Free-Form Optics Enhanced Confocal Raman Spectroscopy for Optofluidic Lab-on-Chips

Coster, Diane De; Loterie, Damien; Ottevaere, Heidi; Vervaeke, Michael; Erps, Jürgen Van; Missinne, Jeroen; Thienpont, Hugo

doi:10.1109/jstqe.2014.2381470

Cited by 20 publications

(14 citation statements)

References 13 publications

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“…Our previous reported lab-on-chip consists of three layers [14], as shown in Figure 1a. The 200 μm thick bottom layer contains a freeform reflector with 200 nm gold coating to focus the excitation beam and collect the scattered Raman signal.…”

Section: Design Of the Microfluidic Chip And Freeform Segmented Reflementioning

confidence: 99%

“…However, the analytes can contaminate the fiber facets easily during a measurement, therefore decreasing the reliability and stability of the Raman analysis. To prevent this, a compromise is to miniaturize some of the optical components into micro-optics and integrate them with microfluidic chip [14,15]. These optofluidic chips typically have higher sensitivity in comparison with the fiber-based microfluidic chips due to the higher excitation and collection efficiencies.…”

Section: Introductionmentioning

confidence: 99%

“…These optofluidic chips typically have higher sensitivity in comparison with the fiber-based microfluidic chips due to the higher excitation and collection efficiencies. We have reported a freeform reflector-based lab-on-chip for Raman spectroscopy with a noise-equivalentconcentration (NEC) for urea solution of 20 mM [14]. The lab-on-chip has suppressed the background of PMMA material-out of which the chip is fabricated-by a factor of 7.…”

Section: Introductionmentioning

confidence: 99%

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A Tunable Freeform-Segmented Reflector in a Microfluidic System for Conventional and Surface-Enhanced Raman Spectroscopy

Qīnɡ

Schmidt

Thienpont

et al. 2020

Sensors

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We present a freeform-segmented reflector-based microfluidic system for conventional Raman and Surface-Enhanced Raman Scattering (SERS) analysis. The segmented reflector is directly designed by a numerical approach. The polymer-based Raman system strongly suppresses the undesirable background because it enables confocal detection of Raman scattering through the combination of a freeform reflector and a microfluidic chip. We perform systematic simulations using non-sequential ray tracing with the Henyey-Greenstein model to assess the Raman scattering behavior of the substance under test. We fabricate the freeform reflector and the microfluidic chip by means of ultra-precision diamond turning and laser cutting respectively. We demonstrate the confocal behavior by measuring the Raman spectrum of ethanol. Besides, we calibrate the setup by performing Raman measurements on urea and potassium nitrate solutions with different concentrations. The detection limit of our microfluidic system is approximately 20 mM according to the experiment. Finally, we implement a SERS microfluidic chip and discriminate 100 µM urea and potassium nitrate solutions.

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Section: Design Of the Microfluidic Chip And Freeform Segmented Reflementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Tunable Freeform-Segmented Reflector in a Microfluidic System for Conventional and Surface-Enhanced Raman Spectroscopy

Qīnɡ

Schmidt

Thienpont

et al. 2020

Sensors

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“…In cancer research for example, there is a need for identifying tumor cells and discriminating these from healthy cells. Raman spectroscopy is a non-destructive labelfree method that can be used for the analysis of biological or chemical samples by determining the molecular fingerprint of molecules or cells [1][2]. Since Raman scattering is a weak process, the molecular fingerprint of flowing particles would be hard to measure.…”

Section: Introductionmentioning

confidence: 99%

Dual fiber optical trapping in a polymer-based microfluidic chip

et al. 2016

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We present a microfluidic chip in Polymethyl methacrylate (PMMA) for optical trapping of particles in an 80µm wide microchannel using two counterpropagating single-mode beams. The trapping fibers are separated from the sample fluid by 70µm thick polymer walls. We calculate the optical forces that act on particles flowing in the microchannel using wave optics in combination with non-sequential ray-tracing and further mathematical processing. We use a novel fabrication process that consists of a premilling step and ultraprecision diamond tooling for the manufacturing of the molds and double-sided hot embossing for replication, resulting in a robust microfluidic chip for optical trapping. In a proof-of-concept demonstration, we show the trapping capabilities of the hot embossed chip by trapping spherical beads with a diameter of 6µm, 8µm and 10µm and use the power spectrum analysis of the trapped particle displacements to characterize the trap strength.

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“…Once a design is optimized, the mastering and prototyping of the component can start. Thanks to our Deep Proton Writing [4] and Ultraprecision Diamond Tooling technologies, we can process optical components to feature extreme optical quality finish, high-aspect ratio structures and absolute freeform shapes [5,6]. Next to their obvious use non-imaging applications, we have recently shown that freeform optics also hold great potential for imaging applications [7,8].…”

Section: Introductionmentioning

confidence: 99%