3 research outputs found
Microcantilever-integrated photonic circuits for broadband laser beam scanning
Laser beam scanning is central to many applications, including displays,
microscopy, three-dimensional mapping, and quantum information. Reducing the
scanners to microchip form factors has spurred the development of
very-large-scale photonic integrated circuits of optical phased arrays and
focal plane switched arrays. An outstanding challenge remains to simultaneously
achieve a compact footprint, broad wavelength operation, and low power
consumption. Here, we introduce a laser beam scanner that meets these
requirements. Using microcantilevers embedded with silicon nitride nanophotonic
circuitry, we demonstrate broadband, one- and two-dimensional steering of light
with wavelengths from 410 nm to 700 nm. The microcantilevers have ultracompact
~0.1 mm areas, consume ~31 to 46 mW of power, are simple to control, and
emit a single light beam. The microcantilevers are monolithically integrated in
an active photonic platform on 200-mm silicon wafers. The
microcantilever-integrated photonic circuits miniaturize and simplify light
projectors to enable versatile, power-efficient, and broadband laser scanner
microchips
Implantable photonic neural probes for light-sheet fluorescence brain imaging
Significance: Light-sheet fluorescence microscopy (LSFM) is a powerful technique for highspeed volumetric functional imaging. However, in typical light-sheet microscopes, the illumination and collection optics impose significant constraints upon the imaging of non-transparent brain tissues. We demonstrate that these constraints can be surmounted using a new class of implantable photonic neural probes.
Aim: Mass manufacturable, silicon-based light-sheet photonic neural probes can generate planar patterned illumination at arbitrary depths in brain tissues without any additional micro-optic components.
Approach: We develop implantable photonic neural probes that generate light sheets in tissue. The probes were fabricated in a photonics foundry on 200-mm-diameter silicon wafers. The light sheets were characterized in fluorescein and in free space. The probe-enabled imaging approach was tested in fixed, in vitro, and in vivo mouse brain tissues. Imaging tests were also performed using fluorescent beads suspended in agarose.
Results: The probes had 5 to 10 addressable sheets and average sheet thicknesses <16 μm for propagation distances up to 300 μm in free space. Imaging areas were as large as ≈240 μm × 490 μm in brain tissue. Image contrast was enhanced relative to epifluorescence microscopy.
Conclusions: The neural probes can lead to new variants of LSFM for deep brain imaging and experiments in freely moving animals
Implantable photonic neural probes for light-sheet fluorescence brain imaging
Significance: Light-sheet fluorescence microscopy is a powerful technique for high-speed volumetric functional imaging. However, in typical light-sheet microscopes, the illumination and collection optics impose significant constraints upon the imaging of non-transparent brain tissues. Here, we demonstrate that these constraints can be surmounted using a new class of implantable photonic neural probes. Aim: Mass manufacturable, silicon-based light-sheet photonic neural probes can generate planar patterned illumination at arbitrary depths in brain tissues without any additional micro-optic components. Approach: We develop implantable photonic neural probes that generate light sheets in tissue. The probes were fabricated in a photonics foundry on 200 mm diameter silicon wafers. The light sheets were characterized in fluorescein and in free space. The probe-enabled imaging approach was tested in fixed and in vitro mouse brain tissues. Imaging tests were also performed using fluorescent beads suspended in agarose. Results: The probes had 5 to 10 addressable sheets and average sheet thicknesses < 16 μm for propagation distances up to 300 μm in free space. Imaging areas were as large as ≈ 240 μm x 490 μm in brain tissue. Image contrast was enhanced relative to epifluorescence microscopy. Conclusions: The neural probes can lead to new variants of light-sheet fluorescence microscopy for deep brain imaging and experiments in freely-moving animals