Physics Commons^™

The Development And Characterisation Of A Red-Sensitised Photopolymer Holographic Recording Material, Clodagh Feely

Doctoral

The development and characterisation of a photopolymerisable photopolymer holographic recording material, for red sensitisation is described. The material comprises dye (methylene blue), an electron donor (triethanolamine) and monomer (acrylamide and methylene-bis-acrylamide). A binder is also included (poly(vinylalcohol) to allow recording in dry layer format. One of the main advantages of the material is its ability to self-develop, which makes it highly suitable for a range of applications which includes the fabrication of Holographic Optical Elements (HOEs). The optimisation of the material formula for red-sensitisation using holographic techniques is described. Diffraction efficiencies of over 70% were obtained in 25 seconds with …

Measured Stark Widths And Shifts Of Several Niii Sectral Lines: Temperature Dependence, Stevan Djenize, Vladimir Milosavljevic

Articles

Stark parameters (width and shift) of four doubly ionized nitrogen spectral lines, that belong to 3s-3p and 3p-3d transitions (lower multiplets), have been measured in a linear pulsed, low pressure, arc discharge in the nitrogen-oxygen and helium-nitrogen-oxygen plasmas in a (30 000 - 54 000) K electron temperature and a (0.75 10²³ - 2.8 10²³) electron density ranges. The measured values have been compared to the existing experimental and calculated data.

On The Stark Broadening Parameters Of The Two Nii Spectral Lines Of The 3d-4f Transition, Vladimir Milosavljevic, Stevan Djenize

Articles

Stark parameters (width and shift) of two singly ionized nitrogen spectral lines, that belong to 3d-4f transition have been measured in a linear pulsed, low pressure, arc discharge in the nitrogen-oxygen plasma at a 54000 K electron temperature and at a 2.8×10 23 m−3 electron density. The measured values have been compared to the existing experimental and calculated data

Measured Stark Widths Of A 425,94 Nm Ari Spectral Line, Ljiljana Skuljan, Vladimir Milosavljevic, Aleksandar Sreckovic, Stevan Djenize

Articles

No abstract provided.

A New Photopolymer Recording Material For Holographic Applications: Photochemical And Holographic Studies Towards An Optimized System, Suzanne Martin

Doctoral

Photopolymer materials are a practical alternative to high resolution silver halide photographic emulsions for the recording of holograms and high spatial frequency holographic gratings. The new holographic recording material reported in this thesis consists of a green sensitive dye (erythrosine B), an electron donor (triethanolamine), and a monomer mixture (acrylamide and methylene bisacrylamide) in a polyvinyl alcohol binder. ON illumination with light of the appropriate wavelength the dye absorbs a photon and the excited triplet state of the dye reacts with the electron donor to produce free radicals. These free radicals may then initiate local polymerization of the monomer. The …

Experimental Stark Shift Of Several Nii And Oii Spectral Lines, Mara Scepanovic, Vladimir Milosavljevic, Stevan Djenize, Mihajlo Platisa, Jaroslav Labat

Articles

Stark shift of four NII and seven OII spectral lines have been measured for the first time in the linear low pressure pulsed arc plasma and compared with existing theoretical values.

Dielectric Response Of Ferroelectric Liquid Crystal Cells, Yuri Panarin, Huan Xu, Seamus Mac Lughadha, Jagdish Vij

Articles

No abstract provided.

Resonant Vibrations Of The Irish Folk Harp, Patrick Healy

Other Resources

An analysis of the resonant vibration of an O’Meachair cedar and mahogany Irish folk harp is reported. A report is also made of a small number of measurements carried out on an O’Meachair spruce and maple Irish folk harp. The structure and operation of the harp is described.

The theory of small vibrations of plates and wooden boards is set out.

The system devised to measure input admittance at driving points on the harp body over a frequency range O-2 kHz is described. Tests of its linearity and out of its frequency flatness are reported.

Resonant vibrations of an isolated …

Hysteresis And Anchoring Energy In Ferroelectric Liquid Crystals, Yuri Panarin

Articles

The frequency dispersion of the coercive force of Ferroelectric Liquid Crystals (FLC) cells has been detected and examined in the range of infralow (lower than 0.1 Hz) frequencies. To clarify the low-frequency dispersion, the model has been suggested, based on the arrangement of free charges and well describing the experimental curves. The method for determination of the energy of FLC anchoring at the surface, developed on the basis of the static hysteresis loop, has been proposed. The dependence of bistability and the anchoring energy upon the orientant layer thickness has experimentally been investigated.

Degnerate Four-Wave Mixing In Rhodamine Doped Epoxy Waveguides, B. Rossi, Hugh Byrne, W. Blau

Articles

Self-diffraction from laser-induced gratings is observed in a 13 pm-thick film of rhodamine I3 doped epoxy. The decay of the grating is measured to be 2.05 ns. Degenerate forward four-wave mixing in a guided geometry is observed by coupling out all beams after nronagation over 1 mm. At 595 nm the third-order nonlinear susceptibility of the film is measured to be 1.5~10-‘~ m2Ve2.