Growth and optical limiting properties of oxalic acid dihydrate crystals for photonic applications

The oxalic acid dihydrate (OAD) single crystal has been successfully grown by the slow evaporation solution technique (SEST) by water as a solvent. Crystals reaching a maximum size of [Formula: see text] were obtained, with their nucleation and growth processes visually documented. Using powder XRD analysis, Miller index and (h k l) planes were identified. The FTIR analysis was conducted on the OAD crystal to find out the OAD functional groups. UV–Vis–NIR studies showed high transparency in the 300–1100[Formula: see text]nm range, with an optical band gap of 5.2[Formula: see text]eV. Photoluminescence (PL) studies indicated the potential suitability of the material for LED applications. Dielectric measurements were performed to analyze the frequency dependence of the dielectric constant and loss. Negative photoconductivity was also observed, highlighting its relevance for optoelectronic devices. Surface morphology was examined using chemical etching and scanning electron microscopy (SEM). Furthermore, Z-scan analysis confirmed the presence of two-photon absorption and effective optical limiting behavior, supporting the application of OAD crystals in laser safety and nonlinear optical devices.