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A fully suspended mid-infrared racetrack resonator is experimentally demonstrated. It has good mechanical stability and broad spectral range of transparency. The measured loaded optical Q factor is 16,440 at 2402.38 nm, with an extinction ratio of 11.83 dB.
A TM-pass integrated waveguide polarizer based on hyperuniform disordered wall network is proposed and experimentally demonstrated for the first time. Its working principle is based on strong interaction between the waveguide modes and hyperuniform disordered solids (HUDS) with large photonic bandgaps, which creates distinct transmission for the TE and TM modes. In our fabricated waveguide polarizers...
Portable nuclear imaging devices have been pursed for intraoperative localization and visualization of tumors for a complete removal of malignant tissues. In the proximity of the tumor site, beta imaging is advantageous over gamma imaging due to far less long-range contamination and no need of heavy metal collimation for a compact size. The traditional beta particle detection usually uses a thin scintillation...
Optical isolators are devices that allow for unidirectional light transmission. We propose an integrated optical isolator by exploiting photonic spin-orbit interaction and graphene's magneto-optical property. Numerical simulation shows its extinction ratio over 45 dB and insertion loss less than 12 dB near 1.55 μm.
Light carries both spin and orbital momentum. It is found recently that the spin and orbital properties are strongly coupled with each other when light is tightly confined to subwavelength waveguiding structures. Here we exploit this spin-orbit interaction to propose an on-chip photonic isolator.
Portable functional imaging devices can be used in oncological surgeries to locate residual tumors for better patient recovery and survival. Taking the patient dose and the limited time of surgery into account, the count in such images could be very low. In this study, we investigate effectiveness of different spatial denoising methods, such as Gaussian filtering, bilateral filtering, Rudin-Osher...
Functional imaging probes can help surgeons to accurately locate residual tumors for a complete destruction of malignant tissues with minimal damage to healthy ones that can lead to better patient survival and recovery. In our previous work, we demonstrated that the combination of spatial and temporal processing could yield image frames with a fast update rate and good image quality for superior tumor...
A quick localization of the tumor site to guide the therapeutic administration is important for an image guided cancer therapy to decrease both mortality and morbidity, especially in prolonged procedures, such as photodynamic and photothermal therapies. Consequently, the images have to be updated quickly enough to capture the patient motion and the movement of therapeutic device, which poses a significant...
Wavelength-sized silicon disk cavities in superfluid helium exhibit blue-shifted bistability near the λ-point when subject to high optical input power. At lower temperature, we observe symmetric lineshapes and obtain a large intracavity photon number of 40,000.
We develop a piezoelectrically actuated, one-dimensional photonic and phononic crystal nanocavity fabricated from aluminum nitride. High-quality piezo-optomechanical nanobeam cavities with optical Qo of 1.2 × 105 and mechanical Qm over 10,000 are obtained.
We develop an all-integrated optoelectromechanical system that operates up to 4.20 GHz. The in-plane bulk acoustic modes of a photonic crystal membrane are electrocapacitively actuated and optically detected by a high-Q slotted photonic crystal cavity.
Aluminum nitride (AlN) has been widely used in microeletromechanical resonators for its excellent electromechanical properties. Here we demonstrate the use of AlN as an optomechanical material that simultaneously offers low optical and mechanical loss. Integrated AlN microring resonators in the shape of suspended rings exhibit high optical quality factor (Q) with loaded Q up to 125,000. Optomechanical...
We demonstrate a micron-sized ultrahigh-Q (Qo=740,000) disk cavity by embedding it in a sunflower-type circular photonic crystal. The disk's fundamental mechanical radial-contour mode is optically transduced at 2.19 GHz with a displacement sensitivity of 6.4 am/Hz1/2.
We present a nano-optomechanical system consisting of a 25-fg doubly-clamped nanomechanical resonator embedded in an engineered high-Q (Qo∼10,000) defect nanocavity supported by two-dimensional photonic crystal. Optically transduced flexural nanomechanical motion is demonstrated at 1 GHz.
Wheel- and disk-shaped Si optomechanical resonators are demonstrated with frequency up to 1.75 GHz and mechanical Q factors as high as 4370 at 1.41 GHz measured in air. Displacement sensitivity of 4.16×10−17 m/Hz1/2 is achieved.
Supermode Si/InGaAsP hybrid lasers with a varying-width Si waveguide have been fabricated and shown to be superior to those lasers with a uniform-width Si waveguide. Edge emission images demonstrate mode evolution.
We report the synthesis and characterization of multi-color gold nanoparticle based tags (Raman nanotags) for molecular imaging. The multi-color Raman nanotags are PEGylated gold nanoparticles (AuNPs) encapsulating a Raman reporter dyes which can be functionalized with any ligand of interest for targeted molecular imaging. The Raman nanotags synthesized with 65 nm gold nanoparticles exhibit the largest...
We propose using supermode control to enhance the modal gain in integrated hybrid Si/III-V optoelectronic circuits. Numerical simulations predict that a 4-fold enhancement in modal gain can be achieved with optimal design.
Modal properties of two types of surface-emitting circular Bragg micro-lasers (CBMLs) are compared. Disk CBMLs are suitable for low-threshold, high-efficiency, ultracompact laser design, while ring CBMLs are an excellent candidate for high-efficiency, large-area, high-power applications.
We derive the shortest length of adiabatic mode transformers which keep the power scattered into unwanted modes below a certain level. The theory is well supported by the numerical results from a transfer matrix method.
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