Directed Energy Propulsion has made a lot of experimental progress

Philip Lubin, University of California, Santa Barbara, Directed Energy for Interstellar Study

Starting at 26 minutes of this video.

They are making progress with laser locking over kilometer distances.
They are making 2 gram starchip prototypes.
they are looking at making ultrathin starchips that would be a meter across but very lightweight.

Arxiv – A Roadmap to Interstellar Flight

Lubin’s designs would enable wafersats to reach 25% of lightspeed and a 100 ton spaceship to reach 1000 kilometers per second.