I believe the answer is Microwaves (just to clarify, not the oven). They're widely used for communications.<span />
The ozone layer that is inside the stratosphere blocks UV radiation.
The ozone layer contains high concentrations of ozone relative to other parts of the atmosphere. This was discovered by Charles Fabry and Henri Buisson who are both French Physicists.
The ozone in the earth's stratosphere is created through ultraviolet light striking a group of ordinary oxygen molecules containing two oxygen atoms, subsequently splitting them into individual oxygen atoms and finally these said atomic oxygen then combines with unbroken O2 to create ozone (O3).
