Comments on: A remarkable enhancement between optical transparency and SHG efficiency on doped-KHP single crystals

Abstract

The authors of the published title paper (Bull. Mater. Sci. 2020 43 17) claim to have grown a resorcinol-doped potassium hydrogen phthalate (RKHP) crystal by a slow evaporation method. It was reported that the organic dopant enhances the second harmonic generation efficiency (SHG) of potassium hydrogen phthalate (KHP). In this letter to Editor, many points of criticism concerning the crystal growth and the characterization of the so-called RKHP crystal are discussed to prove that the published original paper is erroneous.