What color light does a KTP laser emit when used in continuous wave mode?

• A. Blue light
• B. A brilliant green light
• C. Red light
• D. Yellow light

Answer: (B)

The KTP laser, or potassium titanyl phosphate laser, is known for its specific wavelength emission when operated in continuous wave mode. It emits a brilliant green light, which is due to the frequency doubled from an infrared laser source, typically a Nd:YAG laser. The process of frequency doubling produces light at around 532 nanometers, which falls within the green spectrum visible to the human eye. This characteristic makes KTP lasers especially suitable for a variety of medical applications, including certain types of laser surgery, because the vibrant green light is effectively absorbed by certain biological tissues while minimizing damage to surrounding structures.

In contrast, the other color options do not accurately represent the emitted wavelength of the KTP laser. Blue light would be associated with a different type of laser, and red light typically corresponds to longer wavelengths around 600-700 nanometers. Yellow light also does not match the KTP emission, as it falls between red and green. Hence, the brilliant green light is the definitive feature of KTP lasers in continuous wave mode.