**Working principle**:
The working principle of laser hair removal machine is based on the principle of selective photothermal action. The light wave energy emitted by the laser will be absorbed by the melanin in the hair follicles and then converted into heat energy, making it unable to continue to grow hair, but will not damage the surrounding skin tissue. This destruction process can effectively inhibit or delay the regeneration of hair, thereby achieving the effect of hair removal.



The advantages of high-energy laser hair removal on melanin are mainly reflected in the following aspects:
1. **Precisely destroy hair follicles**: High-energy laser can be more effectively absorbed by melanin in hair follicles, focusing energy on the hair follicles, causing them to generate heat and destroy hair follicle cells, inhibiting hair regeneration. This precise action reduces damage to surrounding skin.
2. **Faster results**: Because high-energy lasers can quickly heat melanin and destroy hair follicles, hair removal results appear faster and typically require fewer treatments.
3. **Adapt to different hair colors**: High-energy laser is more effective on hair containing melanin, especially on darker, thicker hair.
4. **Reduce the risk of pigmentation**: By accurately adjusting the parameters of high-energy laser, side effects such as pigmentation can be reduced, which is safer especially for people with dark skin.
5. **Long-lasting effect**: High-energy laser can destroy the melanin in the hair follicles more thoroughly, providing longer-lasting hair removal effects, and sometimes even achieving permanent hair removal.


1. **755nm (Alexandrite laser)**
- **Advantage**: High melanin absorption rate, suitable for light skin and fine hair.
- **Difference**: Shallow penetration, targeting surface hair follicles.
- **Treatment experience**: More precise, fast processing, suitable for small areas.
2. **808nm (semiconductor laser/diode laser)**
- **Advantage**: Suitable for most skin colors and hair types, good balance.
- **Difference**: Moderate penetration depth, suitable for multi-purpose.
- **Treatment experience**: High comfort, suitable for large-area treatment.
3. **940nm**
- **Advantage**: Deep penetration, suitable for dark skin and deep hair follicles.
- **Difference**: Less damage to the epidermis, reducing the risk of pigmentation.
- **Treatment experience**: Safer, suitable for dark skin users
4. **1064nm (Nd:YAG laser)**
- **Advantages**: Extremely deep penetration, suitable for dark skin and coarse hair.
- **Difference**: Low melanin absorption, reducing the risk of burns.
- **Treatment experience**: Suitable for dark skin, slight discomfort for large-area treatment.




**Difference between 940nm laser and other three wavelengths**:
The commonly used wavelengths for laser hair removal are 755nm, 808nm, 940nm and 1064nm. The difference between them lies in their suitability for different hair types and skin tones.
1. **755nm (Alexandrite laser)**: Mainly suitable for light skin and fine hair. It has a shallow penetration depth and is more suitable for treating superficial hair follicles.
2. **808nm (semiconductor laser/diode laser)**: This is a widely used wavelength that is suitable for a variety of skin tones and hair types, especially medium-colored hair. It can penetrate deep into the hair follicles while causing less thermal damage to the skin.
3. **940nm**: This wavelength can penetrate the skin better than other wavelengths, reducing thermal damage to the epidermis and is suitable for people with darker skin tones. It is more effective when treating deeper hair follicles and can reduce the risk of pigmentation.
4. **1064nm (Nd:YAG laser)**: Suitable for people with darker skin tones, it can penetrate deeper into the skin. Due to its deep penetration depth, it is suitable for treating deeper hair follicles, but usually requires higher energy to achieve hair removal results.
