Study of non-linear optical properties in automobile lubricating oil via Z-Scan technique

Non-linear optical properties were obtained as a function of laser power for the 20W-50 multigrade oil for engines. These properties were obtained by using the Z-scan technique for transmission in closed and open cell configurations. A Nd:YAG laser operating in continuous wave (CW) was used, emitting in 532 nm and regulated in electric current. To control the technique, an interface was implemented in LabVIEW, which allows real-time monitoring of the measurement development. The values of the non-linear absorption coefficient (b), non-linear refractive index (n2), and third-order electrical susceptibility (x(3)) were estimated, finding orders of magnitude of 10-3 cm/W, 10-9 cm2/W, and 10-5 esu, respectively. These previous results show that an automobile lubricating oil has significant non-linear optical properties.