Miniature Neodymium Lasers: Principles and Aspects for Integrated Optics

The search for high gain Nd3+ laser materials has resulted in a new class of materials such as NdP014, NdLiPAO,, NdA1(B0,)A and Nd(A1,Cr)3 (BO3 )4 . The basic properties and principles of the mateflais are desctiBled: limits of concentration, fundamental rare earth spectroscopy, fluorescqnce quenching and laser action. The lasers have typical active volumes of 10-6 to 10-8° cm3 and operate at 1.06pm and 1.3pm with thresholds in the submil-liwatt range. The connection between these lasers and integrated optics is shown in terms of fundamental considerations. Epitaxial growth as well as planar waveguide structures have been demonstrated. Various examples of lasers, e.g., bulk lasers, intracavity SHG, flashlamp pumping, and LED pumping are described, illustrating the materials and the design principles. The approach of cross pumping Nd by Cr allows to improve the spectral power density by an order of magnitude. A simple sun-pumped rare earth laser device should be realizable.