Events
March 24 12:00 p.m.PHO 906 |
Rings of Light: Properties and Applications We are all familiar with light that looks like a spot, with a Gaussian or Bell-shaped spatial profile. Higher order states would not look so simple, and may have varying degrees of spatial complexity, typically manifested in bright and dark ring patterns. It turns out that this spatial complexity is also accompanied by some intriguing properties, such as the ability of doughnut-shaped beams to carry orbital angular momentum, or the ability of Bessel-function beams to navigate around dark objects. This talk will introduce the physics of such interesting beam shapes. We will illustrate their utility, both from the standpoint of propagation of signals in fibers, for telecom and high-power-laser applications, as well as for exploiting their free-space characteristics, in microscopy, quantum-state tailoring, and biomedical applications. Dr Siddharth Ramachandran obtained his Ph.D. in Electrical Engineering from the University of Illinois, Urbana-Champaign, in 1998. Thereafter, he joined Bell Laboratories as a Member of Technical Staff and subsequently continued with its spin-off, OFS Laboratories. After a decade in industry, Dr. Ramachandran moved back to academics, and since 2010, is an Associate Professor in the department of Electrical Engineering at Boston University. Dr. Ramachandran’s research focuses on the optical physics of guided waves. He has authored over 125 refereed journal and conference publications, more than 25 invited talks, plenary lectures and tutorials, 2 book-chapters, and over 40 patent applications. For his contributions in the field of fiber-optics, he was named a Distinguished Member of Technical Staff at OFS Labs in 2003, and a fellow of the Optical Society of America (OSA) in 2010. He is currently a topical editor for Optics Letters and has served on numerous conference and grant-review committees in the field of optics and applied physics. |
Tuesday, 7:00–9:30 p.m. |
BUPC Faculty member, Dr. Selim Unlu is co-chairing the Biomedical Optic Workshop. The Boston Chapter IEEE Photonics Society and Boston University are the sponsors of the workshop. Below you will find the information about the 5 night workshop series and how to register for the talks. Click here to view the complete schedule and to register |
February 1 12:00 p.m.PHO 906 |
PROBLEMS SOLVED AND UNSOLVED IN PHOTONICS Powering the optical fibre internet with its huge global reach, photonics has changed our lives. Optical fibres snake across continents and oceans carrying terabits per second of data in a vast information network that brings untold human connectivity. How did this happen and is that the end of it? Capacity demand continues to grow at a startling rate, doubling every two years, while the internet is estimated as burning 4% of world energy usage. The solution to both of these unexpected consequences of
success is more photonics, reaching further into the
network with optics to overcome the existing bottlenecks and employing
next-generation optical components. The great success of optical fibres and planar circuits in telecommunications has generated numerous applications in a number of related fields, such as sensing, bio and nano-photonics and high-power lasers. Incredibly, the same fibres that carry
tiny internet signals can also generate kilowatts of power, sufficient to cut through inch-thick steel. The talk will explore prospects for building new technologies and applications through harnessing the properties of new optical materials, devices and structures. Professor David N Payne, CBE, FRS, FREng, is the Director of the Optoelectronics Research Centre at the University of Southampton. He led the team that first reported the silica optical fibre laser and the erbium-doped fibre amplifier (EDFA) and is credited with many other key advances in optical bre technology over the last forty years. His career has spanned both the academic and the commercial, where his activities have led to a cluster of ten companies in the local area. Payne has won the John Tyndall Award (USA), the Rank Prize for Optics, the Japanese Computers and Communications Prize, the prestigious Benjamin Franklin Medal (USA), the Basic Research Award by the Eduard Rhein Foundation, and the Mountbatten Medal of the IEE. For his unique contributions to both science and engineering, in 2004 he was awarded the Kelvin medal by the combined UK Societies. In 2007 he received the IEEE Photonics Award for outstanding achievements in photonics and in 2008 he became a Millennium Prize Laureate. |
November 16 8:00 a.m.Photonics Center, 9th Floor |
13th Annual Future of Light Symposium The BU Photonics Center invites you to attend the 13th Annual Future of Light Symposium on November 16, 2009. Join us for the day to explore the latest advances and developments in the field of Biophotonics Sensors and Systems: Point-of-Care Diagnostics. Presentations will be given by Photonics Center faculty, as well as leading researchers from greater Boston and around the US. This year’s program will focus on point-of-care diagnostics based on novel biophotonics technologies, part of a growing field at the intersection life sciences, physical sciences, and engineering, with a focus on the improved delivery of health care. Please join us for faculty presentations from Boston University and the wider biophotonics community. Speakers include:
Seating is limited for this event, so please register to attend. There is no cost for registration, but it is required for attendance. Be sure to check our website (www.bu.edu/photonics) for symposium updates. The symposium will be held at the Boston University Photonics Center 8 St. Mary’s Street, Boston, MA. |
October 28 12:00p.m.Colloquium Room, 9th Floor |
Distinguished Lecture Series Manipulation of Photons by Photonic Crystals Susumu Noda Photonic crystals, in which the refractive index changes periodically, provide an exciting tool for the manipulation of photons and have made substantial progresses in recent years. In this presentation, I will discuss recent progresses in photonic-crystal researches including (i) two-dimensional photonic-crystal cavities and waveguides, (ii) three-dimensional photonic crystals, and (iii) two-dimensional photonic-crystal lasers. (i) Two-dimensional photonic-crystal nanocavities and waveguides: Remarkable progresses in nanocavities and waveguides based on two-dimensional (2D) photonic-crystals have been achieved recently. For example, nanocavity-Q over two millions [1,2] has been successfully achieved while maintaining ultrasmall modal volume based on the concept of Gaussian confinement [3, 4]. The combination of nanocavities and waveguides leads to the realization of photonic nano-devices [5, 6]. Here, if the properties of such photonic-crystal nanocavities and waveguides could be changed or controlled dynamically during their operations, the resulting functionalities would be greatly expanded. In the present talk, I at first discuss the dynamic control of photonic crystals [7,8], where the characteristics of nanocavities and waveguides are dynamically controlled within picosecond time scales, which will contribute to future applications including the stopping/slowing of light, quantum information systems, and next generation ultra-high capacity communications. Then, I will discuss the recent progress of photonic-crystal nanocavities combined with quantum dots, where the stress is on the importance of quantum anti-Zeno effects [9-11] as a third emission mechanism in addition to Purcell effect and vacuum Rabi-oscillation. (ii) Three-dimensional photonic crystals: 3D photonic crystals with 3D periodic refractive-index distributions are expected to possess the capability of ultimate control of photons, and the manipulation of photons by 3D photonic crystals has so far been carried out by embedding artificial defects and light emitters ‘inside’ crystals [12, 13], using 3D directional bandgap effects. In the present talk, I will describe that photons can be manipulated even at the ‘surface’ of 3D photonic crystals, where 3D periodicity is terminated [14]. This phenomenon is of interest because of its relevance to the surface plasmon-polariton effect of metals and the related surface photon physics. We first show that 3D photonic crystals possess surface states and that photons can be confined and propagate through them. Then I will demonstrate that 3D localization of photons at desired surface points is possible by forming a surface-mode gap and introducing artificial surface-defect structures. Surprisingly, the obtained Q factors of the surface-defect mode are the largest reported for 3D photonic crystal nanocavities (up to ~9,000). This represents an important step towards realizing a new route for photon manipulation by 3D photonic crystals, and establishing the surface science of photonic crystals. Furthermore, the absorption-free nature of the 3D photonic-crystal surface could make possible new sensing applications and light-matter interactions. Finally, I will discuss about a new top-down fabrication method of 3D photonic crystals [15]. (iii) Two-dimensional Photonic-Crystal Lasers: Photonic-crystal surface-emitting lasers [16, 17] have recently attracted much attention because of their perfect, broad-area single-mode surface-emitting operation, their narrow beam divergence angles of < 1°, and the possibility of producing tailored beam patterns by controlling the electric field distribution inside the photonic crystal. These fascinating features arise from the photonic band-edge effect, where the group velocity of light becomes zero and a 2D cavity mode is formed. We will describe the recent progresses in such unique photonic-crystal lasers including the recent achievement in producing tailored beam patterns [18] and lasing oscillation in blue-violet wavelengths [19]. Professor Susumu Noda received his M.S. and Ph.D. degrees in electronics from Kyoto University, Japan, in 1984 and 1991, respectively. He worked for Mitsubishi Electric Corporation from 1984 to 1988 where he was engaged in research on optoelectronic devices such as AlGaAs/GaAs distributed feedback (DFB) lasers, multiple quantum well (MQW) DFB lasers, and grating-coupled surface-emitting lasers. His Ph.D. thesis summarizes the above works performed at Mitsubishi Electronic Corporation. In 1988, Dr. Noda joined Kyoto University as a research associate and became an associate professor in the Department of Electronic Science and Engineering in 1992. His research interests cover the quantum optoelectronics field including photonic nanostructures and quantum nanostructures. He actively studies ultrafast optical devices using intersubband-transition in quantum wells, growth and characterization of InAs quantum dots on GaAs substrate, and semiconductor based 3D and 2D photonic crystals. He is the author of more than 200 scientific journals articles. He received the Ando Incentive Prize, Marubun Incentive Prize, IBM Science Award, and Sakurai Award of Optoelectronic Industry and Technology Development Association (OITDA) in 1991, 1999, 2000, and 2002, respectively. Since 2003, he has served as an IEEE/LEOS Distinguished Lecturer. Dr. Noda is a member of IEEE, IEICE, and JAPS. |
