What is the wavelength range for ultraviolet lasers?

• A. 400-200 nm
• B. 700-400 nm
• C. 1400-700 nm
• D. 200-50 nm

Answer: (A)

Ultraviolet lasers emit light with wavelengths shorter than visible light, typically from about 400 nm down to around 200 nm for practical laser sources. This places them entirely in the ultraviolet portion of the spectrum, well below the visible range which ends at about 400 nm and far above the extreme short wavelengths that aren’t common for standard UV lasers. The range 400–200 nm captures the common ultraviolet wavelengths used in lasers (for example, around 355 nm, 266 nm, 248 nm, 193 nm), making it the best match. The other ranges correspond to visible light (longer wavelengths), infrared (longer than visible), or far/ vacuum UV rather than typical UV laser emissions.