Multi-wavelength laser sources are necessary for a functional photoacoustic (PA) spectroscopy. The use of high-power diode lasers (HPDLs) has aroused great interest for their relatively low costs and small sizes if compared to solid state lasers. However, HPDLs are only available at few wavelengths and can deliver low optical energy (normally in the order of μJ), while diode laser bars (DLBs) offer more wavelengths in the market and can deliver more optical energy. We show the simulations of optical systems for beam coupling of single high-power DLBs operating at different wavelengths (i.e. 808 nm, 880 nm, 910 nm, 940 nm, and 980 nm) into 400-μm optical fibers. Then, in a separate design, the beams of the DLBs are combined in a compact system making use of dichroic mirrors and focusing lenses for beam coupling into a 400-μm optical fiber. The use of optical fibers with small core diameter (< 1 mm) is particularly suggestive for future photoacoustic endoscopy (PAE) applications that require interior examination of the body.
In this paper we present a wide viewing angle multi SLMs color holographic 3D display. An extended viewing angle is provided by the use of circular setup configuration. To ensure best utilization of spatial bandwidth of a single SLM a temporal multiplexing method for a color reconstruction is applied. Averaged in time modulated component wavefronts overlap in space and create a real color 3D image. We present the display implementation resulting in color reconstruction of computer generated objects and multi-view 2D real object stereogram converted into holographic representation. The applicability of this approach to allow holographic display of big 3D scenes and the future possibilities to extend the spatio-temporal bandwidth of color holographic displays are discussed.