Rolling-Enabled Nonplanar Heterogeneous Integration for Polarization-Diverse Nanolasers on Silicon Photonics

The continued advancement of silicon photonics increasingly relies on heterogeneous integration beyond monolithic fabrication, with transfer printing emerging as a powerful strategy for deterministic and high-precision assembly. However, existing transfer-printing strategies remain fundamentally limited to planar integration, restricting access to orientation-dependent optical functionalities. Here, we introduce a rolling-enabled transfer-printing strategy that enables deterministic nonplanar heterogeneous integration through precise mechanical orientation control at the nanoscale. By exploiting rolling-induced rotation during assembly, identical photonic-crystal nanobeam lasers are integrated onto silicon waveguides in planar or orthogonal configurations, enabling selective coupling to TE-like or TM-like modes without modifying the cavity design or epitaxial structure. Both configurations exhibit stable lasing and polarization-resolved coupling to silicon waveguides, in good agreement with numerical simulations, confirming that mechanical orientation alone can define optical functionality. By establishing orientation control as a new degree of freedom in heterogeneous integration, this work elevates transfer printing from a placement technique to a functionality-defining platform, opening new opportunities for compact, multifunctional, and reconfigurable photonic systems on silicon.