Self-frequency doubled green NdxY1-xCa4O(BO3)(3) laser

Nd-doped yttrium calcium oxyborate, NdxY1-xCa4O(BO3)(3) (NYCOB), was grown using pulling from the melt, with large sizes and good optical quality as w ell as different Nd3+-ion densities of 0 to 10 at% in the lattice structure . These crystals belong to the monoclinic system with point group m, confor ming space group C-m. The unit cell constants were a = 0.8076(7); b = 1.602 0(10), and c = 0.3527(2) nm for a Nd3+ content of 8 at%, with beta = 101.23 degrees, and z = 2. The measured absorption of the NYCOB was compared to J udd-Ofelt (JO) theory. When applied, the JO theory of parity-forbidden elec tric-dipole transitions of rare earth ions on non-centrosymmetric sites dem onstrates good agreement. The polarized absorption coefficients at 811 nm w ere calculated as alpha (X) = 1.59, alpha (Y) = 1.75, and alpha (Z) = 2.02 1/cm, respectively. The valence-conduction band gap is about 5.39 eV. The f itted intensity parameters Omega (t) (t = 2, 4, and 6) were 3.51x10(-20), 7 .82x10(-20), and 3.79x10(-20) cm(2), with a root-mean square deviation of 6 .30 x 10(-21) cm2. The emission properties of the excited F-4(3/2) state wi th the level lifetime of 216.67 mus were studied, which exhibit the two pas s bands of laser for possible applications in practice. The self-frequency doubling tests are interesting. A very low threshold power of 3 mW for a sa mple with average Nd3+ content of 7 at%, length of 6 mm, and phase matching angles of theta = 64.5 degrees and phi = 35.5 degrees have been measured. The measured output power of green light was 19.4 mW accompanied with a con version efficiency of 3.7%.