Z-scan technique: a review from conventional Z-scan to white light Z-scan

Nonlinear (NL) absorption and refraction are crucial optical phenomena in the development and application of optical materials. The Z-scan technique, first proposed by Bahae, is widely used to accurately measure the coefficients of NL absorption and refraction. This review presents a comprehensive overview of the most established versions of the Z-scan technique, including the transmittance closed aperture (CA) and open aperture (OA) Z-scan, reflecting CA and OA Z-scan, eclipsing Z-scan, and white light Z-scan. In each version, different sources with varying spatial and temporal intensity distributions are usually utilized. Numerical and analytical calculation results are provided for each version considering both continuous wave (CW) and pulsed laser sources. Unlike conventional reviews, which often summarize previously published results, this review primarily focuses on reproducing the findings from the literature. The analytical results, which are typically derived under specific approximations, are compared with numerical calculations to highlight the limitations of analytically derived relations. Furthermore, the necessary criteria and conditions for applying each Z-scan version are discussed.