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Xu X, Thomson DJ, Yan J. Optimisation and scaling effect of dual-waveguide optical trapping in the SOI platform. OPTICS EXPRESS 2020; 28:33285-33297. [PMID: 33114996 DOI: 10.1364/oe.403151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Optical trapping has potential applications in biological manipulation, particle trapping, Raman spectroscopy, and quantum optomechanics. Among the various optical trapping schemes, on-chip dual-waveguide traps combine benefits of stable trapping and mass production. However, no systematic research has been conducted to optimise on-chip dual-waveguide traps so that the trapping capability is maximised. Here, a numerical simulation of an on-chip silicon on insulator (SOI) dual-waveguide optical trap based on Lumerical FDTD Solutions is carried out to optimise the on-chip dual-waveguide trap. It was found that the waveguide thickness is a crucial parameter when designing a dual-waveguide trap, and its optical trapping capability largely depends on the distance between the two waveguides. We show that the optimal waveguide thickness to achieve the maximum trapping capability generally increases with the gap distance, accompanied by a periodic feature due to the interference and the resonant effects within the gap. This optimal waveguide thickness and gap distance are analysed to have clear scaling effects over the input optical wavelength, which paves the way for the design and optimisation of dual-waveguide traps for various applications.
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Ahmad A, Dubey V, Singh VR, Tinguely JC, Øie CI, Wolfson DL, Mehta DS, So PTC, Ahluwalia BS. Quantitative phase microscopy of red blood cells during planar trapping and propulsion. LAB ON A CHIP 2018; 18:3025-3036. [PMID: 30132501 PMCID: PMC6161620 DOI: 10.1039/c8lc00356d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/02/2018] [Indexed: 05/12/2023]
Abstract
Red blood cells (RBCs) have the ability to undergo morphological deformations during microcirculation, such as changes in surface area, volume and sphericity. Optical waveguide trapping is suitable for trapping, propelling and deforming large cell populations along the length of the waveguide. Bright field microscopy employed with waveguide trapping does not provide quantitative information about structural changes. Here, we have combined quantitative phase microscopy and waveguide trapping techniques to study changes in RBC morphology during planar trapping and transportation. By using interference microscopy, time-lapsed interferometric images of trapped RBCs were recorded in real-time and subsequently utilized to reconstruct optical phase maps. Quantification of the phase differences before and after trapping enabled study of the mechanical effects during planar trapping. During planar trapping, a decrease in the maximum phase values, an increase in the surface area and a decrease in the volume and sphericity of RBCs were observed. QPM was used to analyze the phase values for two specific regions within RBCs: the annular rim and the central donut. The phase value of the annular rim decreases whereas it increases for the central donut during planar trapping. These changes correspond to a redistribution of cytosol inside the RBC during planar trapping and transportation.
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Affiliation(s)
- Azeem Ahmad
- Department of Physics and Technology
, UiT The Arctic University of Norway
,
Tromsø N-9037
, Norway
.
;
- Department of Physics
, Indian Institute of Technology Delhi
,
New Delhi 110016
, India
| | - Vishesh Dubey
- Department of Physics and Technology
, UiT The Arctic University of Norway
,
Tromsø N-9037
, Norway
.
;
- Department of Physics
, Indian Institute of Technology Delhi
,
New Delhi 110016
, India
| | - Vijay Raj Singh
- Department of Mechanical & Biological Engineering
, Massachusetts Institute of Technology
,
Cambridge
, MA
02139
, USA
- BioSym IRG
, Singapore-Alliance for Science & Technology Center
,
Singapore
, Singapore
| | - Jean-Claude Tinguely
- Department of Physics and Technology
, UiT The Arctic University of Norway
,
Tromsø N-9037
, Norway
.
;
| | - Cristina Ionica Øie
- Department of Physics and Technology
, UiT The Arctic University of Norway
,
Tromsø N-9037
, Norway
.
;
| | - Deanna L. Wolfson
- Department of Physics and Technology
, UiT The Arctic University of Norway
,
Tromsø N-9037
, Norway
.
;
| | - Dalip Singh Mehta
- Department of Physics
, Indian Institute of Technology Delhi
,
New Delhi 110016
, India
| | - Peter T. C. So
- Department of Mechanical & Biological Engineering
, Massachusetts Institute of Technology
,
Cambridge
, MA
02139
, USA
- BioSym IRG
, Singapore-Alliance for Science & Technology Center
,
Singapore
, Singapore
| | - Balpreet Singh Ahluwalia
- Department of Physics and Technology
, UiT The Arctic University of Norway
,
Tromsø N-9037
, Norway
.
;
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