Transition excitation at 09 μm by multiphoton pumping of Nd^3+-doped fibers

Multiwavelength oscillations near 0.9 microm (i.e., 0.88-0.98 microm) have been obtained in a Nd(3+)-doped silica-based single-mode optical fiber. The laser pump wavelength is 1.064 microm, with an average pump power of approximately 1.8 GW/m(2). The observed emission rate has reached a few percent. We discuss the possibility that this fluorescence or perhaps superfluorescence arises by multiphoton absorption.