Blue Laser Beam Research Articles

Microinjection of Helobdella (Leech) Embryos: Figure 1.

One advantage of using Helobdella (leech) embryos as an experimental system is their amenability for microinjection. Blastomeres ranging in size from the zygote (400 microm diameter) down to micromeres and primary blast cells (approximately 20 microm diameter) can be injected by pressure under a dissecting microscope. Smaller cells can be injected by iontophoresis under a compound microscope. Microinjection is useful for studying embryonic development. For example, developmental fates of a cell can be followed by injecting a lineage tracer. A specific cell can be killed by injecting a toxic substance. Furthermore, cells can be killed at a given developmental stage by directing intense fluorescence illumination or a blue laser beam on fluorescein-labeled cells. Finally, gene expression can be manipulated in leech embryos by injecting zygotes or selected blastomeres with synthetic mRNA, morpholino antisense oligo, or a plasmid construct. Molecules <1500 Da can diffuse freely among early blastomeres via gap junctions. When intercellular diffusion of an injected substance is undesirable, small molecules should be conjugated to larger molecules such as dextran (10 kDa). Different commercial microinjection setups can be adopted for Helobdella embryos. This article describes how to microinject embryos using a versatile homemade pressure injection system. Under a dissecting microscope, embryos are immobilized by suction in a custom-fabricated chamber with the target cell facing upward. Cells are visualized using transillumination via a long-working-distance, dark-field condenser. The tip of a micropipette is brought into the target cell with a micromanipulator, and the injectant is delivered into the cell by pressure.

Crystallization and thermal stability of Sn-doped Ge2Sb2Te5 phase change material

The influence of Sn doping on the crystallization and thermal stability of Ge2Sb2Te5 phase change material was studied. Thermal analysis shows that the phase change of Sn7.0Ge20.6Sb20.7Te51.7 occurs slightly higher than that of Ge2Sb2Te5 at 154 °C and has a lower melting point at 536 °C. The activation energy for crystallization for this material is also higher. It has a face-centred-cubic crystal structure. A fast crystallization speed of 60 ns is realized upon irradiation by a blue laser beam of 405 nm. The use of the Sn7.0Ge20.6Sb20.7Te51.7 phase change material as a mask layer in aperture-type super-resolution near-field phase change disk is realized to increase the carrier-to-noise ratio and thermal stability.

Write-Once Medium with Fe-Doped BiOx Thin Films for Blue Laser Recording

Fe:BiOx films are fabricated on K9 glass substrates by rf-magnetron sputtering of a BiFeO target under argon atmosphere with increasing sputtering power from 80 to 200 W at room temperature. It is found that the thin films grown at the sputtering power of 160 W can be formed at an appropriate deposition rate and have an improved surface morphology. The XPS result reveals that the films investigated are comprised of Bi, Fe and O elements. A typical XRD pattern shows that no phase transition occurs in the films up to 400° C. The results of the blue laser recording test demonstrate that the Fe:BiOx films have good writing sensitivity for blue laser beam (406.7nm) and good stability after reading 10000 times. The recording marks of 200 nm or less are obtained. These results indicate that the introduction of Fe into BiOx films can reduce the mark size and improve the stability of the films.

Ultrafast crystallization and thermal stability of In–Ge doped eutectic Sb70Te30 phase change material

Effect of In and Ge doping in the form of In2Ge8Sb85Te5 on optical and thermal properties of eutectic Sb70Te30 alloys was investigated. Crystalline structure of In2Ge8Sb85Te5 phase change material consists of a mixture of phases. Thermal analysis shows higher crystallization temperature and activation energy for crystallization. Isothermal reflectivity-time measurement shows a growth-dominated crystallization mechanism. Ultrafast crystallization speed of 30ns is realized upon irradiation by blue laser beam. The use of ultrafast and thermally stable In2Ge8Sb85Te5 phase change material as mask layer in aperture-type super-resolution near-field phase change disk is realized to increase the carrier-to-noise ratio and thermal stability.

Phase change behaviors of In-Ge-Sb-Te alloy

Phase change behaviors of In2Ge8Sb85Te5 material were studied. Thermal analysis shows the phase change occurs around 160 °C and melting at 572 °C. Isothermal reflectivity-time measurement of In2Ge8Sb85Te5 shows a growth-dominated crystallization mechanism. A high crystallization speed of 30 ns is realized upon irradiation by blue laser beam of 405 nm. It has face-centered-cubic NaCl-type and rhombohedral Sb crystal structures. The weaker binding energy of In and In-Sb bond energy are believed to be the reasons for fast crystallization speed of In2Ge8Sb85Te5.

氧化铋薄膜用于蓝光可录存储的研究

BiOx films are prepared by reactive direct current (DC) magnetron sputtering from a metallic bismuth target in Ar + O2 with different O2/Ar ratios. It is found that the optical property of BiOx films is sensitive to O2/Ar ratios and the films deposited at O2/Ar ratio of 0.5 have the best reflectivity contrast under the same conditions. The structure and optical characteristics of the films are studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectrophotometer. As revealed by investigations, the phase transition is mainly responsible for the change of optical properties. The static test results indicate that the BiOx films have good writing sensitivity for blue laser beams. A high reflectivity contrast of about 52% at a writing power of 11 mW and writing pulse width of 800 ns is obtained. In addition, the films demonstrate good stability after being read for 10000 times.

Write-once blue laser recording using silicon doped SbO x thin films prepared by reactive dc-magnetron sputtering

Si:SbO x films have been deposited by reactive dc-magnetron sputtering from a Sb target with Si chips attached in Ar + O 2 with the relative O 2 content 7%. The as-deposited films contained Sb metal, Sb 2O 3, SiO, Si 2O 3 and SiO 2. The crystallization of Sb was responsible for the changes of optical properties of the films. The results of the blue laser recording test showed that the films had good writing sensitivity for blue laser beam (406.7 nm), and the recording marks were still clear even if the films were deposited in air 60 days, which demonstrated that doping silicon in SbO x films can improve the stability of SbO x films. High reflectivity contrast of about 36% was obtained at a writing power 6 mW and writing pulse width 300 ns.

SbOx Thin Films Used for Write-Once Blue Laser Recording

SbOx thin films are deposited by reactive dc-magnetron sputteringfrom an antimony metal target in Ar+O2 with the relative O2content 7%. It is found that the as-deposited films can represent atwo-component system comprising amorphous Sb and amorphousSb2O3. The crystallization of Sb is responsible for thechanges of optical properties of the films. The results of the statictest show that the SbOx thin films have good writing sensitivityfor blue laser beams and the recording marks are very clear andcircular. High reflectivity contrast of about 41% is obtained at awriting power 6 mW and writing pulse width 300 ns. In addition, thefilms show a good stability after reading 10000 times.

Laser beam propagation through inertial confinement fusion hohlraum plasmas

A study of the laser-plasma interaction processes have been performed in plasmas that are created to emulate the plasma conditions in indirect drive inertial confinement fusion targets. The plasma emulator is produced in a gas-filled hohlraum; a blue 351-nm laser beam propagates along the axis of the hohlraum interacting with a high-temperature (Te=3.5keV), dense (ne=5×1020cm−3), long-scale length (L∼2mm) plasma. Experiments at these conditions have demonstrated that the interaction beam produces less than 1% total backscatter resulting in transmission greater than 90% for laser intensities less than I&amp;lt;2×1015Wcm−2. The bulk plasma conditions have been independently characterized using Thomson scattering where the peak electron temperatures are shown to scale with the hohlraum heater beam energy in the range from 2keV to 3.5keV. This feature has allowed us to determine the thresholds for both backscattering and filamentation instabilities; the former measured with absolutely calibrated full aperture backscatter and near backscatter diagnostics and the latter with a transmitted beam diagnostics. Comparing the experimental results with detailed gain calculations for the onset of significant laser scattering processes shows a stimulated Brillouin scattering threshold (R=10%) for a linear gain of 15; these high temperature, low density experiments produce plasma conditions comparable to those along the outer beams in ignition hohlraum designs. By increasing the gas fill density (ne=1021cm−3) in these targets, the inner beam ignition hohlraum conditions are accessed. In this case, stimulated Raman scattering dominates the backscattering processes and we show that scattering is small for gains less than 20 which can be achieved through proper choice of the laser beam intensity.

Fabrication of micro-coils using laser scan lithography on copper pipes

Novel fabrication methods of micro-coils were developed. Copper pipes with a diameter of less than 100 μm covered with resist films were exposed to a blue laser beam spot. The pipes were rotated and moved axially for exposing them spirally, and resist patterns were formed on pipe surfaces by dipping the pipes in developer. When copper pipes masked by the spiral resist patterns were etched in ferric chloride solution, fine micro-coils were obtained successfully.

Development of a PC interface board for true color control using an Ar–Kr white-light laser

For the optimal laser display, it is crucial to select and control color signals of proper wavelengths in order to construct a wide range of laser display colors. In traditional laser display schemes, color control has been achieved through the mechanical manipulation of red, green, and blue (RGB) laser beam intensities using color filters. To maximize the effect of a laser display and its color contents, it is desirable to generate laser beams with wide selection of wavelengths. We present an innovative laser display control technique, which generates six channel laser wavelengths from a white-light laser using a RF-controlled polychromatic acousto optical modulator (PCAOM). This technique enables us not only to control the intensity of individual channels, but also to achieve true color signals for the laser beam display including RGB, yellow, cyan, and violet (YCV), and other intermediate colors. For the optimal control of the PCAOM and galvano-mirror, we designed and fabricated a PC interface board. Using this PC control, we separated the white-light from an Ar–Kr mixed gas laser into various wavelengths and reconstructed them into different color schemes. Also we demonstrated the effective control and simultaneous display of reconstructed true color laser beams on a flat screen.

14‐Fluoro‐Bacteriorhodopsin Gelation Films for Dynamic Holography Recording¶

ABSTRACTThe first dynamic holography recording using 14‐fluoro‐(14‐F) bacteriorhodopsin (BR) gelatin films has been achieved. 14‐F BR is an artifical BR pigment made by reconstitution of bacterioopsin (native BR without chromophore) with synthetic 14‐F ratinal. Low‐intensity red light from a cw HE‐Ne laser was used for dynamic holography recording on the 14‐F wild type (WT) BR and 14‐F D96N mutant BR in gelatin films. There is not true comparing the diffraction efficiency for 14‐F D96N BR and 14‐F WT gelatin film, unlike the increase diffraction efficiency for D96N BR gelation film with native chromphore relative to the WT BR gelatin film with native chromophore. Pre‐illumination with blue light of the 14‐F BR gelatin films significantly increases the differaction effciency of both the the 14‐F WT and the 14‐F D96N BR pigments. The sequential application of blue and red laser beams indicates that 14‐F WT and the 14‐F D96N BR pigments. The sequential application of blue and red laser beams indicates taht 14‐F BR gelation films can be useful for optical memory.

Photostability of liquid crystals and alignment layers

— Photostability of liquid-crystal (LC) materials and surface alignment layers was evaluated using a UV lamp and a blue laser beam. Both organic polyimide (PI) and inorganic silicon-dioxide (SiO2) alignment layers were studied under nitrogen environment. Two commercial TFT-grade LC mixtures (low-birefringence MLC-9200-000 and high-birefringence TL-216) were used for comparisons. Results indicate that SiO2 alignment layers are much more robust than PI layers, and low birefringence LCs are more stable than the high-birefringence ones. At the He-Cd laser wavelength (λ = 442 nm), both LC mixtures and SiO2 alignment layers are hardly damaged. To lengthen the lifetime of an LCD projector, inorganic SiO2 alignment layers, high-optical-density UV filter, long cutoff-wavelength blue filter, and short-conjugation (low birefringence) LC materials should be considered.

14-Fluoro-Bacteriorhodopsin Gelatin Films for Dynamic Holography Recording¶

The first dynamic holography recording using 14-fluoro-(14-F) bacteriorhodopsin (BR) gelatin films has been achieved. 14-F BR is an artificial BR pigment made by reconstitution of bacterioopsin (native BR without chromophore) with synthetic 14-F retinal. Low-intensity red light from a cw He-Ne laser was used for dynamic holography recording on the 14-F wild type (WT) BR and 14-F D96N mutant BR in gelatin films. There is not true comparing the diffraction efficiency for 14-F D96N BR and 14-F WT gelatin film, unlike the increased diffraction efficiency for D96N BR gelatin film with native chromophore relative to the WT BR gelatin film with native chromophore. Pre-illumination with blue light of the 14-F BR gelatin films significantly increases the diffraction efficiency of both the 14-F WT and the 14-F D96N BR pigments. The sequential application of blue and red laser beams indicates that 14-F BR gelatin films can be useful for optical memory.

Photochromic gratings in sol–gel films containing diazo sulfonamide chromophore

Abstract The photochromic sol–gel hybrid materials were prepared by incorporation of an azo chromophore containing sulfonamide fragment into polysiloxane cross-linked network. The materials were used to form transparent films on glass by spin-coating and/or casting. The reversible change of refraction index of the films on illumination with white light was observed by ellipsometry. The experiments with two beam coupling (TBC) and four wave mixing (4 WM) arrangement with green or blue laser beams as writing beams showed formation of a diffraction grating. The diffraction efficiency of the first order was 0.025–0.038 which yielded refraction index modulation in the range of up to 0.0066.

Simultaneous green and blue laser radiation based on a nonlinear laser crystal Nd:GdAl 3(BO 3) 4 and a nonlinear optical crystal KTP

Simultaneous generation of green and blue laser beams based on a Nd:GdAl 3(BO 3) 4 (NGAB) crystal operating in the 4 F 3/2→ 4 I 11/2 laser channel and a KTiOPO 4 (KTP) crystal is reported. Pumped by a Ti:sapphire laser at 811 nm with absorbed pump power of 653 mW, a continuous wave green laser radiation with output power of 0.12 mW was generated by frequency doubling of the fundamental laser at 1062 nm in the KTP crystal. At the same time, a blue laser radiation with output power of 42 μW was also generated by self-sum-frequency-mixing of the fundamental laser at 1062 nm and the pump light in the NGAB crystal.

Curved Resist Surface Fabrication by Scanning a Blue Laser Beam with Positional Dose Distribution

A new fabrication method of a wing profile using lithography is proposed, and smoothly curved wing profiles are successfully fabricated in a thick resist layer of about 80 µm. The developed depth after exposure changes linearly or logarithmically to the exposure dose when a special positive novolak resist is used. The resist is scanned by a solid blue laser beam with a wavelength of 473 nm. After the scan exposure with positional dose distribution and the development, cross-sectional profiles of the resist are observed to depend on the scan dose distribution. It is clarified that the scan position interval should be narrower than the beam radius in order to obtain smooth surface profiles, and that the scan interval should be optimized considering the roughness of the required surface curve. The resist surface profiles are calculated on the assumption that the laser beam has Gaussian intensity distribution. The calculated surface profiles roughly agree with the actually printed resist patterns. By refining the scanning method and resist process, the new method will be applicable for fabricating miniature components with smoothly curved surfaces such as wings, rotor blades and propellers.

Nd:GdCOB: overview of its infrared, green and blue laser performances

Abstract GdCOB (Ca4GdB3O10) is a new non-linear optical material which can be grown in large sized crystals by the Czochralski method. In this material, part of the gadolinium ions can be replace by Nd3+ without significant decrease of the crystal quality. Nd:GdCOB single crystals exhibit laser action in the infrared at 1060 and 1091 nm simultaneously. The two transitions involved originating from the two Kramers doublets of the 4F3/2 state, their respective contributions depend upon the temperature of the Nd:GdCOB crystal. By combining the non-linear properties of the GdCOB matrix and the laser emission due to ND3+ ions, it is possible to generate directly by self-frequency doubling 115 mW of green laser light at 530.5 nm under diode pumping at 810 nm. It is also possible to self-double the 936 nm emission of Nd:GdCOB, leading to blue laser emission, but only under pulsed titanium-sapphire laser pumping. However, a CW blue laser beam is obtained in Nd:GdCOB by self sum-frequency mixing of the 1090 nm laser emission and the residual pump beam at ∼812 nm, yielding 1.2 mW of 465 nm laser light, with an optical to optical efficiency of 0.3%. This paper ends with a survey of the Nd:YCOB laser characteristics which are compared to those of Nd:GdCOB.

The effect of boron on the uniaxial magnetic anisotropy energy and the polar Kerr rotation in amorphous NdFe films

Amorphous light rare earth–transition metal alloys are candidates for magneto-optical recording materials in the wavelength region of a blue laser beam (λ≈400 nm) due to the large Kerr rotation angle θK. However, the large demagnetizing energy (shape anisotropy) prevents the films from developing an effective perpendicular anisotropy. The addition of boron to the amorphous Nd Fe matrix reduces the magnetization, enhances the effective perpendicular anisotropy, and enhances the Kerr rotation angle θK.

Magneto-Optical Fe/Tb/Nd/Tb Multilayers: Anisotropy and Kerr Rotation

To increase the recording density of magneto-optic materials, they have to fulfill some special features: High coercivity Hc, Curie-temperature T c between 100 and 200°C, measurable Kerr rotation θ K at low wavelengths, perpendicular magnetic anisotropy and rectangular shaped magnetization loops. For the commercial magneto-optical applications FeTbCo-alloys are used. This conventional material does not suffice the requirements of high density storage media at the wavelength of blue laser beam. For this propose the idea was born to combine Fe/Tb-multilayers with the light rare-earth metal neodymium to increase the Kerr rotation [2]. To study the magnetic properties of such systems, different multilayer setups, including the elements iron, terbium and neodymium, were sputter deposited. These multilayers were analyzed magnetically with a vibrating sample- (VSM), a torque magnetometer (TOM) and with a polar magneto-optical Kerr-effect-instrument (PMOKE), respectively a Kerr-spectrometer to find the best layer combination for fulfilling the above named features.