bluuebunny/crossref_metadata_2025 huggingface dataset:
Target Reflectance Measurements for Calibration of Coherent Lidar Atmospheric Backscatter Data
Authors: Kavaya Michael J. , Menzies Robert T. , Flamant Pierre H. , Oppenheim Uri P.
Published: February 2023

Aerosol backscatter measurements at CO2 laser wavelengths are important for assessing the feasibility of an earth-orbiting tropospheric winds measurement technique using Doppler lidar to provide data for forecasting and for studies of transport processes (e.g. the NOAA WINDSAT satellite mission) [1, 2]. We have built a coherent laser radar, using an injection-locked TEA-CO2 laser transmitter which is grating tunable from 9-11 μm, to measure backscatter coefficients as a function of wavelength over an altitude range of 1-10 km.
Surface-Layer Micrometeorology by Optical Scintillation Techiques
Authors: Hill R. J. , Ochs G. R.
Published: February 2023

The atmospheric surface layer is the lowest few tens of meters of the atmosphere. The vertical fluxes of horizontal momentum, of heat, and of humidity are the basic statistical quantities describing turbulence in the surface layer. These three fluxes are sufficient information to determine the stability of the horizontally homogeneous surface layer (i.e., determine the Richardson number or equivalently the Monin-Obukov length), with the humidity flux being of secondary importance compared with the heat flux. These fluxes then determine the height profiles of many other surface-layer characteristics, such as the gradients of mean temperature and humidity, temperature variance and structure parameter (or those of humidity), vertical velocity variance and velocity structure parameter, and energy dissipation rate. Basically, all surface layer turbulence statistics that obey Monin-Obukov similarity are predicted from these three fluxes, with the humidity flux usually being unimportant for those quantities not involving averages of humidity fluctuations. An example of a quantity that does not obey Monin-Obukov similarity is the variance of horizontal wind speed fluctuations in the unstable surface layer; this quantity is affected by the large eddies of the mixed layer above the surface layer. By way of terminology: unstable conditions occur when part of the turbulence energy is generated by upward convection of heat; neutral conditions occur when the turbulence is generated by wind shear near the ground with convection providing no energy; finally, stable conditions occur when part of the turbulence energy is damped by stable stratification, but turbulence persists because of wind shear.
The Effects of Multiple Scattering on Optical Pulses
Authors: Elliott Richard A.
Published: February 2023

The spatial resolution and precision of atmospheric LIDAR systems are ultimately limited by the time resolution of the detecting system and the duration of the pulses transmitted. In the presence of clouds, fog, and aerosols scattering can introduce multiple path effects which can seriously degrade system performance. Both a loss in longitudinal spatial resolution due to temporal stretching of the received pulses and loss of precision due to enhanced delay result from multiple paths. In addition lateral resolution is degraded due to beam spreading and the signal to noise ratio decreased by the attenuation due to scattering.
Recent Millimeter and Sub millimeter Observations of Species of Atmospheric Importance.†
Authors: Bowman Wayne C. , Charo Arthur , Kolena John , De Lucia Frank C. , Helminger Paul
Published: February 2023

We have recently made and currently have under way extensive millimeter and submillimeter measurements on a number of important atmospheric species. As a complement to this work, we have theoretically analyzed this data with the goal of producing "complete" spectral maps of these species in the region up to 1000 GHz. Among the species studied are hydrogen peroxide (HOOH), the hydroperoxy radical (HO2), difluoromethylene (CF2), nitric acid (HNO3), nitrous acid (both cis and trans) HNO2, nitrogen dioxide (NO2), and water (H2O). Details of the theoretical techniques and illustrations based upon earlier work of the laboratory are given in another paper at this meeting.
Microwave Rotational Spectrometry in the Analysis of Trace Atmospheric Constituents
Authors: Rinehart Edgar A. , Harder Jerald
Published: February 2023

For several years Microwave Rotational Spectrometry (M.R.S.) has(1,2) shown promise of becoming a powerful analytic method for polar gases. The particular features of interest in M.R.S. are the very high specificity and linearity of response over a wide dynamic range. Because of the high specificity, it is possible to measure the concentrations of several gases by the same technique, in the same instrument, with a single sample. For example one can detect and quantify any one of many sulfur containing molecules (such as OCS, SO2, H2S, CH3SH, etc.) without regard to interferences. The wide range linear response provides an ease of calibration not found with most other techniques.
Effect of Line-Width Data on Retrievals of Gas Concentrations in Limb-Viewing Experiments
Authors: Smith M. A. H. , Russell J. M. , Gordley L. L.
Published: February 2023

It has long been understood that accurate knowledge of collision-broadened halfwidths is necessary for infrared remote sensing of stratospheric minor gases. A careful examination of the curve of growth for typical stratospheric absorption lines indicates that for limb-viewing experiments, the long geometric paths through the atmosphere may result in higher sensitivity to collision broadening, relative to that of nadir-viewing experiments. Unfortunately, efforts in laboratory spectroscopy have usually been concentrated on obtaining line positions, strengths, and assignments, while the more difficult halfwidth measurements have been made very infrequently. In this paper, we present the results of halfwidth-sensitivity studies for ozone retrievals from typical limb-viewing absorption or emission experiments using both high-resolution spectroscopy and broad-band radiometric techniques.
Analytic Characterization of Spectral Actinic Flux and Spectral Irradiance in the Middle Ultraviolet
Authors: Schippnick P. F. , Green A. E. S.
Published: February 2023

We have made use of the multi-model calculations of upward and downward spectral irradiance of Braslau and Dave (1973) (BD) and the multi-ozone level calculations of Dave and Halpern (1975) (DH). The model-specific character of the BD data enables us to isolate and model separately the effects of Rayleigh scattering, ozone absorption, and aerosol scattering and absorption (in that order). The actinic flux "data" that we made use of consisted of calculated values of Peterson (1976, 1979).
The B-Component of the Transition Moment for the v2 Band of Nitric Acid Vapor
Authors: Farrow L. A. , Richton R. E.
Published: February 2023

Atmospheric measurements of nitric acid are relevant both in the troposphere, where it is a precursor of inorganic free radicals as well as of nitrates and aerosols1, and in the stratosphere2, where it is a principal repository of odd nitrogen3,4. Single frequency laser detection offers the possibility of distinguishing nitric acid from other atmospheric species if the effective extinction coefficient for a given laser line is known; such information on more than one line heightens the discrimination. Recently, the constants of the Hamiltonian for this band have been published5, so that the transition frequencies and relative line strengths may be calculated. This information has been combined with transmittance data at four different CO laser frequencies which are coincident with the v2 band of nitric acid such that the extinction coefficient is determined for each laser frequency. In addition, the b-component of the transition moment for the band is found at each CO laser line used; these values are consistent among themselves and overlap the earlier determination of Goldman et al. 6 within the quoted uncertainties.
Spectral Line Profiles in the 4.3 Micron Band of Carbon Dioxide
Authors: Cann M.W.P. , Nicholls R.W. , Roney P.L. , Findlay F.D. , Blanchard A.
Published: February 2023

Accurate computation of atmospheric transmission requires the complete description of both the atmospheric path, in terms of the thermodynamic conditions, and of the spectroscopic properties of all optically active elements in the path. One of the major sources of extinction in the infrared spectral region is absorption by CO2. It has been known for many years now that the spectral line profiles for CO2 are significantly non-Lorentzian and this paper describes a method for obtaining the true line profiles from experiment and presents results for CO2 spectral lines in the 4.3 micron band.
Ozone Line Widths and Strengths Near 1129.4 CM−1
Authors: Majorana L.N. , Copeland G.E. , Harward C.N.
Published: February 2023

With the advent of semi-conductor lasers and their recent application to spectroscopy (1,2), there has been a revolution in the study of infrared spectra. Use of the tunable diode laser(TDL) has permitted high resolution (<0.0001 CM−1) studies of several molecules of high current interest (C10,HNO3,SO2,CF2C12,etc.). This study is concerned with the experimental determination of the pressure broadened characteristics of a single O3 line near 1129.4 CM−1. This line has been selected by NASA as a possible candidate for remote sensing experiments using either infrared heterodyne spectroscopy or differential lidar, since it is relatively well isolated from other atmospheric lines and has significant strength. A Beer's Law experiment is performed to determine the absorption coefficients and collisional self-broadening parameters.
Cutoff-Free Theory of Impact Broadening and Shifting of Microwave and Infrared Molecular Spectra
Authors: Leavitt Richard P. , Korff David
Published: February 2023

The semiclassical Anderson-Tsao-Curnutte (ATC) impact theory [1,2] of pressure broadening in molecular spectra has been successful in calculations of linewidths and shifts in the microwave and infrared regimes. However, the theory suffers from a fundamental defect in that, for small impact parameter, b, the interruption function, S(b), attains unphysically large values. In an attempt to circumvent this difficulty, Murphy and Boggs [3] developed an alternative method that used an exponential expansion of the collision matrix elements; this expansion led to finite values of the matrix elements for all impact parameters. Cattani [4] grafted the Murphy-Boggs expansion onto the ATC theory; a similar result was later derived by Salesky and Korff [5]. These latter three approaches neglect the important reorientation terms that were shown by Gordon [6] to be significant.
The Role of Chemistry in Glass Polishing
Authors: Cook Lee M.
Published: February 2023

The aqueous chemistry of both glass surfaces and polishing compounds is discussed within the context of current mechanical models for the polishing process.
Chemo-Mechanical Effects in Loose Abrasive Grinding of ULE
Authors: Golini Donald , Jacobs Stephen D.
Published: February 2023

This study examined chemo-mechanical effects in loose abrasive microgrinding (grinding with micron and sub-micron sized abrasives). The work was directed specifically at understanding loose abrasive grinding dependency on slurry fluid chemistry. Several slurry fluids were investigated, including water, a homologous series of n-alcohols, and several other organics selected for various properties including molecular size and dielectric constant. Chemistry was found to play a major role in this process; in fact, by simply changing slurry fluid composition, it was possible to induce the transition from brittle fracture to ductile mode grinding in ULE® (Corning Code 7971 Titanium Silicate Low Expansion Glass). Data revealed that the dependency of loose abrasive grinding on slurry chemistry can best be explained as Rebinder-Westwood chemo-mechanical effects [1-4].
Designing of Persistent Hole-burning Materials: Spectral Widths and Electronic Structures in Proton Transfer Molecular Systems
Authors: Tani Toshiro
Published: February 2023

Persistent spectral hole burning (PSHB) has attracted much attention due not only to its usefulness in site-selective spectroscopy but also to its applicability to wavelength multiplexed optical memory in the future.1) Though the application is still far from realization, potentially 103 times higher storage density would be attainable. Technological breakthrough is largely concerned with the issue of optimizing the storage materials. For the formation of persistent holes, the existence of both photoreactive centers and a solid matrix is essential, hence the comprehension of intramolecular and intermolecular electron-phonon interaction is of great importance. We have already proposed one working hypothesis, which, derived mainly from the experiments related to the intermolecular interactions, emphasizes the possibility of controlling the mesoscopic structure of the materials.2-4)
High Pressure Effects In Spectral Hole-Burning
Authors: Kikas J. , Laisaar A.
Published: February 2023

Persistent spectral holes have been shown to be very effective probes for studying various optical properties of solids [1]. Spectral hole-burning (SHB) studies include, in principal, two different types of experiments. In type I experiments the physical conditions (temperature, pressure, electric or magnetic fields etc.) are varied between the burning and measuring procedures. Such experiments yield information mostly on the shifts of energy levels (transition energy changes) of impurity molecules embedded in various matrices. Starting with the pioneering studies by Haarer et al. [2] a lot of interesting results were obtained on the influence of pressure (both uniaxial and hydrostatic) on the spectral holes in type I (nonisobaric) experiments in the low-pressure range (<200 bar).
A Solid as a Single-Molecule Trap: Optical Spectroscopy of Single Impurity Centers in a Solid
Authors: Moerner W. E.
Published: February 2023

The power of laser-recoil cooling and optical trapping of single ions has led to a variety of fascinating experiments investigating the fundamental interactions between light and matter which test our understanding of quantum physics 1,2. Cooling and trapping of molecules, however, has failed to date because the large number of vibrational and rotational modes present prevent the use of laser cooling techniques.
Single molecule spectroscopy: Stark effect of pentacene in p-terphenyl
Authors: Güttler Frank , Pirotta Marco , Renn Alois , Wild Urs P.
Published: February 2023

Based on the occurrence of extremely narrow zero phonon lines and their inhomogeneous distribution spectroscopic isolation of single absorbers in solid matrices can be achieved. Pentacene molecules in a p-terphenyl host crystal have been studied at cryogenic temperatures using absorption [1] and fluorescence excitation [2,3] techniques. Such investigations provide information on a variety of guest host properties such as homogeneous dephasing, spectral diffusion [3] and inhomogeneous broadening. Single molecule detection also is a key to the investigations of fundamental spectroscopic properties of individual molecules.
Hole-burning and site selection spectroscopy of porphyrins in various sol-gel matrices.
Authors: Kulikov S. , Galaup J.P. , Chaput F. , Boilot J.P.
Published: February 2023

Various organic dyes have been embedded in matrices of transparent silica porous glasses prepared at room temperature by the sol-gel technique (1). The basic reaction of this process is an inorganic polymerization between silanol reactive monomers (≡Si-OH). These inorganic hosts are a link between organic and high temperature inorganic glasses. Hole-burning measurements have been published previously on chlorin and oxazine-4 perchlorate in a silicate glass (2).
Quantitative and Theoretical Analysis of PHB-Hole Feature under Applying Electric Field.
Authors: Yagyu Eiji , Nishltnura Tetsuya , Yoshimura Motomu
Published: February 2023

We have investigated the stark effect on the spectral hole characteristics in the photochemical hole burning systems of anthraquinone derivatives, such as, 1,4-dihydroxyanthraquinone (HAQ) and 4-amino-2,6-bis(4-butylphenoxy)1,5-dihydroxyanthraquinone (ABDAQ) as guest molecules embedded in host polymers such as 2-hydroxyethyl methacrylate (PHEMA) or poly(vinyl butyral) (PVB)1-3). Consequently, we evaluated the dipole moment differences |δμ| of guest molecules. These dipole moment differences depended on the characteristics of the guest and host molecules. This material dependence of the dipole moment differences was able to be explained qualitatively by Hammett’s substituent constant and the Taft’s polar substituent constant3).
Single Molecule Spectroscopy: Fluorescence Lifetime of Pentacene in p-Terphenyl
Authors: Pirotta Marco , Güttler Frank , Sepiol Jerzy , Renn Alois , Wild Urs P.
Published: February 2023

Single molecule spectroscopy opens a wide field of research. Fundamental spectroscopic properties such as inhomogeneous broadening, spectral diffusion, and homogeneous dephasing can be investigated. Moerner and Kador first succeeded in detecting single pentacene molecules in a p-terphenyl host crystal by using a double modulated absorption technique [1]. Orrit and Bernard used a fluorescence excitation [2] technique to detect single molecules. Spectroscopic measurements of the quadratic Stark effect were performed by Wild, Güttler, Pirotta, and Renn [3].
Long-lived stimulated photon echo: the ideal probe of glass dynamics
Authors: Meijers Hans C. , Wiersma Douwe A.
Published: February 2023

In the last two decades the dynamics of glasses has been a field of great interest. In order to explain the dynamical properties of glasses the two-level-system model has been proposed. In this model an atom, or group of atoms, can access two potential minima separated by a barrier. Phonon-assisted-tunneling between the two minima of this asymmetric double well potential represents a jump between two different local glass structures. These double well potentials are referred to as two-level-systems (TLS). In the standard TLS-model the potentials do not change in time. The intrinsic disorder of the glass provides a wide range of asymmetries and a broad distribution of transition rates. Consequently the dynamics of the glass takes place over a broad range of time scales.
Spectral Diffusion in Glasses: A Study by Time-Resolved Hole-Burning with a Diode Laser
Authors: Wannemacher R. , Smorenburg H.E. , Schmidt Th. , Völker S.
Published: February 2023

The dynamics of structural fluctuations in glasses can be probed by following the ’homogeneous linewidth’ Γhom of optical transitions in doped amorphous solids as a function of time [1-5]. Owing to the wide distribution of barrier heights associated with two-level systems (TLS) in glasses, these fluctuations are thought to occur over a broad range of time scales.
Picosecond Energy Transfer in Genetically Modified Photosynthetic Antenna Complexes Studied by Hole-Burning.
Authors: van der Laan H. , De Caro C. , Völker S.
Published: February 2023

Information on dynamic guest-host interactions is contained in the homogeneous linewidth Γhom [1]: where T1 represents the population decay time of the excited state, and T2* the pure dephasing time determined by thermally induced fluctuations of the optical transition frequency. The first term includes all de-excitation steps, i.e. direct de-excitation to the ground state and energy transfer processes from the excited state. If energy transfer does not occur, then T2* usually dominates, since T1 ≫ T2*. This is the case for most organic molecules doped in glasses and polymers [1] and some biological model systems at low temperature [2]. By contrast, for many pigment-protein complexes Γhom is principally given by population decay, thus T1 ≪ T2* [3].
Inhomogeneous broadening and spectral hole burning in SryBa1-yFClxBr1-x: Sm2+
Authors: Jaaniso R. , Hagemann H. , Bill H.
Published: February 2023

The present work was undertaken at first due to the attractive properties of this class of compounds with respect to hole burning applications (see, e.g. [1-3]).
Temperature Cycling of Persistent Hole Spectra: A Method for Investigating the TLS Density in
Authors: Materials Amorphous , Kador L.
Published: February 2023

Persistent hole burning yields a spectral resolution of the order of the homogeneous linewidth, which, especially in the case of amorphous materials, greatly improved the utility of optical spectroscopy. However, the homogeneous linewidth itself can in general not be measured in a hole-burning experiment, since in virtually all disordered solids the hole width is affected by spectral diffusion [1,2]. The time [3] and temperature [4] dependence of spectral diffusion, on the other hand, can be investigated by fast hole-burning measurements and by thermal cycling, respectively. During a thermal cycle, spectral diffusion gives rise to an additional irreversible inhomogeneous broadening component of a hole spectrum because at a higher excursion temperature more tunneling states or TLS of the glassy matrix are in thermal equilibrium than at the burning temperature. This irreversible broadening yields information on the activation energies of the TLS [4,5].
Investigations of Quinizarin Adsorbed on 7-Alumina Using Persistent Spectral Hole-Burning
Authors: Kettner R. , Sauter B. , Bräuchle C.
Published: February 2023

In former investigations of quinizarin (Q) adsorbed on the surface of γ-alumina , the glasslike character of this system could be demonstrated [1,2,3]. Also, a binding model has been assumed, which is in accordance to a well known condensation reaction between surface hydroxyl (OH)groups and the OH groups of Q, leading to a stable adsorbate complex[1]. The temperature dependence of the Debye-Waller factor was found to be determined by one dominant low-frequency mode of the chromophore environment. This frequency corresponds to the spectral distance between the peak of the zero-phonon-hole(ZP) and the phonon sideband-hole (PS).
Hole-burning and site selection spectroscopy of porphyrins in various sol-gel matrices
Authors: Kulikov S. , Galaup J.P. , Chaput F. , Boilot J.P.
Published: February 2023

Various organic dyes have been embedded in matrices of transparent silica porous glasses prepared at room temperature by the sol-gel technique (1). The basic reaction of this process is an inorganic polymerization between silanol reactive monomers (≡Si-OH). These inorganic hosts are a link between organic and high temperature inorganic glasses. Hole-burning measurements have been published previously on chlorin and oxazine-4 perchlorate in a silicate glass(2).
Thermal Filling and Laser-induced Filling of Spectral Hole in Zn-tetraphenylbenzoporphyr in/p-hydroxybenzaldhyde in Poly(methylmethacrylate)
Authors: Luo Baozhu , Tian Mingzhen , Li Wenlian , Huang Shihua , Yu Jiaqi
Published: February 2023

Photochemical hole burning (PHB) is attracting much interest [1] due to its potential in high density optical memory, and its power in high resolution spectroscopy. The PHB is expected to a 103 to 104-fold increase in storage density over conventional optical storage. The PHB enables one to select a group of photoreactive molecules in the system, and obtain much information on the circumstances around them. Thermal stability of system at low temperature has been studied extensively with the cycle annealing experiments[2,3]. From these experiments, two types of information can be obtained, i.e. thermal activated backward reaction of photoproduct and spectral diffusion[3]. The systems studied were concentrated on one-color hole burning systems. The information of thermal stability in photon-gated hole burning system is scarce. The laser-induced hole filling were studied in rare earth ion and dyes doped into BaFC1.5Br.5 and polymers respectively[2,4,5].
On The Origin of Linear Stark Effect on Spectral Holes in Centrosymmetric Impurity Systems
Authors: Renge Indrek
Published: February 2023

It has been shown that a linear Stark broadening of spectral holes occurs in centrosymmetric impurity molecules devoid of intrinsic dipole moments [1-9], The dipole moment changes as large as 0.58D for perylene [2] and 0.8-1.6D for pentacene [7,8] have been observed in polar poly(vinyl butyral) (PVB) and poly(methyl methacrylate) (PMMA) matrices, respectively. To our knowledge, a second order Stark shift of spectral holes have not been established even in non-polar hosts.
Concentration Effects on Spectra and Persistent Hole-Burning of Porphyrin Doped Langmuir-Blodgett Films
Authors: Romanovskii Yu. V. , Personov R. I. , Samoilenko A. D. , Holliday Keith , Wild Urs P.
Published: February 2023

Persistent spectral hole-burning has recently been employed in investigations of pseudo-two-dimensional systems such as porphyrin and organic dye doped Langmuir-Blodgett films [1]. In order to perform spectral measurements on such ultra-thin materials, especially in the case of monolayers, the necessity to work with highly concentrated samples arises. For example, in a spectral hole-burning study of porphyrin centres in a multilayer assembly [2], the average distance between chromophores was about 3.5 nm which is of the same order as the Forster radius for energy transfer. Energy transfer and aggregation of impurities at high concentrations may strongly interfere with other processes under investigation such as optical dephasing and spectral diffusion. The effect of impurity concentration on spectral properties is an effective way of determining the dominant processes. Some data has already been published for conventional bulk systems such as tetracene doped alcohol glass [3] and chlorin and tetraphenylporphyrin doped polystyrene [4]. Here we present results of investigations of concentration effects on spectra and hole-burning of impurity doped Langmuir-Blodgett films.
Effect of Photocrosslinking in Polymer Matrix on Hole Properties: Quinizarin Sulfonate Doped Poly(vinyl alcohol)s with Pendent Styrylpyridinium Groups
Authors: Tani Toshiro
Published: February 2023

Persistent spectral hole burning (PSHB) has attracted much attention due not only to its usefulness in high resolution spectroscopy but also to its applicability to wavelength multiplexed optical memory.1) Though its application is still far from realization, potentially 103 times higher storage density would be attainable. Technological breakthrough is largely concerned with the issue of optimizing storage materials. For the formation of persistent holes, the existence of both photoreactive centers and a solid matrix is essential, and therefore, the comprehension of intramolecular and intermolecular electron-phonon interaction is of great importance. We have already proposed one working hypothesis in connection with the latter, which emphasizes the possibility of controlling the mesoscopic structure of the materials.2-4)
On the Study of Inhomogeneous Broadening and Related Quantities by Molecular Dynamics and Quantum Chemistry.
Authors: Brown Ross
Published: February 2023

Most resonances of molecules, such as optical, infra-red or electron spin resonance transitions are shifted and broadened in solids, compared to the spectra of the isolated molecule in the gaseous phase. Inhomogeneous or statistical broadening reflects the variety of surroundings felt by the many molecules probes in a sample while homogeneous broadening, a dynamical effect, is caused for example by the elastic Interaction of the electronic degrees of freedom with intermolecular phonons, or structural rearrangement by tunneling relaxation (two level systems). Homogeneous linewidths at low temperatures are much larger in amorphous materials than in crystals, with quite different temperature dependencies, reflecting the kind and density of modes coupled to the electronic transition. Hence, homogeneous broadening can add to our understanding of the differences between crystals and glasses, and has been studied intensively.
Science and Applications of Photorefractive Polymeric Materials
Authors: Moerner W. E. , Silence S. M. , Bjorklund G. C. , Burland D. M. , Miller R. D. , Stankus J. J. , Twieg R. J.
Published: February 2023

In the past few years, a new class of polymeric materials for photonic applications has appeared called photorefractive (PR) polymers. Photorefractivity is defined as modulation of the index of refraction in an electro-optic material by internal electric fields produced by optical redistribution of charge carriers; hence it must not be confused with local mechanisms of index change such as photochromism, excited state population, heating, etc. When a material shows the required properties of charge generation, transport, trapping, and dependence of the index of refraction upon the internal electric field, it can be tested for photorefractivity by observation of asymmetric energy transfer (two-beam coupling) between two laser beams in the material.
Photochromic Memory Media for Photon-Mode Optical Recording
Authors: Irie Masahiro
Published: February 2023

Photon-mode optical recording offers advantages over magnet-optic or
phase change recording, which utilizes light as a heat source for
recording, with regard to resolution, speed of writing, and multiplex
recording capability. One of the candidates for the photon-mode
recording media is organic photochromic media. Although much effort
has been made in this field in the past, the photochromic materials
still await practical application. The limitation is due to the lack
of suitable materials which fulfill the requirements for the
reversible recording media. The requirements for the use are:

1. Archival storage capability

2. Low fatigue (write/erase cycles can be repeated many times)

3. High sensitivity at diode laser wavelengths and rapid response

4. Non-destructive readout capability.
Photon echo spectroscopy on biological systems: Application to tissues and antigen-antibody systems
Authors: Furusawa Akira , Suga Takayuki , Uchikawa Kiyoshi
Published: February 2023

A biological system has a huge internal degree of freedom originating from the variety of its function. Proteins of which a biological system is composed have a huge number of conformational substates microscopically and show complex dynamics. Elucidation of the microscopic dynamics and the internal degree of freedom in biological systems is thought to be a key to the elucidation of the physiological activity and life.
Femtosecond Time-Space Holograms: Diffraction on the Edge of Time
Authors: Rebane Alexander , Ollikainen Olavi , Schwoerer Heinrich , Wild Urs P.
Published: February 2023

Time- and space domain (TSD) holography [1-3] can be viewed upon as a more general case of conventional holographic process, in which the recording media re members, in addition to the spatial picture, also the spectral intensity of the illuminating light. The resolution of TSD-holograms in time is Fourier-related to the spectral properties of the recording media. The longest time interval that can be recorded is given by the inverse value of the homogeneous width of the zero-phonon line and the shortest time is given by the inverse value of the width of the inhomogeneous distribution in the frequency dimension. By using photochemical spectral hole-burning in organic dye-polymer systems with very broad inhomogeneous bands TSD-holograms of full scenes of ultrafast events with subpicosecond time resolution have been recorded [4, 5].
Photon Echo Spectroscopy in Dye-Polymer Systems
Authors: Saikan Seishiro
Published: February 2023

Recent experimental results on femtosecond accumulated photon echo in dye-polymer system are reviewed. This talk consists of two parts. The first half is concerned with the linear electron-phonon coupling in dye-polymer systems.1) The aim of this research is to clarify the parameter that is most important in significantly affecting the linear electron-phonon coupling in these materials,2) and to find the materials which have extremely weak linear electron-phonon coupling. In the theory of electron-phonon interaction, two parameters of Huang-Rhys factor and phonon frequency are important to characterize each material. Therefore, this research is closely related to the unsettled problem on the low frequency phonon mode in amorphous materials. It has been found that the peak frequency of the phonon sideband spectrum nearly coincides with the frequency of the boson peak that is observed in the Raman scattering spectrum of polymers,3) and that the Debye-Waller factor is larger for the polymers with higher boson peak frequency, such as hydrogen-bonded polymers. However, there seems to exist a maximum of the boson peak frequencyat around 40 cm-1 in organic polymers. This result explains the reason why it is difficult to develope the PHB memory material that works above the temperature of liquid nitrogen, so long as the dye-polymer systems are employed. As far as the dye-polymer system is concerned, the porphyrin substituted hemeproteins are, to the best of our knowledge, samples with very weak linear electron-phonon coupling.4) It is my opinion that the hydrophobic compartmentalization of the chromophores is the dominant mechanism that markedly reduces the electron-phonon coupling in the iron-free hemeproteins.
Spectral Hole-Burning in NMR: Experimental Test of Relaxation Theories by Using Well-Characterized Noise Fields
Authors: Kohmoto T. , Fukuda Y. , Kunitomo M. , Ishikawa K. , Ebina K. , Kaburagi M.
Published: February 2023

An experimental approach for the verification of relaxation theories is presented. Relaxation phenomena in spectroscopy commonly appear in experiments such as nuclear magnetic resonance (NMR), electron spin resonance (ESR), and optical or laser spectroscopy. Their analyses with relaxation theories give much useful information on various physical system. For the experimental test of relaxation theories, a study of NMR relaxation phenomena in noise fields, whose statistical properties are well known and can be controlled, is very useful [1], since the time evolution of the system can be fully monitored.
The Effect of Pressure, Time and Concentration in Hole-Burning Studies
Authors: Volker Silvia
Published: February 2023

The study of spectral diffusion of an electronic transition of a molecule in an amorphous host yields information on the structural relaxation of the system. Although this phenomenon has recently been investigated by many groups, no unambiguous picture has yet emerged as regards the dynamics of glasses at low temperature. Furthermore, the relation between spectral diffusion and energy transfer resulting from a concentration increase has so far not been addressed.
High Pressure Hole-Burning Studies of Transport Dynamics in Photosynthetic Protein Complex
Authors: Small G. J. , Reddy N. R. S. , Jankowiak R.
Published: February 2023

Hole burning spectroscopies have proven to be powerful tools for the elucidation of the excited state (Qy) electronic structure and transport (energy, charge) dynamics of photosynthetic protein-chlorophyll complexes.1-3 Furthermore, hole burning has proven that such complexes are glass-like on a microscopic scale, which results in inhomogeneous broadenings of ~50-150 cm-1 (ΓI) for the Qy←S0 Chi absorption transitions. Importantly, it has also been shown that the zero-phonon line (ZPL) frequency distribution functions for different Qy-states of the same complex are uncorrelated, meaning that the widths of the distribution functions for energy gaps relevant to energy and electron transfer are ~21/2 ΓI. This raises the possibility that the kinetics for transport could be dispersive.4 Whether or not they are turns out to be dependent on the .strength of the electron-phonon coupling associated with the transport process. Fortunately, hole burning has proven to be capable of characterizing the nature and strength of this coupling. Required was the development of an accurate theory for entire hole profile (zero-phonon hole [ZPH] plus phonon sideband holes) applicable for arbitrarily strong electron-phonon coupling in the low temperature limit. More recently, this theory5 has been extended to arbitrary temperature.6 A key point is that the ZPH is only one small part of the entire profile. It is the entire hole profile that is important to the problem of transport dynamics in the photosynthetic unit. Thus it is that single molecule (complex) detection would be of little consequence to the problem of energy and electron transfer.
Tunneling Dynamics and Spectral Diffusion in the Millikelvin Regime
Authors: Haarer D. , Maier H.
Published: February 2023

The tunneling model [1] is the theoretical basis for several anomalous and time dependent phenomena in amorphous materials, which are caused by a broad distribution of relaxation rates of the so-called two-level systems (TLS). This model has also been applied to interpret spectral diffusion in glasses and to explain the observation of time dependent spectral linewidths [2]. In terms of spectral hole-burning, the TLS dynamics leads to a logarithmic hole broadening for times larger than the minimum TLS relaxation time, while the hole widths approach a constant value for times larger than the maximum TLS relaxation time [3]. This functional dependence is caused by a hyperbolic distribution of relaxation rates; all the above described phenomena follow from the “weak coupling” model: In polymer glasses a logarithmic broadening has been found on time scales between milliseconds and days [4, 5].
High-temperature spectral hole burning on single crystal materials of PbFCl:Sm2+family
Authors: Jaaniso Raivo , Bill Hans
Published: February 2023

We have extended our room-temperature hole burning studies, first performed on SrFCI0.5Br0.5: Sm2+ mixed crystals [1], to a wider class of single crystal materials with general composition MeIyMeII1-y YXIxXII1-x: Sm2+(Me=Ca,Sr,Ba; Y=F,H; X=CI,Br,l). This allowed to widen the spectral range for hole burning and to study the functional properties in dependence of the material structure. Because of the possibility to vary the composition (x,y) almost continuously and because of the relatively simple description of the disorder in the mixed crystals the formation of inhomogeneous broadening could have been described in a very detailed manner in these materials [2]. The above mentioned reasons make it enticing to study also the electronic and ionic movements through the hole burning at elevated temperatures.
High Density Frequency Domain Data Storage using a Stabilized Dye Laser
Authors: Zhu Miao , Jefferson C. Michael
Published: February 2023

There has been a great deal of interest in the use of rare earth doped materials such as Eu3 +: Y
2
SiO
5
for ultra-high density data storage using time domain techniques 1,2,3,4. These materials can exhibit T2 times as long as 800 μsec or more3,5 with corresponding projected linewidths of only several hundred Hertz. Since the typical linewidth of lasers used to investigate these materials (e.g. dye lasers) is of the order of 1 to 5 MHz, detailed studies of phenomena which can exploit the long coherence time of the excited state are difficult. Studies of phase modulation, continuous correlation, population gratings, free induction decay and so forth are greatly impacted by the laser linewidth. In addition, the actual linewidth of single persistent spectral holes has never been directly measured in these materials.
Coherent erasure and processing in time-domain optical storage
Authors: Elman Ulf , Kröll Stefan
Published: February 2023

Persistent spectral hole-burning and photon echoes can provide insight into the dynamics of amorphous and crystalline materials on the molecular/atomic level. Part of the current interest in these methods, however, is also caused by the existence of potential applications in optical data storage and processing. At present it may be difficult to specify exactly at what applications these techniques should try to target but, based on current research efforts and results, it appears that persistent spectral hole burning is a possible candidate for high density, possibly long time, volumetric storage, while photon echoes have properties more attractive for short time storage or storage connected to processing applications.
Single molecule spectroscopy: measurements of spectral shifts and fluorescence images
Authors: Croci Mauro , Irngartinger Thomas , Pirotta Marco , Palm Victor , Plakhotnik Taras , Moerner W. E. , Renn Alois , Wild Urs P.
Published: February 2023

Spectral shifts of the molecular resonance frequency have been observed since the early days of single molecule spectroscopy (SMS) [4]. We call these effects for concreteness light-induced spectral shifts (LISS) or spontaneous spectral shifts (SSS or S3) to distinguish the two possible reasons for the spectral change. In order to gain a more complete picture of these effects we have undertaken three different approaches.
Spectral Phase-Encoding Of Addresses For Optical Data Storage In Frequency Selective Media
Authors: Sonajalg H. , Débarre A. , Le Gouët J.-L. , Lorgeré I. , Tchénio P.
Published: February 2023

The persistent spectral hole burning property is known to add a fourth dimension to the optical data storage volume. Full advantage of the large capacity of such memories and of the intrinsic parallelism due to their optical nature can be taken in an application such as image storage. In this frame, the read-out operation has to be effected at video rate at least. This is not achieved by currently developed image-addressing methods. The present paper proposes a new procedure to overcome the so far encountered limitations.
Non - Lorentzian hole shape induced by spectral diffusion in H2-protoporphyrin substituted myoglobin
Authors: Shibata Y. , Kurita A. , Kushida T.
Published: February 2023

The temperature cycling hole-burning experiment is a good means to study the irreversible structural relaxation in disordered materials [1,2]. By observing the hole shape as well as the hole area and the hole width carefully, we investigated the relaxation of two-level-systems (TLS) that is characteristic of protein.
Rotational tunneling dynamics of methyl groups measured by spectral hole burning
Authors: Orth K. , Friedrich J.
Published: February 2023

Rotational tunneling of methyl groups has been studied extensively in the past decades [1]. The specific features of the dynamics of rotational tunneling are a consequence of the basic laws of quantum mechanics. The reason is that a
2π3-rotation of a methyl group is equivalent to a two-fold permutation of identical particels. As a consequence, the symmetry of the total wave function of the methyl group has to be invariant with respect to a rotation. This symmetry correlation has a dramatic influence on the relaxation dynamics between different rotational states. To observe a rotational tunneling relaxation an interaction is necessary, which breaks the strict symmetry correlation. For the CH3-methyl group this interaction is the nuclear spin-spin coupling and for the CD3-methyl group it is the nuclear quadrupole interaction of the deuteron with the electric field gradient. The magnitude of this interaction is so small that the respective relaxation times can be as long as months at low temperatures. Because of the influence of the nucleus involved in the rotational tunneling dynamics the relaxation of the rotational states is called nuclear spin conversion. Theoretical models have been published for the protonated [2, 3] as well as for the deuterated methyl group [4]. They basically predict three different kinds of relaxation processes (Direct, Raman and Orbach process) depending on the rotor parameters which are the V3-potential, the tunneling splitting and the phonon coupling. These, in turn depend on isotopic substitution.
Persistent Spectral Hole Burning In The Antenna Protein CP47 Of Synechocystis SP. Mutant H114Q
Authors: Polivka T. , Engst D. , Dian J. , Kroh P. , Pšenčík J. , Vácha M. , Nedbal L. , Vermaas W.I.M. , Hála J.
Published: February 2023

Spectral hole-burning is powerful tool for the study of fast relaxation processes (e.g. excited energy transfer - EET, electron transport - e.t.) in photosynthetic systems. Fast e.t. was systematically studied by transient hole-burning (THB) in absorption spectra of reaction centra in purple bacteria and green plants [1]. The THB in fluorescence of PSII particles was described in [2]. Persistent spectral hole-burning (PSHB) enabled to determine the hole-burning mechanism, the EET rate constants, electron-phonon coupling and frequency of protein phonons. The PSHB in fluorescence has been measured in antenna complexes: CP43 and CP47 of PSII [3], B800-850 of purple photosynthetic bacteria [4] and in chlorosomes of green sulphur photosynthetic bacteria [5]. Laser induced hole filling in fluorescence spectra of CP43 of PSII was presented recently in [6]. These data were obtained using wild type organisms. Here, we report an investigation of EET by fluorescence PSHB in photosynthetic antenna using H114Q mutation in the CP47 complex of Synechocystis sp. PCC 6803.
Spectral Hole Stability and Laser Induced Hole-Filling in Zinc-Tetrabenzoporphurin/Aromatic Cyanide System
Authors: Yuxin Nie , Lizeng Zhao , Duoyuan Wang , Lingzhi Hu
Published: February 2023

The importance of photon-gated persistent spectral hole burning for scientific studies and for frequency domain optical storage (FDOS) has stimulated much recent research to discover new photon-gated materials. For FDOS the practical materials should posses the characteristics of high hole formation efficiency, large multiplicity of spectral hole, good thermal and spectral stability etc.
Electron transition process of 5D2→7F0 of Sm2+ in spectral hole-burning
Authors: Song Hongwei , Zhang Jiahua , Huang Shihua , Yu Jiaqi
Published: February 2023

Materials of MyM’1-yFClxBr1-x:Sm2+ have been widely applied in spectral hole-burning since the first observation of persistent spectral hole-burning in BaFCl:Sm2+ at 2K was reported by A. Winnaker, etc. in 1985[1]. From then on, hole-burning in BaFCl0.5Br0.5:Sm2+ at 77K[2] in SrFCl and Mg0.5Sr0.5FCl0.5Br0.5:Sm2+ at room temperature[3, 4] were reported. Room temperature hole-buring of Sm2+ in fluorohafnate glasses[5,6] were reported in recent years also. These materials are of potential use in high temperature hole- burning. But comparing to organic materials, they have lower hole- burning efficiency and narrower inhomogenous line width. In order to apply spetral hole- buring in frequency domain optical storage, it is important to improve these materials.
Low-Temperature Structural Relaxation in Polymers Probed by PHB
Authors: Tanaka Satomi , Machida Shinjiro , Horie Kazuyuki , Yamashita Takashi
Published: February 2023

Photochemical hole burning (PHB) is attracting an interest as a means for frequency-domain optical storage. Besides, PHB is expected as a probe for understanding the dynamic behavior in polymers at low temperatures. The low-temperature properties of polymers have been investigated mechanically and dielectricly for many years. In the present study, excursion temperature dependence of hole profile for chromophore/polymer systems is investigated, and is compared with mechanical and dielectric behavior of polymers, so as to get hold of the relationship between relaxation properties and chemical structure of polymers.
Fragile Systems: a Comparative Study of Glassy and Crystalline Phases
Authors: Kikas J.
Published: February 2023

A full understanding of the strycture and dynamics of different condensed phases of matter (liquids, glasses, crystals) is hardly possible without addressing the processes of their mutual transformations and the interrelations between different phases. This view has become more and more common in the condensed matter research. A well-known example concerns the studies of the liquid-glass transition.