This is equivalent to saying, "So it's not the semiconductor that makes it fast, it's the electrical current." The medium that is changing conductivity is wate

This is equivalent to saying, "So it's not the semiconductor that makes it fast, it's the electrical current." The medium that is changing conductivity is water in this case, and it is able to do it much much faster. That said, the system involves a laser that adds to the ability to switch quickly. "Because the laser pulse is so fast"