-energy states than lower ones—is essential for stimulated emission. Excitation is achieved through light or electrical pumping. Three-level lasers produce pulses, while four-level lasers can provide continuous beams.

Laser Components and Beam Characteristics:
Lasers consist of a gain medium and an optical resonator with mirrors to amplify light. Laser light is monochromatic, coherent, and highly collimated. Beam divergence depends on aperture size and wavelength. The coherence length measures phase uniformity, important for applications like holography. Lasers can produce continuous-wave or pulsed outputs, with peak powers reaching extremely high levels in ultrashort pulses.

Holmium YAG Lasers:
Ho:YAG lasers are solid-state lasers using YAG crystals doped with holmium ions. Operating at a wavelength of 2.1 µm, they are primarily powered by laser diodes and used in medical applications such as dentistry, tissue ablation, and surgical procedures.

Conclusion

A solid state laser is a holmium laser. A YAG laser is created by doping YAG (Yttrium Aluminum Garnet) crystals with rare-earth holmium ions (Ho3+). The YAG laser was originally doped with holmium in tests conducted in the 1960s. These trials produced laser output with a wavelength of 2.1 µm. The primary use of this laser is in medical procedures. Its primary application is in tissue ablaMedical procedures are the main use for holmium YAG lasers. It is utilized for several surgical operations, including dentistry, urology, prostate surgery, and tissue ablation. [22]

References

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Copyright

Copyright © 2025 Muhammad Arif Bin Jalil. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.