Palm

Electromagnetic diffraction has been known and understood for more than 200 years; despite this, new phenomena have been observed even in the past few years. Four examples will be discussed: enhanced transmission by arrays of holes in metal films (where transmission exceeds the geometric optics limit even though the hole diameters are much smaller than the wavelength), beaming of light from a single hole surrounded by a corrugated (bullseye) pattern, phase effects in diffraction gratings (which defeated an attempt to make a broadband resonant cavity), and finally, the use of arrays of holes as a "photon sieve" to make images.