Location:	Optikos Corporation, 107 Audubon Road, Bldg. 3, Wakefield, MA 01880
	Dinner Reservation Deadline:	Friday, October 21, 2016 @ 6pm

Coherence in Modern Optics

NOTE: Attendees who are foreign nationals are requested to bring a passport to this event

Coherence manifests itself in many ways in optics and photonics. Well known are the classic phenomenon in which light from stellar objects gains coherence by mere propagation, the measurement of coherence by observing fringe visibility, coherence-induced changes of the spectrum even in free space, the intriguing polarization states and geometric phases of light beams, and many other fascinating effects. With the rapid development of near-field optics and nanophotonics, the theory of optical coherence has undergone important refinements so as to account for the various vectorial features of the light. In many instances the electromagnetic coherence properties have to be measured by means of nanoscatterers.

Partially polarized and temporally partially coherent light beams play central roles in metrology and optical instrumentation. Even fully unpolarized beams of light experience rapid polarization-state fluctuations that convey information about the source or the transmitting medium. Such ultrafast polarization dynamics and temporal coherence can be modelled theoretically and measured in a polarization-selective Michelson interferometer by using two-photon absorption. The so-called supercontinuum generated in a nonlinear optical fiber has an ultrabroad spectrum. Under a wide range of circumstances its coherence properties can be represented as a superposition of two contributions, a nearly coherent part and an almost incoherent component. These contributions can be controlled by the pump pulse, thereby leading to supercontinuum of tailored coherence. 

Some novel imaging techniques involve intensity correlations. Optical coherence tomography is a versatile biomedical imaging method based on the interference of low-coherence light. The resolution could be improved through the use of intensity correlations, but the rapid intensity fluctuations in incoherent light cannot be measured. A novel quantum-inspired spectral intensity correlation approach only utilizes mean intensities, resulting in enhanced image resolution and dispersion cancellation. A remarkable intensity-based technique called ghost imaging utilizes two beams neither of which contains image information but their correlation makes the image of the target magically appear. This method has been transcribed into the time domain enabling fully distortion-insensitive ghost imaging of ultrafast temporal signals.

“Ghost imaging in the time domain,” Nature Photonics 10, 167 (2016)  

MEETING SPONSORED BY

	Location:	Rebecca's Cafe, 275 Grove St., Auburndale, MA 02466
	Dinner Reservation Deadline:	Monday, September 12, 2016 @ 6pm

Wearable Diffuse Optical Imaging Probes for Guiding Cancer Treatment

Diffuse optical spectroscopy and imaging techniques provide quantitative measurements of human tissues up to several centimeters in depth using near-infrared light. These measurements are non-invasive, safe, and provide quantitative assessments of fundamental aspects of the in vivo tissue state without the use of exogenous agents or ionizing radiation. My research group is rapidly advancing these devices towards wearable probes, allowing a level of patient access unparalleled with most currently available medical imaging modalities. We are applying these new diffuse optical technologies to several major challenges in clinical oncology, including chemotherapeutic drug resistance and the personalization of therapies. Diffuse optical probes provide an in vivo macroscopic view of the tumor state in real time with supreme sensitivity to the dynamic effects of a diverse array of chemotherapeutic agents. We anticipate this will provide a plethora of new possibilities for better understanding of the dynamics of treatment response, including indications of the best times for interventions and/or altering the drug regimen. I will present developments my lab has made in new clinical and preclinical diffuse optical technologies and discuss their applications and potential to change the standard of care.

Building the First Microprocessor that Communicates using Light

Joint Meeting with Boston Chapter, IEEE Photonics Society

Four decades on from the pioneering first steps at Bell Labs, microphotonics is at a transition from a few components to large-scale integrated systems on chip.  In the near term, this can address severe bottlenecks seen in complex digital electronic systems – through integration with relatively simple but efficient photonic systems.  In the longer term, tight integration and control means complex passive, active and nonlinear photonic structures enabling novel functions will become practical and may enable a new generation of integrated systems-on-chip for analog signal processing, computation, metrology and sensing.

In this talk, I will describe work on a new CMOS technology that enabled the simultaneous integration of millions of advanced CMOS transistors and thousands of photonic devices side-by-side on a single chip for the first time.  The approach, "zero change CMOS photonics", bucked the trend in the photonics community of tailoring fabrication to design, instead pursuing a "design for manufacture" philosophy to photonic device design within fixed advanced-node CMOS microelectronics technology.  It produced the efficient electronic-photonic systems of unprecedented integration scale, including record-energy optical transmitters, receivers and links, and resulted in the demonstration of the first microprocessor that communicates using light, with significant implications for computer architecture.

I will describe the approach, some of the device innovations and the system demonstrations they made possible, and will address some of the implications of this work in computing and its potential in other domains including datacom, quantum information processing, RF front ends and LIDAR.