WorldCat Identities
Fri Mar 21 17:14:34 2014 UTClccn-n879437190.00Mechanisms of Photorefractivity in Polymeric Materials0.841.00Persistent spectral hole burning /85174606W._E._Moernern 879437192214196Moerner, W. E.Moerner, William E. (William Esco), 1953-Moerner, William Esco, 1953-lccn-n87943720Bjorklund, G. C.(Gary C.)nc-ibm almaden research center san jose caIBM ALMADEN RESEARCH CENTER SAN JOSE CAlccn-nr98040780Stanford UniversityDepartment of Chemistrynp-ambrose, w pAmbrose, W., t pCarter, T. P.lccn-nr97028501Basche, T.lccn-no2010060546Pande, Vijaythsnc-ibm research lab san jose caIBM RESEARCH LAB SAN JOSE CAnp-kador, lKador, L.viaf-233701287Small, Gerald J.Moerner, W. E.(William Esco)1953-Conference proceedingsEnergy-band theory of solidsOptical hole burningCrystallographyPhysicsPhysical organic chemistryNuclear excitationMolecular relaxation19531982198319851986198719881989199019911992199619971998199920002002200420102011201220132676678530.41QC176.8.O58ocn613559849ocn847349574ocn858068757ocn745022304ocn707461021ocn794277954ocn795013004ocn690908960ocn794361077ocn666885589ocn489629741ocn7971967001908ocn017354656book19880.92Moerner, W. EPersistent spectral hole-burning : science and applicationConference proceedingsThis book describes the underlying scientific fundamentals and principal phenomena associated with persistent spectral hole-burning in solids, and presents an overview of possible future applications to optical storage of digital data and optical signal processing. Organization of the material is by the general physical mechanism responsible for the formation of persistent spectral holes. After a description of the basic principles and methods of hole-burning, with examples from photochemical processes in crystalline and amorphous hosts, the unusual proton tunneling phenomena that occur in hydrogen-bonded polymers and glasses are described. Persistent spectral hole-burning in inorganic materials due either to photoionization or to photophysical effects is then summarized, followed by a detailed discussion of nonphotochemical hole-burning mechanisms for electronic transitions in amorphous solids. The book concludes with a description of potential applications to data storage and optical processsing using frequency-domain, holographic, and electric field techniques. Readers of this volume will gain a detailed appreciation of both the generality of the persistent spectral hole-burning phenomenon and the power of the technique in studying microscopic dynamics and mechanisms of phototransformation in low-temperature solids42ocn035508692book19921.00Persistent spectral hole burning44ocn074259337file1999Mechanisms of Photorefractivity in Polymeric MaterialsThis six month grant provided a continuation at Stanford University of AFOSR Grant No. F49620-96-1-0135, which ended 31 Mar 1999 at the University of California, San Diego (UCSD). During the period of this grant, accomplishments are of note. A major study of the effect of nonlinear chromophore energetic on the several speed of photorefractive polymers showed that rational design can improve the properties of these materials. Second, the entire laboratory moved from UCSD to Stanford University in July 1999. During this time, a major review article on photorefractive polymers for the Encyclopedia of Materials Science and Technology was completed (Pub. 171). Finally, in the new laboratories at Stanford, a first demonstration of fast image amplification with photorefractive polymers was completed32ocn745512160com19820.92Moerner, W. EVibrational relaxation dynamics of an IR-laser-excited molecular impurity mode in alkali halide lattices31ocn068528195book19960.47Single molecules and atoms21ocn613559849com20100.47Lord, Samuel JosephFluorophores for single-molecule imaging in living cells characterizing and optimizing DCDHF photophysicsThe number of reports per year on single-molecule imaging experiments has grown roughly exponentially since the first successful efforts to optically detect a single molecule were completed over two decades ago. Single-molecule spectroscopy has developed into a field that includes a wealth of experiments at room temperature and inside living cells. The fast growth of single-molecule biophysics has resulted from its benefits in probing heterogeneous populations, one molecule at a time, as well as from advances in microscopes and detectors. There is a need for new fluorophores that can be used for single-molecule imaging in biological media, because imaging in cells and in organisms require emitters that are bright and photostable, red-shifted to avoid pumping cellular autofluorescence, and chemically and photophysically tunable. To this end, we have designed and characterized fluorescent probes based on a class of nonlinear-optical chromophores termed DCDHFs. This Dissertation describes various physical and optical studies on these emitters, from sensing local environment to photoactivation. Chapter 1 is a general introduction to fluorescence and single-molecule spectroscopy and imaging. Single-molecule experiments in living cells are discussed and probes used for such experiments are summarized and compared. Chapter 2 explores the basic photophysics of the DCDHF fluorophores and some general methods of measuring relevant spectroscopic parameters, including photostability. Chapter 3 discusses the various approaches we have taken to modify particular properties by changing the fluorophore's structure. We have redesigned the DCDHF fluorophore into a photoactivatable fluorogen--a chromophore that is nonfluorescent until converted to a fluorescent form using light--described in Chapter 4. Finally, a different, chemical route to fluorescence activation is presented in Chapter 5. The remainder of the Dissertation is the Appendix and a full Bibliography. The Appendix includes a table of photophysical parameter for DCDHF fluorophore, various protocols used in the experiments discussed, MatLab codes, and NMR spectra21ocn609974029com19960.47Moerner, W. ESingle-Molecule Optical Detection, Imaging and SpectroscopySingle Molecule Spectroscopy is one of the hottest topics in today's chemistry. It brings us close to the the most exciting vision generations of chemists have been dreaming of: To observe and examine single molecules!. While most of chemistry deals with myriads of molecules, this books presents the latest developments for the detection and investigation of single entities. Written by internationally renowned authors, it is a thorough and comprehensive survey of current methods and their applications11ocn227688619book1986Persistent Infrared Spectral Hole-Burning for Impurity Vibrational Modes in SolidsOne unusual group of excitations in which persistent spectral hole burning has been observed consists of infrared vibrational transitions of impurity molecules in solids. Examples include 1,2,-difluoroethane in rare gas matrices, perrhenate ions in alkali halide crystals, and most recently, cyanide and nitrite ions in KBr. The hole formation mechanisms involve molecular reorientation or conformational changes at low temperatures induced by excitation of an internal vibrational mode of the impurity molecule. Keywords: Persistent spectral hole burning; vibrational mode; infrared; reorientation11ocn437088271book19960.47Single molecules and atom11ocn865449742file20130.47Sung, JongminAdvanced single molecule fluorescence analysis and force spectroscopy to understand myosin motorsMyosins are actin-based molecular motor proteins that are associated with numerous cellular functions both in muscle and non-muscle cells. In the past decades, single molecule biophysics has provided many useful in-vitro techniques that enable one to understand detailed molecular mechanisms of myosin-actin interaction. I will describe our results and continuing efforts in (i) single-molecule fluorescence localization analysis with TIRF microscopy, and (ii) single-molecule force spectroscopy with optical traps to understand myosin motors. Our theoretical point-spread function combined with maximum-likelihood-estimation precisely extracts both positions and orientations of fixed fluorescent molecules simultaneously. This approach is now mature as a structural tool, and I have applied it to two examples: myosin V labeled with a fixed dye walking on actin filaments, and dsDNA with two differently colored probes doubly attached to its backbone. We experimentally show that our method is not only precise but also accurate. Familial hypertrophic cardiomyopathies (HCM) are common genetic heart diseases that are often caused by single point mutations, especially in human beta cardiac myosin II. Using an optical trap assay, we found that the human beta cardiac myosin with the R453C HCM-causing mutation produces significantly elevated intrinsic force. We further developed a new method called harmonic force spectroscopy that can extract a force-velocity curve from a single cardiac myosin molecule. We found that a strong-to-weak transition of a cardiac myosin bound to an actin filament is modulated by an external load, which can be explained by simple Arrhenius transition theory11ocn227749851book1989Photon-Gated Persistent Spectral Hole-BurningThis article reviews recent progress in the area of photon gated persistent spectral hole burning, in which one photon selects absorbers in an inhomogeneously broadened line and a second gating photon of a different wavelength completes the excitation necessary to produce a spectral hole. This phenomenon provides a crucial threshold in the hole formation process, allowing reading with the first wavelength alone to be nondestructive. Examples of photo gating in both inorganic and organic materials are summarized, with emphasis of the organic materials. Keywords: Photo gating; Persistent spectral hole burning; Frequency domain optical storage11ocn227720635book1988Pseudo-Stark Effect and FM/Stark Double Modulation Spectroscopy for the Detection of Statistical Fine Structure in AlexandriteUsing laser-FM spectroscopy and transient spectral hole burning, the R1m transition of Cr3+ ions in alexandrite is shown to exhibit a linear pseudo-Stark effect with coefficients of 0.141 MHz-cm/V and 0.0538 MHz-cm/V at 1.6 K for electric fields along the crystal a and c axes, respectively. This result was used to develop a sensitive FM/Stark double modulation method for the detection of statistical fine structure (SFS) on the inhomogeneously broadened R1m line. While the final signal-to-noise ratio is not much greater than unity, autocorrelation of the measured spectra provides the first strong evidence for the presence of SFS in an inorganic material. Keywords: Statistical fine structure, Alexandrite, Stark effect, Modulation spectroscopy, FM Spectroscopy11ocn227565988book1983Reading and Writing of Photochemical Holes Using GaA1As Diode LasersA current tuned (gallium aluminum arsenide) diode laser is utilized both to burn and to detect narrow photochemical holes in the inhomogeneously broadened 833 nm zero phonon line of the R' color center in LiF. Applications for reading and writing data into frequency domain optical memories based on photochemical hole burning are discussed. (Author)11ocn666885589com20100.47Kinkhabwala, Anika AmirCoupling fluorophores to nanophotonic structuresFluorescence imaging and spectroscopy is an important tool in many areas of research. Biology has particularly benefitted from fluorescence techniques, since a single molecule's position, local environment, and even activity can be studied in real time by tagging it with a fluorescent label. It is, therefore, important to be able to understand and manipulate fluorescence. One way to control fluorescence is to shape the local electromagnetic fields that excite the fluorescent molecule. This thesis studies the interaction between fluorescent molecules and two nanophotonic structures that highly modify local electromagnetic fields: the bowtie nanoantenna and the photonic crystal cavity. The study of plasmons, or coherent excitations of free electrons in a metal, has led to the fabrication of antennas at optical frequencies. In particular, gold bowtie nanoantennas have been shown to concentrate light from the diffraction limit at 800 nm (~300 nm) down to ~20 nm, while also enhancing the local electric field intensity by a factor of 1,000. This huge change in the local field greatly alters the absorption and fluorescence emission of nearby molecules. This thesis will show that the fluorescence from an initially-poor single-molecule emitter can be enhanced by a factor of 1,300, allowing for the measurement of one highly enhanced molecule over a background of 1,000 unenhanced molecules. By extending this experiment to molecules in solution, dynamics of single molecules in concentrated solutions can also be measured. While bowtie nanoantennas act to concentrate light, light does not remain in the structure for long. The photonic crystal cavity can be used to trap and store light, which has interesting implications for molecular emitters located nearby. This thesis will show that molecules can be lithographically positioned onto a photonic crystal cavity and that the molecule's fluorescence emission is coupled to the cavity modes11ocn227765177file1991Finding a Single Molecule in a Haystack: Laser Spectroscopy of Solids from Sqrt. N to N 1Recent progress in the optical detection and spectroscopy of single ions in vacuum confined in electromagnetic traps has led to novel measurements that further our understanding of quantum physics. For example, various workers have achieved direct measurement of quantum jumps, Doppler sidebands, and other fundamental phenomena such as ion crystallization of ions in vacuum trapped by electromagnetic fields. By using laser induced fluorescence and a novel hydrodynamically-focused flow to confine the molecules and reduce the scattering volume, single molecules of the protein B-phycoerythrin with the equivalent of 25 rhodamine 6G chromophores have also been detected. In contrast to the far- field optical approach, recent advances with various near-field spectroscopies such as scanning tunnelling microscopy (STM) have provided images of single molecules of benzene and CO on Rh surfaces and images of liquid crystal molecules on graphite to name a few examples11ocn227704173book1987Statistical Fine Structure of Inhomogeneously Broadened Absorption LinesUsing laser frequency-modulation spectroscopy; we have observed statistical fine structure (SFS) in the inhomogeneously broadened optical absorption of pentacene in p-terphenyl at liquid helium temperatures. SFS is the actual frequency-dependent, time-independent structure of the inhomogeneous line caused by the randomly varying number of centers in each frequency interval. The size of the SFS varies as the square root of the number of centers, and the autocorrelation of the SFS yields and estimate of the homogeneous linewidth without requiring spectral hole-burning or coherent transients. Keywords: Spectroscopy of defects in solids; Molecular spectroscopy; Statistical effects11ocn227715461book1988Statistical Fine Structure in the Inhomogeneously Broadened Electronic Origin of Pentacene in p-TerphenylRecently, the first observation of statistical fine structure on an inhomogeneously broadened absorption profile was reported (W.E. Moerner, T.P. Carter, Phys. Rev. Lett. 59,2705(1987) for mixed crystals of pentacene in p-terphenyl using laser FM spectroscopy. Statistical fine structure is time-independent structure on the inhomogeneous line caused by statistical variations, in the spectral density of absorbers in each frequency interval. In this work, a model and an analysis of statistical fine structure using autocorrelation techniques are presented, and the dependence of the effect for pentacene in p-terphenyl at 1.4K on modulating frequency, detection phase, sample position, center concentration, and site is described. Keywords: Statistical fine structure, Inhomogeneous broadening, Molecular spectroscopy, Defects, Solids11ocn707461021com20110.47Lee, Jungjoon KempthorneDevelopment of techniques for live cell RNA imagingThe development of live cell RNA imaging techniques will lead to the unraveling of many important biological processes. To achieve this goal, there have been three different strategies developed. They are the development of small molecule probes, nucleic acid probes, and green fluorescent protein (GFP) probes. In the following thesis, the pros and cons of each approach are discussed, followed by a proposal to resolve the limitations. In the small molecule case, a probe was developed that utilized a quenched sulforhodamine dye. It was designed so that its structure can be rationally modified from the initial lead compound. An aptamer sequence that activates the sulforhodamine probe with micro molar affinity was found by in vitro Systematic Evolution of Ligands by Exponential Enrichment (SELEX), followed by fluorescence screening in E.coli. The rational modification of the structure of the initial sulforhodamine probe resulted in an overall 33-fold increase in binding affinity compared to the initial lead compound. Instead of the chemical modification of the lead compound, the small molecule's cell permeability and binding affinity to the target could be improved by linking to cell penetrating peptides (CPP). A CPP is a short peptide sequence composed of poly arginine amino acids which shows excellent cell uptake and affinity to RNA. However, the use of the CPP-linked dye in live cell imaging has been limited by strong signals in the endosome region. An attempt was made to overcome this difficulty by linking a quencher molecule to the dye-CPP via a disulfide bond, which only breaks when it enters the cytosol. For the nucleic acid probe, the major problem was its low cell permeability and low signal-to-background ratio due to the low copy number of mRNA targets within the cell. We made mutant Hammerhead ribozymes and embedded them in a non-coding region of the GFP expression vector that can be transfected to mammalian cells. This modified Hammerhead ribozyme acts as a logic gate, and the signal is amplified by the expression of GFP in the presence of the target mRNA. In vitro and in vivo results are discussed. Finally, a fragmented GFP system, the fluorescence of which could be recovered by binding to a specific RNA tag, was developed. The major problem for the GFP-mediated RNA imaging system was the low signal-to-background ratio from the GFP probe that is not bound to the RNA tag. To find the non-fluorescent GFP, the GFP was truncated from the C-terminus such that it loses its fluorescence with minimum loss of amino acids. An RNA sequence that has high affinity to this GFP was found by in vitro SELEX. The subsequent E.coli screening found an RNA sequence that reactivates the fluorescence of the GFP probe11ocn227749850book1989Optical Detection and Probing of Single Dopant Molecules of Pentacene in a p-Terphenyl Crystal by Means of Absorption SpectroscopyOptical absorption lines of impurity molecules or ions in a solid matrix are usually subject to inhomogeneous broadening, thereby reflecting various imperfections in the structure of the host material. The inhomogeneous distribution can be roughly described by a Gaussian profile. A fundamental statistical fine structure (SFS) is superimposed on the smooth Gaussian curve. Using a combination of laser frequency-modulation absorption spectroscopy and either Stark, longitudinal ultrasonic, or transverse ultrasonic internal modulation, the optical absorption spectrum of a single impurity molecule of pentacene in p-terphenyl crystal may be measured at liquid helium temperatures. The general properties of this detection method are illustrated by first applying the technique to the detection of persistent spectral holes in the pentancene/p-terphenyl system. Selection of a single absorber for-measurement is accomplished by tuning the probing laser far out into the wings fo the inhomogeneously broadened 0-0 absorption lines for either the 0(1) or 0(2) sites. The single-molecule line shape is similar to that predicted by a simple model of the double-modulation process. The approximate amplitude of the single- molecule signals suggests that triplet bottleneck power broadening is suppressed for out in the wings of the inhomogenous line. This work probes the ultimate N=1 limit of the statistical fine structure present in all inhomogenous absorption lines11ocn227688554book1986Dynamical Hole-Burning Requirements for Frequency Domain Optical StoragePersistent spectral hole burning (PHB) is a frequency selective bleaching phenomenon that potentially provides a new dimension for optical storage of information, if suitable materials can be found. In the most general form of PHB, narrow depressions or holes are formed (burned) in an inhomogeneously broadened absorption line of an absorber in a solid at low temperatures whenever light absorption causes a change in the absorbing center that persists longer than any excited state lifetime. Previously studied materials involve monophotonic mechanisms for the photochemical or photophysical change leading to hole formation; such mechanisms have serious limitations as to the number of reads that can be performed without distortion of the written data. Recently, photon gated spectral hole burning has been observed in both inorganic and organic materials, indicating that nondestructive reading of spectral holes is possible. This talk will focus on the properties of the organic photon gated material in particular and describe the properties of what might be termed an ideal photon gated system. Keywords: Frequency domain optical storage, Photon gating, Biphotonic, and Nondestructive readingFri Mar 21 15:30:21 EDT 2014batch26885