Efficient conversion of blue light into white light by means of rare‐earth‐ion‐doped transparent material

The possibility and applicability limit of rare‐earth‐ion‐doped transparent materials as wavelength conversion materials for white‐light‐emitting light sources have been investigated. In a previous paper an efficient conversion from blue to white light was reported using a YAG:Ce single crystal. It is now shown that a high conversion efficiency from blue or UV light to green light can be expected in Er3+‐doped glass having a low Er3+ ion content. However, the practical usefulness is limited because of a low absorption constant and narrow spectral absorption band of Er3+ ions. Luminescence processes in Er3+‐containing materials have been examined and compared with the results of simulation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)