A method of manufacture for optical spectral filters with omnidirectional properties
in the visible, near IR, mid IR and/or far IR (infrared) spectral ranges is based
on the formation of large arrays of coherently modulated waveguides by electrochemical
etching of a semiconductor wafer to form a pore array. Further processing of said
porous semiconductor wafer optimizes the filtering properties of such a material.
The method of filter manufacturing is large scale compatible and economically favorable.
The resulting exemplary non-limiting illustrative filters are stable, do not degrade
over time, do not exhibit material delamination problems and offer superior transmittance
for use as bandpass, band blocking and narrow-bandpass filters. Such filters are
useful for a wide variety of applications including but not limited to spectroscopy,
optical communications, astronomy and sensing.