Technology

TDLAS

Tuneable Diode Laser Absorption Spectroscopy

Our standard configuration can be assembled in-situ for cross stack analysis, or as an open-path solution to analyse a cross-section of a room or production facility.

Visibly it can be noticed that our transmitter and receiver units are very compact for ease-of-integration., However, the true difference arises as a result from our proprietary electronic hardware and firmware, which can extract useful information even in very challenging cases.

If you are in need of a reliable gas sensing product, whether to trigger an alarm when a toxic gas reaches a threshold concentration, or if you are obliged to report accurate levels of emissions to authorities, our technology provides the solution.

The Beamonics TDLAS systems are based on innovative designs of electronic hardware and firmware, with a solid foundation in science, which deliver performances able to extract information even from very challenging settings, even in cases where TDLAS traditionally cannot be used.

How does TDLAS work?

The basic principle of TDLAS is based on simple absorption spectroscopy., When a gas molecule is exposed to specific wavelengths of light, part of the photon energy will be absorbed and eventually converted into heat. This occurs at several different wavelengths for each gas molecule, creating a unique “fingerprint” of absorption lines as can be seen in a gas absorption spectrum.

Since we know the intensity of light emitted from the transmitter or light source, If the light is absorbed by a gas molecule, there will of course be slightly less light reaching the receiver or detector. The amount of light that has been absorbed along the way, allows us to calculate the concentration or density of the gas, as well as temperature and pressure.

For each target gas, we optimize the light source or laser diode based on the gas absorption spectrum, selecting the wavelength where the highest absorption occurs, and where there is no overlap of other gases.

The main principle is the same as in all existing TDLAS systems on the market. Tuning a very narrow-band laser diode by increasing the current to scan over the wavelength of the selected absorption line:

If the target gas is present we will see a small dip in the light intensity reaching the receiver at that specific wavelength:

This dip in the measurement of light intensity can then be analysed, the amplitude and width of the curve correspond to the concentration, temperature and pressure:

Beamonics unique TDLAS key data

The Beamonics TDLAS technology stands out in the following areas:

  • Speed, we can reach a sampling rate as high as 20 kHz, meaning that our system can perform 20.000 unique analysis per second.
  • Transmission sensitivity, we can perform reliable analysis in applications or environments where only 1 out of 1 million photons actually reach the detector, which can be translated into that we can perform analysis where we have a transmission of light as low as 10-6. This allows for some of unique applications, such as non-intrusive gas-analysis inside the human body.
  • Detection precision, although the detection precision differs from gas to gas, depending on the absorption lines available, and which light sources are available, we have an extremely good signal to noise ratio. If you are curious about our detection precision for a specific gas, please have a look at the product data sheet, if your gas of interest is not represented, please contact us for further information.
  • Self-referencing, simplifying regular calibration procedures. Our system is intrinsically self-referencing and does not even require a container of reference/calibration gas.
  • Power consumption, allowing for a portable or semi-stationary system for gas analysis without access to power. The low power consumption allows for us to soon offer a battery powered instrument. This is enabled by our power consumption of less than 5 W in continous fast-mode.

In general, TDLAS as compared to other types of gas sensors, is usually attributed with the following benefits:

  • Insensitive to background light, daylight, fluorescent light or complete darkness.
  • No cross-talk, meaning no false alarms from other gases.