Three dimensional processing of silicon with pulsed lasers for optical applications

Micromachining of silicon with lasers is being investigated for the last three decades. Until now, interior silicon modification without inscribing the surface has not resulted in success. Such an ability could enable disruptive technologies in nanophotonics by paving the way for producing monolithic optoelectronic chips. Here, we report a maskless, one step photo-induced method to generate subsurface modifications in silicon with pulsed infrared lasers for indefinitely large areas. We demonstrate continuous, highly controllable structures buried in the bulk of silicon wafers and investigate the underlying mechanism. Further, we utilize the method for spatial information encoding and fabrication of optical components in the infrared regime in silicon. This silicon processing technology can be useful in various applications, including multilayer silicon chips, solar cells and opto uidics.