Ultraviolet and Visible Semiconductor Lasers

High Performance Optoelectronic Laser Device Technology

Since the invention of the laser in 1958, these sophisticated devices have continued to revolutionize our lives. In the process, they have contributed to the generation of an enormous list of new applications in the fields of telecommunications, data storage, consumer electronics, spectroscopy, materials processing, bio-photonics, and life sciences.

We have made major contributions to the development of novel semiconductor laser technologies. Our scientists have a deep understanding of the physics and materials science of compound semiconductors, as well as extensive experience in the design, growth, fabrication, and testing of semiconductor optical emitters. We have also developed a strong record in device innovation.

We have been a major innovator and technology driver for group-III Nitride based materials and prototype device demonstrators. Our scientists have pioneered the development of cutting-edge visible and UV LEDs and lasers, with record-breaking device performances both in vertical and lateral device architectures. These achievements include the following:

1997: First InGaN laser diode (outside Japan)
1998: First distributed feedback (DFB) InGaN laser diode
2003: First AlGaN MQW UV laser diode (357.9 nm)
2011: First in-well pumped InGaN VECSEL (vertical-external cavity surface emitting laser)
2012: Low-threshold photo-pumped UV AlGaN lasers (237 – 291 nm)
2016: Record optical output power from electron-beam-pumped UV-C light source
2016: First e-beam pumped ridge-waveguide UV-A laser
2017: Watt-level UV-A laser diode

Applications

UV curing
Chemical and biological detection and identification (native fluorescence, Raman spectroscopy)
Optical communications (LIFI, non-line-of-sight)
Medical (e.g., psoriasis, skin treatment)
Atomic clocks
General and task illumination
Automotive
Water purification
Germicidal disinfection (surfaces)
Precision manufacturing
Real-time medical diagnostics
Document authentication

How the Technology Works

The unique properties of laser light (such as high spatial and temporal coherence) are particularly relevant in areas where light must be focused to tiny spots that allow for extremely high-power densities; or where the spectral quality and / or modulation speed of the emission is important.

Semiconductor lasers are often realized as edge-type emitting laser diodes (Fig. 1). The heterostructure is epitaxially grown by using either metal-organic vapor phase epitaxy (MOVPE) or molecular beam epitaxy (MBE). The active zone typically consists of several quantum wells (QWs) and is embedded in waveguide layers that are surrounded by p- and n-type cladding layers that confine the optical mode in transversal direction.

For the electrically driven devices, electrons and holes are injected from opposite sides into the active region where they recombine via stimulated emission to generate the desired photons. To achieve current densities of several kA/cm2 and to confine the optical mode in lateral direction, the current is typically imposed through a narrow ridge that is only several microns wide and etched into the semiconductor material. A Fabry-Perot resonator with a typical length in the range of 400 µm to 2000 µm is formed with cleaved or etched mirror facets and provides feedback of photons through reflections at the semiconductor/air interfaces. Additionally, mirror coatings can be deposited to change the reflectivity properties for high power or low threshold operation.

Our R&D efforts focus on the identification of materials and device issues, the invention of solutions, the reduction of practice, the demonstration of prototypes, and the capture of intellectual property. Our resources are available to support sponsored R&D and product development for external clients who wish to prototype novel optical sources and systems that are transferable to manufacturers.

Contact us today to discuss how our optoelectronic laser device technology can be used for your application.

Technical Publications:

Wunderer, T.; Jeschke, J.; Yang, Z.; Batres, M.; Teepe, M. R.; Vancil, B.; Johnson, N. M. Resonator-length dependence of electron-beam-pumped UV-A lasers. IEEE Photonics Technology Letters, 2017.

Tabataba-Vakili, F.; Wunderer, T.; Kneissl, M. A.; Yang, Z.; Teepe, M. R.; Batres, M.; Johnson, N. M.; Feneberg, M.; Vancil, B. Dominance of radiative recombination from electron-beam-pumped deep-UV AlGaN multi-quantum-well heterostructures. Applied Physics Letters, 2016.

Wunderer, T.; Northrup, J. E.; Johnson, N. M. AlGaN-based ultraviolet laser diodes . III-Nitride Ultraviolet Emitters – Technology & Applications. Book chapter, 2015.