Spatial frequency modulated imaging of real-time laser-matter interactions

Abstract

Laser modification of materials or biological systems would benefit from imaging systems that are able to quantify the interaction in real-time. One of the important constraints for such an imaging system is that it must be robust against optical scattering, as interactions may take place deep within a scattering material. Here, for the first time, we demonstrate confocal spatial frequency modulation imaging that can show real-time changes and make two and three dimensional images of the material. Single element detection is used to aid in mitigating scattering effects of the optical signal, and an 800nm excitation wavelength enables detection down to millimeter depths in glass and plastic scattering systems.