Nd-YAG Laser: Advantages and Disadvantages

This page covers the structure, working operation, advantages, and disadvantages of the Nd-YAG laser. It mentions the benefits and drawbacks of Nd-YAG lasers.

What is an Nd-YAG Laser?

Introduction:

• Its structure and working operation are similar to the ruby laser.
• It utilizes Neodymium doped with Yttrium Aluminum Garnet (i.e., Nd:Y₃Al₅O₁₂) as the active material. Nd³⁺ ions are used to achieve the necessary metastable states. It’s used in various scientific and medical fields.
• The Nd:YAG laser emits a lasing output wavelength of about 1.064 µm. This wavelength region is referred to as the near-infrared region. The laser also emits light at other wavelengths.
• This laser type can be used in CW (Continuous Wave) and pulse modes with a peak power of about 1000 Watts and about 2 x 10⁸ Watts, respectively.

• Figure 1 depicts the structure of an Nd:YAG laser. As shown, it consists of an energy source (e.g., flashtube or laser diodes), an active medium (Nd:Y₃Al₅O₁₂), and an optical resonator.
• The energy source supplies energy to the active medium in order to achieve population inversion. The crystal is placed between two mirrors, which are optically coated or silvered.
• This laser is a four-level laser system. This means four energy levels are employed in the laser action.

Benefits or Advantages of Nd-YAG Laser

Following are the benefits or advantages of Nd-YAG lasers:

• It is very useful for thin materials for quick processing.
• It offers high DPI (dots per inch) capabilities.
• It is also useful for applications that need high power density, such as metal marking.
• It offers higher energy output and a very high repetition rate.
• It is very easy to attain population inversion.
• It can be Q-switched for CW or pulse mode operations. This helps in minor laser ablation processes.
• Nd:YAG laser machines can cut very high reflecting materials, e.g., aluminum, copper, non-ferrous metals, which can’t be cut by other laser cutting machines.
• It is easy to operate and maintain.
• The purchasing cost is relatively lower.

Drawbacks or Disadvantages of Nd-YAG Laser

Following are the drawbacks or disadvantages of Nd-YAG lasers:

• It is not ideal to be used for materials that have moderate thickness.
• Slow production is possible for thicker materials using this laser type. Hence, it offers lower efficiency.
• It has low absorption of radiation of lighter materials very close to the visible spectrum.
• It will not allow for a larger scan gap despite high engraving resolutions. This makes the process slower.
• The electron energy level structure of Nd³⁺ in YAG is complex.