FBH to present latest technology at Berlin-based Photonics Days trom October 4th to 7th

The Ferdinand-Braun-Institut, Leibnis-Institut für Höchstfrequenztechnik (FBH) will participate in Photonics Days conference and exhibition trom October 4 - 7, 2021 in Berlin-Adlershof.

The four-day conference brings together experts from photonics, optics, microsystems technology, and quantum technology. Scientists from the Ferdinand-Braun-Institut will present the latest results on high-power diode lasers, UV LEDs including the corresponding irradiation systems for medical applications, and quantum technologies.

At the booth, FBH will show a diode laser stack optimised for high output powers and a UVC LED irradiation system for medical studies. Moreover, an exhibit exemplifying the application of yellow-green laser modules in ophthalmology will be displayed for the first time. FBH is developing the directly tunable laser sources in the wavelength range from 532 nm to 561 nm to 590 nm with up to 2 watts output power in continuous wave operation. The compact laser sources have the potential to replace significantly larger dye and copper bromide lasers.

LED irradiation systems to fight multidrug-resistant pathogens and coronaviruses

FBH has developed UV LED-based irradiation systems, which are already being tested at the Charité, Universitätsmedizin Berlin and at the Greifswald University Hospital. In the future, this irradiation concept will be used to inactivate multidrug-resistant pathogens such as MRSA and coronaviruses including SARS-CoV-2 directly on humans in a way that does not harm the skin.

Each system is equipped with 120 LEDs that emit at 233 nm wavelength, developed jointly with TU Berlin. Thanks to optimised semiconductor epitaxy and chip process technology, these latest-generation LEDs can be operated with twice the current as before - they deliver more than 3 mW output power at 200 mA. Furthermore, FBH has developed new silicon-based LED packages in collaboration with the CiS Forschungsinstitut für Mikrosensorik.

In addition to efficient heat dissipation, aluminium reflectors and a plano-convex lens ensure a beam angle of only 60 degrees. This, in turn, increases the transmission, i.e. the light that the integrated spectral filter allows to pass through. The systems can irradiate an area of 70 mm diameter with a homogeneity of more than 90 percent. The UVC light is free of skin-damaging wavelengths above 240 nm and has an irradiance of 0.4 mW/cm2 - ten times more than that achieved by previous systems.

Record values for diode lasers

FBH will also present its advances in high repetition rate pump lasers for future high-energy class solid-state laser systems. The institute was able to increase the peak output power of its diode laser bars in quasi-continuous operation by up to four times while maintaining excellent efficiency. This reduces the cost in euros per watt - a key parameter for industry.

FBH builds the optimised diode lasers into stack modules (pictured above), with improvements in packaging and optics.

For example, a fibre-coupled pulsed pump laser source with 1 kW output power at 780 nm wavelength was demonstrated for the first time in a 1 mm core fibre (previously 1.9 mm). The passively cooled module was able to increase the duty cycle from 20 percent to up to 50 percent (10 ms 10...50 Hz).