| 1. |
- AlSalhi, M S., et al.
(author)
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Growth and characterization of ZnO nanowires for optical applications
- 2013
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In: Laser physics. - : Institute of Physics Publishing (IOPP). - 1054-660X .- 1555-6611. ; 23:6
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Journal article (peer-reviewed)abstract
- In the present work, cerium oxide CeO2 nanoparticles were synthesized by the sol-gel method and used for the growth of ZnO nanorods. The synthesized nanoparticles were studied by x-ray diffraction (XRD) and Raman spectroscopic techniques. Furthermore, these nanoparticles were used as the seed layer for the growth of ZnO nanorods by following the hydrothermal growth method. The structural study of ZnO nanorods was carried out by means of field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and XRD techniques. This study demonstrated that the grown ZnO nanorods are well aligned, uniform, of good crystal quality and have diameters of less than 200 nm. Energy dispersive x-ray (EDX) analysis revealed that the ZnO nanorods are composed only of zinc, cerium as the seed atom, and oxygen atoms, with no other impurities in the grown nanorods. Moreover, a photoluminescence (PL) approach was applied for the optical characterization, and it was observed that the near-band-edge (NBE) emission was the same as that of the zinc acetate seed layer, however the green and orange/red emission peaks were slightly raised due to possibly higher levels of defects in the cerium oxide seeded ZnO nanorods. This study provides an alternative approach for the controlled synthesis of ZnO nanorods using cerium oxide nanoparticles as the seed nucleation layer, improving both the morphology of the nanorods and the performance of devices based upon them.
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| 2. |
- Bossi, Alesandra, et al.
(author)
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Ice matrix inreconfigurable microfluidic systems
- 2013
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In: Laser physics. - : Institute of Physics (IOP). - 1054-660X .- 1555-6611. ; 23:7
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Journal article (peer-reviewed)abstract
- Microfluidic devices find many applications in biotechnologies. Here, we introduce a flexible and biocompatible microfluidic ice-based platform with tunable parameters and configuration of microfluidic patterns that can be changed multiple times during experiments. Freezing and melting of cavities, channels and complex relief structures created and maintained in the bulk of ice by continuous scanning of an infrared laser beam are used as a valve action in microfluidic systems. We demonstrate that pre-concentration of samples and transport of ions and dyes through the open channels created can be achieved in ice microfluidic patterns by IR laser-assisted zone melting. The proposed approach can be useful for performing separation and sensing processes in flexible reconfigurable microfluidic devices.
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| 3. |
- Mohamed, Tarek, et al.
(author)
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A seeded dye laser cavity for intracavity experiments
- 2015
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In: Laser physics. - 1054-660X .- 1555-6611. ; 25:9
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Journal article (peer-reviewed)abstract
- A seeded dye laser cavity, synchronously pumped by the 2nd harmonic of the Nd:YAG laser has been designed and experimentally tested. The used seed signal was the well defined narrow linewidth output laser signal (Delta lambda = 0.013 nm) from the excimer-dye laser system. Energy considerations showed that the intracavity laser energy, that can be used for an experimental section inside the cavity, can reach an efficiency of 20% of the pumping energy. The wavelength and linewidth are fully controlled by the wavelength and linewidth of the seeding laser.
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| 4. |
- Naveed, H. B., et al.
(author)
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Model microcavity laser with CdSe/CdS quantum dots as lasing media
- 2016
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In: Laser physics. - : Institute of Physics Publishing (IOPP). - 1054-660X .- 1555-6611. ; 26:2
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Journal article (peer-reviewed)abstract
- A model is established for a microcavity laser with cadmium selenium/cadmium sulfide (CdSe/CdS) core/shell quantum dots (QDs) as a lasing medium, The research was organised to develop and solve the rate equations for the above mentioned microcavity laser to calculate the output parameters during lasing. Using time-resolved fluorescence spectroscopy, the radiative life time of the lasing medium was measured along with its fluorescence and absorption spectra. A model is also established on the basis of the segment contact method (SCM) to demonstrate the threshold gain profile using the absorption spectrum of CdSe/CdS core/shell type II QDs residing in the cavity. A laser cavity of size 1 mu m was pumped with an optical source (532 nm) to achieve an optimised laser peak at 470nm,
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| 5. |
- Andersson, Mats, et al.
(author)
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Laser spectroscopy of gas in scattering media at scales ranging from kilometers to millimeters
- 2007
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In: Laser Physics. - 1054-660X. ; 17:7, s. 893-902
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Journal article (peer-reviewed)abstract
- Free gases are characterized by their narrow line width, and they can conveniently be studied by laser spectroscopy. The present paper discusses the monitoring of such ambient pressure gases, which are dispersed in scattering media such as aerosol-laden atmospheres, solids, or liquids. Atmospheric work basically constitutes the well-known field of differential absorption lidar (DIAL), while the study of free gas in solids and liquids was initiated more recently under the name of GASMAS (GAs in Scattering Media Absorption Spectroscopy). We discuss the connections between the two techniques, which are extensively used in our labortory. Thus, we span the field from trace-gas mapping of gases in the lower atmosphere to gas studies in construction materials, food products, and the human body. We show that the basic ideas are very similar, while the spatial and temporal scales vary greatly.
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| 6. |
- Bogdanova, M.V., et al.
(author)
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Absorption spectra versus field distribution for metal-dielectric three-dimensional photonic crystals
- 2008
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In: Laser physics. - : Pleiades Publishing Ltd. - 1054-660X .- 1555-6611. ; 18:4, s. 417-423
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Journal article (peer-reviewed)abstract
- The absorption spectra of three-dimensional metal-dielectric photonic crystals (PCs) are studied using computer simulation by the finite difference time domain method and the layered Korringa-Kohn-Rostoker method. The band structure of a three-dimensional dielectric PC is obtained by the plane wave expansion method. The explanation of absorption spectra of PC based on its comparison with the band structure and Fabry-Perot resonances inside a PC plate is given. The intensity distribution of an electric field using FDTD inside the metal-dielectric PC for three various structures is analyzed. It is shown that spherical cavities in a dielectric PC "focus" the field inside cavities at certain wavelengths. This leads to an increase of absorption at these wavelengths if metal spheres are located in the centers of those cavities. This effect can be considered as an analogue of the Borrmann effect in X-ray spectroscopy. © 2008 MAIK Nauka.
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| 7. |
- Chen, Daru, et al.
(author)
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Single-longitudinal-mode erbium-doped fiber laser based on a fiber Bragg grating Fabry-Perot filter
- 2007
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In: Laser physics. - 1054-660X .- 1555-6611. ; 17:10, s. 1246-1248
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Journal article (peer-reviewed)abstract
- A novel single-longitudinal-mode (SLM) erbium-doped fiber laser with a simple linear cavity based on a fiber Bragg grating Fabry-Perot filter (FBG-FPF) and a narrowband (similar to 0.06 nm) FBG is proposed and demonstrated experimentally. Two uniform FBGs form the FBG-FPF, which has two ultranarrow transmission bands with a bandwidth of 0.12 pm and a wavelength spacing of 0.095 nm. By slightly tuning the central wavelength of the narrowband FBG, SLM lasing at 1549.658 or 1549.563 nm (corresponding to the two transmission peaks of the FBG-FPF) is achieved with a laser output power of similar to 4 mW, when the pump power is similar to 75 mW.
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| 8. |
- Elman, U., et al.
(author)
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Statistical modeling and theoretical analysis of the influence of laser phase fluctuations on photon echo data erasure and stimulated photon echoes
- 1996
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In: Laser Physics. - 1054-660X. ; 6:4, s. 721-728
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Journal article (peer-reviewed)abstract
- The effect of random laser phase fluctuations on stimulated photon echoes (SPEs) and on coherently added SPEs was studied and evaluated both experimentally and analytically with statistical methods. The general concept of describing laser frequency fluctuations as a stationary stochastic process is presented and applied to three specific SPE configurations. The effect of phase fluctuations on erasing an SPE by coherently adding another SPE, phase-shifted by 180 degrees relative to the first, is presented.
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| 9. |
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| 10. |
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