H.J. Caulfield

Publications (7)2.02 Total impact

• Conference Proceeding: Coherence studies in a powder laser

  M A Noginov, S.U. Egarievwe, J.C. Wang, H.J. Caulfield
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  ABSTRACT: Not Available
  Quantum Electronics Conference, 1998. 1998 EQEC. European; 10/1998
• Conference Proceeding: Color center powder laser: spectroscopy and stimulated emission

  M A Noginov, N. Noginova, S.U. Egarievwe, H.J. Caulfield, P. Venkateswarlu, A Williams, S.B. Mirov
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  ABSTRACT: Not Available
  Lasers and Electro-Optics, 1997. CLEO '97., Summaries of Papers Presented at the Conference on; 06/1997
• Source

  Available from: Irina T. Sorokina

  Article: Transient light induced grating study of excitation diffusion in Y3Sc2Ga3O12 laser crystals

  M.A. Noginov, H.J. Caulfield, P. Venkateswarlu, M. Mahdi, I.T. Sorokina
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  ABSTRACT: Excitation migration over the lower energy levels in Y3Sc2Ga3O12 (YSGG) laser crystals doped with Cr, Er, Tm, and Ho ions was studied using the two-wave mixing light induced grating (LIG) technique. The results of the LIG measurements were compared to the data obtained from the luminescence kinetics and spectra overlap studies of the migration. The comparison of the three different spectroscopic techniques allowed more detailed analysis of the complicated pattern of the energy transfer processes in the crystals than any one method alone. The migration was found to be very efficient, especially in highly doped crystals. The diffusion coefficients determined from direct LIG measurements were much higher than those calculated in dipole-dipole approximation from absorption and emission spectral measurements. This implies stronger than dipole-dipole coupling between interacting ions. In Tm doped crystals a surprisingly strong increase of the migration efficiency between Tm concentrations 8 × 1020 cm−3 and 1.5 × 1021 cm−3 was observed both in LIG diffusion and luminescence kinetics experiments. This too cannot be explained in terms of low multipolar energy transfer. Exchange energy transfer and the percolation model are discussed as possible explanations for the experimental results.
  Optical Materials 11/1996; 6(4):245-259. · 2.02 Impact Factor
• Article: Stimulated emission without cavity in powders and single crystals of Nd doped materials

  M. A. Noginov, N. E. Noginova, H. J. Caulfield, P. Venkateswarlu, T. Thompson, M. Mahdi, V. Ostroutnov
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  ABSTRACT: Short (>300 ps) pulses of stimulated emission were found from powders of NdAl3(BO3)4, NdSc3(BO3)4, and Nd:Sr5(PO4)3 laser crystals under 532 nm and 805 nm excitation. Study of stimulated emission in the mixture of two powders has shown that different components influenced each other. The main features of experimentally observed stimulated emission are described with a simple model accounting for 4F_3/2 excited state concentration and emission energy density.
  01/1996;
• Source

  Available from: nsu.edu

  Article: Demonstration of a second-harmonic powder laser

  M A Noginov, S U Egarievwe, N Noginova, J C Wang, H J Caulfield
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  ABSTRACT: We demonstrate second-harmonic generation in a mixture of powders of laser Nd 0.5 La 0.5 Al 3 (BO 3) 4 and frequency-doubling (2-methyl-4-nitroaniline) (MNA) materials. We quantitatively describe short-spike 1.06-m stimulated emission and its second harmonic with the model accounting for the population inversion and the energy density of 1.06-m and 0.53-m radiation in the pumped volume. The experimental results are in a good agreement with the model predictions. The optimum MNA concentration was shown to be de-pendent on the pumping energy. The determined optimum nonlinear coefficient in (pulverized) nonlinear ma-terial was shown to be 10 2 – 10 3 times larger than that in MNA. © 1998 Optical Society of America [S0740-3224(98)01510-0] OCIS codes: 140.3580; 300.2140; 160.0160.
• Article: Study of the pumping regimes in Ti-sapphire and Nd0.5La0.5Al3(BO3)4 powders

  M.A. Noginov, N. Noginova, S.U. Egarievwe, H.J. Caulfield, C. Cochrane, J.C. Wang, M.R. Kokta, J. Paitz
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  ABSTRACT: Stimulated emission without a cavity was obtained (at λ=800 nm) in powders of Ti-sapphire laser crystal and compared to that in Nd0.5La0.5Al3(BO3)4. The formation of a narrow channel in a powder sample by a pumping laser beam was found to be advantageous for stimulated emission in Ti-sapphire and disadvantageous in Nd0.5La0.5Al3(BO3)4. The effect of the material volume density on stimulated emission in scattering Nd0.5La0.5Al3(BO3)4 was experimentally studied. The experimental results are explained in terms of absorption of pumping light in scattering materials, penetration depth for pumping, and residence time for emission photon in the pumped volume.
  Optical Materials. 10(4):297-303.
• Article: Diffusion and pseudo-phase-conjugation effects in coherent backscattering from Nd0.5La0.5Al3(BO3)4 ceramic

  M.A. Noginov, S.U. Egarievwe, H.J. Caulfield, N.E. Noginova, M. Curley, P. Venkateswarlu, A. Williams, J. Paitz
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  ABSTRACT: We study coherent backscattering in Nd0.5La0.5Al3(BO3)4 ceramic and demonstrate what we call the effect of pseudo phase conjugation from scattering medium. We show that coherent backscattering can correct for large-scale distortions of the light wave front. The imperfections in the backscattering imaging as well the impossibility of correcting for small-scale wave front distortions are discussed. An `optical equivalent circuit' of known components which give the same behavior as a scattering medium is offered.
  Optical Materials.