TY - JOUR

T1 - Deflected Talbot-Mediated Overtone Spectroscopy in Near-Infrared as a Label-Free Sensor on a Chip

AU - Katiyi, Aviad

AU - Karabchevsky, Alina

PY - 2020/6/26

Y1 - 2020/6/26

N2 - 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.

AB - 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.

KW - integrated photonics

KW - molecular overtones

KW - multimode interference

KW - near-infrared spectroscopy

KW - optical waveguide

U2 - 10.1021/acssensors.0c00325

DO - 10.1021/acssensors.0c00325

M3 - Journal article

VL - 5

SP - 1683

EP - 1688

JO - ACS Sensors

JF - ACS Sensors

SN - 2379-3694

IS - 6

ER -