Unique Gas Cells

Molecules have specific absorption lines dependent on the molecular energy level transitions particular to the species. For gases these lines are also particularly accurately known (subpicometer), narrow, and insensitive to environmental conditions. A gas cell is simply a tube filled with a gas or gas mixture of known chemical and isotopic purity and pressure and may be used as is or coupled to fiber optic cables. In addition to the standard gas cells equivalent to those offered by NIST Wavelength References offers a variety of gas cells that greatly expand their application. If you have a custom application please do not hesitate to inquire, we welcome custom orders. Some examples of gas cells materials we have fabricated include methane, ammonia, hydrogen fluoride, hydrogen chloride, carbon dioxide, water vapor, hydrogen sulphide, nitrogen, argon, nitrogen dioxide, as well as the more standard acetylene, hydrogen cyanide, and carbon monoxide. Cells can be filled to any pressure lower then atmosphere and can be filled with either pure gases or mixtures.

Bare glass absorption tubes can be fabricated with diameters from 3mm to 25mm and a length up to 20cm. All tubes use wedged windows broadband AR coated for the wavelength range of interest. Optical artifacts due to residual etalon effects are generally <0.01dB P-P.

We can offer fiber coupled gas cells with several path lengths which are optimized for the absorption strength of the gas present. Path lengths from 3 cm to 80 cm are available.
Some of the more popular unique gas cells we offer include:

  • Dual gas C+L gas cell.
    This is fabricated in our 80 cm path housing and includes carbon 12 HCN combined with carbon 12 CO. This combination covers the wavelength range from 1520nm to 1590n
  • Tri-gas C+L band gas cell. This cell is also fabricated in our 80 cm path housing and includes carbon 12 HCN, carbon 12 CO, and carbon 13 CO. This combination covers the wavelength range from 1520nm to 1640nm.
  • Four gas S+C+L band gas cell. This cell incorporates four gases: water vapor, C12 carbon monoxide, C13 carbon monoxide, and acetylene to cover the wavelength range from 1330nm to 1640nm.
  • HF 1300nm band gas cell. The HF cell is fabricated with hydrogen fluoride gas. This gas has very strong isolated gas lines from 1260nm to 1330nm. Due to the corrosive nature of hydrogen fluoride the cell is fabricated so the only copper, sapphire, and silver contact the gas. This cell is unique to Wavelength References and shows the high level of processing procedures available at our company.
  • Water Cell The water cell is fabricated in our multipass housing and has numerous lines throughout the 1330-1480nm band as well as at other wavelengths. Some customers have successfully used this device for the 980nm region as well and the tube can be fabricated with windows optimized for this region.