Stimulated emission and excited state absorption in neodymium-doped CaNb2O6 single crystal fibers grown by the LHPG technique

Abstract

This work presents the structural and spectroscopic characterization of undoped and neodymium doped CaNb2O6 single crystal fibers grown by the low cost and versatile Laser Heated Pedestal Growth technique. To evaluate the potentialities of doped fibers, polarized absorption (σGSA,max809nm = 5.85×10−20cm2 with FWHM = 18 nm), luminescence and lifetime (τexp = 145 μs) measurements were taken, and radiative properties were also assessed by the Judd–Ofelt approach. The gain (σSE−σESA) spectrum was measured using the pump-probe technique and stimulated emission was observed at 1.064 μm with (σSE, max1.064 μm = 7.2× 10−20 cm2 and FWHM = 12 nm). The results are comparable to those of other well known niobate bulk laser crystals, but the easier, cheaper and faster growth of compact CaNb2O6:Nd3+ single crystal fibers makes them more attractive media for compact optical devices, such as diode laser pumped miniature lasers in the near infrared region.