We present experimental evidence showing that the period of the rippled surface structure induced on germanium by 1.06-μm laser pulses undergoes a discontinuous shift above a certain threshold intensity. The measured shift, as a function of the angle of incidence of the damaging beam, is quantitatively interpreted as a transition between a regime of inhomogeneous melting controlled by radiation-remnant field structures and a regime of ripple formation involving surface plasmons in an optically thick layer of liquid, metallic germanium formed at the surface.
© 1983 Optical Society of America
Original Manuscript: April 21, 1983
Published: August 1, 1983
Jeff F. Young, J. E. Sipe, and H. M. van Driel, "Regimes of laser-induced periodic surface structure on germanium: radiation remnants and surface plasmons," Opt. Lett. 8, 431-433 (1983)