Speckle illumination holographic non‐scanning fluorescence endoscopy

Abstract

Optical sectioning endoscopy such as confocal endoscopy offers capabilities to obtain three-dimensional (3D) information from various biological samples by discriminating between the desired in-focus signals and out-of-focus background. However, in general confocal images are formed through point-by-point scanning and the scanning time is proportional to the 3D space-bandwidth product. Recently, structured illumination endoscopy has been utilized for optically sectioned wide-field imaging, but it still needs axial scanning to acquire images from different depths of focal plane. Here, we report wide-field, multiplane, optical sectioning endoscopic imaging, incorporating 3D active speckle-based illumination and multiplexed volume holographic gratings, to simultaneously obtain images of fluorescently labeled tissue structures from different depths, without the need of scanning. We present the design, and implementation, as well as experimental data, demonstrating this endoscopic system's ability to obtain optically sectioned multiplane fluorescent images of tissue samples, with cellular level resolution in wide-field fashion, and no need for mechanical or optical axial scanning.(A) Schematic drawing of the SIHN endoscopy to simultaneously acquire multiplane images from different depths. (B) Uniform, and (C) SIHN illuminated images of standard fluorescence beads (25 μm in diameter) for the two axial planes. (D) Intensity profile on fluorescently labeled signal (ie, in-focus) and background (ie, out-of-focus) of microspheres.

Telecentric design for digital‐scanning‐based HiLo optical sectioning endomicroscopy with an electrically tunable lens

“…System performance parameters like spatial resolution and axial scanning range are in good agreement with the estimated values. In combination with other techniques such as multiplexed volume holographic gratings [16] or defocused gratings [22], the imaging speed of the system to acquire multiplane imaging can be further enhanced. We demonstrate imaging performance of our system with optically sectioned images using fluorescently labeled beads, as well as ex vivo mT/mG mice cardiac tissue samples.…”

“…In this work, a rigid endoscopic probe is used to construct the endomicroscope. The probe is designed based on previous work [16]. It consists of an objective lens and relay lenses.…”

“…The field lenses are used to reduce refractive angles to avoid vignetting. The configuration of the probe was designed and modeled using ZEMAX (ZEMAX Development Corporation, Bellevue, Washington) based on our previous design [16]. The simulation results show that the theoretical lateral resolution of the endoscopic probe is roughly 1.32 μm, which indicates the system can image a 780 lp/mm component of the sample with the contrast of 10%.…”

“…In addition, a galvanometric mirror is used to direct the laser beam between uniform‐illumination and sinusoidal illumination light paths [15]. Another method to improve the acquisition speed of HiLo endomicrocopy is the application of multiplexed volume holography to obtain simultaneous multiplane images [16]. Fast scanning in the axial direction is, however, still required for high‐speed volumetric imaging.…”

Holography applications toward medical field: An overview

“…It employs reliable and efficient management of all records, and with better devices and improved storage facility, it is easy to analyse the progress. [ 17 18 ] Holograms are available for various medical test and devices and are used to monitor diabetes, infections and check the proper functioning of soft and hard tissues. This technology is available to check drug, hormones, alcohol and glucose.…”