Donato Conteduca

A High-

The design, fabrication, and optical characterization of the sensing element of a photonic InP-based gyroscope intended for applications in the field of aerospace and defense are reported in this paper. The sensing element is a spiral resonator coupled to a straight bus waveguide through a multimode interference coupler and exhibits a Q factor of approximately 600 000 with a footprint of approximately 10 mm 2. The design of each component of the sensor is based on some well-established numerical methods such as the Finite Element Method, the beam propagation method, and the film mode matching method. The spiral cavity was designed using the standard transfer matrix method. The selected fabrication process, which is an enhanced version of the standard COBRA process, allows the monolithic integration of the sensing element with the other active components of the gyroscope, e.g., lasers, photodiodes, and modulators. Each component of the fabricated sensing element was optically characterized using an appropriate setup, which was also used for the optical characterization of the whole sensor. Based on the results of the characterization, the gyro performance was evaluated, and a way to improve both the resolution and the bias drift, i.e., down to 10°/h and 1°/h, respectively, was also clearly identified. The achieved results demonstrate, for the first time, the actual feasibility of a photonic gyro-on-chip through a well-established InP-based generic integration process.

Q

A multi-analyte biosensing platform with ultra-high resolution ( = 0.2 ng/mL),-which is appropriate for the detection in the human serum of a wide range of biomarkers, e.g. those allowing the lung cancer early diagnosis, has been designed. The platform is based on a new configuration of planar ring resonator. The very strong light-matter interaction enabled by the micro-cavity allows a record limit-of-detection of 0.06 pg/mm(2), five times better than the state-of-the-art. The device with footprint = 2,200 μm(2) for each ring, due to its features, has the potential to be integrated in lab-on-chip microsystems for large-scale screenings of people with high risk of developing cancer.

InP Resonant Angular Velocity Sensor for a Monolithically Integrated Optical Gyroscope

A novel photonic/plasmonic cavity based on a 1-D photonic crystal cavity vertically coupled to a plasmonic gold structure is reported. The design has been optimized to achieve an ultra-high Q/V ratio, therefore improving the light-matter interaction and making the device suitable for optical trapping applications. Accurate 3-D finite element method (FEM) simulations have been carried out to evaluate the device behavior and performance. The device shows Q = 2:8 × 10³ and V = 4 × 10^-4(λ=n)³, which correspond to a Q=V = 7 × 10⁶(λ=n)^-3 with a resonance transmission around 50% at λ_R = 1589:62 nm. A strong gradient of the optical energy has been observed in the metal structure at the resonance, inducing a strong optical force and allowing a single particle trapping with a diameter less than 100 nm. The device turns out very useful for novel biomedical applications, such as proteomics and oncology.

New ultrasensitive resonant photonic platform for label-free biosensing.

The ability to manipulate and sense biological molecules is important in many life science domains, such as single-molecule biophysics, the development of new drugs and cancer detection. Although the manipulation of biological matter at the nanoscale continues to be a challenge, several types of nanotweezers based on different technologies have recently been demonstrated to address this challenge. In particular, photonic and plasmonic nanotweezers are attracting a strong research effort especially because they are efficient and stable, they offer fast response time, and avoid any direct physical contact with the target object to be trapped, thus preventing its disruption or damage. In this paper, we critically review photonic and plasmonic resonant technologies for biomolecule trapping, manipulation, and sensing at the nanoscale, with a special emphasis on hybrid photonic/plasmonic nanodevices allowing a very strong light–matter interaction. The state-of-the-art of competing technologies, e.g., electronic, magnetic, acoustic and carbon nanotube-based nanotweezers, and a description of their applications are also included.

Design of an Optical Trapping Device Based on an Ultra-High Q/V Resonant Structure

A rigorous mathematical method to simulate an ultra-high Q-factor 1D PhC ring resonator (1D PhCRR) is proposed. The integration of a 1D PhC in a ring cavity resonator allows an enhancement of the Q-factor of a single ring resonator up to 109 or more, without enlarging the device footprint, with an improvement of at least two orders of magnitude in comparison with the values obtained without the grating. Rigorous modelling and simulations of such ultra high-Q resonant cavities are very challenging, because of the structure complexity, due to the large device footprint and the requirements for an accurate spectral analysis. Conventional numerical methods, such as Finite Element Method (FEM) and Finite Difference Time Domain (FDTD) require very long simulation time and huge computing resource. Therefore, a general mathematical method, able to reduce the computing time, assuring accurate solutions, and investigating the effect of the grating in the coupling region, is a real need. Several configurations of 1D PhCRRs have been investigated. An ultra-high Q-factor (> 109) for a 1D PhCRR in Si3N4 technology with a footprint of 64 mm2 has been calculated. Similar performance makes the 1D PhC ring resonator suitable for several applications, such as optical gyroscopes for space environment and ultra-sensitive biosensors.

Photonic and Plasmonic Nanotweezing of Nano- and Microscale Particles:

Abstract. Guidelines for the design and fabrication of polymer photonic crystal channel drop filters for coarse wavelength division multiplexing are provided. A Fabry-Perot cavity consisting of a membrane-type slab photonic crystal, where a hole row perpendicular to the propagation direction is removed, is considered. We selected nanoimprinting as the manufacturing technique. The influence on the cavity performance of several key parameters, i.e., polymer core material, lattice geometry, defect length, and holes’ radius, has been investigated in a device compliant with the requirement of the ITU-T G.694.2 standard. A detailed analysis of the fabrication tolerances has been carried out at 1551 nm. The maximum acceptable drift of the geometrical parameters has been accurately evaluated by using the finite element method to prove that the fabrication tolerances do not significantly affect the performance of polymer filters for coarse wavelength division multiplexing, when manufactured by thermal nanoimprinting lithography.

Rigorous model for the design of ultra-high Q-factor resonant cavities

Microwave photonic filters with a performance not achievable by the conventional RF technology, are currently a hot topic in the field of microwave photonics. In this paper, after a brief review of the state-of-the-art of microwave integrated photonic filters and their application in space engineering, the design of a new band-pass filter configuration based on a ring resonator with a photonic crystal included in the resonant path is proposed. The achieved performance parameters are a full-width-at-half-maximum of 10 pm, a Q-factor of 1.5×105, with an extinction ratio equal to 40 dB, and a maximum ripple less than 0.5 dB, within the wavelength range λ0 ± FWHM/4 (with λ0 = 1550 nm). The ring is in silicon technology and it can be integrated with other optoelectronic/photonic components of the filter through a hybrid approach.

Effect of fabrication tolerances on the performance of two-dimensional polymer photonic crystal channel drop filters: a theoretical investigation based on the finite element method

In this paper, we report on the design of a bio-multisensing platform for the selective label-free detection of protein biomarkers, carried out through a 3D numerical algorithm. The platform includes a number of biosensors, each of them is based on a plasmonic nanocavity, consisting of a periodic metal structure to be deposited on a silicon oxide substrate. Light is strongly confined in a region with extremely small size (=1.57 μm2), to enhance the light-matter interaction. A surface sensitivity Ss = 1.8 nm/nm has been calculated together with a detection limit of 128 pg/mm2. Such performance, together with the extremely small footprint, allow the integration of several devices on a single chip to realize extremely compact lab-on-chip microsystems. In addition, each sensing element of the platform has a good chemical stability that is guaranteed by the selection of gold for its fabrication.

New microwave photonic filter based on a ring resonator including a photonic crystal structure

The ability to confine light at the nanoscale continues to excite the research community, with the ratio between quality factor Q and volume V, i.e., the Q/V ratio, being the key figure of merit. In order to achieve strong light-matter interaction, however, it is important to confine a lot of energy in the resonant cavity mode. Here, we demonstrate a novel cavity design that combines a photonic crystal nanobeam cavity with a plasmonic bowtie antenna. The nanobeam cavity is optimised for a good match with the antenna and provides a Q of 1700 and a transmission of 90%. Combined with the bowtie, the hybrid photonic-plasmonic cavity achieves a Q of 800 and a transmission of 20%, both of which remarkable achievements for a hybrid cavity. The ultra-high Q/V of the hybrid cavity is of order of 106 (λ/n)−3, which is comparable to the state-of-the-art of photonic resonant cavities. Based on the high Q/V and the high transmission, we demonstrate the strong efficiency of the hybrid cavity as a nanotweezer for optica...

Design of a new ultracompact resonant plasmonic multi-analyte label-free biosensing platform

In the last few years, the interest towards chip-scale microphotonic resonant label-free biosensor is quickly growing. In this context, novel low-cost platforms able to simultaneously detect, with high resolution, several target molecules in an ultra-small volume of biologic fluid are strongly demanded. In this paper, the recent advances in the field of resonant microphotonic platforms for label-free biosensing are critically reviewed, with a special emphasis on the devices exhibiting an ultra-high sensitivity due to a strong light-matter interaction. A new multi-analyte biosensing platform in silicon nitride technology is reported. The platform is based on a properly designed configuration of planar ring resonator and exhibits a record limit-of-detection of 0.06 pg/mm2. The applications of the platform in the field of medical diagnostics and environmental monitoring are discussed.