Colorized trace of pulses from the NIST/JILA dark pulse laser, indicating the light output nearly shuts down about every 2.5 nanoseconds (Image: NIST)
OK, you’re right, it 's impossible to actually beam “nothing” across a room. It is, however, possible to beam light across a room, sending information in the form of extremely short dips in that light. That’s what America’s National Institute of Standards and Technology (NIST) has been doing with its dark pulse laser. Whereas regular lasers transmit information by using darkness as a zero point and light pulses as data, this one uses light as a zero point, with darkness as the data.