Original technique for third-harmonic-generation measurements in liquids

An original technique, with a special design of liquid cell, is proposed for third-harmonic generation in liquids. The technique is based on a principle of harmonic generation in an infinite medium by focused laser beam applied for liquid cell windows and uses a thin wedge-shaped liquid compartment. The measurements can be performed in air, and a high precision in cubic susceptibility and refractive index dispersion determination can be obtained. The technique also allows measurements to be made on liquids absorbing at harmonic and fundamental frequencies and in function of external parameters like temperature, pressure, and electric or magnetic fields. Some results for organic solvents are presented and compared with those obtained by other methods.