Which of the following is a chromophore for Nd:YAG lasers?

The correct answer identifies melanin as a chromophore for Nd:YAG lasers due to its ability to absorb specific wavelengths of light emitted by these lasers. Melanin is a pigment found in various tissues, particularly in skin and dental structures, which makes it effective in absorbing laser energy.

In the context of Nd:YAG lasers, the wavelength is typically around 1064 nm. Melanin has a strong absorption coefficient at this wavelength, allowing it to efficiently convert the laser energy into heat, which is beneficial for procedures such as soft tissue surgery or pigmentation removal.

While water and hydroxyapatite do have roles in laser applications, they do not act as effective chromophores for Nd:YAG lasers. Water is a primary component of tissues that can absorb laser energy at different wavelengths, but its absorption characteristics are not as distinctly aligned with the specific action of Nd:YAG lasers as those of melanin. Hydroxyapatite, primarily found in mineralized tissues like bone and dentin, has limited absorption characteristics at this wavelength, rendering it less relevant in this context.

Consequently, melanin stands out as the primary chromophore in this scenario due to its compatibility with the laser's wavelength and its clinical application in dentistry and dermatology.