  Canada-France-Hawaii-Telescope adaptive optics bonnette images through
narrow-band filters in the $K-$band are presented for the Arches cluster.
Continuum fluxes, line fluxes, and equivalent widths are derived from high
angular resolution images, some near diffraction limited, for the well known
massive stars in the Arches cluster. Images were obtained in the lines of
\ion{He}{1} 2.06 \mic, \ion{H}{1} Br$\gamma$ (2.17 \mic), and \ion{He}{2} 2.19
\mic as well as continuum positions at 2.03 \mic, 2.14 \mic, and 2.26 \mic. In
addition, fluxes are presented for \ion{H}{1} P$\alpha$ (1.87 \mic) and a
nearby continuum position (1.90 \mic) from Hubble Space Telescope archival
data. The 2 \mic and P$\alpha$ data reveal two new emission-line stars and
three fainter candidate emission-line objects. Indications for a spectral
change of one object between earlier observations in 1992/1993 and our data
from 1999 are found. The ratio of \ion{He}{2} 2.19 \mic to Br$\gamma$ emission
exhibits a narrow distribution among the stars, suggesting a narrow
evolutionary spread centered predominantly on spectral types O4 If or
Wolf-Rayet stars of the WN7 sub-type. From the approximate spectral types of
the identified emission-line stars and comparisons with evolutionary models we
infer a cluster age between $\sim$ 2 and 4.5 Myr.
