Mid-infrared beam shaping concepts are presented, which rely on coherent emission from QCLs. Grating coupled
surface emitting quantum cascade ring lasers allow for far-field tuning, ranging from highly symmetric spot- to ringshaped
beam patterns, depending on the grating period. In single-mode operation, the devices exhibit low beam
divergence, represented by a full width at half maximum of ~3°. Moreover, a tree shaped resonator is investigated, which
enables coherent parallel coupling of six laser elements into a single waveguide by means of several Y-junctions. The
lasers were investigated in terms of optical power, near and far field characterization. Phase-locking was observed and
leads to in-phase emission on both sides of the devices. Both concepts demonstrate the feasibility of high-brightness midinfrared
quantum cascade lasers with prospective applications in spectroscopy and high power laser arrays.
This paper presents a new concept for bonding micro-parts with dimensions in the range of 50 μm to 300 μm. Two different kinds of adhesives - polyurethane adhesive foil and hot melt glue - were applied to a basic substrate by different techniques. The focused and concentrated hot gas stream softened glue which had been applied in a solid state. Micro-parts were then embossed in the softened glue, or covered and shielded by it. In this way, a rigid and compact bond was obtained after cooling. For the positioning of micro-parts (optical fibers), it has been necessary to manufacture adequate V-grooves. Finite element analyses using the ANSYSTM program package were performed in order to evaluate parameters which govern the heat transfer to the adhesive and substrate respectively. Experimental results are in good agreement with results obtained by the numerical simulations. The advantages of this new approach are small system size, low capital costs, simple usage, applicability to many material combinations, easy integration into existing production lines, etc.