Positive Gain Observation in a Nd-Doped Active Fiber Pumped by Low-Concentrated Solar-Like Xenon Lamp

摘要

Neodymium-doped silica glass fiber is pumped by a Xe arc lamp as a simulated solar light. The fiber is immersed in rhodamine 6G solution to enhance the photon flux at the 588 nm absorption band of the Nd~(3+), The chamber that contains the active fiber and dye solution is made of a pair of reflectors. The bottom reflector is highly reflective over the entire visible spectrum, while the top reflector is a short-pass dichroic mirror whose cutoff wavelength is set at 580 nm. As a result, the dye fluorescence of the absorption band is confined by the multiple reflections, like a "greenhouse effect". The expected confinement factor as a function of the angular-dependent reflectivity of the reflectors is discussed. The highest gain observed is 1.0 × 10~(-2)m~(-1) when the lamp light intensity is 2.7W/cm~2.