  Near-IR observations are important for the detection and characterization of
exoplanets using the transit technique, either in surveys of large numbers of
stars or for follow-up spectroscopic observations of individual planets. In a
controlled laboratory experiment, we imaged $\sim 10^4$ critically sampled
spots onto an Teledyne Hawaii-2RG (H2RG) detector to emulate an idealized
star-field. We obtained time-series photometry of up to $\simeq 24$ hr duration
for ensembles of $\sim 10^3$ pseudo-stars. After rejecting correlated temporal
noise caused by various disturbances, we measured a photometric performance of
$<$50 ppm-hr$^{-1/2}$ limited only by the incident photon rate. After several
hours we achieve a photon-noise limited precision level of $10\sim20$ ppm after
averaging many independent measurements. We conclude that IR detectors such as
the H2RG can make the precision measurements needed to detect the transits of
terrestrial planets or detect faint atomic or molecular spectral features in
the atmospheres of transiting extrasolar planets.
