Tag Archives: Stephen Warren-Smith

Tailoring third-harmonic generation

25 January 2019:

CNBP Associate Investigator Dr Stephen C. Warren-Smith is lead author on a new publication that has demonstrated multi-wavelength third-harmonic generation from an exposed-core microstructured optical fibre.

Journal: Optics Letters.

Publication title: Tunable multi-wavelength third-harmonic generation using exposed-core microstructured optical fiber.

Authors: Stephen C. Warren-Smith, Kay Schaarschmidt, Mario Chemnitz, Erik P. Schartner, Henrik Schneidewind, Heike Ebendorff-Heidepriem, and Markus A. Schmidt.

Abstract: We demonstrate that exposed-core microstructured optical fibers offer multiple degrees of freedom for tailoring third-harmonic generation through the core diameter, input polarization, and nanofilm deposition. Varying these parameters allows control of the phase-matching position between an infrared pump wavelength and the generated visible wavelengths. In this Letter, we show how increasing the core diameter over previous experiments (2.57 μm compared to 1.85 μm) allows the generation of multiple wavelengths, which can be further controlled by rotating the input pump polarization and the deposition of dielectric nanofilms. This can lead to highly tailorable light sources for applications such as spectroscopy or nonlinear microscopy.

Soft-glass imaging microstructured optical fiber

10 December 2018:

A proof-of-concept fabrication of a soft-glass imaging microstructured optical fiber has been demonstrated by CNBP scientists in a new research paper published in the journal Optics Express. Lead author of the paper is Dr Stephen C. Warren-Smith, CNBP Associate Investigator at the University of Adelaide who notes that it is envisaged that the glass-based optical fibers will find potential use in applications such as in-vivo white-light and spectroscopic imaging.

Journal: Optics Express.

Publication title: Soft-glass imaging microstructured optical fibers.

Authors: Stephen C. Warren-Smith, Alastair Dowler, and Heike Ebendorff-Heidepriem.

Abstract: We demonstrate the fabrication of multi-core (imaging) microstructured optical fiber via soft-glass preform extrusion through a 3D printed titanium die. The combination of extrusion through 3D printed dies and structured element (capillary) stacking allows for unprecedented control of the optical fiber geometry. We have exploited this to demonstrate a 100 pixel rectangular array imaging microstructured fiber. Due to the high refractive index of the glass used (n = 1.62), such a fiber can theoretically have a pixel pitch as small as 1.8 µm. This opens opportunities for ultra-small, high-resolution imaging fibers fabricated from diverse glass types.

A novel, high sensitivity Sagnac-interferometer biosensor

30 April 2018:

A new publication featuring CNBP co-authors (Dr Stephen Warren-Smith pictured left and Prof Heike Ebendorff-Heidepriem) reports on the design and implementation of a novel, high sensitivity Sagnac-interferometer biosensor based on an exposed core microstructured optical fiber (ECF).

Journal: Sensors and Actuators B: Chemical.

Publication title: High-sensitivity Sagnac-interferometer biosensor based on exposed core microstructured optical fiber.

Authors: Xuegang Li, Linh V. Nguyen, Yong Zhao, Heike Ebendorff-Heidepriem, Stephen C. Warren-Smith.

Abstract: A novel, high sensitivity Sagnac-interferometer biosensor based on exposed core microstructured optical fiber (ECF) has been designed and implemented in this paper. The exposed core fiber has noncircular symmetry and thus exhibits birefringence and can form a sensing element within a Sagnac loop interferometer. The exposed-core fiber design provides direct access to the evanescent field, allowing the measurement of bulk refractive index (RI) with a sensitivity of up to −3137 nm/RIU while maintaining the fiber’s robustness. The sensor can also detect the localized refractive index changes at the fiber core’s surface as the result of a biological binding event. We demonstrate the use of this sensor for label-free sensing of biological molecules by immobilizing biotin onto the fiber core as the probe to capture the target molecule streptavidin.

Third harmonic generation of ECFs

Stephen Warren-Smith28 July 2016:

Researchers from CNBP and The Institute of Photonic Technology (IPHT), have had a paper published today on the topic of third harmonic light generation using ECFs.

Journal: Optics Express.

Publication title: Third harmonic generation in exposed-core microstructured optical fibers.

Authors: Stephen C. Warren-Smith, Jingxuan Wie, Mario Chemnitz, Roman Kostecki, Heike Ebendorff-Heidepriem, Tanya M. Monro and Markus A. Schmidt.

Inter-modal phase-matched third harmonic generation has been demonstrated in an
exposed-core microstructured optical fiber. Our fiber, with a partially open core having a
diameter of just 1.85 µm, shows efficient multi-peak third-harmonic generation between 500nm and 530 nm, with a maximum visible-wavelength output of 0.96 μW. Mode images and simulations show strong agreement, confirming the phase-matching process and polarization dependence. We anticipate this work will lead to tailorable and tunable visible light sources by exploiting the open access to the optical fiber core, such as depositing thin-film coatings in order to shift the phase matching conditions.

The paper is available online.

Dr Stephen Warren-Smith to become CNBP AI

Stephen Warren-Smith27 June 2016:

Dr Stephen Warren-Smith, currently working at the Leibniz Institute of Photonic Technology (IPHT), Jena, Germany will return to the University of Adelaide in October this year, to take-up a four-year 2016 Ramsay Fellowship.

In exciting news for the Centre, and in conjunction with this Fellowship commencement, Stephen will also be granted official CNBP Associate Investigator status.

A University of Adelaide graduate, Stephen will be looking to develop very fine optical fibres with a range of potential industrial and diagnostic imaging applications, including bronchoscopy, where very thin endoscopes are required to reach the periphery of the lung.

We look forward to working closely with Stephen in this exciting area of research!

For further information on this story, please visit the University of Adelaide news site.