Deflected Talbot-Mediated Overtone Spectroscopy in Near-Infrared as a Label-Free Sensor on a Chip

Aviad Katiyi, Alina Karabchevsky

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Rapid, sensitive, and reliable detection of aromatic amines, toxic manufacturing byproducts, has been previously achieved with molecular vibrations in the mid-infrared (Mid-IR) region. However, Mid-IR spectroscopic tools are hampered by a need to prepare the samples and the sensor cost. Here, we develop an affordable label-free sensor on a chip, operating in near-infrared (NIR) for ultrasensitive detection of absorption line signatures based on molecular vibrations overtones of the aromatic amine N-methylaniline probe molecule. We design a perforated silicon rib waveguide and fabricate it by milling cylindrical inclusions through the waveguide core. The molecular signatures were monitored when waveguides are embedded in toxic N-methylaniline, experiencing a deflected Talbot effect. We observed that when the Talbot effect is deflected, the absorption lines in NIR are enhanced despite the weakly absorbing nature of the probe molecules. This new spectroscopic strategy can potentially be extended to detect other common toxic byproducts in a chip-scale label-free manner and to enhance the functionality of chemical monitoring.

Original languageEnglish
Pages (from-to)1683-1688
Number of pages6
JournalACS Sensors
Volume5
Issue number6
DOIs
StatePublished - 26 Jun 2020

Keywords

  • integrated photonics
  • molecular overtones
  • multimode interference
  • near-infrared spectroscopy
  • optical waveguide

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