The world’s shortest bursts of light comes from a new device called the Lasetron. It’s a tool physicists in the United States have dreamt up to chop light into smaller pieces than ever before. If it works, pulses of light lasting just a few zeptoseconds could soon be looking inside atomic nuclei. A zeptosecond is one-billion-trillionth of a second (10-21 s).

More About the Lasetron Here