Shapiro steps are quantized plateaus in the velocity-force curve of a driven system, where velocity remains constant despite increasing the force. Previously, integer steps have been observed for microscopic particles in sinusoidal potentials. By driving a colloidal particle through a time-modulated, non-sinusoidal optical landscape, the authors demonstrate the emergence of fractional Shapiro steps and uncover their microscopic mechanisms, enabling precise control through optical potential design.
- Andris P. Stikuts
- Seemant Mishra
- Pietro Tierno
