skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Integrated photonic slow light Michelson interferometer bio sensor
Diverse chip-based sensors utilizing integrated silicon photonics have been demonstrated in resonator and phase shifter/interferometer configurations. Till date, interferometric techniques with the Mach-Zehnder Interferometer (MZI) and Young’s interferometer have shown the lowest mass detection limits (in pg/mm2). Slow light in photonic crystal waveguides integrated with MZIs enables compact geometries due to enhanced optical path lengths as light propagates with high group index. In a typical MZI, light propagating in the signal arm overlaps with analytes and undergo a relative phase change with respect to the light in the reference arm which leads to measured output intensity changes. In this paper, using integrated photonic methods, we demonstrate a slow light enhanced Michelson interferometer (MI) biosensor, wherein the reference and signal arms are traversed twice by the propagating optical mode. As a result, the analyte interaction length is effectively doubled since the propagating optical mode undergoes twice the phase shift as would be observed in a MZI. In an asymmetric MI configuration, the resultant doubling of the phase shift is observed as a doubling of the resonance wavelength shift for a fixed change in the analyte concentration. The device sensitivity is thus doubled with respect to a conventional MZI while also effectively halving the geometric length compared to the MZI sensor  more » « less
Award ID(s):
2210707
PAR ID:
10421764
Author(s) / Creator(s):
; ;
Editor(s):
García-Blanco, Sonia M.; Cheben, Pavel
Date Published:
Journal Name:
Proceedings of SPIE
Volume:
124241B
Page Range / eLocation ID:
85
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; (, Optics Letters)
    We experimentally demonstrated slow-wave-enhanced phase and spectral sensitivity in asymmetric Michelson interferometer (MI) sensors. Compared to Mach–Zehnder interferometers (MZI) that experimentally demonstrated a phase sensitivity of 84,000 rad/RIU-cm, the reflected path enhancement of the optical path length coupled with slow light enhancement with photonic crystal waveguides in on-chip slow light Michelson interferometer sensors resulted in experimentally demonstrated phase sensitivity of 277,750 rad/RIU-cm with theoretical phase sensitivity as high as 461,810 rad/RIU-cm, at the same form factor as the MZI of identical interferometer arm lengths. 
    more » « less
  2. ; ; (, Proceedings of the SPIE)
    Miller, Benjamin L.; Weiss, Sharon M.; Danielli, Amos (Ed.)
    Evanescent field silicon photonics in a silicon-on-insulator or silicon-nitride-on-insulator platforms have been effectively utilized to demonstrate chemical and biosensors over the past decade with applications in the detection of nucleic acids and protein biomarkers for cancers, viruses and infectious diseases, and environmental toxins. By balancing the requirements for efficient low-loss transmission through the waveguide and enhancing light-matter interaction such as with molecules binding on the high index material surfaces in resonant microcavities, slow light and interferometer geometries, various high sensitivity biosensors have been experimentally demonstrated down to few femtograms/ml. various slotted microcavities and waveguides have been experimentally demonstrated. In recent years, subwavelength waveguides have demonstrated high bulk spectral sensitivities approaching ~500nm/RIU (RIU=refractive index unit) in periodic structures with lattice constant (Λ) <<(λ/2n eff ) where n eff is the effective index at wavelength λ. While most experimental demonstrations have been in subwavelength ring resonator geometries, in this research, in addition to experimental demonstration of bulk spectral sensitivity ~775nm/RIU in subwavelength waveguides in interferometer configurations, we investigate optimized geometries that can reach sensitivities ~70,000nm/RIU in compact dimensions. In contrast to Mach-Zehnder interferometer (MZI) sensors of the same geometric interferometer arm lengths, the reflected path in Michelson interferometers (MI) doubles the optical path length, and thus effectively doubles the phase shift in the presence of an analyte. The interference fringe linewidths are narrowed compared to the equivalent MZI and would thus enable smaller changes in analyte concentration to be discerned from the fringe spectra. 
    more » « less
  3. ; ; (, Proceedings of the SPIE)
    Sanders, Glen A.; Lieberman, Robert A.; Udd Scheel, Ingrid (Ed.)
    Evanescent wave sensors in photonic integrated circuits have been demonstrated for gas sensing applications. While some methods rely on the distinctive response of certain polymers for sensing specific gases, absorption spectroscopy identifies any gas uniquely from their unique vibration signatures. Based on the Beer-Lambert principle, the sensitivity of absorption by a gas on chip relies on the length of the sensing region, the optical overlap integral with the analyte gas and the absorption cross-section at the wavelength with the fundamental vibration signature. The overlap of the optical mode with the analyte has been enhanced in photonic devices by combining slot waveguide confinements with photonic crystal slow light effects. While the absorption cross-section is a property of the gas, the length of the sensing region is limited by the available area on a chip and waveguide propagation losses that limit the minimum signal to noise ratio. In this paper, we show that by incorporating reflecting loop mirrors, the absorption path length can be doubled for the same geometric length of the absorption sensing waveguide. Light from a waveguide is split into two paths, each with a slow light photonic crystal waveguide, by a 2×2 multimode interference (MMI) power splitter. Each path is terminated by a loop mirror that causes the light to retrace its path back down the sensing arms thereby doubling the optical path length over which light interacts with the analyte. Results on the enhancement of phase sensitivity and absorbance sensitivity in the interferometric configuration are presented 
    more » « less
  4. ; ; ; ; (, IEEE Sensors Journal)
    We experimentally demonstrate slow light photonic crystal waveguide (PCW) and subwavelength waveguide (SWWG) loop terminated Mach-Zehnder interferometer (LT-MZI) sensors in a foundry-fabricated silicon-on-insulator (SOI) platform. We compare the experimental results on sensitivity and limit of detection (LOD) on the interferometer sensors with microcavity-type sensors. We show experimentally that 2-D PCW interferometers have higher phase sensitivities than SWWGs of the same length. Based on experimental results, 20- μ m-long 2-D PCW LT-MZI sensors and 200- μ m-long SWWG LT-MZI sensors achieve an LOD of 3.4×10−4 and 2.3×10−4 RIU, respectively, with nearly the same insertion losses in foundry-fabricated devices. We show that by considering the various sources of loss in our benchtop fiber-to-fiber photonic integrated circuit measurement system, it will be possible to reach 10−7 LOD in both slow light PCW and SWWG-based LT-MZI sensors with on-chip integrated light sources and detectors. We show via simulations and experiment that the LOD of a 20- μ m-long slow light PCW LT-MZI is equivalent to that of a 100- μ m-long SWWG LT-MZI, thus enabling more compact LT_MZI sensors when using slow light PCWs versus SWWGs 
    more » « less
  5. ; ; ; ; ; (, Advanced Quantum Technologies)
    Abstract The authors demonstrate a form of two‐photon‐counting interferometry by measuring the coincidence counts between single‐photon‐counting detectors at an output port of a Mach–Zehnder Interferometer (MZI) following injection of broad‐band time‐frequency‐entangled photon pairs (EPP) generated from collinear spontaneous parametric down conversion into a single input port. Spectroscopy and refractometry are performed on a sample inserted in one internal path of the MZI by scanning the other path in length, which acquires phase and amplitude information about the sample's linear response. Phase modulation and lock‐in detection are introduced to increase detection signal‐to‐noise ratio and implement a “down‐sampling” technique for scanning the interferometer delay, which reduces the sampling requirements needed to reproduce fully the temporal interference pattern. The phase‐modulation technique also allows the contributions of various quantum‐state pathways leading to the final detection outcomes to be extracted individually. Feynman diagrams frequently used in the context of molecular spectroscopy are used to describe the interferences resulting from the coherence properties of time‐frequency EPPs passing through the MZI. These results are an important step toward the implementation of a proposed method for molecular spectroscopy—quantum‐light‐enhanced 2D spectroscopy. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email