Growth and spectroscopic properties of Nd3+-doped PbMoO4 laser crystals

Abstract

Lead molybdate (PbMoO₄, PMO) crystal is a multifunctional material with diverse applications in acoustic-optics, scintillation and lasers. Herein, transparent 1 mol% and 2 mol% Nd³⁺-doped PMO crystals were readily grown via the Bridgman method, with dimensions of Φ 25.6 mm × 60 mm. The effective segregation coefficients of Nd³⁺ ions for the 1 mol% and 2 mol% Nd³⁺:PMO crystals were 0.58 and 0.63, respectively. The optical and fluorescence spectra were evaluated in detail, and the spectroscopic properties were determined using the Judd–Ofelt (J–O) theory. For 1 mol% Nd³⁺:PMO crystals, the absorption cross-section at 804 nm was 13.81 × 10⁻²⁰ cm², with an FWHM of 20.3 nm. The absorption cross-section and FWHM at 804 nm were calculated to be 9.29 × 10⁻²⁰ cm² and 14.8 nm for 2 mol% Nd³⁺:PMO crystals, respectively. Additionally, the emission cross-sections at 1.06 μm were calculated as 12.71 × 10⁻²⁰ cm² and 12.79 × 10⁻²⁰ cm² for 1 mol% and 2 mol% Nd³⁺:PMO crystals, respectively. The fluorescence decay time was moderately decreased from 145.84 μs (1 mol% Nd³⁺:PMO crystal) to 137.83 μs (2 mol% Nd³⁺:PMO crystal). Compared with other Nd³⁺ ion-doped laser gain medium, Nd³⁺:PMO crystals were featured with relatively larger absorption cross-sections and emission cross-sections and longer decay times. This work provides a deeper insight into the design of novel laser crystals in the near infrared region.