Institute of Optics
2013 Xerox Research Opportunities
Prof. Robert W. Boyd
Institute of Optics
boyd@optics.rochester.edu
Research Project #1: Development of a "Slow-Light" Spectrometer on a Chip
There is increasing demand for real-time diagnostic tools such as hand-held, lab-on- chip systems capable of identifying dangerous chemicals or pathogens. However this requires miniaturized spectrometers capable of high-resolution spectral measurements. Our goal is to design such a miniaturized spectrometer using slow light. It has been demonstrated over the last decade that the velocity at which light pulses travel through a material medium can be greatly slowed down by modifying the structure of the material. Two-dimensional photonic crystal structures are prime examples of such slow-light (SL) media with extremely low group velocities or extremely large group indices. We have designed such SL waveguides to form a critical component of a miniaturized spectrometer on a silicon chip since the spectral resolution of the SL spectrometer increases proportionally to the group index of the SL waveguide. We have submitted the waveguide designs for fabrication by deep-UV photolithography and electron-beam lithography. The specific goal of this project is to characterize the fabricated samples for insertion loss and optical dispersion using a recently developed setup in our laboratory. We will perform design iterations to the slow-light waveguide structures in order to further optimize the performance of the on-chip slow-light spectrometer.
Research Project #2: Quantum Cryptography Using the Orbital Qngular Momentum States of Light
In this project, we will encode quantum information single photons of light. This means of transmitting information is highly immune to interception by an eavesdropper, because the information is impressed on a single photon. Any attempt to measure the properties of this photon would necessarily modify its quantum state. A specific goal of our approach is to encode many bits of information onto each photon. In this way the data transmission rate can exceed the photon transmission rate. We will encode this excess by making use of the transverse structure of the electromagnetic field and specifically by making use of states that carry orbital angular momentum, such as the Laguerre-Gauss modes of the field.
Prof. Jannick Rolland
Institute of Optics
rolland@optics.rochester.edu
Research Project #1: Imaging and Sensing with Laser Light
The objective of this project is to bring biophotonics technology developed in our laboratory known as Gabor Domain Optical Coherence Tomography to the clinic and show clinical value of the images acquired for various applications within the dermatology department at the University of Rochester Medical Center. Applications include Mohs surgery and photodynamic therapy. Part of this project is to decide how the system may also be upgraded from its prototype state to better serve the physicians and surgeons and best interface with their work flow. The research thus involves the engineering of the next system generation, while collecting in vivo clinical data.
Research Project #2: Bringing Optical Design to 3D with Kinect Technology
The objective of this project is to develop computer code in C++ to interface with existing software platforms that will bring the optical design of instruments to a 3D desktop. In this process, we will interface Kinect technology to provide means for users of the 3D design software to interact with a 3D GUI that will be designed and implemented. This project will bridge the world of numeric s with optics and focus on 3D visualization.
Prof. Jonathan Ellis
Institute of Optics and Department of Mechanical Engineering
j.d.ellis@rochester.edu
The Precision Instrumentation Group is focused on building the next generation of systems to advance metrology and manufacturing. The research in this group is highly multidisciplinary with students from Mechanical Engineering, Optics, and Electrical & Computer Engineering.
Research Project #1: Optical Probes for Measuring Freeform Optics
Freeform optics can expand the optical design workspace by allowing for more complex optical systems with a smaller package and decreased numbers of optical elements. Optical design software packages are beginning to incorporate tools to more effectively design these systems and advances in sub-aperture manufacturing have made the manufacture of these components possible. There is just one catch: there are no tools that can measure these optics with the desired accuracy to ensure they are manufactured properly and meet specification. The goal of this research project is to design, build, and test a prototype optical probe that can measure freeform optics when used with a 5-axis coordinate measuring machine.
Research Project #2: High Power, High Frequency Stability HeNe Lasers
Multi-axis displacement interferometry systems are widely used in complex manufacturing systems like lithography tools and semiconductor inspection equipment. As more fiber-based systems are used, the amount of available optical power becomes an issue. The goal of this research is to use a novel 3-mode stabilization technique to achieve better frequency stability (<1 part in 1010) while maintaining >3 mW of output power. One part of this research is to build a system capable of demonstrating this stabilization technique, which will entail a combination of optical alignment, mechanical design, and some controls. Additionally, the underlying theory as to why this technique works is not well understood nor is the stability limit known. Models will be developed to better understand the locking methodology and the mechanical requirements for the cavity stability to be better than <1 part in 1010.
Prof. Duncan Moore
Institute of Optics
moore@optics.rochester.edu
Research Project:
Professor Moore's major areas of research are in gradient-index materials, computer-aided design (including design for manufacturing methods), the manufacture of optical systems, medical optics (especially optics for minimally invasive surgery), and optical instrumentation. His most recent Ph.D. thesis student topics have been: very high efficiency solar cells; polymer gradient index optics; built-in accommodation system for the eye; terahertz imaging; generalized three-dimensional index gradients; single-point diamond turning of glass; design methods for gradient-index imaging systems; effect of diffusion chemistry on gradient-index profiles formed via sol-gel; quantitative phase imaging in scanning optical microscopy; integration of the design and manufacture of gradient-index optical systems; and interferometric characterization of the chromatic dispersion of gradient-index glasses.
Prof. Nick Vamivakas
Institute of Optics
nick.vamivakas@rochester.edu
Research Project #1: On-chip Quantum Photonics with Single Quantum Dots
Recent advances in material science have made it possible to engineer physical structures with characteristic length scales of a few to tens of nanometers. The ability to tailor a structure’s geometry and material composition at these lengths directly influences the exhibited optical, electrical and mechanical properties ushering in an era where it is necessary to consider the quantum behavior of a material’s excitations in device design and development. Quantum dots are nanostructures that result when a semiconductor’s elementary electronic excitations, excitons (Coulomb bound electron-hole pairs), are confined in all three dimensions to a size that is comparable to the exciton’s effective Bohr radius – just a few nanometers. The confinement is typically introduced by embedding one semiconductor material into a second semiconductor with a larger bandgap. A manifestation of the quantum confinement is a discrete spectrum of optical transition energies, observable both in optical absorption and emission, resulting in quantum dots being referred to as artificial atoms. The objectives of this project will be accomplished by marrying state-of-the-art resonant optical spectroscopy techniques with advanced nanoscale fabrication procedures to realize quantum dot devices exhibiting controlled quantum mechanical behavior in geometries suitable for on-chip quantum photonics. The student will be involved in device design aided by computer simulations and optical characterization of the fabricated devices.
Research Project #2: Optomechanics with Optically Levitated Nanocrystals
Experimental progress in the optical control of mechanical systems has reached a degree of sophistication where it is now possible to observe truly quantum effects. To date most investigations have focused on mechanical resonators that are rigidly clamped to a support structure. We are currently pursuing a different approach where the mechanical oscillator is an optically levitated nanocrystal situated in the focus of a high numerical aperture objective. By removing the support typical of clamped mechanical resonators the oscillator is freed from decoherence and thermalization imparted from the support. Remarkably these mechanical resonators exhibit quality factors that can approach ~1012 and sub-aN/√Hz force sensitivities. We are looking for a summer student to assist in one of two aspects of the project. First, we are interested in developing an approach to trap, translate and then transfer the optically trapped crystal to a second optical trap. The project will involve optical design, experiment construction and computer-based instrumentation control. A second project is geared toward modeling the optical trap in the presence of a boundary. The boundary can not only lead to displacements of the focus location, but also result in a modification of the trap potential well due to weak forces between the levitated nanocrystal and the proximal boundary. The goal of the modeling effort is to understand the limitations of using optically levitated nanocrystal for nanoscale force sensing.
Prof. Geunyoung Yoon
Department of Biomedical Engineering, Institute of Optics, and Center for Visual Science
yoon@cvs.rochester.edu
Research Project #1: Overcoming Presbyopia: Extending Depth of Focus using Wavefront Interaction
Accommodation refers to the ability of the crystalline lens of the human eye to dynamically change focus in order to visualize objects at various distances clearly at the retina. The accommodative ability steadily decreases with aging and this age-related loss of accommodation known as presbyopia becomes noticeable as a lack of unassisted near vision in middle age. Many strategies exist for overcoming presbyopia, however none truly return the eye to its youthful, accommodating state of dynamic power change. From simple solutions, like reading glasses and bifocal spectacles, presbyopic solutions have greatly evolved in the last few decades. Our approach is to develop multifocal designs to extend depth of focus. Specifically, we use optical interactions between different wavefront aberrations and these designs can be adapted to ophthalmic lenses such as contact lens and intraocular lens. The project involves both theoretical and experimental investigations using wavefront/aberration theory, Fourier optics, advanced optical metrology systems to assess image quality through the multifocal designs. Visual performance of human subjects will also be made.
Research Project #2: Overcoming Presbyopia: Extending Depth of Focus using Wavefront Interaction
Dry eye is a multifactorial disease of the ocular surface and tears, resulting in symptoms of discomfort, visual disturbance, and instability of the tear film with the potential for ocular surface damage. It is recognized as one of the most common ocular disorders affecting many patients aged 50 years and older. Current clinical measurement techniques used for dry eye evaluation is a critical barrier to effectively diagnosing and treating the disease because they are often invasive and ineffective to comprehend the complex interplay between tear film, ocular surface and environmental variations. We use the state-of-art multimodal tear imaging technology developed in the laboratory for the accurate and objective assessment of the tear parameters and their response to controlled environmental changes. The multimodal tear imaging technology such as tear surface topography/wavefront sensor, ocular surface optical coherence tomography, imaging ellipsometer and thermal imaging will be used to characterize the tear. The project also involves development of various computer algorithms to analyze tear images automatically.
