Who developed the first working laser in 1960?

The first working laser was developed by Theodore Maiman in 1960. Maiman's achievement was significant because he successfully demonstrated the first functioning laser using a ruby crystal as the gain medium. This breakthrough in laser technology laid the groundwork for the various applications of lasers we see today, from medical devices to telecommunications. Teddy Maiman's work was the culmination of years of theoretical and experimental research on the principles of stimulated emission that were originally described by Albert Einstein, but it was Maiman who turned those principles into a working device.

The other figures mentioned contributed greatly to the field of physics but are not directly tied to the development of the laser. For example, Einstein’s theoretical groundwork paved the way for understanding laser mechanisms, while Fermi and Planck made their contributions in other areas of quantum mechanics and physics. However, Maiman's achievement stands out as the moment when laser technology became a reality.