1：Experimental Design and Method Selection:

The bulk size single crystal of potassium aluminium sulphate (KAS) was grown by slow solvent evaporation technique. The crystalline phase was determined by powder X-ray diffraction analysis and structural parameters by single crystal XRD technique. Optical transparency was examined within the wavelength range of 200-900 nm using UV-visible spectral analysis. The luminescence behavior was investigated within the visible range. The laser damage threshold was determined using a pulse mode operated 1064 nm Nd:YAG laser. The third order nonlinear optical (TONLO) properties were examined at 640 nm.

2：Sample Selection and Data Sources:

The KAS crystal was grown from potassium aluminium sulphate dodecahydrate salt dissolved in double distilled water.

3：List of Experimental Equipment and Materials:

Bruker Advanced D8 powder X-ray diffractometer, Enraf Nonius CAD4 single crystal X-ray diffractometer, Shimadzu UV-2450 spectrophotometer, Hitachi F-7000 FL spectrophotometer, Litron Nd:YAG laser.

4：Experimental Procedures and Operational Workflow:

The saturated solution of KAS was prepared, filtered, and housed in a constant temperature water bath for crystal growth. The grown crystal was subjected to various characterization techniques.

5：Data Analysis Methods:

The optical transmittance, luminescence behavior, laser damage threshold, and TONLO properties were analyzed using respective equipment and techniques.