bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Luminous State of Bacteriorhodopsin
Authors: Hirai Masamitsu , Suzuki Yoshiro , Nakayama Tomonori
Published: February 2023

In spite of change of the luminescence spectra during the illumination of light for the spectral measurement of the bacteriorhodopsin, most reports failed to notice this change. We have made the change clear and propose a new model for the luminescence species. Trans-bacteriorhodopsin is refered as T-bR.
Vibrational Excitation Dynamics of Small Molecular Impurities in Crystals.
Authors: Dubost H.
Published: February 2023

In this paper time resolved infrared spectroscopy of small impurities in crystals is presented. Optical pumping into the fundamental or overtone absorption results in vibrational emission of several molecular species in solid hosts, Van der Waals-type or ionic crystals. Vibrational relaxation in solids is also probed by infrared double resonance which is a more appropriate technique for short lived systems. Line narrowing techniques involving site selection by a narrow band laser are employed in both molecular and ionic systems. IR time resolved hole burning experiments very similar to those performed in optical spectroscopy of luminescent ions in insulators have become feasible. Coherent transient spectroscopy is also very promising.
Laser Study of No-phonon Lines in the Inhomogeneously Broadened Spectra via Photochemical Hole Burning.
Authors: Rebane Karl K.
Published: February 2023

When the inhomogeneous broadening (IHB) is eliminated, the no-phonon lines (NPL) in optical spectra (absorption, luminescence, hot luminescence, light-scattering, excitation of luminescence) actually become the optical analogues of the Mössbauer γ-resonance lines. The basic reason of this analogue lies in the symmetry of the Hamiltonian of the harmonic oscillator in coordinates and momenta[1,2]
Spectral Narrowing of Excitation Spectra in n-Photon Upconversion Processes by Energy Transfers
Authors: Auzel F.
Published: February 2023

See WE5 for summary.
Photoluminescence Studies of Ga(As,P) Strained-Layer Superlattices
Authors: Gourley P. L.
Published: February 2023

See FE18 for summary.
The 3T1 (P) → 3T1 (F) luminescence of ZnS:Ni2+ and other internal transitions of the Ni2+ (3d8) configuration
Authors: Roussos G. , Schulz H.-J.
Published: February 2023

ZnS:Ni crystals exhibit at low temperatures a new emission [1] which is assigned to the transition 3T1 (P) → 3T1 (F) of the

Ni

Zn

2
+

(
3

d
8

)

ion, based on absorption data [2,3] and on preparation evidence. The structured emission spectrum observed in Ni-doped cubic crystals is superimposed on the tail of a broad Ni-related recombination band peaking at higher energy. A dip (c1) coincides with the most prominent absorption line at

v
¯

=
12438

cm−1 thus indicating self-absorption. The luminescence is dominated by a sharp peak C4 at

v
¯

=
12259

cm−1. By shifting the emission spectrum along the

v
¯

abscissa such that C4 coincides with the main emission line A4 at

v
¯

=
4200

cm−1 representing the 3T1(F) → 3T1 (F) Ni2+ transition [3], a striking similarity of these structures is revealed (Fig.).
Photoluminescence Properties of Disordered GaAs Heavily Doped with Si
Authors: Takano H. , Kamijoh T. , Sakuta M.
Published: February 2023

The GaAs heavily doped with Si is one of prototypes of disorder-semiconductor with high concentration of charged impurities.1) Si impurities show the amphoteric behavior in the GaAs, namely Si on Ga- and As-sites act as donor and acceptor, respectively. In LPE grown GaAs, the distribution of Si impurities on each site is mainly due to the growth temperature.2) The coexistence of both positive (donor) and negative (acceptor) ions cause the large potential fluctuations mixing with conduction and valence band states1), and luminescence properties of this system are very interesting because of heavy-doping and compensation effects in the radiative recombination processes. In this report, we show photoluminescence properties of the GaAs heavily doped with Si which is highly compensated. Aspects of radiative recombination process in this system are proposed.
Luminescence Recombination in Magnetron Sputtered a-Si:H
Authors: Rhodes A J , Bhat P K , Searle T M , Austin I G
Published: February 2023

Recent work has shown that a-Si:H films prepared by magnetron sputtering (MSP) have a defect density much lower than that produced by Rf sputtering, because of the decrease in damage from electron bombardment. Photoluminescence (PL) studies on a-Si:H show a broad peak near 1.3 - 1.5 eV due to tail state recombination and a peak near 0.9 eV which is generally ascribed to a dangling bond defect. The 0.9 eV band has been observed in a wide range of a-Si films when excited with subgap light, but comparatively little has been reported on MSP films, especially the effects of doping.
Time Dependent Luminescence Spectroscopy of highly doped Zn1-xMnxS and Cd1-XMnXTe
Authors: Busse W. , Gumlich H.-E. , Krause M. , Moros H.-J. , Schliwinski J. , Tschierse D.
Published: February 2023

The present interest in the luminescence of II-VI compounds doped by high amounts of Mn is due to the role which the Mn plays in thin film electroluminescence of ZnS:Mn and in the field of semimagnetic semiconductors such as Cd1-XMnXTe. In both cases more than one emission band are observed when the amount of Mn passes a lower limit. For Zn1-XMnXS this limit is x=0.01 (1). Above this limit emission bands peaking at 1.97, 1.66 and 1.3 eV are registered in addition to the wellknown band peaking at 2.1 eV (4T1(G) → 6A1(S)). Recently Goede et al. tried to explain parts of these bands by octahedraly coordinated Mn2+ within local α-MnS domains (2).
Energy transfer studies of Nd3+ doped borate glass
Authors: Sen S.C.
Published: February 2023

The results of X-ray diffraction and energy transfer studies of glass with composition 14K2O, 2KCl, 85B2O3, with Tl+, Mn2+ and Nd3+ have been reported. In absorption studies an absorption edge at 280 nm and bands with peaks at (310 and 355 nm) are obtained for 0.2 5%, Tl+ in the glass. These bands (310, 355 nm) are quenched by the addition of Mn2+ (1.25%). Addition of Nd3+ (1%) with Tl+ and Mn2 + introduces new bands which grow in intensity very rapidly and for Nd3+ (5%) the bands with peaks at 570,600 and 750 nm are found to saturate in intensity. The band responsible for laser action at 870 nm (4I9/2 - 4F3/2) is found to split in two sublevels with a difference of 140 cm−1. The emission spectra when excited with 265 nm shows four bands with peaks at (330, 365, 420, 600 nm) for Tl+ (0.25%) and Mn2+ (0.25%) in the glass. Introduction of Nd3+ (5%) enhances the growth of long wave length bands at the cost of 330 nm. No emission in the visible region could be recorded when excited by Neodymium absorption bands even with the laser source. The ordered region of alkali borate glass is found to be (15-20 Å).
Studies of Ion Pair Interaction in KNdxGd1-xP4O12 Crystals Using Site Selection Time Resolved Spectroscopy
Authors: Malinowski M. , Woliński W.
Published: February 2023

KNdP4O12 crystals belong to the group of so called stoichiometric laser compounds characterized by a very weak concentration dependent fluorescence quenching.
Nonradiative Energy Transfer Without Quenching of Donor Lifetime in Mn-Based Crystals
Authors: Di Bartolo B. , Danko J. , Pacheco D.
Published: February 2023

Nonradiative energy transfer between donor and acceptor ions in solids takes place by various processes, i.e. dipole-dipole, exchange, etc. Also, before transfer, migration of excitation energy among donors may occur and may influence the time evolution of the donor and acceptor luminescence. It is well known that, regardless of the process present, the decay pattern of the donor ions is affected by the presence of the acceptor ions.
Energy Upconversion and Energy Transfer Processes in LaF3:Nd3+
Authors: Venkateswarlu Putcha , Reddy B. R.
Published: February 2023

On resonant excitation of the D levels of LaF3:Nd with a tunable dye laser, fluorescence is observed from the R, S, A, D, E, K and L levels of which the last three levels are higher than the D levels. It has been reported by the authors1 recently that both sequential two photon excitation process (STEP) and energy upconversion process (ETU) are responsible for the population drain mechanism from the lower D levels to the higher L level. In the present paper, the fluorescence from the R, S, and E levels and the processes through which they are populated will be discussed. Excitation spectra of the fluorescence from the R, S, and E levels have been recorded using the tunable laser excited by N2 laser. The decay times for the D, R and S levels for three different concentrations 0.5, 2.0 and 5.0 percent by weight of Nd3+ have been determined. The decay times for R and S come out to be equal and they are 600, 400 and 150µs respectively for the three concentrations respectively. The fluorescence spectrum from the R level has been studied for concentrations of Nd3+ (0.1, 0.5, 2.0 and 5.0 percent by weight). The intensity increases as the concentration increases from 0.1 to 2.0 percent and then it decreases when the concentration becomes 5.0 percent. These studies indicate that the R level gets populated and depopulated through ion pair relaxations. The S levels are found to be populated due to thermal contribution from R levels. The two processes STEP and ETU are possibly responsible for the population of E level in the same manner as for the L level.
Raman Scattering Resonant With Two Dimensional Excitons in Semiconductor Heterostructures
Authors: Zucker J. E.
Published: February 2023

There is much current interest in GaAs-(AlGa) As heterojunctions as model semiconductor systems of reduced dimensionality. One of the striking features of GaAs-(AlGa) As quantum well heterostructures is the strong enhancement of exciton properties. We have recently discovered that the resonant Raman scattering (RRS) method has novel applications in the study of quasi-two dimensional excitons in GaAs quantum wells. The resonantly enchanced Raman signal can be observed even in the presence of a large luminescence background. RRS also shows extremely high contrast as a spectroscopic tool for higher-lying exciton states where absorption and excitation spectroscopy are less effective. In addition, RRS provides new insight into the electron-phonon interactions and vibrational properties unique to this layered system. The Raman spectra show direct evidence of the degree of exciton localization within the quantum wells. Also, the shape of the resonant Raman profile can be used to determine exciton-phonon scattering channels. Polarization selection rules for the scattered light have established the effects of reduced dimensionality on the optical lattice vibrations and allow comparison between deformation potential and Frohlich exciton-phonon interactions.
Fractal Structures in Condensed Matter
Authors: Witten T. A.
Published: February 2023

Polymers in solution and colloidal aggregates form complex structures which are statistically invariant under spatial dilation. We survey the special properties of these "fractal" structures.
Physical Processes in High-Field Electroluminescence
Authors: Allen J W
Published: February 2023

High-field electroluminescence offers the promise of large area solid-state displays with a wide range of applications. It also presents a challenge to our understanding, requiring a synthesis of atomic and solid-state physics. Early work was on copper-doped ZnS AC powder panels which were spatially heterogeneous, amenable to precise measurement of only macroscopic properties, and unreliable. Recent devices use thin films of ZnS:Mn which are better defined physically. In addition, Schottky diodes on n-type ZnS:Mn have been used to study particular physical mechanisms.
Fluorescence Technology Biopolymer Binding Studies
Authors: O'Donnell C. Michael
Published: February 2023

A review of fluorescence technology in immunochemical procedure will be presented. The extension of this technology into the area of DNA probes will be discussed along with additional future opportunities for research.
Excitation of the 1S0 State of Pr3+ in Crystal Hosts
Authors: Levey C. G. , Glynn T. J. , Yen W. M.
Published: February 2023

We excite the (4f2)1s0 state directly through a two photon excited state absorption (from the 1D2 level) and indirectly through excitation of the 4f5d band (using an ArF excimer laser). In Pr3+:LaF3 the 1S0 state lies below the band, and only 1S0 emission is observed. In most hosts examined, it is above the band, and only 4f5d emission is observed. In Pr3+:CaF2 there are sites with each of these properties, and both 1S0 and 4f5d emission are observed, with a relative strength that is concentration dependent.
The effect of La substitution in Eu3+-activated Y2O3 phosphors on their luminescent property.
Authors: Anonymous
Published: February 2023

The effect of impurity oxide on the luminescent property of yttrium oxide activated by Eu3+ was reported by Fuller1). In this report it was found that lanthanum oxide had no influence on the luminescent property of EU3+-activated yttrium oxide phosphor when 0.067m/o lanthanum oxide was added. Meanwhile the solid solution between Y2O3 and La2O3 is found to be stable till about 20 mol% of La2O3 between 700 and 1400°C.2) We found that the addition of La2O3 to Eu3+-activated Y2O3 made the intensity of luminescence under 2537Å stronger.
Enamel-Type Electroluminescent Display
Authors: Chou-jen Wu , Hao-liang Tan
Published: February 2023

For more than ten years ago, electroluminescent display devices have been used primarily for lighting purposes, and have been largely confined to glass constrution. The simplest variable dis play device is a seven- or nine-segment numeric readout, by increasing the number of segments and changing rectangular to circular segments, more number and letter displays have been obtained. The familiar 35-dots-per-letter in 5x7 array is the best-known example
[Title not available]
Authors: Genack A. Z.
Published: February 2023

In this communication a method of electro-optic phase-sensitive detection is described. Phase-sensitive detection is exploited to suppress fluorescence which lags the modulated laser in phase while detecting Raman scattering, which is in phase with the excitation. In addition, ultra-fast phenomena may be studied using slow detectors by measuring the phase shift of the emission relative to the phase of the exciting laser light, which is modulated at high frequencies.
Frequency-Domain Phase-Modulation Fluorometry: Resolution of Complex Decays of Intensity and Anisotropy
Authors: Lakowicz Joseph R. , Gratton Enrico , Cherek Henryk , Maliwal Badri P.
Published: February 2023

We describe the use of frequency-domain phase-modulation fluorometry to determine time-resolved emission decay kinetics. Using newly constructed instruments (1,2) we measured the frequency-dependent phase angles and demodulation factors at frequencies ranging from 1 to 200 MHz. Such data were obtained for two and three-component mixtures of fluorophores. Two decay times were easily recovered if they differed by a factor of two, and a three-component mixture was resolved with decay times of 1.3, 4.4 and 12. nsec. Measurement at several emission wavelengths enhanced our ability to resolve closely spaced two and three-component decays.
Cavity and Destriau Effect
Authors: Chou-jen Wu , Hao-liang Tan
Published: February 2023

Despite intensive research efforts, the theoretical situation about the Destriau effect is still in a state of confusion. The main reason for this is the deviation of observation. One of the most important eloctroinminascent finds has been made is that electroluminescent particles contain numerous voids at which the internal surfaces are deposited with thin, conducting, and transparent copper or copper sulfide layers. That such layers can indeed exist.
Non-Degenerate Four-Wave Mixing in CuCl
Authors: Levy R. , Tomasini F. , Grun J.B.
Published: February 2023

As it is well known from non-linear optics, the dielectric susceptibility χ of semiconductors is a function of the intensity of the impinging light. The non-linear part of the susceptibility gives rise to different light-mixing processes, the efficiency of which depends on the phase mismatch of the beams involved.
Self-Trapping of Excitons at the Surface of Rare-Gas Solids and its Manifestation in Luminescence and Desorption
Authors: Coletti F. , Debever J. M.
Published: February 2023

See MCI for summary.
Optical-Environment-Dependent Lifetimes and Radiation Patterns of Luminescent Centers in Very Thin Films
Authors: Fattinger Ch. , Lukosz W.
Published: February 2023

See MC4 for summary.
Excitad States of Transition Metal Complexes
Authors: Ballhausen C. J.
Published: February 2023

The pure crystal field calculation by Finkelstein and Van Vleck "On the Energy Levels of Chrome Alum", published in 1940, marked the first quantitative calculation of the excited states of a large molecular entity. It succeeded also in identifying the emitting state in this (3d)3 system as a 2Eg state.
Direct Optical Studies of Proton Tunneling in Hydrogen Bonded Mixed Molecular Crystals.
Authors: Trommsdorff H. P.
Published: February 2023

Numerous carboxylic acids crystallize as cyclic dimers linked by two hydrogen bonds. The mobility of the acid protons is sufficiently high such that proton rearrangements, which can be induced thermally or by optical excitation, will anneal even at the lowest temperatures (T < 1.5 K). Dye molecules doped substitutionnally into carboxylic acid host crystals exhibit, at low temperatures, well resolved quasiline spectra as is commun for mixed crystal systems. These spectra are sensitive to changes in the environment of the dye molecule and can therefore be used to monitor the above mentionned proton rearrangement processes.
High-Density Excitation and Raman Spectroscpy of the Bound-Exciton Complex (Ao, X) in CdS
Authors: Broser I. , Gurpwski J.
Published: February 2023

See FE10 for summary.
Excitons in CuCl Microcrystals Embedded in NaCl
Authors: Itoh Tadashi , Kirihara Toshio
Published: February 2023

See MB15 for summary.
Unusual green emission from Mn2+ in Gd(BO2)3
Authors: Peters T.E. , Pappalardo R.G. , Hunt R.B.
Published: February 2023

Recent reports1,2 by Philips researchers on novel, efficient phosphors for lamp applications highlight the role of Gd3+ as sensitization intermediate in the process of cascade sensitization S→Gd3+→A (where S is a broad-band sensitizers, such as Ce3+ or Bi3+, and A an acceptor, such as a trivalent rare-earth or Mn2+). On investigating Ce, Mn-coactivated Gd(BO2)3 we observed, following excitation at 254 nm, a green emission-band, peaking at ≃530 nm, ≃60% as intense (in brightness units) as current willemite phosphors (Zn2SiO4:Mn) for lamp applications.
Luminescence Centers in Quartz
Authors: Kristianpoller N.
Published: February 2023

The photoluminescence (PL), radioluminescence (RL) and thermoluminescence (TL), excited in natural Norwegian quartz crystals by monochromatic uv light, beta and X-rays, were studied. Excitation and emission spectra were measured and the dependence of the intensities and the spectral composition of the emission on irradiation temperature as well as on thermal pre-treatment was investigated. The PL excitation spectra in the vacuum uv region between 115-185 nm shows a main maximum at 127 nm. A strong excitation maximum of the TL has recently been recorded at the same wavelength and the TL intensities were found to be comparable to those induced by a 10 m Ci 90Sr beta source.(1) The 127 nm excitation maximum coincides with the long-wavelength tail of an exciton peak, previously recorded in the reflectance spectrum of quartz.(2) However, the PL and TL could also be excited with photons of energies lower than the absorption edge. The PL, as well as the RL and TL emissions showed a broad emission band centered at 440 nm (with a half­width of about 0.80 ev), which was dominant at 80K. Another broad main emission band appeared near 370 nm and could be resolved under certain conditions in 355 and 380 nm bands (with half-widths of 0.50 and 0.42 ev). Additional weaker bands were recorded at about 340 and 520 nm. The relative intensities of these bands depend markedly on the temperature of excitation as well as on thermal pre-treatment. The 440 nm band decreases sharply with increasing temperature near 200K, which resembles the temperature dependence of a STE luminescence. This band may possibly be due to radiative decay of a self trapped exciton. The 355 and 380 nm bands showed a different temperature dependence. Emission bands near 380 nm have previously been reported by various authors.(e.g.3,4) Alonso et al. ascribed the broad 380 nm band, recorded in the X-luminescence,to a recombination of electrons with holes, trapped at an adjacent Al-M+ center.(4) The fact that the samp emission bands appeared in the uv excited PL as in the X and beta excited RL and TL, indicates that the emission is due to the same luminescence centers.
The Effect of Hydrostatic Pressure on the Luminescence of CaO:Ni2+
Authors: Radlinski Andrzej P. , Hasan Zameer U. , Manson Neil B.
Published: February 2023

In CaO, Ni2+ impurity ions replace Ca2+ ions at sites of octahedral symmetry and give rise to several crystal field bands each with considerable vibronic structure.1,2 In this work the influence of hydrostatic pressure on the structure of two of these bands has been investigated.
Host lattice dependence of the Bi3+ luminescence in orthoborates LnBO3
Authors: Wolfert A. , Oomen E.W.J.L. , Blasse G.
Published: February 2023

The luminescence properties of Bi3+ in the orthoborates LnBO3 are strikingly different and depend in a dramatical way on the choice of the host lattice cation Ln. These borates are isomorphous with the several modifications of calcium carbonate. ScBO3 and a modification of LuBO3 have calcite structure with Ln in six coordination. Another modification of LuBO3 and also YBO3 and GdBO3 have vaterite structure with a six- and a twelve coordinated site. Finally LaBO3 has aragonite structure with a nine coordinated site.
Importance of Pseudo-Jahn-Teller Effect in the Excited State for (TL+)2-Type Centers in Alkali Halides
Authors: Kamishina Yoshio , Matsushima Akira , Fukuda Atsuo
Published: February 2023

The excited states for (Tl+)-type centers in alkali halides have been established to be characterized by the Jahn-Teller effect in both aspects of absorption and emission process. In the case of (Tl+)2-type centers, on the other hand, there is a general belief that the interaction between the paired ions lifts the orbital degeneracy of the active electrons and Jahn-Teller effect can not be expected any more. As a matter of fact, the absorption spectra for (Tl+)2-type centers have been successfully interpreted in terms of the interaction between the paired ions. The luminescence, however, is not so clear-cut to be understood with the same model. For the purpose of understanding the relaxed excited states (RES's) responsible for the luminescence in (Tl+)2-type centers, we have investigated their spectral and polarization characteristics and the temperature dependence of the radiative decay times in KI:(Ga+)2, KI:(In+)2, and KI:(Tl+)2, and concluded that some of the RES's are principally determined by the Jahn-Teller effect in (Tl+)2-type centers, just like in (Tl+)-type centers. In all the investigated emission bands, the degree of polarization measured as a function of azimuthal angle in the (001) plane is zero in the <110> direction and its absolute value is maximum in the <100> direction. Therefore, <100> is the direction connecting the paired ions. The emission band excitable by the A∑ and A∏ absorption bands in the paired-ion center is located close to the AT emission band in the corresponding single-ion center for KI:(Ga+)2 and KI:(In+)2, while that is close to the AX emission band for KI: (Tl+)2. Since the interaction between the paired ions is small in the triplet excited states, the interaction can be regarded as a perturbation to the RES's responsible for AT and AX emission bands due to the Jahn-Teller effect. The perturbation destroys the equivalence of the three tetragonal distortions for AT RES; one of them becoms slightly different from the other two. Thus the AT∑ and AT∏ emission bands are observed separately as in KI:(Ga+)2. Although these two bands could not be separated in KI: (In+)2, the polarization characteristics observed indicate that the 2.76 eV emission band consists of at least two component bands, AT∑ and AT∏.
Excited State Absorption and the 4p-electron Levels of Cu+ in Alkali Halide Hosts
Authors: Chien Ring-Ling , Siraonetti John , McClure Donald S.
Published: February 2023

The Cu+ ion in NaF, LiCl and NaCl shows weak near UV and strong vacuum UV sets of absorption bands, identifiable as 3d→4s and 3d→4p respectively.1 The weak, temperature-dependent 4s transitions occur 1–2 eV higher in energy than in the free Cu+ ion, while the 4p bands lie 1–2 eV lower. The simplest interpretation of these facts is that the 4s electron is more strongly antibonding toward the ligands than are the 3d electrons, while the 4p electron is partly bonding and partly spread out beyond the nearest neighbor anion shell into the next neighbor cation shell. This general description was confirmed by the calculations of Harrison and Lin.2
Optical Properties of Rare Earth and 3d Ions in Fluorozirconate Glass
Authors: Sibley W. A. , Shinn M. D. , Tanimura K. , Feurhelm L.
Published: February 2023

Fluorozirconate and fluoroha fnate glasses have great potential in fiber optics and laser host applications. For this reason, there has been exceptional interest in the optical properties of ions in this material. In this work, the optical absorption, emission, excitation and lifetimes of the various transitions for impurities such as Ho3+, Pr3+, Er3+, and Mn2+ in these glasses is presented. The measured oscillator strengths and radiative rates for several transitions are compared with calculated values based on Judd-Ofelt theory. Non-radiative transition rates for the excited states were determined by the difference between the measured rates and the calculated radiative rates. As the impurity levels approach 2% energy transfer becomes important. In almost all cases multiphonon emission and energy transfer account for the nonradiative transitions. The low temperature multi-phonon emission rates are generally in agreement with the rates predicted by the phenomological energy gap law. In addition, the crystallization of ZBLA glass was studied using Er3+, Ho3+ and Mn2+ ions as probes. Isocronal heating data indicate that the glass undergoes rapid devitrification around 630K.
Luminescence of Titanium-Containing Fluorophosphate Glass
Authors: Fuxi Gan , Huiming Liu
Published: February 2023

With the development of turnable solid state lasers much attention has been paid to the study on luminescence of inorganic glasses doped with transition metal ions. However, in traditional oxide glasses, even though a great deal of spectral studies had been made, luminescence due to titanium ions so far has never been reported to our knowledge.
Photoluminescence in Amorphous Alloys: a-SiOx:H, a-SiNx:H, a-SixC1-x:H
Authors: Carius R. , Jahn K. , Siebert W. , Fuhs W.
Published: February 2023

We report on the photoluminescence (PL) in the amorphous alloys: a-SiOx:H, a-SiNx:H, a-SixC1-x:H over a wide range of x. The films were prepared by glow discharge decomposition of suitable mixtures of SiH4 with N2O, NH3, and CH4 (C2H4), respectively.
Interpretation of Hydrostatic Pressure Dependence of Ruby R-lines
Authors: Berry D. E. , Curie D. , Williams F.
Published: February 2023

The R-lines of ruby are red-shifted linearly with hydrostatic pressure, with no quadratic effect, to 200 kbars.1 The shift has been attributed, from crystal field analyses, to delocalization of the d-orbitals resulting in changes in the Racah parameters B and C.2,3 From the adiabatic potential theory of pressure effects the linear shift of the R-lines is attributed to differences between the effects of pressure on the zero point energies of the excited and ground electronic states, primarily due to difference in anharmonicities of the two states; a quadratic shift arises from differences in the change in equilibrium energies with pressure, due to differences in coupling and/or force constants for the two states.
Efficient Sensitization of Mn2+ emission by Sn2+ in Fluoroapatites.
Authors: Pappalardo R.G. , Peters T.E.
Published: February 2023

New schemes1 for increasing the brightness output of fluorescent lamps rely on combining a yellow emission band, as produced by Mn2+, with a narrow, blue emission band, as provided by Eu2+. In this connection we have observed that coactivation of Ca fluoroapatites [Ca5(PO4)3F, or CaFAP in brief] with Sn2+ and Mn2+ can provide in the yellow spectral region a Mn2+ emission, with intensity exceeding by roughly 20% the highest intensity obtained from current Ca fluoroapatites coactivated with Sb and Mn.
Fluorescence Characteristics of X-ray Excited CaF2:Mn(x) (x = 0.1%, 1.0%, 3.0%)
Authors: Rhodes Joanne F. , Abbundi R. J. , Wayne Cooke D. , Mathur V. K. , Brown M. D.
Published: February 2023

The characteristic 500 nm emission of CaF2:Mn has been attributed to the de-excitation of Mn2+. However, several mechanisms have been proposed for the formation of the excited Mn2+ ion. We have conducted a detailed systematic study of the emission spectra of CaF2:Mn over the temperature range, 13 - 672 K, which covers the entire thermoluminescence glow peak region. We compared our data for samples with 0.1% and 1.0% Mn to previously reported1 data for a sample with 3.0% Mn to determine the effects of Mn concentration on the spectra. The entire spectral region was simultaneously recorded by a microcomputer-based diode array, which allowed the accumulation of a large number of spectra with good reproducibility. The data were analyzed to quantitatively determine the centroid, full-width at half-maximum (FWHM), intensity, and skewness of the spectra.
Phonon Processes in Disordered Systems, Probed by Spectral Hole Burning and Refilling of Dyes
Authors: Bogner U. , Röska G. , Schätz P.
Published: February 2023

With heat pulse technique (pulse duration Δt ≧ 20 ns) we measured the effects of phonons on the persistent spectral holes of dye molecules in thin organic films, e.g. Langmuir-Blodgett films, or of dye molecules adsorbed at the surface of crystals. The measurements include phonon memory1 and real time effects of phonons, i.e., the irreversible and the reversible phonon-induced filling in the center of the spectral hole. In particular we measured the dependence on the duration and on the power density or calculated temperature TH of the heat pulses. The dependence of the fluorescence intensity IO of the first vibronic zero phonon line on the number N of the irradiated heat pulses (or to be precise on the time t = N•Δt) in the case of the phonon memory is demonstrated in Fig. 1. The observed logarithmic time dependence is explained by a theory based on thermally activated processes in double well potentials2with constant density of states concerning their barrier heights.
Electric-Field-Induced Changes of Persistent Spectral Holes in Amorphous Solids and their Applications
Authors: Bogner U. , Schätz P. , Beck K. , Maier Max
Published: February 2023

The effect of an external electric field on spectral holes of dye molecules in disordered systems, e.g. polymer films and Langmuir-Blodgett films, [1, 2] and its applications are studied. We observed a filling in the center of the persistent spectral hole, which is caused by electric-field-induced shifts of the electronic levels of the dye molecules. The experimental results for perylene in polyvinylbutyral (PVB) are explained by a linear electric field dependence of the level shifts which is ascribed to the interaction of the dye molecules with the amorphous matrix. The magnitude of the level shifts is determined by comparing the experimental results with the calculations [2]. Experiments are reported which provide information about phonon-induced transitions in the double well potentials which are characteristic of amorphous solids.
Time-resolved Excimer Dynamics in Perylene Crystals
Authors: Port H. , Walker B. , Wolf H.C.
Published: February 2023

Perylene crystals of the α-phase are prototypes for excimer formation, since the molecules are arranged in sandwich configuration. The prominent feature of the perylene fluorescence spectrum is the appearance of two spectral contributions, an actual excimer-type emission and the Y-emission, which has been attributed to a partially relaxed excimer.
Mobility and Conformation of Side Chains in Copolymers of the Methacryl Amide Type. Study of Depolarization of Fluorescence and Nonradiative Energy Transfer
Authors: Mikeš František , Vyprachtický Drahomír , Králíček Jaroslav , Labský Jiří
Published: February 2023

The authors studied the mobility and conformation of side chains of different lengths in the copolymers of the N-al-kyl acryl amide and methacryl amide types from the depolarization of fluorescence and from the efficiency of the nonradiative energy transfer between tryptophane fluorochrome bonded in the immediate vicinity of the polymer backbone and 1-dimethyl amino-5-naphthalene sulphonamide fluorochrome at the end of the side chain.
A Direct Observation of Excitation Energy Transfer in Ruby Induced by the Resonant 29 cm-1 Phonons
Authors: Kaplyanskii A.A. , Basoon S.A. , Feofilov S.P.
Published: February 2023

Participation of the 29 cm-1 phonons resonant with the

2

A
¯

−

E
¯

interval in the Cr3+ metastable E-state in the excitation energy transfer between the Cr3+ ions in ruby has been discussed repeatedly in the literature[1,2]. The present experiments have been carried out at 1.8 K on Al2O3:0.02% Cr crystals under stationary laser pumping. The inhomogeneously broadened R1 luminescence line reveals weak extended structured wings associated with

E
¯

−
4

A
2

transitions in the strongly perturbed Cr3+ ions (Fig.1). Injection into the sample of heat pulses from a heater film deposited on its surface has been found to generate positive luminescence pulses I(t) on the short wavelength wing of the R1 line. These-pulses originate from the phonon induced

E
¯

-excitation energy transfer from the main distribution ions (line center) to the perturbed ions.
Optical Dephasing of Impurities in Amorphous Organic Solids down to 0.3 K
Authors: Volker Silvia , Thijssen H. P. H. , van den Berg R.
Published: February 2023

See WE14 for summary.
Cr3+-Induced Nucleation and Luminescence in Silicate Glasses
Authors: Champagnon B. , Durville F. , Duval E. , Loulon G.
Published: February 2023

See WD31 for summary.
Photoluminescence in Amorphous Alloys: a-SiOx:H, a-SiNx : H, a-SixC1-x: H
Authors: Carius R. , Jahn K. , Siebert W. , Fuhs W.
Published: February 2023

See WD36 for summary.
Measurement of Exciton Absorption Spectrum in KI Using New Method
Authors: Nishimura H.
Published: February 2023

See MB10 for summary.
Dynamic Effects and Instabilities in Semiconductor Lasers in External Cavities
Authors: Tatah K. , Garmire E.
Published: February 2023

We have observed self-sustained relaxation oscillations of GaAlAs lasers in external cavities for DC drive currents greater than 20% above threshold. The frequency of relaxation oscillations depends on drive current as shown in Figure 1. Using standard rate equations and including a current-dependent cavity decay time give good agreement with theory. Without this current dependence, we obtain the linear curve shown in Figure 1, which does not agree with the experiment.
Chaotic Behavior in a CO2 Ring Laser with Injected Signal
Authors: Van Lerberghe A. , Cottin P. , Boulnois J.L. , Arecchi F.T. , Puccioni G.P.
Published: February 2023

Laser instabilities and chaotic behavior have been observed in several single mode laser systems. In the case of homogeneously broadened media with rapidly relaxing polarization rates, it has been theoretically predicted that introduction of an unmodulated external field can destabilize the system (1). In the case of such lasers with an injected signal, numerical results show the existence of a self Q-switch process with induced relaxation oscillations (2).
Laser Pulse Formation by Balanced Self Phase Modulation, Group Velocity Dispersion, Saturable Absorption, and Saturable Gain
Authors: Fork R. L. , Gordon J. P. , Valdmanis J. A.
Published: February 2023

We examine, experimentally and theoretically, the nonlinear dynamics of a laser which generates pulses as short as 27 fs directly from the laser (1), Fig. 1 . The laser shapes the intracavity pulses by a balanced combination of self phase modulation, group velocity dispersion, saturable absorption, and saturable gain which appears different from the shaping mechanisms in earlier lasers where the pulse shaping was due principally to saturable absorption and gain (2), or to soliton-like mechanisms in an optical fiber (3). The shaping which we discuss also offers advantages over prior modelocking mechanisms in that it yields enhanced stability, a close approach to transform limit, and pulses which are, to our knowledge, the shortest yet generated from a laser.
Soliton Structures in the Excitation due to Induced Absorption
Authors: Haug H. , Koch S.W. , Schmidt H.E. , Lindberg M.
Published: February 2023

It will be shown that in a nonlinear optical medium whoes absorption coefficient increases with the excitation density (e.g., free-carrier concentration in a semiconductor or temperature) , a soliton structure in the excitation density can occur, which in the stationary case is approximately the solution of a Sine-Gordon equation. For changing light intensity the soliton wall between the highly excited front part of the crystal and the weakly excited end part can move only in discrete jumps due to the intrinsic bistability. Experimental observations of these predictions have been obtained recently by Gibbs et al..
Chaotic Emission of Solid State Lasers in Multitransversal Mode Operation
Authors: Hollinger F. , Jung Chr. , Weber H.
Published: February 2023

Chaotic behavior of nonlinear systems is a well known phenomenon, which recently was observed in several laser systems. This paper now deals with chaotic emission of solid state lasers running in single longitudinal but multitransversal mode operation. It is demonstrated that, irregular spiking, so far explained by experimental imperfections is a type of chaotic emission. It can be evaluated theoretically and is confirmed experimentally.
Quantized Chaotic Systems
Authors: Graham R.
Published: February 2023

Chaos is a typical form of dynamical behavior of classical nonlinear dynamical systems. In conservative Hamiltonian systems with f degrees of freedom chaos appears if the system is not intergrable and in some regions of phase space trajectories are not restricted to f-dimensional smooth manifolds. In dissipative systems chaos in the dynamical steady state appears if the system has a strange attractor in configuration space.
Dwell Times and Average First Passage Times in the Dye Ring Laser*
Authors: Lett P. , Mandel L.
Published: February 2023

The dye ring laser, like other homogeneously broadened two-mode lasers, is predicted to have a steady state with two distinct regions of metastability.1-3 If we write for the probability density of the two-mode intensities I1, I2 where U(I1,I2) is the steady state potential, then U(I1,I2) has the form in dimensionless units where a1, a2 are pump parameters of the two laser modes, and ξ=2 is the mode coupling constant.4 A two-dimensional plot of the surface U(I1,I2) exhibits minima at I1=a1, I2=0, and I1=0, I2=a2 with a saddle point in between.5
Gain and Loss Fluctuations in Nonlinear Optical Systems
Authors: Schenzle Axel
Published: February 2023

The interaction of light and matter can be described by a set of coupled nonlinear evolution equations for the material and electromagnetic fields. In order to account for the effects of vacuum fluctuations, noise forces which cause spontaneous transitions have to be included. In these macroscopic systems various sources of noise besides fundamental quantum fluctuations exist which are of macroscopic origin. These cause fluctuations of the cavity dissipation as well as of the external pumping power. In the course of an adiabatic elimination procedure, these fluctuations appear as multiplicative noise in the equations of motion (e.g. for the field intensity, due to the nonlinearity of the interaction). While fluctuations of the cavity damping create noise linear in the field intensity, randomness in the pump strength causes fluctuations that depend nonlinearly on the light intensity. In this respect, the noise terms enter the equations of motion quite differently and have to be distinguished from spontaneous emission noise which is independent of the field strength, and is the basis of all traditional laser models.
Single and multimode instabilities in optical systems
Authors: Lugiato L.A.
Published: February 2023

Since the very early days of laser theory, it is well known that optical systems are able to display instabilities which lead to self-oscillatory or self-pulsing behaviour (1). All investigations of this problem have focused separately on what can be conveniently identified as single or multimode instabilities. Instabilities of the first type involve only the cavity mode that lies nearest to the atomic transition, or the carrier frequency of an incident field, for externally driven systems; these phenomena can be analyzed in the context of a single-mode model. The second type involves the growth of out-of-resonance cavity modes, and therefore requires a multi-mode treatment for a correct description.
Experimental and Theoretical Studies of Bifurcations by Measuring the Optical Spectrum of a Ring Laser
Authors: Tarroja M. F. H. , Bandy D. K. , Isaacs T. , Abraham N. B. , Gioggia R. S. , Adams S. P. , Narducci L. M. , Lugiato L. A.
Published: February 2023

We have conducted careful measurements of the changes in the output of a single-mode, inhomogeneously-broadened, unidirectional ring laser as the excitation and cavity detuning are varied. We are able to track the splitting of the optical spectrum as the laser makes a transition from stable cw operation to pulsed operation by heterodyning the laser output with a stabilized reference laser. For a resonantly tuned cavity, we see that with increasing excitation the laser makes an abrupt transition from a single optical carrier wave to two equally strong components in the optical spectrum. The splitting between these two components increases with increasing excitation above the instability threshold.
On Delay-differential Equations Modelling Nonlinear Optical Resonators
Authors: Ikeda K.
Published: February 2023

The aim of present talk is to survey the method of modelling the nonlinear optical resonators by a class of delay-differential equations. Instabilities exhibited by the model equations are summarized and classified.
Universal Scalings for Transitions to Chaos
Authors: Cvitanovic P.
Published: February 2023

Period doublings and mode lockings for circle maps are characterized by universal scalings which can be measured in a variety of nonlinear physical systems.
Search for Deterministic Chaos in the Mode Switching Instability of the Dye Ring Laser*
Authors: Chyba T.H. , Christian W. , Cage E. , Lett P. , Mandel L.
Published: February 2023

The two-mode dye ring laser when operated moderately far above threshold exhibits an instability that causes it to switch seemingly at random between clockwise and counterclockwise modes. The phenomenon has been explained in terms of spontaneous emission fluctuations,1-4 which cause the representative point in phase space to tunnel between two metastable states, and this interpretation has so far proved to be in good agreement with all experimental measurements. By implication the switching phenomenon is a macroscopic manifestation of quantum fluctuations in the laser, and it can be described by two coupled Langevin equations in the two mode amplitudes, with additive quantum noise.1 Although these equations account for the mode switching, better quantitative agreement with experiment is obtained when pumping fluctuations are also introduced.5
Noise Effects In Optical Bistability
Authors: Horowicz R.J. , Lugiato L.A.
Published: February 2023

We formulate a running wave, singlemode model for purely dispersive optical bistability, which incorporates amplitude and frequency fluctuations in the incident field, cavity length fluctuations, thermal noise in the radiation field and in the material (1). This model is given by a set of three Langevin-type equations for the real and the imaginary part of the slowly-varying electric field, and for the material variable. In the white noise limit, it is equivalent to a Fokker-Planck equation in three variables. Even if our model can describe also a Kerr medium or a two-level system in a suitable range of parameters, we are mainly interested in the case of miniaturized all–optical bistable devices which utilize semiconductor dispersive media. In this situation, we can adiabatically eliminate the field variables and therefore reduce the problem to a single stochastic differential equation in one variable, which contains several terms of additive and multiplicative noise. We find that noise in the imaginary part of the slowly varying electric field does not contribute to this equation. In the white, -noise case, our stochastic equation is equivalent to a Fokker-Planck equation in one variable, whereas in the case of colored noise we obtain a onedimensional Fokker-Planck equation only in the limit of short correlation times.
Quantum Beat Superfluorescence
Authors: Haus J. W. , Glauber R. J. , Woger W. , King H.
Published: February 2023

That superfluorescence remains a fundamental cooperative phenomenon in quantum optics is attested to by the wealth of research publications and review articles on the subject1. Beyond the subfield of quantum optics, it is an important example of the decay of an unstable equilibrium state. Quantum fluctuations are necessary to trigger the decay of the atoms to the ground state; however, once begun the unstable nature of the process amplifies the tiny quantum fluctuations to macroscopic levels. Thus, superfluorescence gives us an insight into the nature of quantum stochastic processes.
An Overview of Microoptic Signal Processing Research
Authors: Giallorenzi T. G.
Published: February 2023

Significant device advantages in the areas of microwave spectrum analysis and high speed A/D conversion appears to be possible through the use of microoptics. The attractive features of microoptics for these applications include a compact, rugged means to package optical singal processors, and an approach to achieve increased performance over existing technologies. Emphasis in this paper will center on the spectrum analyzer, will include comparisons of acoustooptics technqiues with conventional approaches for signal sorting, and will describe the state of the technology and its proposed uses.
Aberration Corrected Geodesic Lens for Integrated Optics Circuits
Authors: Kassai D. , Chen B. , Marom E. , Ramer O. G. , Barnoski M. K.
Published: February 2023

Utilizing a geometrical optics approach, one defines focusing as the conversion of a planar wavefront to a spherical one due to variations in optical path length. In most lenses, the optical path length variation is determined by a refractive index distribution. However, in Integrated Optics Circuits (IOC) materials only a very limited range of refractive indices can be obtained. Moreover, variations in refractive index can cause an excessive amount of scattering. A more acceptable approach for IOC is to generate physical path length differences by changing the profile of the waveguiding layer, while maintaining a uniform refractive index. We have designed and fabricated aberration corrected geodesic lenses having a single axis of revolution.