To investigate the optical limiting performance of the wavelengths of 266 nm 355 nm 532 nm 1064nm we demonstrated series of series of intensity-dependent Z-scan measurements and fitted results in Figu

To investigate the optical limiting performance of different wavelengths (266 nm, 355 nm, 532 nm, 1064 nm), we conducted a series of intensity-dependent Z-scan measurements and obtained fitted results shown in Figure 6(a). The optical limiting (OL) thresholds were determined to be 0.18 J cm-2, 0.11 J cm-2, 0.08 J cm-2, and 0.05 J cm-2 for 1064 nm, 532 nm, 355 nm, and 266 nm, respectively. At 355 nm, the lowest normalized transmittances were observed at 1.2 μJ (91%), 7.4 μJ (62%), and 17 μJ (15%), with corresponding maximum modulation depths of 9%, 38%, and 85%, respectively. The two-photon absorption coefficients for 266 nm, 355 nm, and 532 nm were measured to be 0.22 cm/GW, 0.28 cm/GW, and 0.08 cm/GW, respectively. The three-photon absorption coefficient for 1064 nm was found to be 2.82 ×10-4 cm3/GW2. The significant reverse saturable absorption (RSA) observed in GaN nanowires, along with their large modulation depths and nonlinear refractivity, suggests their potential for various optical device applications, particularly in optical switching and optical limiting.