Waves characterized by variations of electric and magnetic fields.
In the order of ascending wavelength, electromagnetic waves are
classified to gamma rays (0.01 nm or shorter), X-rays (0.01 nm to 10 nm), ultraviolet rays (10 nm to
400 nm), visible rays (400 nm to 800 nm), infrared rays (800 nm to 1 mm), and radio waves (0.1 mm or
longer). In order to make a micromachine capable of moving freely through complicate paths,
non-contact energy supply and communication are desired. For these purposes, transfer of energy and
information by the use of electromagnetic waves are being studied.