Components in the MIRDIAL project
The emitted mid-infrared laser light is generated in an optical parametric oscillator, which is pumped by near-infrared high-energy nanosecond pulses. Using state-of-the-art nonlinear crystals from HC Photonics the mid-infrared laser pulses may be tuned from 2.8 μm to 4.5 μm, enabling us to target a large number of gasses.
Direct detection in the mid-infrared spectral region is notorious for low detection efficiencies and a great deal of detector noise. By using NLIR’s up-conversion based detectors the mid-infrared light is instead converted to the near-infrared spectral region where silicon technology offers both highly efficient and low-noise detection.
Absorption line spectra of molecules in a gaseous environment depend on quantities such as temperature and pressure. With the developed tunable transceiver system we intend to investigate a wide range of molecular absorption lines in the mid-infrared as well as their dependence on changes in the gaseous environment.
By integrating the transmitter and receiver into an electronically synchronized system in a common package, the MIRDIAL system will enable in-field monitorization of a variety of greenhouse gasses. Want to know more?
What you need to know
LIDAR is a remote sensing technology and is based on an optical transceiver that both emits optical pulses and detects the backscattered, or reflected, signal. There are many applications of LIDAR, ranging from wind-direction measurements and landscape mapping to steering guidance in self-driving cars. In the MIRDIAL project we use LIDAR in the DIAL configuration for performing range-resolved trace-gas measurements.
Differential absorption LIDAR (DIAL) is a LIDAR configuration which can be used for trace-gas concentration measurements. It works by alternately sending light on and off an absorption line of the trace gas under investigation. The differential on-off return signal may be used to extract spatially resolved concentration maps.
The mid-infrared (MIR) spectral region is often called the spectroscopic fingerprint region. The reason behind this name comes from the fact that various molecules can be identified through their unique absorption spectra in this region. By utilizing a wavelength-tunable LIDAR system in the MIR spectral region, we enable concentration measurements of a large number of important greenhouse gasses.