The Company is a designer, developer and manufacturer of proprietary gas analysers and gas emission monitoring systems that can measure multiple gases simultaneously in real-time. Through innovation, product performance and commercial success, Cascade is the premier name in Quantum Cascade Laser (“QCL”) technology.
The Company’s technology is based on a principle called Tunable Diode Laser Absorption Spectroscopy (TDLAS), which measures the concentration of species in gaseous mixtures using tunable diode lasers and laser absorption spectrometry. Compared to other measurement techniques, such as paramagnetic detectors (“PMD”) and Chemi-luminescence, TDLAS offers multi-element detection capabilities, high accuracy with a wide dynamic range, low maintenance requirements, and a long life cycle. The use of lasers as spectroscopic light sources allows for high resolution spectroscopy (HRS), with QCLs offering access to the valuable mid infrared (MIR) part of the electromagnetic spectrum.
For years, mid infrared HRS has proven to be an effective tool for carrying out highly specific and selective analyses of molecules in the gas phase. However, this technology tended to be bulky and complex to operate (i.e. gas, solid state lasers, etc.) or could not operate at room temperature (i.e. lead salt diode lasers). With the development of QCL, a mid-infrared HRS no longer needed cryogenic cooling and could still have large spectral coverage, excellent spectral quality and good tenability.
Cascade’s QCL technology operates on the principle whereby electrons cascade down a series of quantum wells, which result from the growth of very thin layers of semiconductor material. Traditional single electron-hole recombination methods (bipolar semiconductor diode laser) can only produce a single photon, whereas the quantum cascade laser can cascade down between 20 and 100 quantum wells producing a photon at each step. This technology produces an electron waterfall providing a step change in performance in terms of lasing efficiency, which enables the QC lasers to emit several watts of peak power in pulsed operation and tens of milliwatts continuous wave (“CW”).
Because the lasing wavelength for the QCL is not determined by the semiconductor material (as is with conventional lasers), but by adjusting the physical thickness of the semiconductor layers themselves, it allows the removal of material barriers associated with conventional semiconductor laser technology and opens up the possibility of near-infrared to THz spectral coverage.
Cascade’s patented Laser Chirp technique enables a shift in the scanning acquisition bandwidth of the detector to the MHz regime, to simultaneously operate the QCLs (spectrometer light sources) in a low duty cycle pulse manner. This novel development forms the basis for the technology’s unique and superior performance and capabilities. The chirp technique enables high averaging (reducing noise by root N averages) while using high speed room temperature detectors. Cascade’s patented technique gives its high frequency pulse operated QCL-based spectrometers an unbeatable performance advantage, separating it from any other MIR light source based gas sensing systems.
Researchers at Cascade have developed and generated novel, patented techniques maximizing the QCL’s performance as a spectroscopic tool for industrial gas sensing and analysis.
Cascade’s innovative technology provides many key advantages over conventional analysers:
- Up to a million measurements-per-second
- Sub-parts per billion sensitivity
- Operation at room temperature
- Operation in harsh environments
- Up to 20 gases simultaneously
- No consumables
Solid State – Compact Design - The QCL’s solid state and compact design (size of a pinhead) ensures operational reliability and easy integration into various components. Existing methodologies, including gas chromatography (“GC”), ion mobility spectrometry (“IMS”), and mass sensitive detector (“MSD”) techniques, struggle to meet the increasingly stringent demands in the global legislated industrial markets. In addition, the low lifetime cost of the all solid state QCL solutions will substantially disrupt the GC process analytics market. The QCL is suitable for use in extreme environments owing to its rugged design compared to other Non-Dispersive Spectrometer (NDS) systems’ monitoring technologies. Cascade’s development of multicomponent TDLAS analyser platforms capable of measuring up to 20 different gases in one instrument, allows a single multicomponent analyser to replace multiple analysers in the field (e.g. NDIR, chemi-luminescence). The QCL technology provides significant advantages in production throughput, accuracy and cost.