Andrew Kirk

McGill University | McGill · Department of Electrical & Computer Engineering

Photothermal therapy (PTT) has emerged as a promising alternative to conventional cancer treatments such as radiation therapy, chemotherapy, and surgery. PTT uses light‐absorbing nanomaterials to induce localized hyperthermia and selectively eliminate cancer cells, thus offering advantages over traditional interventions. This literature review focu...

The basic principles of ultrafast plasmonic PCR have been promulgated in the scientific and technological literature for over a decade. Yet, its everyday diagnostic utility remains unvalidated in pre-clinical and clinical settings. Although the impressive speed of plasmonic PCR reaction is well-documented, implementing this process into a device fo...

Photothermal therapy (PTT) is a promising approach for cancer treatment that selectively heats malignant cells while sparing healthy cells. Here, the light-to-heat conversion efficiency of multiwalled carbon nanotubes (MWCNTs) within the near-infrared biological transmission window is enhanced by decorating them with plasmonic gold nanorods (GNRs)....

Multiwalled carbon nanotubes (MWCNTs) are being widely investigated in multiple biomedical applications including, and not limited to, drug delivery, gene therapy, imaging, biosensing, and tissue engineering. Their large surface area and aspect ratio in addition to their unique structural, optical properties, and thermal conductivity also make them...

In response to the world’s medical community need for accurate and immediate infectious pathogen detection, many researchers have focused on adapting the standard molecular diagnostic method of polymerase chain reaction...

A mathematical model for DNA quantification was calibrated using experimental results from real-time 260nm absorption measurements of plasmonic PCR thermocycling. The effect of different PCR parameters on template amplification was investigated using the calibrated model.

Plasmonic-driven Polymerase Chain Reaction is accomplished by a surface-emitting laser with real-time amplification detected via monitoring of DNA-UV transmission. This miniature device provides high amplification efficiency and rapid sample analysis for point-of-care applications.

A loop-mirror modulator (LMM) combines a Mach-Zehnder modulator with an integrated loop-mirror. Differential phase shift keying modulation for a LMM with dual-drive traveling wave electrodes is investigated. We show analytically that when operated with the proper bias conditions the LMM can achieve arbitrary phase and amplitude modulation. We demon...

This paper presents a novel method employing the maximum likelihood estimation (MLE) technique alongside a nonlinear sensor response model to improve and extract more quantitative sensing results for localized surface plasmon resonance biosensors. The nonlinear response model treats the sensor response as a nonlinear function of the biomolecular ad...

We present a simple and accurate method to improve both accuracy and precision for localized surface plasmon resonance biosensors based on gold nanotube structures. The finite difference time domain (FDTD) method and the nanoimprint lithography technique were used in simulating and fabricating the nanotubes, respectively. The method provides a dire...

We present a novel approach to improve self-referenced sensing based on multiple-resonance nanorod structures. The method employs the maximum likelihood estimation (MLE) alongside a linear response model (LM), relating the sensor response (shifts in resonance wavelengths) to the changes due to surface binding and bulk refractive index. We also prov...

Bacterial biofilms are a leading cause of infections in health-care settings. Surface plasmon resonance (SPR) biosensors stand as valuable tools not only for the detection of biological entities and the characterisation of biomaterials but also as a suitable means to monitor bacterial film formation. This article reports on a proof-of-concept study...

Polymerase Chain Reaction (PCR) is a critical tool for biological research investigators but recently it also has been making a significant impact in clinical, veterinary and agricultural applications. Plasmonic PCR, which employs the very efficient heat transfer of optically irradiated metallic nanoparticles, is a simple and powerful methodology t...

Surface plasmon resonance (SPR) is an attractive method for the measurement of refractive indices due to its high accuracy and its broad range of applications. However, the use of this technique for the measurement of complex refractive indices in real-time has not yet been demonstrated. This article discusses and demonstrates how an SPR biosensor...

This paper presents a simple and accurate method (the projection method) to improve the signal to noise ratio of localized surface plasmon resonance (LSPR). The nanostructures presented in the paper can be readily fabricated by nanoimprint lithography. The finite difference time domain method is used to simulate the structures and generate a refere...

DPSK modulation at 10 Gb/s with a low-power loop mirror Mach-Zehnder (MZ) modulator is presented. The drive voltage required is one half that of conventional MZ devices and hence the modulator consumes only one quarter of the energy (estimated at 8.4 pJ/bit).

We present the design, analysis, and experimental characterization of a novel integrated add-drop filter capable of filtering simultaneously two independent channels that is based on a contra-directional grating assisted coupler with two different periods. The device performance is explained using Fourier analysis and confirmed with numerical simul...

We present the design and characterization of a silicon-on-insulator based bandwidth and wavelength-tunable add-drop filter. The tunability of the device is achieved by independently controlling the central wavelength of two cascaded contra-directional grating assisted couplers. The device was fabricated using e-beam lithography and the tuning is d...

The large signal characterization of a loop mirror Mach-Zehnder interferometer (MZI) is reported. We demonstrate that this device is capable of 20 Gb/s modulation rate with reduced power requirements in comparison to a conventional MZI.

We propose a novel configuration to implement bandwidth-tunable add-drop filters using integrated contra directional grating assisted couplers with a bandwidth tunable from 8 nm to 16 nm. Measurement results of passive structures are presented and the tuning method is analyzed.

This presentation will describe the issues associated with a design-based course in optical engineering. The original purpose of this course was to provide senior undergraduate and graduate students with a good foundation in free-space optics, including topics such as geometric aberrations, Gaussian beam theory, diffractive optics, interference fil...

Optical characterisation of liquids through the measurement of their complex refractive index is critical in environmental monitoring, food industry and medicine. While surface plasmon resonance is widely used for measurement of the real part of the refractive index there have been few studies to date on measurement of complex refractive index with...

A novel technique to fabricate metallic nanocrescents is presented. Their optical response is simulated using the finite difference time domain (FDTD) method and validated via experimental investigation and surface characterization. Nanocrescents support multiresonance extinction spectra, making them good candidates for sensing applications. In thi...

Phase shift cavity ring down spectroscopy (PS-CRDS) in conjunction with microcavities provides a highly sensitive approach for sensing applications. However, there have been no complete and accurate analytical expressions demonstrated so far for PS-CRDS based upon measurement of the transmitted waveguide signal only in a microcavity–waveguide syste...

A new method for LRSPP wave excitation using Si-based grating couplers is proposed. We report a coupling efficiency of 32 % in design and 16.5 dB loss in measurement from optical fiber to the plasmon wave.

Metallic nanostructures possess many advantages for utilization in various applications including sensing applications. However, achieving an easy to fabricate platform with high sensitivity performance is considered the main challenge in designing such nanostructures. Two factors should be considered when designing a wavelength based nanostructure...

Surface plasmon resonance (SPR) sensing is one of the most widely used methods to implement biosensing due to its sensitivity and capacity for label-free detection. Whilst most commercial SPR sensors operate in the angular regime, it has recently been shown that an increase in sensitivity and a greater robustness against noise can be achieved by me...

Optical microcavities are widely used for biological and chemical sensing applications. In these devices, a sensing event is estimated by measuring the shift in the resonant wavelength, or in the quality factor of the microcavity. However, all published works to date only use one of these measures to estimate the sensing event. Here, we show that t...

We introduce a novel bandwidth and wavelength-tunable switch which is a balanced MZI structure having two grating structures on each arm. The tunability is achieved by separate tuning of the gratings.

We demonstrate the plasmonic properties of double gold nanotube structures using the finite difference time domain (FDTD) method, and present the techniques that we have used to fabricate them on cyclic olefin polymer (COP) substrate.

We present a finite difference time domain (FDTD) study of gold nanofin structures to elucidate the effect of the structure parameters on their plasmonic properties. Fabrication techniques and measured results are also demonstrated.

In this paper, rolled-up semiconductor tube optical cavities, formed when coherently strained nanomembranes are selectively released from the host substrate, have emerged as a promising approach to realize high performance lasers on Si. 1-3 We have investigated the design, fabrication, and characterization of InAs/InGaAsP quantum dot tube lasers. W...

Due to ultra high quality factor (10⁶ − 10⁹), axisymmetric optical microcavities are popular platforms for biosensing applications. It has been recently demonstrated that a microcavity biosensor can track a biodetection event as a function of its quality factor by using phase shift cavity ring down spectroscopy (PS-CRDS). However, to achieve maximu...

Phase shift ring down measurement approach (PS-CRDS) is used to develop a real time biosensor which can simultaneously track the quality factor Q and the resonant wavelength λr of microcavities as a function of the biodetection event. We have developed a mathematical model to predict the binding event with high accuracy by utilizing the information...

Surface plasmon resonance (SPR) sensing is one of the most widely used methods to implement biosensors due to its sensitivity and capacity for label-free detection. Most conventional SPR sensors measure the change in reflectance at a metal-dielectric interface as a function of either angle or wavelength. However, it has recently been shown that an...

Iridescence is an example of structured color that is widespread in the biosphere, exhibited by multilayer inorganic thin films for optical filters, photonic crystals and other materials in which the periodic patterning of matter interacts with an electromagnetic field. Nanocrystalline cellulose (NCC) can be cast in the form of thick iridescent fil...

Optical space switching is an important functionality in dense wavelength division multiplexing (DWDM) optical communication systems, particularly within reconfigurable optical add-drop multiplexers (ROADMs) [1]. Current commercially available ROADMs are based on micro-electromechanical systems (MEMS) or liquid crystal switches but these do not hav...

We present a study of gold nanopyramids and their optical properties. A comparison with the extinction properties of gold nanorods and nanocubes is also undertaken. The Finite Difference Time Domain (FDTD) method is used for the study of optical properties. The nanopyramids display a dual plasmon resonance when excited with a perpendicularly polari...

A plasmonic heating method for the polymerase chain reaction is demonstrated by the amplification of a section of the human androgen receptor gene. The thermocycler has a simple low-cost design, demonstrates excellent temperature stability and represents the first practical demonstration of plasmonic thermocycling.

We report on the design, modeling, and characterization of apodized comb filters in the silicon-on-insulator platform. These devices are based on sampled gratings, wherein the comb response is generated by a convolution of a regular grating by a predetermined periodic sampling function. We show that dual and complementary apodization of the etch de...

We report on the design, fabrication, and demonstration of waveguide coupled channel drop filters at 1550 nm, on a silicon-on-insulator (SOI) substrate. These devices rely on resonant power transfer from a bus waveguide to side-walled Bragg resonators with quarter-wave shifts in the middle. By employing a second mirror resonator, and a tap-off wave...

We report on the observation of a dynamical thermal effect in InGaAsP microtubes at telecom wavelengths. The microtubes are fabricated by releasing a strained semiconductor bilayer and are picked up by abruptly tapered optical fibers for subsequent coupling with adiabatically tapered optical fibers. As a result of absorption by InAs quantum dots em...

We propose comb filters using sidewalled sampled gratings, where the etch depths in the fingers and spaces have been apodized in a complementary fashion. We numerically demonstrate filters with 40 dB SMSR, 92 GHz bandwidth, 200 GHz channel spacing, and 120 dB/decade roll-off.

The development of gold nanorod plasmonic sol–gel polymer is presented and characterised with respect to its sensitivity to refractive index change. Structural characterisation of the polymer was conducted using Raman microscopy and energy dispersion spectroscopy while plasmonic function was investigated using UV/VIS spectroscopy. Refractive index...

Optical resonant microcavities with ultra high quality factors are widely used for biosensing. Until now, the primary method of detection has been based upon tracking the resonant wavelength shift as a function of biodetection events. One of the sources of noise in all resonant-wavelength shift measurements is the noise due to intensity fluctuation...

Optical resonant microcavities with ultra high quality factors are widely used for biosensing. Until now, the primary method of detection has been based upon tracking the resonant wavelength shift as a function of biodetection events. One of the sources of noise in all resonant-wavelength shift measurements is the noise due to intensity fluctuation...

Cavity ring down measurement approach is a promising technique for biosensing as it is insensitive to intensity uctuations of a laser source. This technique in conjunction with ultra high Q microcavities have a great potential for ultra sensitive biosensing. Until now, most work on microcavity biosensors has been based on measurement of the resonan...

The cost of fabrication and instrumentation presents a significant barrier to uptake of optical mapping as a tool for genomic investigation. Here a low cost optical instrumentation system to perform optical genomic mapping of DNA fragment restriction digestion by nanochannel confinement is presented. Specifically, the system is used for the detecti...

In previous work, we demonstrate a simple approach to creating a plasmonic polymer. Reflecting upon the need for greater spot density while still maintaining the objective of low cost analysis, the next generation of device is described where density up to 24000 sensing spots is achievable. A localized surface plasmon micro-array is described forme...

Visceral leishmaniasis (L.donovani) is a protozoan infection that attacks mononuclear phagocytes and causes the liver and spleen damage that can cause death. The investigation presented is a proof of concept development applying a plasmonic diagnostic platform with simple microfluidic sample delivery and optical readout. An immune-assay method is a...

Nanocrystalline cellulose solid films derived from spruce pulp exhibit iridescence when cast from chiral nematic aqueous phase suspensions of the nanocrystals. Iridescence is a color travel phenomenon that might have potential for overt encryption as an anti-counterfeiting measure. The iridescent phase also offers an intrinsic level of covert encry...

A new design for a wideband and compact demultiplexer for coarse wavelength-division-multiplexing applications is proposed. This is based on the superprism effect, using diffraction compensation in a stratified hetero-lattice photonic crystal (PhC) operating in reflective mode. Modeling the variation of the beam envelope within the hetero-lattice,...

We report on Q-factor measurement, selective polarization mode excitation, and optical-optical modulation response at transparent wavelengths of InGaAs/GaAs microtubes. These microtubes demonstrate very promising applications in photonics integrated circuits.

We report on the design, fabrication, and characterization of rolled-up 1.3–1.5 µm InAs quantum dot tube nanoscale lasers and coherent light sources as well as their monolithic integration with Si waveguides on a Si platform.

We report on the demonstration of waveguide coupled side-walled grating filter fabricated on SOI using e-beam lithography. We obtain a dropped channel extinction of 20 dB and a flat top response using coupled cavities.

The design principles and measurement results for a compact shallow etched distributed diffraction grating waveguide demultiplexer are presented. The deeply etched diffraction grating facets are replaced with a shallow etched odd-order quarter wavelength Bragg reflector to increase the Fresnel reflection coefficient. A prototype device was designed...

It is numerically shown that incorporation of a distributed Bragg reflector at the facets of an etched diffraction grating (EDG) can be used to tailor the output spectral response of the device. This technique is used to optimize the overall insertion loss envelope of a distributed etched diffraction grating (DEDG) demultiplexer to improve the outp...

We report on selective polarization mode excitation in InGaAs/GaAs rolled-up microtubes. The microtubes are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from its host GaAs substrate. An optical fiber abrupt taper is used to pick up the microtube, while an adiabatically tapered optical fiber is used to coup...

We present results on InGaAsP rolled-up microtube resonators with embedded InAs quantum dots with strong coherent emission at ~1.55 μm. We also show coupling of these resonators to Silicon-on-Insulator waveguides.

We report on single rolled-up microtubes integrated with silicon-on-insulator waveguides. Microtubes with diameters of ~7 μm, wall thicknesses of ~250 nm, and lengths greater than 100 μm are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from the handling GaAs substrate. The microtubes are then transferred f...

We propose a tunable hybrid silicon evanescent laser with vertical sidewalled sampled grating distributed Bragg reflectors (SG-DBR) on SOI. The device utilizes a Vernier comb and the electrooptic effect in silicon for tuning within a 30 nm range. c 2010 Optical Society of America OCIS codes: (230.1480) Bragg reflectors; (130.3120) Integrated optics...

Porous silicon is a potentially useful substrate for fluorescence and scattering enhancement, with a large surface to volume ratio and thermal stability providing a potentially regenerable host matrix for sensor development. A simple process using XeF2 gas phase etching for creating porous silicon is explained. Moreover, how pores diameter can be c...

High throughput plasmonic sensors are a popular research field, standard surface plasmon resonance (SPR) instruments can achieve high throughput only in imaging configuration. This leads to consideration of pattern substrates and isolated nanoparticle arrays, both of which have some disadvantages. Spot functionalisation relies upon mask or pin prin...

We report on the fabrication, characterization and integration of semiconductor microtube lasers on silicon. These microtubes are fabricating using standard photolithography techniques on epitaxially grown strained bilayer films, and show remarkable spectral properties attributable to whispering-gallery-mode type optical resonances. We have demonst...

Nano Crystalline Cellulose (NCC) in aqueous suspension gives rise to anisotropic order that leads to iridescence from the fluid phase. Phase separation and order formation were studied using polarized optical microscopy and laser diffraction. Factors affecting liquid crystal phase separation, such as hydrolysis time, wood pulp species, sonication a...

Optical biosensors can detect biomarkers in the blood serum caused by either infections or exposure to toxins. Until now, most work on the micro-cavity biosensors has been based on measurement of the resonant frequency shift induced by binding of biomarkers to a cavity. However, frequency domain measurements are not precise for such high Q micro-ca...

Numerical methods are required to develop an accurate electromagnetic model for various axisymmetric resonators such as micro-discs and micro-toroids. A finite element model for such resonators already exists, however there are number of issues with that model: 1) No perfectly matched layer or any other absorbing boundary conditions are used, 2) Qu...

A hybrid III-V silicon evanescent laser with sidewalled gratings as the feedback element, and having 60% waveguide confinement is proposed. The device is fabricated using e-beam lithography, and low-temperature plasma assisted direct bonding.

Developmental work towards a camera phone diagnostic platform applying localized surface plasmon resonance (LSPR) label-free sensing is presented. The application of spherical gold nanoparticles and nanorods are considered and assessed against ease of application, sensitivity, and practicality for a sensor for the detection of CCL2 (chemokine ligan...

Wavelength-spacing tunable multi-wavelength source by controlling the intermodal transitions induced via dynamic reconfiguration of a nested photonic crystal cavity, through optically induced free carriers, is proposed. Optical combs spanning the entire C-band are demonstrated numerically.

A surface plasmon biosensing technique based on real-time measurement of the spectro-angular reflectance spectrum of a gold surface is presented. A significant improvement in refractive index resolution and drift compensation has been achieved for the spectro-angular technique to demonstrate a biosensing platform that is, in addition, applicable to...