Search results

1

Spectral Study of Caesium Dimer Excited with 476.5, 472.7, 465.8 and 457.9 nm Argon Ion Laser Lines

100%

Szonert J., Bieniak B.

Acta Physica Polonica A

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1991

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vol. 79

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issue 6

789-804

EN

The results of a study of Cs_{2} fluorescence excited by different blue lines of the Ar^{+} laser are reported. Special attention was paid to the analysis of the narrow fluorescence band at 522 nm. Approximate assignments of the fluorescence transitions were obtained. The origin of the observed fluorescence is discussed and a rough reconstruction of a fragment of the E'(3)^{1}Π_{u} upper-state potential curve is presented and found to be nearly parallel to the corresponding portion of the ground-state X^{1}Σ^{+}_{g} potential curve.

2

TheÅ ngström (B^1Σ^+ → A^1Π) Band System of ^{13}C^{16}O: New Observations and Analyses

100%

Kępa R., Domin U., Porada K.

Acta Physica Polonica A

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2003

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vol. 103

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issue 5

441-451

EN

The emission spectrum of the Ångström system (B^1Σ^+ → A^1Π) of ^{13}C^{16}O was recorded and analysed by classical photographical spectroscopy. Under high resolution and with a precision estimated to be 0.010-0.020 cm^{-1} the bands 1-2, 1-7, and 0-6 were recorded for the first time and the 0-1, 0-2, 1-1, and 1-5 bands were rephotographed and reexaminated. After the rotational analysis of the bands the following constants were calculated: (1) the rotational constants B_v, D_v for the B^1Σ^+ and A^1Π states; (2) the equilibrium constants B_e,α_e, D_e, andβ_e for the B^1Σ^+ state; (3) theν_0 band origins. A combined analysis of the currently observedÅ ngström bands and the previously observed Herzberg (C^1Σ^+ → A^1Π) and the (E^1 Π → A^1Π) bands made it possible to perform a precise relative characteristic of the B^1 Σ^+(v=0 and 1), C^1Σ^+(v=0) and E^1Π(v=0) Rydberg levels in ^{13}C^{16}O. Numerous rotational perturbations observed in the A^1 Π state were confronted with the perturbations predicted from the theoretical calculations.

3

Analysis of the A^1Π State on the Basis of the Douglas-Herzberg Bands System in the CH+ Ion Molecule

100%

Hakalla R., Kępa R., Szajna W., Zachwieja M.

Acta Physica Polonica A

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2007

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vol. 111

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issue 6

821-834

EN

This paper presents an attempt of examining the irregularities appearing in a complicated A^1Π state of the CH^+ molecule with their reasons provided. By using the experimental data for the A^1Π-X^1Σ^+ bands system of the ^{12}CH^+ ion radical, it was proved that the vibrational and rotational quanta of the upper state reveal the same unusual behaviour, i.e. very clear nonlinear dependence on vibrational quantum number (v'≥3) of the upper state. Therefore, upper vibrational levels (v'≥3) of the A^1Π state cannot be determined by means of the equilibrium constants calculated in the previous works. Due to so far unidentified A^1Π state perturbations, the reduction of the wave numbers to the rovibronic parameters was carried out by means of individual, band-by-band analysis method, using with this end in view the nonlinear least squares method introduced by Curl and Dane, and Watson. This method allowed one to make already calculated constants of the rovibronic structure of regular lower state X^1Σ^+ of A-X system independent of possible perturbations appearing in the upper state of A^1Π of this system. It also enabled one to calculate for the first time the real (perturbed) term values for the A^1Π (v' =0, 1, 2, and 3) state of the ^{12}CH^+ ion molecule. These values suggest that rotational irregularities in the A^1Π state examined are negligibly small. In order to confirm the nonexistence of rotational perturbations in the A^1Π (v' =0, 1, 2, and 3) state, up to the observed J_max level, appropriate graphs of functions f_x(J) and g_x(J) introduced by Gerö and Kovács, where x = Q, PR, and overline{PR}, were drawn. Also, their course was analysed in detail.

4

Emission Spectroscopy of AlH: the X¹Σ⁺, A¹Π and C¹Σ⁺ States Characteristics

63%

Szajna W., Zachwieja M., Hakalla R., Kępa R.

Acta Physica Polonica A

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2011

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vol. 120

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issue 3

417-423

EN

The visible spectrum of AlH has been investigated at high resolution between 20000 and 21500 cm^{-1} using a conventional spectroscopic technique. The AlH molecules were formed and excited in an aluminium hollow-cathode lamp with two anodes, filled with a mixture of Ne carried gas and a trace of NH_3. The emission from the discharge was observed with a plane grating spectrograph and recorded by a photomultiplier tube. The 0-0 and 1-1 bands of the C¹Σ⁺-A¹Π system and 0-2 band of the A¹Π-X¹Σ⁺ were identified at 21126, 21368 and 20276 cm^{-1}, respectively. In total 121 transition wave numbers belonging to three bands were precisely measured (with accuracy of ±0.003 cm^{-1}) and rotationally analysed. The new data were elaborated with the help of recent X¹Σ⁺ state parameters reported by White et al. and of the C¹Σ⁺, A¹Π states constants reported by Szajna and Zachwieja. As a result of this merged analysis the set of the molecular parameters and rotational terms values for the three lower lying states of the AlH molecule have been significantly improved.

5

Spectral and Time-Resolved Studies of Green Cs_{2} Fluorescence

63%

Bieniak B., Głódź M., Jastrzębski W., Szonert J.

Acta Physica Polonica A

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1993

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vol. 84

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issue 2

229-246

EN

The origin and dynamic properties of the green fluorescence of Cs_{2} excited by laser lines in the 457-488 nm range are studied. Emphasis is placed on the analysis of the 501-527 nrn range. The identified fluorescence line progressions are attributed to the E'(3)^{1}П_{u} → X^{1}∑^{+}_{g} transition. An extension of the attractive branch of the E'(3)^{1}П_{u} potential towards longer inter-nuclear distances is reconstructed by the semi-classical method. A narrow feature at 522 nm is found to be connected with a minimum of the difference potentiał. The lifetime values are measured. The multicomponent fluorescence decays are interpreted as evidence of perturbations of the E'(3)^{1}П_{u} state by a number of bound and repulsive states of dicherent symmetry. The predissociation rates are estimated.

6

Laser Induced Fluorescence of Indium Vapour

63%

Weyh T., Kopystyńska A., Kowalczyk P., Radzewicz C.

Acta Physica Polonica A

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1991

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vol. 80

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issue 6

801-804

EN

Indium vapour was illuminated with laser light in the wavelength range 350-372 nm and at 410.3 nm. A few fluorescence bands of In_{2} as well as a strong background emission of indium-quartz compounds were observed. An evidence of energy transfer processes in indium vapour was found.

7

Activation of Silver Colloids for Enhancement of Raman Scattering

51%

Kruszewski S., Cyrankiewicz M.

Acta Physica Polonica A

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2011

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vol. 119

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issue 6A

1018-1022

EN

Obtaining of systems that provide ever-increasing enhancement of the Raman scattered light is a big challenge. The silver colloids obtained by reduction of silver nitrate by trisodium citrate are the most promising enhancement systems. Nanoparticles of silver forming fresh colloid obtained by this way exhibit in extinction spectrum the absorption band proving of the surface plasmons excitation, but do not enhance the Raman scattered light, are not surface enhanced Raman scattering active. Adding of KCl or HNO_3 causes the surface enhanced Raman scattering activation, i.e. causes that the conditions for aggregation of nanoparticles and for adsorption on their surface of molecules providing Raman scattering are created. Increasing amount of added KCl or HNO_3 leads to significant changes in the extinction spectrum and to significant increase in intensity of surface enhanced Raman scattering. The observed changes in extinction spectrum are mainly due to progressive aggregations of nanoparticles. In junctions between nanoparticles existing inside aggregates the condition for single molecule surface enhanced Raman scattering are fulfilled and therefore aggregation leads to increase in average surface enhanced Raman scattering intensity. Silver colloid activated by using KCl provides about 10-fold higher surface enhanced Raman scattering than that treated with HNO_3.

8

Magnetooptic Effects in the Photonic Crystal Fiber as a Function of the Polarization State

51%

Barczak K.

Acta Physica Polonica A

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2013

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vol. 124

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issue 3

384-386

EN

In optical fibers there exists an optical birefringence induced by external factors and stress produced in technological processes. The induced birefringence makes difficult to apply optical fibers in heads of polarimetric sensors. It has been proposed to use a photonic crystal fiber working in an index guiding regime due to the small value of stress in a fiber core produced by internal and external factors. This article presents an expansion of our earlier investigations. The expansion consists of investigations concerning the influence of external magnetic field induction on the state of polarization of light in the function of an azimuth of the input linear polarization ϕ. On the basis of the resulting characteristics optimal working points of the tested fiber were determined.

9

The C^1Σ^+ State of KLi Studied by Polarisation Labelling Spectroscopy Technique

51%

Grochola A., Kowalczyk P., Jastrzębski W., Crozet P., Ross A.

Acta Physica Polonica A

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2002

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vol. 102

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issue 6

729-738

EN

The polarisation labelling spectroscopy method is applied to study the C^1Σ^+← X^1 Σ^+ band system of the KLi molecule. Rotationally resolved polarisation spectra are observed in the spectral range of 17150-20350 cm^{-1}. A set of Dunham coefficients describes the C^1Σ^+ state to 95% of its potential well depth, and the potential curve is constructed by the Rydberg-Klein-Rees procedure. The molecular parameters deduced from this work are compared with theoretical calculations.

10

Purely Electronic and Vibronic Fluorescence Excitation of Single Terrylene Molecules in a Naphthalene Crystal

51%

Banasiewicz M., Dresner J., Morawski O., Wiącek D., Kozankiewicz B.

Acta Physica Polonica A

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2007

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vol. 112

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issue S

S-85-S-94

EN

Fluorescence excitation spectra of spatially resolved single terrylene molecules in a naphthalene crystal were studied at 5 K as a function of exciting laser light intensity. The fully saturated fluorescence detection rate for purely electronic transition (0,0) was found to be about twice smaller than that for the two main vibronic components located 239 and 251 cm^{-1} above. This relation is fulfilled when the triplet population rate k_{23} is much weaker than the depopulation rate k_{31}. We propose that the weak fluorescence excitation lines observed at the frequencies of 38, 67, 97, and 145 cm^{-1} correspond to nontotally symmetric low-frequency vibration modes of terrylene.

11

Survey of the Excited State Dissociation οf Gas-Phase Bromine Monochloride in the Visible-Near UV Wavelength Region

51%

Zhang D.

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issue 3

457-465

EN

The spectroscopic transitions and photoabsorption/dissociation processes of bromine monochloride (BrCl) via several low-lying covalently bound electronic states and repulsive states have been investigated by performing electronic structure calculations and wave packet simulations of nuclear motion. The absorption spectra for 52-electron singlet systems are obtained by employing time-dependent propagation methods or the real-time propagation of the time-dependent Schrödinger equations in the adiabatically exact approximation. Based on the elastic scattering calculations, the results of angular distributions of the products of photodissociation of BrCl molecules are examined on two aspects: (1) the nature of the state that is prepared by excitation from a bound level into a continuum, and (2) under avoided crossing cases, the influences of nonadiabatic coupling processes on the fragmentation process are evaluated by virtue of a semiclassical Landau-Zener model, which treats an avoided crossing between two states of a given nature and evaluates a nonadiabatic effect relevant to the molecule during photodissociation. The model qualitatively reproduces the key aspects of the full processes related to the transfer of dissociating flux between states of 0+ symmetry, indicating that the proposed coupling scheme is generally correct.

12

Tm^{3+}/Ho^{3+}-Doped ASE Fibre Source for Mid-Infrared Sensor Applications

51%

Dorosz D., Żmojda J., Kochanowicz M., Miluski P., Dorosz J.

Acta Physica Polonica A

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2012

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vol. 122

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issue 5

927-932

EN

The infrared emission of Tm^{3+}/Ho^{3+}-doped antimony-silicate optical fiber has been presented. Luminescence at 2.1 μm corresponding to ⁵I₇ → ⁵I₈ transition in holmium was obtained by energy transfer between Tm^{3+} and Ho^{3+} ions. According to the Förster-Dexter theory, the efficiency of energy transfer of the ³F_4 (Tm^{3+}) → ⁵I₇ (Ho^{3+}) transition was calculated. The optimization of the activator content and the donor (Tm^{3+})/acceptor (Ho^{3+}) ions concentration ratio were conducted with the purpose of maximizing the efficiency of energy transfer. It made possible to select best-suited glass which was used to manufacture double-clad optical fiber. Strong and narrow bands of amplified spontaneous emission which formed as a result of energy transfer between thulium and holmium ions were observed in the fiber under exciting with radiation at 795 nm wavelength.

13

^{7}F_{6}(Γ_{1g}) → (Γ_{1g})^{5}D_{4} Two-Photon Transition of Tb^{3+} in Cs_{2}NaTbCl_{6}

51%

Chua M., Tanner P.

Acta Physica Polonica A

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1996

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vol. 90

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issue 1

169-180

EN

Two-photon spectroscopy has expanded the scope of studies of excited states of ions and has also enabled the examination of the validity of conventional theories. In this study, the direct theoretical calculation of the two-photon intraconfigurational crystal field transitions of ^{7}F_{6}(Γ_{1g}) → ^{5}D_{4} of Tb^{3+} in Cs_{2}NaTbCl_{6} has been performed, based on third-order perturbation theory including electric dipoles and spin-orbit coupling. The core 4f^{7} (^{8}S_{7/2}} Γ_{6}, Γ_{7}, Γ_{8}) and 4f^{7}(^{6}P_{7/2} Γ_{6}, Γ_{7}, Γ_{8}) states coupled with 5d(Γ_{3}, Γ_{5}) are taken as the intermediate states. The calculated transition intensity ratios are in good agreement with the experimental results. In particular the two-photon transition ^{7}F_{6}(Γ_{1g}) → ( Γ_{1g})^{5}D_{4} is allowed in third-order perturbation instead of the proposed fourth-order process by Ceulemans et al. using the Judd-Pooler-Downer model. The inconsistency between the two studies arises from the failure of application of the Judd-Ofelt closure approximation. The closure approximation does not only simplify the two-photon calculation but also sacrifices the physical accuracy by changing the selection rule of the two-photon transition from that of two electric dipole transitions to that of one electric quadrupole transition.

14

Upconversion Luminescence in Yb^{3+}/Tm^{3+} Doped Double Clad Optical Fibre

51%

Zmojda J., Dorosz D., Kochanowicz M., Dorosz J.

Acta Physica Polonica A

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2011

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vol. 120

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issue 4

776-781

EN

The paper presents luminescence properties of telluride glass doped with Yb^{3+}/Tm^{3+} ions. Strong blue emission at 477 nm corresponding to the transition ^1 G_4 → ^3 H_6 in thulium ions was measured under the excitation of a 976 nm diode laser. The dependence of the upconversion emission upon the thulium ions concentration was studied in order to determine the optimal ion content. The results showed that intensity of upconversion emission enhances, with the increase of Tm^{3+} content up to 0.1 mol.%. The most effective energy transfer Yb^{3+} → Tm^{3+} occurs in the glassy matrix with molar ratio of dopant 1 Yb^{3+} : 0.1 Tm^{3+}. Double-clad optical fibre was made of glass with the highest upconversion intensity at the wavelength of λ = 477 nm (TGPF101). As a result of optical excitation (λ = 976 nm) of the produced optical fibre, an additional emission line, which was not noticed in the glass, was observed at the wavelength of 351 nm corresponding to the ^1 D_2 → ^3 H_6 transition.

15

Comparative Study of Orientational Order of Some Liquid Crystals from Various Homologous Series

51%

Bielejewska N., Chrzumnicka E., Mykowska E., Przybylski R., Szybowicz M., Władysiak K., Bauman D.

Acta Physica Polonica A

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2006

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vol. 110

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issue 6

777-793

EN

The long-range orientational order of liquid crystals from homologous series of 4-n-alkyl-4'-cyanobiphenyl, 4-n-alkoxy-4'-cyanobiphenyl, trans-4-n-alkyl(4'-cyano-phenyl)-hexane, and 4-(trans-4'-n -alkylcyclohexyl)-isothiocyanato-benzene was studied by means of classical methods of optical spectroscopy: absorption of the polarized light, fluorescence depolarization, and Raman scattering depolarization. The absorption, emission, and Raman scattering spectra of linearly polarized light were recorded as a function of temperature in the whole range of the mesophase. On the basis of these spectra the order parameters ⟨P_2⟩ and ⟨P_4⟩ as well as the orientational distribution function were determined. The results obtained for members of various series with the same number of carbon atom in the alkyl chain were compared. It was found that the orientational order of liquid crystal molecules depends on the structure of the rigid core, on the kind of the terminal group as well as on the alkyl chain length. The odd-even effect for the order parameters, explained as the alteration of interaction between alkyl chains, was observed.

16

Reanalysis of the Ångström System (B^1 Σ^{+} - A^1Π) in the ^{13}C^{16}O Isotopic Molecule

51%

Hakalla R., Szajna W., Zachwieja M., Kępa R.

Acta Physica Polonica A

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2012

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vol. 122

|

issue 4

674-682

EN

The emission spectrum of the Ångström system (B^1 Σ^{+} - A^1 Π) of ^{13}C^{16}O was obtained under high resolution with an accuracy estimated to be ± 0.002 cm^{-1} as an emission spectrum using a high accuracy dispersive optical spectroscopy. The light source was a hollow-cathode lamp with two anodes built in our laboratory, with a previously deposited small quantity of ^{13}C carbon on the electrodes. The emission from the discharge was observed with a plane grating spectrograph and recorded by a photomultiplier tube. In total 195 transition wave numbers belonging to the strongest 0-1 and 0-2 bands of the B - A system were precisely measured. The modern rotational reanalysis made it possible to verify the molecular information for the both combining states of the Ångström system. In particular the rovibrational constants for the B^1 Σ^{+} Rydberg state have been significantly improved (B_0 = 1.8625054(65) cm^{-1} and D_0=6.1384(52) × 10^{-6} cm^{-1}) and the obtained equilibrium rotational constants of this state are more accurate than known to date. Numerous rotational perturbations observed in the A^1 Π state were reanalysed and confronted with the previously known ones.

17

White Upconversion in Yb^{3+}/Tm^{3+}/Ho^{3+} Co-Doped Antimony-Germanate Glasses

51%

Żmojda J., Dorosz D., Kochanowicz M., Miluski P., Dorosz J.

Acta Physica Polonica A

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2013

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vol. 124

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issue 3

598-601

EN

In the paper the spectroscopic properties of antimony-germanate glass co-doped with $Yb^{3+}/Ho^{3+}$ has been investigated. Fabricated $Yb^{3+}/Tm^{3+}/Ho^{3+}$ co-doped glass is characterised by the emission of simultaneous multicolour upconversion luminescence. Strong blue $^{1}G_{4} → ^{3}H_{6}(Tm^{3+})$, green $^{5}F_{4} → ^{5}I_{8}(Ho^{3+})$ and red $^{5}F_{5} → ^{5}I_{8}(Ho^{3+})$ upconversion emission bands have been measured under 976 nm excitation at room temperature. Influence of molar ratio of active ions and excitation power on the colour coordinates (CIE-1931) have been investigated.

18

Multicore Optical Fibres for an External Talbot Cavity

51%

Dorosz D., Kochanowicz M., Dorosz J.

Acta Physica Polonica A

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2009

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vol. 116

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issue 3

298-301

EN

In the paper the application of multicore optical fibres in phased-locked high power lasers is presented. The manufacturing and properties of multicore active optical fibres were presented. The thermally stable aluminosilicate glass doped with Nd^{3+} (0.5 mol%) ions were melted and used as cores in manufactured multicore optical fibres. Two configurations of double clad multicore optical fibres with the circular array containing 15 and 30 Nd^{3+} doped cores on ring inside a large pump clad were realized. Absorption and luminescence spectra of obtained glasses and fibres were presented. An external plane mirror located at certain distance of the array forms the basic Talbot cavity. The possibilities of mode selection and phase-locking by using Talbot resonator applied to fabricated multicore fibres were investigated.

19

Application of Photonic Crystal Fiber in Optical Fiber Current Sensors

51%

Barczak K.

Acta Physica Polonica A

|

2012

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vol. 122

|

issue 5

793-795

EN

Optical fibers may be applied in the technique of measuring electric current, particularly as so-called optical current transducers. They are small in size, cheap, light and safe. Their sensitivity, however, connected with the Faraday effect, is rather poor, and they are also susceptible to considerable disturbances (deformations of the fibers). Their sensitivity can be increased by lengthening the path of effect, but this involves also an increase of noise and greater fluctuations of the measured signal due to changes of internal stresses induced by external factors. These negative phenomena can be reduced by applying fibers less sensitive to deformations. The author supposes that photonic crystal fiber with a glass core may display such properties. Orifices in the cladding can to some extent prevent the propagation of deformations from outside the core, and thus decrease the birefringence of the fiber induced by elastooptic effects. The paper presents preliminary measurements of typical photonic crystal fiber exposed to mechanical vibrations.

20

Nd^{3+}/Yb^{3+} Doped Phosphate and Antimony Glasses for Optical Fibre Source

51%

Dorosz D., Żmojda J., Kochanowicz M., Dorosz J.

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issue 6

1108-1112

EN

In the article there are presented two different series of glass: fluorophosphate with molar composition: 65P_2O_5-8Al_2O_3-2BaO-5BaF_2-6ZnF_2-5Na_2O-6MgF_2-3B_2O_3 and antimony glasses 40Sb_2O_3-3Al_2O_3-57SiO_2 doped with Nd^{3+} and Yb^{3+} ions. Dopant contents influence efficient spatial overlapping of emission level for neodymium and absorption level for ytterbium was analyzed. While exciting the produced glasses with a laser diode (λ = 808 nm) a broad luminescence spectrum (Δλ = 100 nm) has been obtained in both cases in the vicinity of 1 μm, being the superposition of the following transitions: ^4F_{3/2} → {^4I_{11/2}} for Nd^{3+} and ^2F_{5/2} → {^2F_{7/2}} for Yb^{3+}. Based on the luminescence measurements the probability of non-radiative energy transfer was described. Because of a small difference in energy ( ≈1190 cm^{-1}) between the laser levels of neodymium and ytterbium the resonant process of energy transfer has been obtained.

Refine search results

Spectral Study of Caesium Dimer Excited with 476.5, 472.7, 465.8 and 457.9 nm Argon Ion Laser Lines

TheÅ ngström (B^1Σ^+ → A^1Π) Band System of ^{13}C^{16}O: New Observations and Analyses

Analysis of the A^1Π State on the Basis of the Douglas-Herzberg Bands System in the CH+ Ion Molecule

Emission Spectroscopy of AlH: the X¹Σ⁺, A¹Π and C¹Σ⁺ States Characteristics

Spectral and Time-Resolved Studies of Green Cs_{2} Fluorescence

Laser Induced Fluorescence of Indium Vapour

Activation of Silver Colloids for Enhancement of Raman Scattering

Magnetooptic Effects in the Photonic Crystal Fiber as a Function of the Polarization State

The C^1Σ^+ State of KLi Studied by Polarisation Labelling Spectroscopy Technique

Purely Electronic and Vibronic Fluorescence Excitation of Single Terrylene Molecules in a Naphthalene Crystal

Survey of the Excited State Dissociation οf Gas-Phase Bromine Monochloride in the Visible-Near UV Wavelength Region

Tm^{3+}/Ho^{3+}-Doped ASE Fibre Source for Mid-Infrared Sensor Applications

^{7}F_{6}(Γ_{1g}) → (Γ_{1g})^{5}D_{4} Two-Photon Transition of Tb^{3+} in Cs_{2}NaTbCl_{6}

Upconversion Luminescence in Yb^{3+}/Tm^{3+} Doped Double Clad Optical Fibre

Comparative Study of Orientational Order of Some Liquid Crystals from Various Homologous Series

Reanalysis of the Ångström System (B^1 Σ^{+} - A^1Π) in the ^{13}C^{16}O Isotopic Molecule

White Upconversion in Yb^{3+}/Tm^{3+}/Ho^{3+} Co-Doped Antimony-Germanate Glasses

Multicore Optical Fibres for an External Talbot Cavity

Application of Photonic Crystal Fiber in Optical Fiber Current Sensors

Nd^{3+}/Yb^{3+} Doped Phosphate and Antimony Glasses for Optical Fibre Source