With increasing power, brightness and new wavelengths on the horizon, semiconductor lasers may one day be as ubiquitous as LEDs.
Improvements to semiconductor lasers promise big changes, from increases in power to expanded wavelengths.
Other innovations could mean faster data rates for a bandwidth-hungry world. And then there are self-driving cars. Equipped with lidar, autonomous vehicles are likely to spark demand for improved semiconductor lasers. Finally, researchers are investigating semiconductor lasers that can be built to output any desired wavelength, enabling new uses.
For some applications, what’s important is not just increasing the power that a semiconductor laser can deliver. Instead the key is achieving more intensity per unit area.
“The real trend is to increase brightness. That means to get more power with a better beam quality, or for fiber-coupled products, more power out of smaller fibers,” said Jörg Neukum, product line manager for high-power diode lasers at Mainz, Germany-based Coherent-Dilas, which manufactures high-power diode laser components and systems based on a scalable edge emission architecture.
Neukum added that more power alone means that only some direct applications can be targeted, like plastic welding. In the kilowatt regime, the direct applications are hardening, cladding and additive manufacturing. In contrast, greater brightness would allow semiconductor lasers to tackle cutting and other uses.
The required brightness increase varies with application, Neukum said. For instance, cutting of copper and gold would profit from brighter semiconductor lasers in the blue because those metals absorb shorter wavelengths better than they do light in the red. On the other hand, a 3D projection system could use brighter red, green and blue lasers. In such an approach, lasers at 650 and 660 nm, for example, might be employed, with filters ensuring that each eye only sees one wavelength, different from the other. Similar color splits would be used for the blue and green.
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