Fast photothermal spatial light modulation for quantitative phase imaging at the nanoscale

Spatial light modulators have become an essential tool for advanced microscopy, enabling breakthroughs in 3D, phase, and super-resolution imaging. However, continuous spatial-light modulation that is capable of capturing sub-millisecond microscopic motion without diffraction artifacts and polarization dependence is challenging. Here we present a photothermal spatial light modulator (PT-SLM) enabling fast phase imaging for nanoscopic 3D reconstruction. The PT-SLM can generate a step-like wavefront change, free of diffraction artifacts, with a high transmittance and a modulation efficiency independent of light polarization. We achieve a phase-shift > and a response time as short as 70 mu s with a theoretical limit in the sub microsecond range. We used the PT-SLM to perform quantitative phase imaging of sub-diffractional species to decipher the 3D nanoscopic displacement of microtubules and study the trajectory of a diffusive microtubule-associated protein, providing insights into the mechanism of protein navigation through a complex microtubule network. Here, the authors present a high-speed photothermal spatial light modulator which can generate a step-like wavefront change without diffraction artifacts. They use this to perform quantitative phase imaging, capturing sub-millisecond motion with a nanometer resolution in 3D.

Automated summary

The study introduces a high-speed photothermal spatial light modulator capable of generating a step-like wavefront change without diffraction artifacts, used for quantitative phase imaging to capture nanometer-scale 3D displacements.