Lensless multispectral digital in-line holographic microscope

Abstract

An compact multispectral digital in-line holographic microscope (DIHM) is developed that emulates Gabor's original holographic principle. Using sources of varying spatial coherence (laser, LED), holographic images of objects, including optical fiber, latex microspheres, and cancer cells, are successfully captured and numerically processed. Quantitative measurement of cell locations and percentage confluence are estimated, and pseudocolor images are also presented. Phase profiles of weakly scattering cells are obtained from the DIHM and are compared to those produced by a commercially available off-axis digital holographic microscope.

GPU accelerated holographic microscopy for the inspection of quickly moving fluids for applications in pharmaceutical manufacturing

“…Experimental setup and the processing hardware of the fluid inspection process are shown in Figure 1. 10 . Laser source is focused on the pinhole (PH) using a microscope objective and the diffracted light passing through the flow pipe distance z 0 away from the pinhole is recorded at the camera sensor which is at the distance L away from the pinhole.…”

Quantitative phase imaging by wide field lensless digital holographic microscope

“…However, this lens-based magnification suffers from aberrations, which have to be corrected. Lensless digital holography is a well-established microscopic method providing diffraction limited resolution in the order of the wavelength of the used light source [4][5][6][7][8]. The Gabor inline configuration does not allow the separation of the different parts of the hologram after the reconstruction, so that DC part, real and twin images overlap.…”

Diffractive digital lensless holographic microscopy with fine spectral tuning

“…In DLHM multispectral illumination has been achieved not only with coherent sources like a tunable He-Ne laser [11] or a set of lasers that emit at different wavelength lines [12], but also with incoherent light-emitting diodes [8]. However, the above implementations allow only a discrete set of wavelength lines with full width at half-maximum (FWHM), typically on the order of some tens of nanometers.…”

“…Then, the recorded intensity is numerically processed, and the object wavefront is reconstructed. By using digital in-line lensless holographic microscopy technique, several applications have been demonstrated, which include but are not limited to showing in situ organisms and their motion in plankton with micrometer resolution [4], investigating microbial life forms in the Canadian High Arctic [5], tracking micrometer sized particles with high NA [6], analyzing transparent phase objects under femtosecond illumination [7], and successfully imaging latex microspheres, optical fiber, and cancer cells with light sources of varying spatial coherence [8].…”

“…In this context, multispectral imaging has become a tool of increasing use, i.e., as a way to discriminate among several components (e.g., proteins or genes) or functions within the cell [9], or to enlarge the range of application of phase-based digital holographic techniques [10]. In DLHM multispectral illumination has been achieved not only with coherent sources like a tunable He-Ne laser [11] or a set of lasers that emit at different wavelength lines [12], but also with incoherent light-emitting diodes [8]. However, the above implementations allow only a discrete set of wavelength lines with full width at half-maximum (FWHM), typically on the order of some tens of nanometers.…”