Two-Photon Induced Chiral Mass-Transport of Azo-Polymers as a Function of Pulse Duration

We have demonstrated two-photon-absorption induced chiral surface relief formation in an azo-polymer film by the illumination of picosecond 1-μm optical vortex pulses. The chiral surface relief formation required at least several times the response time of trans-cis isomerization of the azo-polymers. The resulting chiral surface relief exhibited a diameter of 3-μm, corresponding to 0.7 times the diffraction limit. We also observed spin-orbital angular momentum coupling in the surface relief formation, even via two-photon-absorption. © 2019 The Author(s)