Gas Cells

Introducing The Omega:
Laser spectroscopy has never been easier

Key Features

Robust, compact gas cells utilizing hollow core fibers that are incredibly simple to align. Within the hollow fiber the probe beam and analyte overlap enabling sensitive laser absorption spectroscopy with minimal sample size for trace-gas and isotope analysis.

  • Low sample volume: < 10 mL
  • Sensitive analysis: < 1 picomole
  • Moderate path length: e.g., 5 m
  • Compact size
  • Incredibly simple and robust alignment
  • Various wavelength ranges, including the entire mid-infrared range


  • Hollow core fiber with reflective inner coating
  • Wedged optical windows (range of materials)
  • Swagelok style gas fittings
  • Compatible with 30 mm cage mount systems
  • Mounting holes for integration onto an optical bench or in a custom housing

Standard Configuration

Omega Gas Cell Specifications


The Omega Gas Cell Variations

Custom Systems

Gas cells can be customized to utilize a wide range of Guiding’s hollow core fiber optic waveguides. Options include different sample volumes, path lengths, and wavelength ranges. In addition, systems can include additional components such as low dead volume pressure sensors and electronically actuated valves.

Laser Absorption Spectroscopy

The Omega is ideal for laser absorption spectroscopy. The relatively large fiber diameter (ID = 1.5 mm) and single pass configuration enables obtaining ‘first light” with minimal effort. In some cases, you can collimate your beam into one end and simply put your detector at the other end. It is that easy.

FTIR Gas Cell

The Omega is also a great solution for FTIR analysis. Standard configurations have excellent transmission from λ = 3 – 12 µm (additional wavelength ranges available) with low sample volume requirements (V < 10 mL).

Species Concentration

2,3 Butanedione:     99.7 ppm

Acetaldehyde:   230.2 ppm

Acetone:  130.8 ppm

Methane:   259.3 ppm

Water:  -38.8 ppm

Sulfur dioxide:          2.5 ppm

Trace Gas Analysis

Versions of our hollow fiber gas cells have been used for a range of trace gas applications.
Typical concentration sensitivities are in the 100 ppb range. Considering the small sample volume, this can equate to picomole level sensitivity.

Isotope Analysis

Stable isotope analysis such as the ratio of `13C/12C, provide additional information for a range of applications from greenhouse gas attribution to plant microbe interactions. Laser spectroscopy is an excellent means to perform isotope analysis due to unambiguous absorption features from different isotopologues; however, reduced pressure (P ~ 0.01 to 0.1 Atm) is often needed to effectively separate the features by “narrowing” their widths. The Omega is designed to be operated at such pressures and due to small sample volume, can be operated with relatively small pumps.

Measured spectrum of carbon isotopes

Guiding Photonics and OptoKnowledge are working together to produce complete systems based around the Omega concept. These devices are called Capillary Absorption Spectrometer (CAS).

The feature of the CAS that distinguishes it from other trace-gas and isotope sensors is the hollow fiber optic cell. The hollow fiber cell can be coiled into a compact form factor. In addition, it has a relatively small internal sample volume (1 – 10 ml depending of fiber size), which enables in-situ isotope analysis with a much smaller, size, weight and power system. For one, smaller pumps can be used, as well as low power requirements on temperature stabilization.

The CAS concept is a versatile platform amenable to a range of applications, including but not limited to, methane isotope (attribution) from a drone or unattended field sensor, carbon isotope analysis of laser ablated samples, and trace gas analysis from human breath.

The Omega in action (video presentation) – “In situ Methane Sensor for Real time Vent and Seep Analysis”

Guiding Photonics

Guiding Photonics