  We have shown via explicit analysis as well as numerical simulation the
design of two large angle interferometers employing two-photon pulses. The
first one uses the technique of adiabatic following in a dark state to produce
a large splitting angle atomic interferometer that is capable of producing one
dimensional gratings with spacings as small as 2 nm. Unlike other large angle
interferometers, this technique is not sensitive to errors in optical pulse
area and decoherence from excited state decay. This may lead to a nearly two
orders of magnitude improvement in the sensitivity of devices such as atomic
gyroscopes, which are already as good as the best laser gyroscopes. The second
interferometer uses the technique of Raman pulses to produce a two-dimensional
interferometer, with independent choice of grating spacings in each direction,
each being as small as 2 nm. This scheme may enable one to produce uniform
arrays of quantum dots with dimensions of only a few nm on each side. In
addition, it may be possible to generalize this process to produce arbitrary
patterns with the same type of resolution.
