The core component of a diode laser is a semiconductor diode. More specifically, this is a p-n junction diode made of one p-type and one n-type semiconductor. The p-n junction acts like a turnstile, allowing electrons to flow through the barrier.

Laser diodes typically use semiconductors made of aluminum or gallium arsenide alloys. Current is supplied through the diode, inducing electrons to flow through the p-n junction. These electrons combine with holes on the other side of the junction, releasing excess energy in the form of photons.

The gap between the two semiconductors acts as a "mirror" that amplifies the intensity of the photons. Photons bounce back and forth across this gap and collide with other incoming electronics. This "resonance" helps generate more photons. Hundreds of collisions are required to achieve the desired optical gain in diode lasers.

In more complex applications, multiple semiconductor diodes can be stacked together. Multiple beams from these diodes can be focused into a single beam, resulting in greatly increased output power. This also makes it possible to create multiple lasers with different wavelength values.

Diode Lasers - Pros and Cons
To demonstrate how simple diode lasers are, the typical lasers used in standard laser pointers are low energy diode lasers. That should already tell you how different diode lasers are - they are cheaper, smaller, and can be powered by a small battery.

1. Less expensive
Today, you can buy a standalone diode laser kit for less than $200. By comparison, CO2 laser engraving kits cost at least closer to $500. This has made diode lasers very popular among the hobbyist community, even for those who want to start a small business.

2. Compact, lightweight, and robust
Diode lasers are very small and lightweight, making them ideal for DIY projects. They are commonly found in 3-in-1 machines that combine a laser engraver with a 3D printer and CNC machine.

Portable laser engraving machines are also slowly gaining popularity, and they are all based on diode laser technology. It also helps that the diode laser is very robust - regular movement of the diode laser is not a problem, as its semiconductors don't need to be perfectly aligned to work.

1. Not as powerful
The biggest trade-off with using a diode laser is that it's very low power. The maximum output of a single diode is 10W. While stacked diodes are possible, laser engraving is not common.

Cutting paper or balsa or engraving on leather is not a problem, but using metal or thicker wood may not be practical. If you're working with more challenging materials, expect multiple passes and longer times with the CO2 laser.

2. Limited applications
Using a diode laser means simply accepting that you cannot engrave or cut many materials. Diode lasers don't have enough power to engrave metal or glass unless some coating has been applied to it. Diode lasers also have difficulty processing any surface that is glossy, clear, translucent, or painted all-white.

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