A targeted illumination optical fiber probe for high resolution fluorescence imaging and optical switching

Abstract

An optical imaging probe with targeted multispectral and spatiotemporal illumination features has applications in many diagnostic biomedical studies. However, these systems are mostly adapted in conventional microscopes, limiting their use for in vitro applications. We present a variable resolution imaging probe using a digital micromirror device (DMD) with an achievable maximum lateral resolution of 2.7 μm and an axial resolution of 5.5 μm, along with precise shape selective targeted illumination ability. We have demonstrated switching of different wavelengths to image multiple regions in the field of view. Moreover, the targeted illumination feature allows enhanced image contrast by time averaged imaging of selected regions with different optical exposure. The region specific multidirectional scanning feature of this probe has facilitated high speed targeted confocal imaging.

Video-rate Volumetric Neuronal Imaging Using 3D Targeted Illumination

“…We note finally that, DMD-based illumination has been widely adopted in optogenetic applications to deliver light to targeted neurons [39][40][41] . These applications have been limited mostly to 2D planes.…”

“…Sparse illumination in SIM leads to improved structure visibility in dense samples, and hence improved contrast, SNR, and utilization of the camera dynamic range for the identification of in-focus sample features. Compared also to methods that make use of spatially controlled illumination [37][38][39] , our technique offers similar advantages of reduced light dosage, presumably leading to reduced photobleaching and phototoxicity. In the case where photobleaching or phototocicity scale with illumination, we expect this reduction to be proportional to the fill factor of our TI patterns.…”

Video-rate volumetric neuronal imaging using 3D targeted illumination

“…Sparse illumination in SIM leads to improved structure visibility in dense samples, and hence improved contrast, SNR, and utilization of the camera dynamic range for the identification of in-focus sample features. Compared also to methods that make use of spatially controlled illumination 37 – 39 , our technique offers similar advantages of reduced light dosage, presumably leading to reduced photobleaching and phototoxicity. In the case where photobleaching or phototocicity scale with illumination, we expect this reduction to be proportional to the fill factor of our TI patterns.…”

Fabrication and characterization of large numerical aperture, high-resolution optical fiber bundles based on high-contrast pairs of soft glasses for fluorescence imaging

“…Hence, FBs offer fully flexible imaging probes. FBs can be used for imaging without the requirement of a scanning mechanism at the distal end of the fiber [24,25], and they can be incorporated in more sophisticated imaging systems that use confocal [24,26,27] or structured light illumination approaches [28][29][30]. Several recent microscopic imaging demonstrations using FBs include: deep-brain imaging of a living animal [31], in vivo subcellular resolution imaging of cancerous tissues such as oral, cervical and ovarian [32][33][34][35], ex-vivo human stomach, animal colon, liver and belly tissue imaging [36], and thermal infrared imaging [37][38][39][40].…”