Digital holographic reflectometry

Colomb, Tristan; Krivec, Stefan; Hutter, Herbert; Akatay, Ahmet Ata; Pavillon, Nicolas; Montfort, Frédéric; Cuche, Etienne; Kühn, Jonas; Depeursinge, Christian; Emery, Yves

doi:10.1364/oe.18.003719

Cited by 37 publications

(28 citation statements)

References 13 publications

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“…It explains why wavelength scanning is performed preferentially in the reflection mode, either for 3-D tomography [57] or reflectometry [58][59][60]. In some cases, only a few wavelengths may be used in order to decouple index fluctuations from thickness variations [61,62].…”

Section: Tomography With Illumination Wavelength Variationmentioning

confidence: 99%

Tomographic diffractive microscopy: basics, techniques and perspectives

Haeberlé

Belkebir

Giovaninni

et al. 2010

Journal of Modern Optics

160

143

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Section: Tomography With Illumination Wavelength Variationmentioning

confidence: 99%

Tomographic diffractive microscopy: basics, techniques and perspectives

Haeberlé

Belkebir

Giovaninni

et al. 2010

Journal of Modern Optics

160

143

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“…The thickness of the chromium was measured by DHM at various locations on the sample to be about 80 nm to 100 nm; this was performed by examining sections of the surface that had been masked and did not have chromium. At this thickness, it is possible that the chromium layer is semitransparent, which would affect the results, because the reflected wavefront can be generated from both the top and the bottom of the chromium layer [39,40]. Under the assumption that the chromium is transparent, the reflection, R, from the top of the chromium surface would be a function of the Fresnel reflection coefficients from the top (air-chromium interface) and bottom (chromium-glass interface) surfaces, r01 and r12, respectively, and the phase change, β, R = 01 + 12 exp(− 2 ) 1 + 01 12 exp(− 2 ) ,…”

Section: Uncertainty In Dhm Phase Measurementsmentioning

confidence: 99%

Phase Uncertainty in Digital Holographic Microscopy Measurements in the Presence of Solution Flow Conditions

Brand¹

2017

J. RES. NATL. INST. STAN.

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Digital holographic microscopy (DHM) is a surface topography measurement technique with reported sub-nanometer vertical resolution. Although it has been made commercially available recently, few studies have evaluated the uncertainty or noise in the phase measurement by the DHM. As current research is using the DHM to monitor surface topography changes of dissolving materials under flowing water conditions, it is necessary to evaluate the effect of water and flow rate on the uncertainty in the measurement. Uncertainty in this study was concerned with the temporal standard deviation per pixel of the reconstructed phase. Considering the effects of solution flow rate, magnification, objective lens type (air or immersion), and experimental configuration, measurements under static conditions in air and in water with an immersion lens yielded the smallest amount of uncertainty (mean of ≤ 0.5 nm up to 40× magnification). Increasing the water flow rate resulted in an increase in mean uncertainty to ≤ 0.6 nm up to 40× with an immersion lens. Observations of a sample through a glass window at 20× magnification in flowing water also yielded increasing uncertainty, with mean values of ≤ 0.5 nm, ≤ 0.8 nm, and ≤ 1.1 nm for flow rates of 0 mL min ) did not significantly impact the uncertainty in the phase. Collecting holograms in single-wavelength versus dual-wavelength modes did impact the uncertainty, with the mean uncertainty at 10× magnification for the same wavelength being ≤ 0.5 nm from the single-wavelength mode compared to ≤ 1.5 nm from the dualwavelength mode. When the quantified uncertainty was applied to simulated dissolution data, lower limits of measured dissolution rates were found below which the measured data may not be distinguishable from the uncertainty in the measurement. The limiting surface-normal dissolution velocity is −10 −11.7 m s ) flowing water conditions in experiments with a glass window, respectively. The data presented by this study will allow for better experimental design and methodology for future dissolution or precipitation studies using DHM and will provide confidence in the data produced in postprocessing.

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“…In the realm of technological improvements a simple, cost-effective and compact optical unit based on a common-path phase shifting interferometry for QPI has been reported [36,37]. Recently, real-time imaging and topography of RBCs from an entire complex optical wavefront (amplitude and phase) has been reported both in reflection and transmission mode using digital holographic reflectometry (DHR) [38]. But in DHR, RBCs are made stationary by adhering them directly to a glass surface that can invoke perturbations from two facets -physical contact and their own weight which might alter their innate morphology.…”

Section: Introductionmentioning

confidence: 99%

“…First to establish the usability of a laser beam of 'arbitrary intensity profile' in photodamage-free trapping of delicate RBCs so that contact activated perturbations, as arising in DHR [38] during phasemicroscopy, can be addressed. Secondly, phase imaging of thus trapped RBC by interferograms generated from a lab-made MMI.…”

Section: Introductionmentioning

confidence: 99%

Role of Arbitrary Intensity Profile Laser Beam in Trapping of RBC for Phase-imaging

Kumar

Srivastava

Mehta

et al. 2016

Journal of the Optical Society of Korea

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Red blood cells (RBCs) are customarily adhered to a bio-functionalised substrate to make them stationary in interferometric phase-imaging modalities. This can make them susceptible to receive alterations in innate morphology due to their own weight. Optical tweezers (OTs) often driven by Gaussian profile of a laser beam is an alternative modality to overcome contact-induced perturbation but at the same time a steeply focused laser beam might cause photo-damage. In order to address both the photo-damage and substrate adherence induced perturbations, we were motivated to stabilize the RBC in OTs by utilizing a laser beam of 'arbitrary intensity profile' generated by a source having cavity imperfections per se. Thus the immobilized RBC was investigated for phase-imaging with sinusoidal interferograms generated by a compact and robust Michelson interferometer which was designed from a cubic beam splitter having one surface coated with reflective material and another adjacent coplanar surface aligned against a mirror. Reflected interferograms from bilayers membrane of a trapped RBC were recorded and analyzed. Our phase-imaging set-up is limited to work in reflection configuration only because of the availability of an upright microscope. Due to RBC's membrane being poorly reflective for visible wavelengths, quantitative information in the signal is weak and therefore, the quality of experimental results is limited in comparison to results obtained in transmission mode by various holographic techniques reported elsewhere.

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Digital holographic reflectometry

Cited by 37 publications

References 13 publications

Tomographic diffractive microscopy: basics, techniques and perspectives

Tomographic diffractive microscopy: basics, techniques and perspectives

Phase Uncertainty in Digital Holographic Microscopy Measurements in the Presence of Solution Flow Conditions

Role of Arbitrary Intensity Profile Laser Beam in Trapping of RBC for Phase-imaging

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