Fraunhofer IZM launches quantum cascade project to develop modular laser system

Creating new laser systems for use in spectroscopy applications is a challenging and costly endeavor. In order to give even small and medium-sized enterprises access to such innovative technology, the Fraunhofer Institute for Reliability and Microintegration (IZM) co-launched the QuantumCascade project to develop a modular laser system for a range of multispectral analytics.
This week the IZM reported on the project, which ran from 2022-2025. IZM stated, “Infrared spectroscopy has many uses in a vast range of applications, from geosciences to medical technology or even waste management and recycling. Spectroscopic analytics have become far more precise over the last two decades, and far more complex over the same period.

Demonstration unit created in the QuantumCascade project

“Current devices use light at different wavelengths for a range of multispectral tests, but they have become bulky and stationary. Putting their capabilities into the original handheld form factor would allow sophisticated analytics out in the field, but designing and miniaturizing the technology to do this is a resource and know-how-intensive feat,” the statement added.

‘Versatile and reliable source for spectroscopy’

This is where the QuantumCascade project enters the picture. Successful development of a modular and powerful laser system, integrated on a glass board, would bring down the R&D effort needed to develop innovative devices and give makers access to a versatile and reliable light source for spectroscopy.

Quantum cascade lasers (QCLs) operate at wavelengths between 2 µm and 15 µm, in the medium infrared (MIR) range. QuantumCascade combines up to three QCLs that can be programmed to emit pulses as short as 5 ns, which are particularly crucial for spectroscopic analytics with organic substances.

Alongside the lasers themselves, the design includes embedded laser drivers that were developed in partnership with Laser Electronics LE GmbH, and integrated optical beamforming using aspherical optics and coupling to special MIR fibers. The novel design places each QCL inside its own cavity in the glass. The temperature in each can be stabilized separately, which means that the lasers can be operated each at the right temperature and, by implication, the right wavelength.

The electronic drivers and control circuits in the design are mounted by industrial soldering processes on a thin-film metallized glass board. Selective laser etching is used to structure this glass board with µm accuracy – so that optical components can be mounted directly. The solution is highly integrated, which makes it possible to encapsulate the entire system – for operation in harsh environments or to get cleaned for use in medical applications.

When working on the laser system, the researchers could draw on the insights won in the prior PhotMan project’s work on a versatile fiber-optical sensor system. QuantumCascade is the next step in the evolution of a thin-glass platform developed at IZM that integrates and couples optical and electronic components efficiently.

Source: optics.org