Modified Z-scan set-up using CCD for measurement of optical nonlinearity in PLD carbon thin film

•CCD camera is used in place of photodiode as a detector.•The synthetic aperture is employed using Matlab programm in place of physical aperture.•Closed aperture Z-scan data can be obtained for any aperture from open Z-scan.

A modified Z-scan set-up utilizing CCD is reported which can be used for open as well as closed aperture configuration in a single scan. The technique is based on recording the transmitted laser beam through the sample on CCD directly. It has the advantage of using the same recorded image for open as well as closed Z-scan for each ‘z’ position, thus minimizing the effect due to beam pointing instability and background vibrations.