  Near-infrared spectra (0.95 - 2.4 micron) of the Cassiopeia A and Kepler
supernova remnants (SNRs) are presented. Low-dispersion (R = 700) spectra were
obtained for five bright fast-moving ejecta knots (FMKs) at two locations on
the main shell and for three bright circumstellar knots (QSFs) near the
southwest rim of Cas A. The main shell FMKs in Cas A exhibit a sparse
near-infrared spectrum dominated by [S II] 1.03 micron emission with a handful
of other, fainter emission lines. Among these are two high-ionization silicon
lines, [Si VI] 1.96 micron and [Si X] 1.43 micron, which have been detected in
AGNs and novae but never before in a supernova remnant. The near-infrared
spectra of circumstellar QSFs in Cas A show a much richer spectrum, with strong
He I 1.083 micron emission and over a dozen bright [Fe II] lines. Observed [Fe
II] line ratios indicate electron densities of 5 - 9 * 10^4 cm^-3 in the QSFs.
The Cas A QSF data are quite similar to the observed spectrum of a bright
circumstellar knot along the northwest rim of the Kepler SNR, which also shows
strong He I and [Fe II] emission with a measured electron density of 2.5 - 3 *
10^4 cm^-3. Finally, we present J- and K-band images of Cas A. The K-band image
shows faint diffuse emission which has no optical or mid-infrared counterpart
but is morphologically similar to radio continuum maps and may be infrared
synchrotron radiation.
