3D printing allows rapid fabrication of complex objects from digital designs. One 3D-printing process, direct laser writing, polymerises a lightsensitive material by steering a focused laser beam through the shape of the object to be created. The highest-resolution direct laser writing systems use a femtosecond laser to effect two-photon polymerisation. The focal (polymerisation) point is steered over the shape of the desired object with mechanised stages or galvanometer-controlled mirrors. Here we report a new high-resolution direct laser writing system that employs a resonant mirror scanner to achieve a significant increase in printing speed over galvanometer-or piezo-based methods while maintaining resolution on the order of a micron. This printer is based on a software modification to a commerically available resonant-scanning two-photon microscope. We demonstrate the complete process chain from hardware configuration and control software to the printing of objects of approximately 400 × 400 × 350 µm, and validate performance with objective benchmarks.Released under an open-source license, this work makes micro-scale 3D printing available the large community of two-photon microscope users, and paves the way toward widespread availability of precision-printed devices.Comments: Corresponding author: BWP (bwpearre@bu.edu). TJG and TMO contributed equally to this work.Conflict-of-Interest statement: TJG is an employee of Neuralink Inc.

The inherent constraints on resolution, speed and field of view have hindered the development of high-speed, three-dimensional microscopy techniques over large scales. Here, we present a multiplane line-scan imaging strategy, which uses a series of axially distributed reflecting slits to probe different depths within a sample volume. Our technique enables the simultaneous imaging of an optically sectioned image stack with a single camera at frame rates of hundreds of hertz, without the need for axial scanning. We demonstrate the applicability of our system to monitor fast dynamics in biological samples by performing calcium imaging of neuronal activity in mouse brains and voltage imaging of cardiomyocytes in cardiac samples.

Hyperspectral imaging in scattering tissue generally suffers from low light collection efficiency. In this Letter, we propose a microscope based on Fourier transform spectroscopy and oblique back-illumination microscopy that provides hyperspectral phase and amplitude images of thick, scattering samples with high throughput. Images can be acquired at >0.1  Hz rates with spectral resolution better than 200  cm, over a wide spectral range of 450-1700 nm. Proof-of-principle demonstrations are presented with chorioallantoic membrane of a chick embryo, illustrating the possibility of high-resolution hemodynamics imaging in thick tissue, based on transmission contrast.

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