Quantum-cascade vertical cavity surface emitting laser for gas sensing

The QCVCSEL project aims to develop a new generation of compact and energy-efficient mid-infrared laser sources for optical gas sensing. The mid-infrared spectral range from 3 to 30 μm is particularly important because many molecules exhibit strong and characteristic absorption lines in this region. This makes mid-infrared absorption spectroscopy a highly sensitive technique for gas detection in industrial, environmental and medical applications. 

The project will demonstrate a quantum-cascade vertical-cavity surface-emitting laser, or QC-VCSEL. This concept combines the advantages of quantum cascade lasers, which operate in the mid-infrared, with the benefits of the VCSEL architecture, including single-mode operation, compact size, high beam quality, low divergence and suitability for integration in compact sensing systems. A key element of the device is a sub-wavelength grating integrated with the quantum cascade active region, acting as one of the laser mirrors and enabling vertical optical resonance. 

The main activities include numerical design and optimisation of the QC-VCSEL structure, epitaxial growth, development of device processing technology, characterisation of QC-VCSEL components and lasers, and demonstration of the QC-VCSEL source in an Airoptic gas sensing system. The project work plan consists of five main work packages: numerical design and optimisation, epitaxial structure development and growth, QC-VCSEL processing, characterisation, and demonstration in a gas sensing system. 

The target groups include companies and institutions using gas analysers, especially in environmental monitoring, industrial process control, safety, security and medical diagnostics. The project results may also be relevant for manufacturers of mid-infrared light sources, optical measurement systems and integrated photonic devices.