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
Drawing for Gas cell for hollow core fiber

Components

  • 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

Variations

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.

Gas cell with hollow core fiber benchtop
Hollow core fiber (Plastic)
Hollow core fiber cross-section

Hollow Fiber Gas Cell Blocks

Hollow Fiber Gas Cell Block for hollow fibers

Key Features

Gas cell blocks include an optical window, a fiber port, and a gas port. With two blocks you can convert a hollow fiber into a bench top gas cell for absorption spectroscopy or wavelength reference applications. Simply swap fibers for different path lengths.

  • Incredibly simple and robust alignment
  • Range of wavelengths: UV to LWIR
  • Range of pathlengths: 0.1 to 5m
  • Low sample volume: < 10 mL
  • Compact size; flexible layout
Hollow Fiber Gas Cell Kit
Hollow fiber cross section

Hollow core fiber cross-section

Components

  • Wedged optical windows (range of materials)
  • SMA of FC fiber port
  • Swagelok style or barbed gas fittings
  • Holes and set screws for 30 mm cage systems
  • Mounting holes for optical bench or housing

Alignment

The relatively large fiber diameter (ID = 0.2 – 1.5 mm) and single pass configuration enables obtaining ‘first light” with minimal effort. In some cases, you can collimate your beam and mount your laser on one end and simply put your detector at the other end. It is that easy.

Standard Kit = 2x Gas Blocks + 1 Hollow Fiber

Versatile Systems

Gas cells kits can utilize a wide range of Guiding’s hollow core fiber optic waveguides. Options include different sample volumes, path lengths, and wavelength ranges.

Variations

Hollow Fiber Gas Cell Kit Variations
Gas cell with hollow core fiber benchtop

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.

Gas cell for hollow core fiber

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