Presentation
27 April 2016 High-speed line-scanning confocal holographic microscopy for quantitative phase imaging (Conference Presentation)
Author Affiliations +
Proceedings Volume 9718, Quantitative Phase Imaging II; 971820 (2016) https://doi.org/10.1117/12.2212033
Event: SPIE BiOS, 2016, San Francisco, California, United States
Abstract
We present a high speed, phase-sensitive, line-scanning reflectance confocal interference microscope. We achieved rapid confocal imaging using a fast line-scan camera and quantitative phase imaging using off-axis digital holography on a 1D, line-by-line basis. In our prototype system, a He-Ne laser (~1.2 mW) was used to demonstrate the principle of operation. Using a 20 kHz line scan rate (1024 pixels per line scan), we achieved a video-rate frame rate of 20 Hz for 1024x500 pixel en-face confocal images (20 MHz total pixel rate). By using an objective lens of a NA 0.65, we achieved an axial and lateral resolution of ~3.5 micrometers and ~0.8 micrometers, respectively. By z-stack imaging of a custom silicon target with a stepped structure, we confirmed that the axial sectioning of the interference microscope is similar to that of a traditional line-scan confocal microscope (our microscope with the reference arm blocked). The utility of phase-sensitive holographic detection in line-scan confocal was demonstrated in two ways. First, using a custom axial height phantom fabricated using chrome deposition, we demonstrated variations in phase corresponding to heights in the 100 nm range with a contrast-to-noise ratio of ~31 dB. Second, we demonstrate digital refocusing of an out-of-focus holographic image. The mechanism of confocality in our line-scan system is 1D physical pinholing. Our ongoing work aims to add an additional mechanism of confocality by using low spatial coherence sources to impose interferometric pinholing.
Conference Presentation
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Changgeng Liu, Sebastian Knitter, Zhilong Cong, Ikbal Sencan, Hui Cao, and Michael A. Choma "High-speed line-scanning confocal holographic microscopy for quantitative phase imaging (Conference Presentation)", Proc. SPIE 9718, Quantitative Phase Imaging II, 971820 (27 April 2016); https://doi.org/10.1117/12.2212033
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KEYWORDS
Confocal microscopy

Holography

Line scan image sensors

Microscopes

Phase imaging

Digital holography

Microscopy

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