A new class of superresolution pairs of pupil filters for three-dimensional
, two-pupil confocal imaging is proposed. A distinctive feature of these fi
lters is the asymmetry of their impulse response. For synthesizing the ampl
itude transmittance of such filters the Fourier transform properties of Her
mitian functions are employed. It is shown that, with simple phase-only fil
ters that belong to the class in question, either axial or unidirectional l
ateral superresolution is achieved. (C) 1998 Optical Society of America.