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Physics Conference Room, SB B326
Coffee starts at 12:00 PM and talk starts at 12:15 PM
Jan '18
Mitsuteru Inoue  -  Monday, January 8, 2018
PDFDownload PDF iCaliCal file GoogleAdd to Google Calendar locationPhysics Conference Room, SB B326 coffee time2:45 pm talk time3:00 pm
The introduction of artificial magnetic structures into magnetic materials can induce novel electromagnetic and spin-wave behavior. Nano- and submicrometer-scale artificial magnetic lattices (AMLs) can control optical (electromagnetic) waves in magnetophotonic crystals [1], volumetric magnetic holograms [2], and labyrinthian magnetic domain structures [3], and can affect spin waves in magnonic crystals [4].
     In this talk, the fundamental properties of such AMLs, mainly in magnetic garnet films and alloy thin films, are discussed, followed by demonstrations of their applications in optical and spin-wave micro-devices driven by magnetic phase interference: volumetric magneto-optic (MO) hologram memories [2] and three-dimensional MO holographic displays [5] with magnetophotonic crystals; high-speed MO Q-switch micro-chip lasers with iron-garnet films with labyrinthian magnetic domain structures [3]; and highly sensitive magnetic sensors and spinwave logic circuits with magnonic crystals [6].
     Prospective future spin-wave devices with AMLs will be discussed in the context of the new paradigm of magnonics (electron non-transport electronics), where spin waves play an important role as the information carrier.
[1] T. Goto et al., “Magnetophotonic crystal comprising electro-optical layer for controlling helicity of light,” J. Appl. Phys., 111, 07A913, 2012.
[2] Y. Nakamura et al., “Error-free reconstruction of magnetic hologram via improvement of recording conditions in collinear optical system,” Optics Exp., 25, 15349-15357, 2017.
[3] R. Morimoto et al., “Magnetic domains driving a Q-switched laser,” Sci. Rep., 6, 38679, 2016.
[4] N. Kanazawa et al., “Metal thickness dependence on spin wave propagation in magnonic .crystal using yttrium iron garnet,” J. Appl. Phys., 117, 17E510, 2015.
[5] K. Nakamura et al., “Improvement of diffraction efficiency of three-dimensional magnetooptic spatial light modulator with magnetophotonic crystal,” Appl. Phys. Lett., 108, 02240, 2016.
[6] N. Kanazawa et al., “Demonstration of a robust magnonic spin wave interferometer,” Sci. Rep., 6. 30268, 2016.
NOTES: Professor Inoue is IEEE Magnetics Society Distinguished Lecturer for 2018
Jan '18
Mircea Trif  -  Monday, January 29, 2018
ABSTRACT: The field of cavity quantum electrodynamics (cQED) with quantum conductors has become an extremely active field of research. The milestone year was 2004, when superconducting qubits have been integrated within a microwave cavity in order to reach, for the very first time in the condensed matter context, the strong coupling regime between photons and matter [1,2]. Since then, many other systems have been successfully coupled to microwave cavities, such as quantum wires [3], carbon nanotubes [4], quantum dots [5], etc. Such hybrid systems offer platforms for new kinds of physics, as one can engineer and manipulate the electromagnetic environment at will. The versatility of the cQED method relies on the fact that it allows to 1) monitor in a noninvasive fashion the electronic states in quantum conductors, both in equilibrium and non-equilibrium situations, 2) to affect and manipulate the electronic transport, 3) to establish long-range correlations between remote quantum conductors and, finally, 4) it opens the pathway to create non-classical states of light by means of electronic transport.

In this talk, I will discuss some of these aspects for various types of quantum conductors out of equilibrium. I will focus on tunnel junctions [5], magnetic tunnel junctions [6], quantum dots [5] and Josephson junctions [7,8], respectively. I will show that one can reveal properties that are invisible in electronic transport (via the conductance), in particular in out-of-equilibrium situations pertaining to a large voltage bias applied over the quantum conductor [8]. For the case of voltage biased Josephson junction, I will show that the emitted radiation is non-classical in the sense that the photonic correlators violate some Cauchy-Schwarz inequalities [9]. I will confront the theory with some recent experimental studies where such violations have been measured [10].

[1] A. Wallraf, D. I. Schuster, A. Blais et al., Nature 431, 162 (2004).
[2] A. Blais et al., Phys. Rev. A 69, 062320 (2004).
[3] K. D. Petersson et al., Nature 490, 380 (2012). [4] J. Viennot et al., Science 349, 6246 (2015).
[4] T. Frey et al., Phys. Rev. Lett. 108, 046807 (2010).
[5] Olesia Dmytruk, Mircea Trif, Christophe Mora, and Pascal Simon, Phys. Rev. B 93, 075425 (2016).
[6] Mircea Trif and Pascal Simon, Phys. Rev. B 90, 174431 (2014).
[7] Mircea Trif and Pascal Simon, Phys. Rev. B 92, 014503 (2015).
[8] O. Parlavecchio et al, Phys. Rev. Lett. 119, 137001 (2017).  
Feb '18
Sateesh Mane  -  Monday, February 5, 2018
Relativistic Spin Polarized Beams in Accelerators
Computer Science, Queens College
ABSTRACT: This talk will present an overview of the subject of relativistic spin polarized beams in particle accelerators. The focus will mainly be high energy accelerators (such as RHIC at Brookhaven National Lab), but lower energy machines for nuclear physics will also be discussed. Highlights such as the precision measurement of the mass of the Z0 boson at CERN will be treated.

Feb '18
Aditi Mitra  -  Monday, February 26, 2018
ABSTRACT: Recent advances in ultra-fast measurement in cold atoms, as well as pump-probe spectroscopy of K3C60 films, have opened the possibility of rapidly quenching systems of interacting fermions to, and across, a finite temperature superfluid transition. However determining that a transient state has approached a second-order critical point is difficult, as standard equilibrium techniques are inapplicable. We show that the approach to the superfluid critical point in a transient state may be detected via time-resolved transport measurements, such as the optical conductivity. We leverage the fact that quenching to the vicinity of the critical point produces a highly time dependent density of superfluid fluctuations, which affect the conductivity in two ways. Firstly by inelastic scattering between the fermions and the fluctuations, and secondly by direct conduction through the fluctuations. The competition between these two effects leads to non-monotonic behavior in the time-resolved optical conductivity, providing a signature of the critical transient state
Mar '18
Donald Weingarten  -  Monday, March 5, 2018
Quantum Mechanics and the Macroscopic World
Indiana University, IBM Research, Finance
Mar '18
James Wynne  -  Monday, March 19, 2018
Illuminating My Career: From Flash Gordon to Laser Surgery
IBM Research Laboratory, Yorktown Heights
The ruby laser first "lased" in May, 1960. It was used for retinal surgery in late 1961. Over the next two decades, many laser surgical procedures were developed to remove undesirable tissue or seal bleeding ulcerated tissue, but they all left "therapeutic" scar tissue. 
In Nov-Dec, 1981, my IBM colleagues and I discovered that the short pulses of energetic ultraviolet light from an ArF excimer laser, emitting at 193nm (6.4 eV), could produces ultra-clean incisions in animal tissue, in vitro. We conceived that this laser could incise living tissue, which might heal without scarring, because there would be minimal damage to the tissue underlying and adjacent to the incision. Collaboration with ophthalmologists led to the laser refractive surgical procedures known as LASIK and PRK, which have improved the vision of more the 40 million people.
In 1983, my colleagues and I discovered that blood absorbed the 6.4 eV light from the ArF excimer laser via a non-thermal process. We thought this meant that we could not use the laser to treat deep skin lesions. 26 years later, in 2009, my dermatologist colleague and I conceived of using the laser as a "smart scalpel" to debride necrotic lesions of the skin, such as burn eschar, leaving the underlying and adjacent viable skin undamaged, resulting in faster healing, less pain, and minimizing scar tissue formation, when compared to "cold steel" debridement. I will report on the latest results of my collaboration with dermatologists at Stony Brook University, where we burn live pigs, debride the necrotic tissue with the ArF excimer laser, and see enhanced healing. Our first peer-reviewed paper, "ArF excimer laser debrides burns without destruction of viable tissue: A pilot study," is In Press, available online, and will be published In Print in the next issue of BURNS.
Mar '18
Yuhang Ren  -  Monday, March 26, 2018
ABSTRACT: Recently, BaZr0.2Ti0.8O3 (BZT) based ferroelectric films have exhibited high energy storage densities (up to 166 joules per cubic centimeter) and recycling efficiencies (up to 96 percent). Here, I will introduce you our new investigation of heterophase polydomain structures in BZT films by optical second harmonic generation (SHG) and photo-induced acoustic waves. We analyzed the spatial distribution of SHG intensities and GHz acoustic phonon oscillations. A rhombohedral symmetry is revealed to grow with increasing film thickness as tetragonal domains relax away from the film-substrate interface. The presence of phase segregated tetragonal and rhombohedral structures is further confirmed through TEM and XRD measurements. The high energy performance of the films is explained by ultra-adaptive nanodomains which can effectively accommodate the competing elastic and electrical stress fields during charge-discharge cycles.
Apr '18
Dimitrios Sounas  -  Monday, April 9, 2018
Nonreciprocal photonics without magnetic biasing
The University of Texas at Austin
ABSTRACT: Reciprocity is a fundamental principle in optics, requiring that the response of a structure is symmetric when source and observation points are interchanged. It is of major significance for the analysis, design and operation of optical systems, but at the same time it poses fundamental limitations on the ways we handle and process optical signals. Nonreciprocal devices, which break this symmetry, have become fundamental in photonic systems for protection of lasers, the separation of signals propagating in opposite directions and the design of photonic topological insulators. Yet, to date they require magnetic materials, making them bulky, costly and unsuitable for integration. This is in stark contrast with most photonic devices, including sources, modulators, switches, waveguides, interconnects and antennas, which may be realized at the nanoscale. In this talk I will show how it is possible to address this problem and design magnetless nonreciprocal devices by using time modulation and nonlinear effects. I will discuss how time modulation allows to impart an effective momentum to a structure and break reciprocity. I will show how this approach can be implemented at different frequency bands, spanning from microwaves to optics. Then, I will present how we can completely remove the requirement of an external bias and realize all-passive nonreciprocal devices by introducing nonlinearities in asymmetric structures. I will discuss fundamental limitations of these devices, stemming from time-reversal symmetry, and show how they can be overcome. I will conclude my talk by providing an outlook for future opportunities of this rapidly advancing research field.
Apr '18
Viktoriia Babicheva  -  Monday, April 16, 2018
ABSTRACT: Optical metamaterials are three-dimensional structures with rationally designed building blocks that enable devices with distinct optical responses not attainable with naturally available materials. Comprising a class of metamaterials with a reduced dimensionality, optical metasurfaces allow the miniaturization of conventional refractive optics into planar structures, and a novel planar technology is expected to provide enhanced functionality for photonic devices being distinctly different from those observed in the three-dimensional case. In this talk, I will show that nanostructures made of high-index materials, such as silicon, transition metal dichalcogenides, or hexagonal boron nitride, support optically induced both electric and magnetic resonances in the visible and infrared spectral ranges. I will present the results on antireflective properties of metasurfaces based on high-index nanoparticle arrays and explain how zero backward scattering from the highly reflective substrate can be achieved [1]. Scattering-type scanning near-field optical microscope (s-SNOM) provides optical, chemical, and structural information of metasurfaces and enables their imaging with nanoscale resolution. I will show an approach to analyze layered of materials with different permittivities and demonstrate a technique to identify material type based on near fields at sample edges [2]. The recent discovery of high-index materials that offer low loss and tunability in their optical properties as well as complementary metal-oxide-semiconductor (CMOS) compatibility can enable a breakthrough in the field of nanophotonics, optical metamaterials, and their applications.

[1] V.E. Babicheva and A.B. Evlyukhin, "Resonant Lattice Kerker Effect in Metasurfaces with Electric and Magnetic Optical Responses," Laser & Photonics Reviews 11, 1700132 (2017).
[2] Y. Abate, S. Gamage, L. Zhen, S.B. Cronin, H. Wang, V. Babicheva, M.H. Javani, M.I. Stockman, “Nanoscopy reveals surface-metallic black phosphorus,” Light: Science & Applications 5, e16162 (2016).
Apr '18
Mohammad Ali Miri  -  Wednesday, April 18, 2018
ABSTRACT: This talk will describe several opportunities for realizing novel nanophotonic devices by employing new degrees of freedom including optical gain and loss as well as mechanical motion. Although most previous efforts on designing photonic devices and structures have been focused on crafting their refractive index profile while avoiding active and dissipative mechanisms, recent investigations suggest the use of such non-conservative processes in order to achieve unusual properties and functionalities. These recent theoretical developments, which are originally inspired by quantum mechanics, have led to the emerging area of non-Hermitian photonics, proposing the conjunctive use of the optical refractive index, gain and loss as three ingredients for photonics design.

In the first part of this talk, I will provide an overview of the fundamental concepts of non-
Hermitian photonics, discuss some of its unique and exotic phenomena and mention potential applications. In particular, I will discuss coupled active/passive resonators and introduce a versatile approach for enforcing single-mode operation in multi-mode laser cavities. The second part of this talk is devoted to micro-/nano-optomechanical cavities as rich platforms for establishing a dynamical coupling between the electromagnetic field and mechanical motion. I will discuss the dynamics of such devices and show that giant optomechanically-induced nonlinear effects, in connection with the optical and mechanical dissipation, offer a viable route for breaking the reciprocity of light in order to realize compact optical isolators and circulators.
Apr '18
Xi Chen  -  Monday, April 23, 2018
Evaporation-Driven Engines and Generators
CUNY Advanced Science Research Center
ABSTRACT: Evaporation, which fuels rain and wind, is one of the largest energy flows on Earth. While we can now access many energy sources powered by evaporation, such as hydropower and wind power, the upstream energy of natural evaporation still remains untapped. Water-responsive materials that swell and shrink in response to changes in humidity level can convert evaporation energy into mechanical energy. Bacillus spores are one example of water-responsive materials developed by nature. Our recent study shows that the energy density of spores is significantly higher than all existing actuator materials and artificial muscles. Using spores, we developed two kinds of evaporation-driven engines that can self-start and continuously convert evaporation into mechanical motions, and subsequently into electricity, when placed at air-water interfaces. The energy harvested from evaporation is enough to power a small light source as well as a miniature car.
Apr '18
Jack Harris  -  Monday, April 30, 2018
ABSTRACT: Topological phenomena appear in a number of systems, from exotic quantum phases to carefully engineered waveguides. They offer potentially powerful forms of control, and are intriguing in their own right. I will describe a topological feature that is generically present in one of nature's simplest systems: a pair of damped coupled oscillators. I will describe experiments in which we demonstrate this Moebius-strip-like feature and use it to achieve topological control over the excitations in an optomechanical system. I will also describe the nonreciprocal dynamics associated with this feature.
May '18
Anthony Pullen  -  Monday, May 7, 2018
ABSTRACT: Emission from ionized carbon, or CII emission, is a promising candidate for tracing the universe through intensity mapping.  In this talk I discuss my latest work, searching for this nearly isotropic CII emission from star-forming galaxies.  After giving an brief introduction to intensity mapping, I will motivate the use of CII intensity mapping  to probe cosmology and galaxy physics.  I will then present the constraints I constructed on CII emission through intensity-galaxy cross-correlations, as well as current research to improve these constraints.  Finally, I will present EXCLAIM, a proposed balloon experiment, of which I am a part, that will aim to map CO and CII emission for studying star formation.