Present considerations of manned missions to Mars all assume a spaceflight duration of about six months. That’s based on the existing propulsion technologies that are available for use in spacecraft.
But a private research company called the Bae Institute has successfully demonstrated a photonic laser thruster that, when scaled up to the size needed for a spacecraft, could generate enough power to speed the vehicle to faster than 100 kilometers per second (that’s nearly 250,000 miles per hour, or just shy of .1 c). At that rate of speed, a spacecraft could reach Mars in ONE WEEK. Needless to say, NASA, JPL, et.al. are very interested in this technology.
Be careful. Not so long ago, NASA was investigating an anti-gravity device that turned out to be a hoax.