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1.
Opt Express ; 32(8): 13628-13639, 2024 Apr 08.
Article in English | MEDLINE | ID: mdl-38859328

ABSTRACT

A mid-infrared (mid-IR) porous silicon (PSi) waveguide gas sensor was fabricated. PSi guiding and confinement layers were prepared by electrochemical anodization. Ridge waveguides were patterned using standard i-line photolithography and reactive ion etching. Due to the open pores, light and gas molecules interact in the inside volume, unlike bulk material in which the interaction takes place with the evanescent part of the light. Propagation losses are measured for a wavelength range spanning from λ = 3.9 to 4.55 µm with a value of 11.4 dB/cm at λ = 4.28 µm. The influence of native oxidation and ageing on the propagation losses was investigated. Limit of detection (LoD) of 1000 ppm is obtained with the waveguide sensor at the carbon dioxide (CO2) absorption peak at λ = 4.28 µm.

2.
ACS Appl Mater Interfaces ; 16(4): 5225-5233, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38258799

ABSTRACT

In this paper, we report on the infrared luminescence of amorphous praseodymium-doped Ge20In5Sb10Se65 waveguides, which can be used as infrared sources in photonic integrated circuits on silicon substrates. Amorphous chalcogenide thin films were deposited by radiofrequency magnetron cosputtering using an argon plasma whose deposition parameters were optimized for chalcogenide materials. The micropatterning as ridge waveguides of the chalcogenide cosputtered films was performed using photolithography and plasma-coupled reactive ion etching techniques. The influence of the rare earth concentration within those thin films on their optical properties and rare earth spectroscopic properties was investigated. Using an excitation wavelength of 1.55 µm, the mid-infrared luminescence of Pr3+ ions from 2.5 to 5.5 µm was clearly demonstrated for studied chalcogenide materials. A wide range of waveguide widths and doping ratios were tested, assessing the ability of the cosputtering technique to preserve the luminescence properties of the rare earth ions initially observed in the bulk glass through the thin-film deposition and patterning process.

3.
Opt Lett ; 48(5): 1128-1131, 2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36857230

ABSTRACT

Climate-active gases, notably carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), display fundamental absorption bands in the mid-infrared (mid-IR). The detection and monitoring of those gases could be enabled by the development of mid-IR optical sources. Broadband mid-IR on-chip light emission from rare-earth-doped chalcogenide photonic integrated circuits could provide a compact, efficient, and cost-effective gas sensing solution. Mid-IR photoluminescence of dysprosium-doped selenide ridge waveguides obtained under optical pumping at a telecommunication wavelength (∼1.3 µm) is investigated for Dy3+ ion concentrations in the 2500-10,000 ppmw range. CO2 detection at around 4.3 µm is then demonstrated based on absorption of this broadband mid-IR emission.

4.
Sensors (Basel) ; 22(3)2022 Jan 22.
Article in English | MEDLINE | ID: mdl-35161590

ABSTRACT

Porous germanium is a promising material for sensing applications in the mid-infrared wavelength range due to its biocompatibility, large internal surface area, open pores network and widely tunable refractive index, as well as its large spectral transparency window ranging from 2 to 15 µm. Multilayers, such as Bragg reflectors and microcavities, based on porous germanium material, are designed and their optical spectra are simulated to enable SF6 gas-sensing applications at a wavelength of 10.55 µm, which corresponds to its major absorption line. The impact of both the number of successive layers and their respective porosity on the multilayer structures reflectance spectrum is investigated while favoring low layer thicknesses and thus the ease of multilayers manufacturing. The suitability of these microcavities for mid-infrared SF6 gas sensing is then numerically assessed. Using an asymmetrical microcavity porous structure, a sensitivity of 0.01%/ppm and a limit of detection (LOD) around 1 ppb for the SF6 gas detection are calculated. Thanks to both the porous nature allowing gases to easily infiltrate the overall structure and Ge mid-infrared optical properties, a theoretical detection limit nearly 1000 times lower than the current state of the art is simulated.

5.
ACS Omega ; 7(51): 47840-47850, 2022 Dec 27.
Article in English | MEDLINE | ID: mdl-36591173

ABSTRACT

Priority substances likely to pollute water can be characterized by mid-infrared spectroscopy based on their specific absorption spectral signature. In this work, the detection of volatile aromatic molecules in the aqueous phase by evanescent-wave spectroscopy has been optimized to improve the detection efficiency of future in situ optical sensors based on chalcogenide waveguides. To this end, a hydrophobic polymer was deposited on the surface of a zinc selenide prism using drop and spin-coating methods. To ensure that the water absorption bands will be properly attenuated for the selenide waveguides, two polymers were selected and compared: polyisobutylene and ethylene/propylene copolymer coating. The system was tested with benzene, toluene, and ortho-, meta-, and para-xylenes at concentrations ranging from 10 ppb to 40 ppm, and the measured detection limit was determined to be equal to 250 ppb under these analytical conditions using ATR-FTIR. The polyisobutylene membrane is promising for pollutant detection in real waters due to the reproducibility of its deposition on selenide materials, the ease of regeneration, the short response time, and the low ppb detection limit, which could be achieved with the infrared photonic microsensor based on chalcogenide materials. To improve the sensitivity of future infrared microsensors, the use of metallic nanostructures on the surface of chalcogenide waveguides appears to be a relevant way, thanks to the plasmon resonance phenomena. Thus, in addition to preliminary surface-enhanced infrared absorption tests using these materials and a functionalization via a self-assembled monolayer of 4-nitrothiophenol, heterostructures combining gold nanoparticles/chalcogenide waveguides have been successfully fabricated with the aim of proposing a SEIRA microsensor device.

6.
Sensors (Basel) ; 21(7)2021 Apr 02.
Article in English | MEDLINE | ID: mdl-33918118

ABSTRACT

The objective of this study is to demonstrate the successful functionalization of the surface of a chalcogenide infrared waveguide with the ultimate goal of developing an infrared micro-sensor device. First, a polyisobutylene coating was selected by testing its physico-chemical compatibility with a Ge-Sb-Se selenide surface. To simulate the chalcogenide platform infrared sensor, the detection of benzene, toluene, and ortho-, meta- and para-xylenes was efficaciously performed using a polyisobutylene layer spin-coated on 1 and 2.5 µm co-sputtered selenide films of Ge28Sb12Se60 composition deposited on a zinc selenide prism used for attenuated total reflection spectroscopy. The thickness of the polymer coating was optimized by attenuated total reflection spectroscopy to achieve the highest possible attenuation of water absorption while maintaining the diffusion rate of the pollutant through the polymer film compatible with the targeted in situ analysis. Then, natural water, i.e., groundwater, wastewater, and seawater, was sampled for detection measurement by means of attenuated total reflection spectroscopy. This study is a valuable contribution concerning the functionalization by a hydrophobic polymer compatible with a chalcogenide optical sensor designed to operate in the mid-infrared spectral range to detect in situ organic molecules in natural water.

7.
Opt Express ; 28(15): 22511-22523, 2020 Jul 20.
Article in English | MEDLINE | ID: mdl-32752511

ABSTRACT

This work reports on the properties of luminescent waveguides based on quaternary Ga-Ge-Sb-Se amorphous thin films doped with praseodymium. The waveguides were fabricated via magnetron co-sputtering, followed by inductively coupled plasma reactive ion etching. The initial thin film thickness and optical properties were assessed and the spectroscopic properties of the waveguides were measured. The measurements show promising results-it is possible to obtain mid-infrared fluorescence at 2.5 and 4.5 µm by injecting near-infrared light at 1.5 µm as the pump beam. By comparing waveguides with various praseodymium concentrations, the optimal doping content for maximum fluorescence intensity was identified to be close to 4100 ppmw. Finally, correlation between the intensity of mid-infrared emission and the width/length of the waveguide is shown.

8.
Opt Express ; 25(24): 30799-30806, 2017 Nov 27.
Article in English | MEDLINE | ID: mdl-29221106

ABSTRACT

We demonstrate the fabrication of a Vernier effect SU8/PMATRIFE polymer optical biosensor with high homogeneous sensitivity using a standard photolithography process. The sensor is based on one micro-resonator embedded on each arm of a Mach-Zehnder interferometer. Measurements are based on the refractive index variation of the optical waveguide superstrate with different concentrations of glucose solutions. The sensitivity of the sensor has been measured as 17558 nm/RIU and the limit of detection has been estimated to 1.1.10-6 RIU.

9.
Opt Express ; 25(6): 7014-7030, 2017 Mar 20.
Article in English | MEDLINE | ID: mdl-28381043

ABSTRACT

A compact amplifier based on chalcogenide Pr3+-doped micro-disk coupled to two ridge waveguides is designed and refined by means of a home-made computer code. The gain G ≈ 7.9 dB is simulated for a Pr3+ concentration of 10 000 ppm, input signal power of -30 dBm at the wavelength 4.7 µm and input pump power of 50 mW at the wavelength 1.55 µm. In the laser behavior, i.e. without input signal, the maximum slope efficiency S = 8.1 × 10-4 is obtained for an input pump power of 2 mW. This value is about six times higher than that simulated for an optimized erbium-doped micro-disk.

10.
Opt Express ; 24(20): 23109-23117, 2016 Oct 03.
Article in English | MEDLINE | ID: mdl-27828376

ABSTRACT

A selenide integrated platform working in the mid-infrared was designed, fabricated and optically characterized at 7.7 µm. Ge-Sb-Se multilayered structures were deposited by RF magnetron sputtering. Using i-line photolithography and fluorine-based reactive ion etching, ridge waveguides were processed as Y-junction, spiral and S-shape waveguides. Single-mode optical propagation at 7.7 µm was observed by optical near-field imaging and optical propagation losses of 2.5dB/cm are measured. Limits of detection of 14.2 ppm and 1.6 ppm for methane and nitrous oxide, respectively, could be potentially measured by using this platform as an evanescent field sensor. Hence, these technological, experimental and theoretical results represent a first step towards the development of an integrated optical sensor operating in the mid-infrared wavelength range.

11.
Adv Mater ; 27(40): 6181-6, 2015 Oct 28.
Article in English | MEDLINE | ID: mdl-26350035

ABSTRACT

Thin films and ridge waveguides based on large-diameter semiconducting single-wall carbon nanotubes (s-SWCNTs) dispersed in a polyfluorene derivative are fabricated and optically characterized. Ridge waveguides are designed with appropriate dimensions for single-mode propagation at 1550 nm. Using multimode ridge waveguides, guided s-SWCNT photoluminescence is demonstrated for the first time in the near-infrared telecommunications window.

12.
Sensors (Basel) ; 9(9): 7398-411, 2009.
Article in English | MEDLINE | ID: mdl-22423209

ABSTRACT

Due to the remarkable properties of chalcogenide (Chg) glasses, Chg optical waveguides should play a significant role in the development of optical biosensors. This paper describes the fabrication and properties of chalcogenide fibres and planar waveguides. Using optical fibre transparent in the mid-infrared spectral range we have developed a biosensor that can collect information on whole metabolism alterations, rapidly and in situ. Thanks to this sensor it is possible to collect infrared spectra by remote spectroscopy, by simple contact with the sample. In this way, we tried to determine spectral modifications due, on the one hand, to cerebral metabolism alterations caused by a transient focal ischemia in the rat brain and, in the other hand, starvation in the mouse liver. We also applied a microdialysis method, a well known technique for in vivo brain metabolism studies, as reference. In the field of integrated microsensors, reactive ion etching was used to pattern rib waveguides between 2 and 300 µm wide. This technique was used to fabricate Y optical junctions for optical interconnections on chalcogenide amorphous films, which can potentially increase the sensitivity and stability of an optical micro-sensor. The first tests were also carried out to functionalise the Chg planar waveguides with the aim of using them as (bio)sensors.

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