Henning Kühn

Model for the calculation of radiation trapping and description of the pinhole method

Radiation trapping is a well-known process that results in the lengthening of observed fluorescence lifetimes in laser materials with significant overlap in their emission and absorption spectra. The pinhole method is a measurement technique that allows the intrinsic fluorescence lifetime of an excited state to be determined in a nondestructive manner. A theoretical description of this method is proposed. A model is developed that identifies the lifetime extrapolated to a zero radius pinhole as the intrinsic fluorescence lifetime. The application of this method to bulk materials and thin discs is discussed.

Amplification in epitaxially grown

Monocrystalline lattice matched

Er:(Gd, Lu)_2O_3

Er(0.6

Low threshold monocrystalline

at.

Nd:{(Gd,Lu)_2O_3}

%):

channel waveguide laser

(Gd,Lu)_2O_3

Monocrystalline

films with nearly atomically flat surfaces and thicknesses up to 3 μm have been grown on

Yb^{3+}:(Gd,Lu)_2O_3

Y_2O_3

channel waveguide laser at 976.8 nm

substrates using pulsed laser deposition. The emission cross sections were comparable with the ones of