Inclusion of an anionic dye in the molecular structure of potassium dihydrogen phosphate crystal for SSDL applications

Single crystals of pure potassium dihydrogen phosphate (KDP) and Reactive Orange 16 or Remazol Brilliant Orange dye-doped (0.1, 0.2 and 0.3 mol%) KDP single crystals were grown by slow evaporation method with the vision to improve the properties of pure KDP crystal. Enhanced dielectric, optical, thermal and NLO properties have been achieved by dye doping. The crystallinity and phase purity of the grown crystals were analysed by PXRD. The identification of various functional groups and dye incorporation in the grown crystals was confirmed qualitatively by FTIR analysis. The linear optical study on pure and dye-doped crystals was carried out using UV–Vis–NIR spectroscopy. The optical band gap, extinction coefficient, refractive index and optical conductivity were calculated using the transmittance spectra for all the samples. The thermal stability and the decomposition temperature were found to increase with the concentration of the dopant. This indicates the high quality of the crystal as well as its perfection. The SHG efficiency measurements were taken for the grown crystals and found that the SHG efficiency increases with doping concentration. The enhanced optical constants, thermal stability and second harmonic generation ability confirm the suitability of the grown crystals for solid-state laser materials.