On-Chip Holographic Microscopy and its Application for Automated Semen Analysis - Biomedical Optical Phase Microscopy and Nanoscopy - page 148

CHAPTER 8
On-Chip Holographic Microscopy
and its Application for Automated
Semen Analysis

Ting-Wei Su 1 , 2 , Aydogan Ozcan 1 , 2 , 3 , 4

1

Electrical Engineering Department, University of California, Los Angeles, CA 2 ADR, Los Angeles, CA
3

Bioengineering Department, University of California, Los Angeles, CA 4 California NanoSystems
Institute, University of California, Los Angeles, CA

Editor: Natan T. Shaked

8.1 Introduction

Lens-based light microscopy provides an indispensable toolset for medicine and biology to
investigate biomedical samples at the microscale. As new microscopy techniques are being
developed to give this centuries-old imaging technology better resolution, speed, sensitivity,
contrast, throughput, and specificity [1 6] , these imaging systems are also becoming more

complicated, bulky, and expensive, which partially limit their use outside of well-equipped
facilities. Furthermore, the relatively small field of view (FOV) of these lens-based imaging
platforms also provides a challenge for various applications such as imaging cytometry, rare
cell analysis, or model organism phenotyping [7 9] , where a wide FOV would be highly

desired to generate reliable statistics and improve throughput of analysis.

To mitigate these existing challenges, a compact, cost-effective, and yet wide-field lensless
imaging platform that utilizes partially coherent light sources has recently been introduced
for conducting microanalysis on a chip [10] . At the core of this technology is a lensless
holographic on-chip microscope ( Figure 8.1 ) that measures B 4.2 cm 3 4.2 cm 3 5.8 cm and
weighs B 46 g while still providing an imaging FOV of B 24 mm 2 with an effective
numerical aperture (NA) of B 0.1 0.2 [11] . Compared to the FOV of a typical 10 3
objective lens, this imaging FOV is more than 20-fold larger and therefore provides a
significant throughput improvement allowing automated monitoring of thousands of cells all
in parallel. This lensless on-chip microscope is based on digital in-line holography, and it