DESIGN AND FABRICATION OF VISIBLE+1.54μm LASER/LONGWAVE INFRARED DICHROIC BEAMSPLITTER

Visible + 1.54 mu m laser/long-wave infrared dichroic beamsplitters, which separate the incident spectrum into visible light, laser and longwave infrared light, take an important role in multichannel imaging spectrum technique. The choice of substrates and coating materials was discussed. Then the coating design of reflecting the visible(400 similar to 800nm) and laser (1540nm) light while transmitting the longwave infrared( 8 similar to 12 mu m) spectrum was analysed, and the beamsplitter was manufactured by e-gun evaporation. The measured reflectivity and transmittance of the corresponding channel are all above 94% and the dichroic beanisplitters has been used in practical optical system successfully.