For a long time, a Morse code proficiency was required to obtain an amateur radio license in many jurisdictions around the world, which was a much higher bar of entry than most new hams have to pass.

Solid-state masers, developed in the 1960s, were realized by pumping the spin states of paramagnetic impurities, such as Cr 3+ ions doped into single-crystal sapphire (ruby). Pumping three-level ...

Laser technology as we know it was first realized in 1951 when Charles Townes envisaged the concept of microwave amplification by stimulated emission of radiation (MASER) on a park bench in Washington ...