The long-wavelength 1064 nm laser is best known for which combination of properties?

• A. Low frequency
• B. Low intensity
• C. Dark skin
• D. Low frequency, low intensity, and dark skin

Answer: (D)

The important idea here is how wavelength affects safety for different skin types. The 1064 nm Nd:YAG laser is longer in wavelength, so it penetrates deeper into the hair follicle while it is less absorbed by epidermal melanin. That means it carries less risk of causing pigment changes or burns in darker skin types, because the energy isn’t dumped into the outer skin where pigment is concentrated.

Because the safety margin is higher with darker skin, practitioners can use gentler energy settings and slower pulse delivery. In practice, that translates to lower intensity (fluence) and lower repetition rate (frequency) compared with wavelengths that are more readily absorbed by melanin. So this laser is best known for being usable safely on dark skin with low energy and slower pulsing, hence the combination of low frequency, low intensity, and dark skin.