What is the laser that produces a visible blue-green beam that is absorbed by red-brown pigmented tissue?

The argon gas laser produces a visible blue-green beam that is effectively absorbed by red-brown pigmented tissue. This characteristic makes it particularly useful in various medical applications, especially in dermatology and ophthalmology. The specific wavelength emitted by the argon laser falls within the visible spectrum, making it easily recognizable and allowing targeted treatment of tissues containing pigmentation, such as blood or melanin in the skin.

In contrast, while other lasers mentioned offer different wavelengths and characteristics, they do not produce the same visible blue-green light or have the same absorption profile. For example, the carbon dioxide laser typically emits a far-infrared beam which is absorbed by water, making it useful for cutting and coagulating tissue but not for selective targeting of pigmented areas. Similarly, the Nd:YAG laser emits near-infrared light, which is absorbed less by pigmented tissues compared to the argon laser. The excimer laser, on the other hand, is used primarily for precise ablations, particularly in corneal reshaping, but does not emit blue-green light.

Thus, the argon gas laser stands out as the correct choice due to its specific absorption properties and the visible spectrum of light it produces.