Research Summary
Development of optical techniques enabling label-free, fast, and quantitative 3D measurements of dynamic processes.
Dielectric tensor tomography
Quantitative 3D characterization of optically isotropic and anisotropic materials.
Label-free tomographic measurements of dielectric tensors which directly provide both of the principal refractive indices and the directors of optic axis.
High temporal resolution with the capability of long time-lapse measurements, due to measuring the elastic light scattering.
a, schematic illustration of dielectric tensor tomography. Light fields diffracted from a sample are measured using the polarization-sensitive interferometer. By inversely solving the vectorial wave equation, 3D dielectric tensor distribution is reconstructed from the measured fields. b, time-lapse 3D measurements of non-equilibrium dynamics of liquid crystal droplets; annihilation when heating, nucleation and merge when cooling. c, a 3D view of the reconstructed directors of the LC polymer network film. The perspective and scale are shown in the top-right box. d, multiple xy cross-sectional slices at different axial planes. e, An enlarged 3D view of the topological defect at the side, indicated by the yellow dashed line in c.
Related paper
Tomographic measurement of dielectric tensors at optical frequency, Nature Materials 21, 317-324 (2022)
Refractive index tomography of biological cells
Label-free measurements of 3D refractive index distribution of biological samples, from which protein concentration, dry mass, and cellular volume can be quantitative obtained.
a, 3D rendered refractive index tomograms of various biological cells. b, Long time-lapse measurements of biological dynamics; apoptosis (top) and necrosis (bottom).
Related papers
Enhancement of optical resolution in three-dimensional refractive-index tomograms of biological samples by employing micromirror-embedded coverslips, Lab on a Chip, 18, 3484-3491 (2018)
Super-resolution three-dimensional fuorescence and optical difraction tomography of live cells using structured illumination generated by a digital micromirror device, Scientific Reports, 8:9183 (2018)
Active illumination using a digital micromirror device for quantitative phase imaging, Optics Letters, 40(22), 5407-5410 (2015)
Reference-free holographic imaging and wavefront shaping
Light field is measured and modulated at the same plane, without the use of an interferometer and an image sensor.
Enabling the registration-free sophisticated light modulations on microscopic samples.
a, Radio waves are measured and modulated by a single bidirectional transducer. b, schematic illustration of optical bidirectional transducer. c, The transducer measures light field diffracted from the sample. d, the phase conjugated field is transmitted by the transducer. After the diffraction from the sample, the field is rewound to a plane wave, which shows outstandingly sophisticated light modulation.
Related papers
Reference-Free Single-Point Holographic Imaging and Realization of an Optical Bidirectional Transducer, Physical Review Applied, 9, 044042 (2018)
Reference-free polarization-sensitive quantitative phase imaging using singe-point optical phase conjugation, Optics Express, 26(21), 26858-26865 (2018)
Effects of spatiotemporal coherence on interferometric microscopy, Optics Express, 25(7), 8085-8097 (2017)