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Resonant Photonic Biosensing
High-Q optical microresonators are excellent candidates
for photonic sensing. These devices have been successfully used for detecting
nanoparticles, biomolecules, gases, chemical compounds down to single nanoparticles
and single molecules resolution. Three main mechanisms are used to detected particles
and molecules that come into contact with microresonator: 1) Resonant frequency
shift , 2) Quality factor degradation and 3) Resonant frequency splitting.-A novel platform for high sensitivity photonic biosensing
In our group we work on different aspects of resonant
photonic biosensing using Whispering-Gallery and microring optical resonators.
We study the theory of resonant photonic detection as well as fabrication of
novel microresonator based sensors with new functionalities.
colleagues Professor Ivory (Washington University) and Professor Han
(UNM), Dr Hossein-Zadeh has developed a new integrated optofluidic
platfrom based on active nanochannels with resonant photonic
sensors. This patent pending technology combines nanofluidic
and resonant photonic detection on a silicon platform compatible with
CMOS technology. In 2012 this technology has been lisceneced to Protomex
to develop a hand held biosesor unit for separating and detection of
protein biomarkers in blood for the presence of heart, cancer and
-Application of Dynamic Linenarrowing in Resonant Photonic Sensing
have proposed and demonstrated the dynamic operational mode and the resulting
as a method for enhancing the resolution and the detection limit of high-Q
resonant optical sensors.Using silica
microtoroid as an experimental platform we demonstrate that
dynamic line narrowing through thermo-optic effect
can significantly improve the detection limit in
both resonant shift and resonance splitting operating modes.
*F. Liu, S. Lan and M.
Hossein-Zadeh, "Application of dynamic line narrowing in
resonant optical sensing”,
-Mass sensing with optomechanical oscillator
Optics Letters, vol. 36, no. 22, pp.
4395-4397, Nov 2011.(Also appeared on Virtual Journal for Biomedical
Optics (VJBO), vol.
7(1), Jan 2012)
We have demonstrated the application of
optomechanical oscillator (OMO) as a high-resolution mass sensor.
The coupling between high-Q optical and mechanical modes of a single optical
microcavity results in narrow
linewidth mechanical oscillation driven by the radiation pressure of the
circulating optical power.The oscillation
frequency can be monitored upon detection of the modulated transmitted optical
power;Therefore the optical wave
plays a dual role as the driving power and a sensitive probe. The narrow
oscillation linewidth combined with sensitivity
of the mechanical resonance to mass changes, make OMO an excellent candidate
for all-optical mass sensing.
Experimental results and theoretical analysis show that OMO can function as a
compact, low-power mass sensor with sub-pg sensitivity.
*F. Liu, and M.
Hossein-Zadeh, "Mass Sensing with Optomechanical Oscillation”,IEEE Sensors journal, vol. 13, no. 1, pp. 146-147, Jan 2013.
*F. Liu, Seyedhamidreza Alaie, Zayd C. Leseman, and M.
Hossein-Zadeh, "Sub-pg mass sensing and measurement with an optomechanical oscillator”,
Optics Express, vol. 21, no.17, pp. 19555-19567, Aug. 2013.
-Mid-IR WGM microresonators for breath monitoring
characteristics of such WGM devices are particularly relevant for mid-IR (MIR)
applications because of the stronger absorption of certain biomarkers in MIR “molecular
fingerprint” region. We have proposed and demonstrate a simple and reliable
method for fabricating high-quality whispering-gallery mode (WGM) optical
microresonators in “mid-IR relevant” low-loss ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN)
glasses. Intrinsic quality factors of 10^7 have been demonstrated, providing
great promise for WGM-based mid-IR (MIR) devices. Absorption-limited Q-factors
of over 3 × 10^8 are anticipated over the 2.0 to 3.2 micron MIR wavelength
range in ZBLAN microcavities in the foreseeable future.
Way, R. K. Jain, and M. Hossein-Zadeh, "High-Q Microresonators
for Mid-IR Light Sources and Molecular Sensors", Optics
Letters, vol. 37, no. 21, pp. 4389-4391, 2012.
- Plasmonic enhancement of microring resonators
quality factor (high-Q) optical microcavities detect the presence of molecules in the vicinity of the cavity surface
through the evanescent field. When combined with an affinity based molecular
recognition mechanism (such as antibody-antigen binding), this optical
transduction mechanism can be used as label free biosensor with extremely low
detection limit. The basic principle used in these biosensors is
resonant wavelength shift (effective refractive index change) due to induced polarization
of bound molecules (by evanescent optical field). The minimum detectable
wavelength shift (MDWS) is inversely proportional to the optical quality factor
while the magnitude of the shift is proportional to the induced molecular
polarization. So the limit of detection is proportional to MDWS and wavelength
shift. While significant effort has been spent on increasing MDWS by improving
the Q-factor and noise reduction techniques, less attention has been paid to the
magnitude of shift. Molecular polarization and therefore is proportional to the
strength of the evanescent optical field so any mechanism that amplifies the
field (confinement and amplification) will also increase wavelength shift.
Based on this basic principle, recently few research groups have demonstrated
that presence of metallic nanoparticles on the microcavity surface can enhance
the sensitivity through plasmonic resonance. We work on novel microresonators
designs that combine high-Q optical resonance and localized plasmonic resonance
to improve the overall sensitivity.