Professional laser hair removal mainly uses Alexandrite and diode systems. Nd:YAG provides another established option when skin pigmentation strongly affects parameter selection.
Their main differences come from the laser source and wavelength, which change melanin absorption and penetration depth. This relationship determines the working range of each technology.
What defines a hair-removal laser?
Pay attention to one distinction here: laser type and wavelength are separate characteristics. Laser type tells us how the beam is generated. Wavelength describes the light that the system emits. One laser technology can work at several wavelengths. The same wavelength can also appear in systems built on different technologies. So the number alone does not identify the laser type.
Melanin in the hair is the optical target. It absorbs light and converts energy into heat. Change the wavelength, and the interaction changes with it. Melanin absorbs some wavelengths more strongly, while others penetrate deeper into tissue. Longer wavelengths reach deeper structures. Their interaction with epidermal melanin is also lower, which becomes especially relevant when skin pigmentation is higher.
When comparing professional systems, five technical parameters are especially useful:
- Wavelength configuration — affects melanin absorption and penetration depth.
- Fluence — shows how much energy is delivered per square centimeter.
- Pulse duration — changes how quickly the target accumulates heat.
- Spot size — influences effective penetration and treatment speed.
- Cooling system — controls heat at the skin surface during exposure.
Alexandrite lasers
Alexandrite lasers operate at 755 nm and have high melanin absorption. Pigmented hair therefore captures a large share of the optical energy when there is a strong contrast with lighter skin. This gives Alexandrite systems a strong working range for dark hair on lighter phototypes.
Diode lasers
Diode systems commonly operate around 800–810 nm and combine strong melanin targeting with deeper penetration than shorter wavelengths. Their semiconductor source also allows manufacturers to build multi-wavelength platforms.
Honest Pro is one example. Its diode platform operates at 755, 808, and 1064 nm, extending the available spectral range within one professional system. The operator gains access to different balances of melanin absorption and penetration without changing laser platforms.
Nd:YAG lasers
Nd:YAG lasers operate at 1064 nm, where epidermal melanin absorbs less light and penetration depth is greater. More of the energy can reach deeper follicular targets with lower relative absorption at the skin surface. This gives long-pulsed Nd:YAG systems a strong working range for darker skin phototypes.
Ruby lasers
Ruby lasers at 694 nm were among the early systems used for hair removal. Their high melanin absorption gives them a working profile centered on fair skin with dark, pigmented hair.
Laser type comparison
| Technology | Typical wavelength | Main optical characteristic | Typical working strength |
|---|---|---|---|
| Ruby | 694 nm | Very high melanin absorption | Dark hair with strong skin–hair contrast |
| Alexandrite | 755 nm | High melanin absorption | Pigmented hair on lighter phototypes |
| Diode | ~800–810 nm | Balance of absorption and penetration | Flexible wavelength configurations and broad professional use |
| Nd:YAG | 1064 nm | Lower epidermal melanin absorption, deeper penetration | Darker skin phototypes |
Where IPL fits in
When comparing equipment, IPL should be treated as a separate light-based technology. Its flashlamp produces a broad spectrum, and optical filters define which part of that spectrum reaches the skin. The operator therefore works with a different method of controlling light exposure than in a system built around a laser source.