upconversion

== English == === Etymology === From up- +‎ conversion. === Noun === upconversion (countable and uncountable, plural upconversions) (physics) The process by which two photons combine in a nonlinear medium to produce a higher-energy photon with a frequency that is the sum of those of the two photons (electronics) Conversion of a lower radio frequency to a higher frequency, possibly using a mixer. ==== See also ==== downconversion