News: Optoelectronics
27 September 2021
FBH presents new diode laser and UV LED developments at Photonics Days 2021
Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) of Berlin, Germany is participating at the Photonics Days Berlin Brandenburg 2021 event (4-7 October), which involves a four-day conference (gathering experts from photonics, optics, microsystems technology and quantum technology) and a two-day exhibition (6-7 October) at the WISTA Science and Technology Park in Berlin-Adlershof.
In Session 7.10 (‘Advanced UV technologies & applications’), scientists from FBH are presenting the latest results on high-power diode lasers, UV LEDs (including corresponding irradiation systems for medical applications) and quantum technologies.
At its booth, FBH is showing a diode laser stack optimized 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 is being displayed for the first time. FBH is developing the directly tunable laser sources in the wavelength range from 532nm to 561nm to 590nm with up to 2W 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 233nm wavelength, developed jointly with TU Berlin. Due to optimized semiconductor epitaxy and chip process technology, these latest-generation LEDs can be operated with twice the current than previously – they deliver more than 3mW output power at a drive current of 200mA.
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 70mm diameter with a homogeneity of more than 90%. The UVC light is free of skin-damaging wavelengths above 240nm and has an irradiance of 0.4mW/cm2 – ten times more than that achieved by previous systems.
Record values for diode lasers – optimized for high output powers
FBH is also presenting 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 optimized diode lasers into stack modules, with improvements in packaging and optics. For example, a fiber-coupled pulsed pump laser source with 1kW output power at 780nm wavelength was demonstrated for the first time in a 1mm core fiber (previously 1.9mm). The passively cooled module was able to increase the duty cycle from 20% to up to 50% (10ms, 10-50Hz).
