  High-resolution spectroscopy in the near-infrared could become the leading
method for discovering extra-solar planets around very low-mass stars and brown
dwarfs. To help to achieve an accuracy of ~m/s, we are developing a gas cell
which consists of a mixture of gases whose absorption spectral lines span all
over the near-infrared region. We present the most promising mixture, made of
acetylene, nitrous oxide, ammonia, chloromethans and hydrocarbons. The mixture
is contained in a small size 13 cm long gas cell and covers most of the H and
K-bands. It also shows small absorptions in the J-band but they are few and not
sharp enough for near infrared wavelength calibration. We describe the working
method and experiments and compare our results with the state of the art for
near infrared gas cells.
