Some users may be unfamiliar with frequency and pulse width, or may not be sure how these two parameters affect laser processing.

This guide explains what frequency and pulse width mean, how they affect MOPA and UV laser processing, and how they work together with other parameters such as power and speed.

What Is Frequency?

Frequency = how many laser pulses are emitted per second.

Low Frequency
●      ●      ●      ●
Fewer pulses

High Frequency
● ● ● ● ● ● ● ●
More pulses

How does frequency affect engraving?

For MOPA:

• Lower frequency generally means more energy per pulse when the average power remains the same. This can produce a stronger effect and may be useful for metal cutting, deep engraving, and other material removal applications.
• Higher frequency produces more pulses per second, which is ideal for fine engraving and can create a more continuous and uniform effect. However, it may also increase heat accumulation depending on the material and settings.

For UV:

• Frequency changes the spacing and energy distribution between pulses.
• Higher frequency can make the processing effect more continuous, but excessively high frequency may increase heat accumulation.
• For fine engraving, frequency should be adjusted together with power, pulse width, speed, and other parameters.

Easy way to remember

Frequency = how many times the laser fires per second.

Higher frequency is not always better. The appropriate frequency depends on the material and the desired result.

What Is Pulse Width?

Pulse Width = how long each laser pulse lasts.

Short Pulse Width
│ █ │     █ │     █ │
Very short duration

Long Pulse Width
│ ███ │   ███ │   ███ │
Longer duration

How does pulse width affect engraving?

For MOPA:

• Shorter pulse width releases the pulse energy in a shorter time, resulting in higher peak power. It is often useful for fine processing, deep engraving, and material removal.
• Longer pulse width releases the energy over a longer period and can produce more heat accumulation. It can also produce different colors or surface effects on certain materials.

Easy way to remember

Pulse Width = how long each pulse lasts.

Frequency vs. Pulse Width

Parameter	Simple explanation
Power	Overall laser output power
Frequency	How many pulses are emitted per second
Pulse Width	How long each pulse lasts
Pulse Energy	How much energy is contained in each pulse
Speed	How fast the laser moves

Frequency
●   ●   ●   ●
↓   ↓   ↓   ↓
How many times?

Pulse Width
█      ███      █
       ↑
   How long is each pulse?

For pulsed lasers, pulse energy is related to average power and frequency. As a simplified example, when average power remains the same, lowering the frequency generally increases the energy contained in each pulse.

Actual engraving results depend on power, frequency, pulse width, speed, focus, material, and other processing conditions. There is no single “best” setting for every material or application.