Adaptive Wave-Front Shaping and Beam Focusing through Fiber Bundles for High-Resolution Bioimaging

Abstract

We demonstrate an adaptive wave-front shaping of optical beams transmitted through fiber bundles as a powerful resource for multisite, high-resolution bioimaging. With the phases of all the beamlets delivered through up to 6000 different fibers within the fiber bundle controlled individually, by means of a high-definition spatial light modulator, the overall beam transmitted through the fiber bundle can be focused into a beam waist with a diameter less than 1 μm within a targeted area in a biotissue, providing a diffraction-limited spatial resolution adequate for single-cell or even subcellular bioimaging. The field intensity in the adaptively-focused continuous-wave laser beam in our fiber-bundle-imaging setting is more than two orders of magnitude higher than the intensity of the speckle background. Once robust beam focusing was achieved with a suitable phase profile across the input face of the fiber bundle, the beam focus can be scanned over a targeted area with no need for a further adaptive search, by applying a physically intuitive, wave-front-tilting phase mask on the field of input beamlets. This method of beam-focus scanning promises imaging speeds compatible with the requirements of in vivo calcium imaging.

Quantum resolution limit via coherent polarization Raman spectroscopy

“…[5][6][7][8][9] Insights from information theory are proving useful in identifying new routes toward optical super-resolution in a vast variety of microscopy-, astronomy-, and signal-analysis-related tasks, including single-molecule detection and fluorescent-nanoprobeassisted neural readout, as well as nanoscale quantum memories and quantum biosensors. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Extending information-theory concepts to spectral analysis could help enhance the performance of a vast class of optical systems whose operation relies on the detection of weak distortions of spectral lines or a discrimination of closely spaced spectral features. This class of instruments has been rapidly growing as one of the recent trends in optical science, expanding to harness new technologies and explore new applications, such as multiplex optical bioimaging, [25,26] electric-and magnetic-field sensing, [27,28] high-precision thermometry, [29][30][31] trace-gas analysis, [32,33] and virus detection.…”

“…[ 5–9 ] Insights from information theory are proving useful in identifying new routes toward optical super‐resolution in a vast variety of microscopy‐, astronomy‐, and signal‐analysis‐related tasks, including single‐molecule detection and fluorescent‐nanoprobe‐assisted neural readout, as well as nanoscale quantum memories and quantum biosensors. [ 10–24 ]…”