Compact and reliable light sources are key for many technologies that shape our everyday lives – from environmental monitoring and health diagnostics to industrial process control. However, producing high-performance lasers in the short-wave infrared range (1.4–3 micrometres), where molecules such as carbon dioxide, methane, and nitrogen oxides strongly absorb light, has remained a significant challenge.
In his dissertation, Maximilian C. Schuchter investigated gallium antimonide (GaSb)-based semiconductor devices to create novel laser solutions. He developed and studied several device types, including semiconductor saturable absorber mirrors (SESAMs), vertical emitting membrane lasers (MECSEL), and modelocked integrated external-cavity surface emitting laser (MIXSEL).
The investigated saturable absorbers revealed absorption recovery dynamics unique to the GaSb-based material system.
“The development of membrane lasers drove significant advances in GaSb processing enabling advanced thermal management and device engineering. For example, bonding a thin membrane of GaSb material to a silicon carbide substrate, we improved device yield and allowed for high-average output power without overheating,” says Schuchter.
What comes to materials engineering, strain-management in quantum wells heterostructures was studied both experimentally and theoretically, revealing a critical role in achieving low threshold and efficient lasing. A further highlight of Schuchter’s work is the first demonstration of a MIXSEL laser architecture operating at 2 micrometres.
“This compact ultrafast laser delivers clean, high-repetition-rate pulses which was used for absorption spectroscopy of carbon dioxide,” he says.
Originally from Germany, Maximilian C. Schuchter earned both his BSc and MSc in Interdisciplinary Sciences at ETH Zurich, Switzerland. He then pursued a joint doctoral program between ETH Zurich, in the Ultrafast Laser Physics Group of Emeritus Professor Ursula Keller, a pioneer of ultrafast laser physics, and Tampere University, working with Professor Mircea Guina, head of the Optoelectronics Research Centre (ORC), one of Europe’s leading groups in this field.
Public defence on Thursday 16 October
The doctoral dissertation of MSc (ETH Zurich) Maximilian C. Schuchter in the field of physics titled GaSb-based semiconductor devices for optically pumped lasers – from saturable absorbers to membrane lasers will be publicly examined at the Faculty of Engineering and Natural Sciences, Tampere University, at 12.00 on Thursday, 16 October 2025 at Tietotalo TB109 (Korkeakoulunkatu 1, Tampere).
The Opponent will be Dr Marcel Rattunde from the Fraunhofer Institute of Applied Solid State Physics (IAF). The Custos will be Professor Mircea Guina.
The doctoral dissertation is available online.
The public defence can be followed via remote connection.
Photo: From left Professor Mircea Guina from Tampere University, Professor Ursula Keller from ETH Zurich, and PhD student Maximilian C. Schuchter from Tampere University.