Optoelectronic devices

We develop photodetectors and semiconductor lasers primarily for the infrared spectral range (wavelength > 1.5 µm).

For infrared detectors we mainly focus on matrix and single element detectors in the mid-wave infrared (MWIR, 3 – 5 µm) and the long-wave infrared (LWIR, 8 – 12 µm) spectral range. These detectors are based on InAs/GaSb type II superlattice active regions. To further increase their performance we develop heterojunction devices, which offer superior characteristics with respect to dark current and noise compared to conventional homojunction devices.

Applications which require detecting extremely weak optical signals are addressed by our highly sensitive avalanche photodiodes (APDs) with internal gain. We develop APDs both for the solar blind ultraviolet spectral range below 280 nm and the short-wave infrared (SWIR, 0.9 – 1.7 µm), based on AlGaN and InGaAs, respectively.

In the field of infrared semiconductor lasers addressing wavelengths between 2 and 11 µm we focus on GaInAs/AlInAs/InP-based quantum cascade lasers as well as optically pumped semiconductor disk lasers based on group III antimonides. Our current research and development involves increasing output power and power efficiency while preserving a high beam quality. Optimizing the epitaxial semiconductor layer structures is one focus of our work, another, efficient cooling using novel mounting and packaging technologies.

We also work on extending the functionality of semiconductor lasers, for instance by integrating the laser chip into an external resonator in a laser module with a small form factor. In this way, we can realize fast, tunable laser systems targeting applications in spectroscopy, chemical sensing as well as safety and security. To highlight the potential of our laser technology we also provide functional demonstrators.