Laser thermal lithography has been proposed for a few years, which has the advantages of breaking through the optical diffraction limit, operation in far-field and in air, and low production cost. In this paper, a new hydrazone metal complex is used as the laser thermal lithography material due to its feature of the one-step fabrication of micro/nano structure without mask and wet-etching process. Based on the laser thermal lithography method, super resolution nano-information pits are directly written on the surface of hydrazone metal complex thin films. Pits with a minimum feature size of about 79 nm are successfully obtained, which is only about 1/7 of the writing spot size. Moreover, the reactive ion etching method can be applied to transfer the pits onto a silica substrate. These results suggest the potential applications of the new material in high density optical data storage and semiconductor industries.
A nickel(II)-azo dye was synthesized in order to obtain a suitable optical recording medium for write-once blu-ray recording with low-to-high signal polarity. Smooth thin film of the nickel(II)-azo dye was prepared by spin-coating method. Absorption, reflectance spectra and optical constants (complex refractive indices <i>N=n+ik</i>) of the thin film were investigated in the wavelength region of 300-700 nm. To demonstrate the physical basis of low-to-high polarity, the relationships between the absorption, reflectivity and optical constants for the nickel(II)-azo dye in spin-coated films were discussed. It is found that the thin film has a strong absorption band in the wavelength region of 370-500 nm and a strong absorbance at 405 nm. The reflectance spectra show that a low reflectivity of the unrecorded thin film at 405 nm can be obtained. The thin film of the nickel(II)-azo dye gives a relatively low n value of 1.36 and a relatively high <i>k</i> value of 0.51 at 405 nm. In addition, in order to examine its possible use as a blu-ray recording medium, the spin-coated film of the nickel(II)-azo dye was studied by a static optical recording testing system. The results demonstrate that high reflectivity contrast (85%) with low-to-high polarity can be obtained at an optimum laser writing power and pulse width using the nickel(II)-azo dye thin film as the recording layer. Moreover, the recording marks on the film are clear, circular, regular, and their size is as small as 200 nm or even less. These results indicate that the nickel(II)-azo dye is promising for applications in high-performance write-once blu-ray recording systems at 405 nm.
Preparation of recording materials with high two-photon absorption activities is one of the important issues to superhigh- density two-photon absorption (TPA) three-dimensional (3D) optical data storage. In this paper, three new carbazole derivatives containing nitrogen heterocyclic ring with symmetric and asymmetric structures are prepared using ethylene as the π bridge between the carbazole unit and nitrogen heterocyclic ring, namely, 9-butyl-3-(2-(1,8- naphthyridin)vinyl)-carbazole (material 1), 9-butyl-3,6-bis(2-(1,8-naphthyl)vinyl)-carbazole (material 2) and 9-butyl-3,6- bis(2-(quinolin)vinyl)-carbazole (material 3). Their one photon properties including linear absorption spectra, fluorescence emission spectra, and fluorescence quantum yields are studied. The fluorescence excited by 120 fs pulse at 800 nm Ti: sapphire laser operating at 1 kHz repetition rate with different incident powers of 9-butyl-3-(2-(quinolin) vinyl)-carbazole (material 3) was investigated, and two-photon absorption cross-sections has been obtained. It is shown that material 3 containing quinoline rings as electron acceptor with symmetric structure exhibit high two-photon absorption activity. The result implies that material 3 (9-butyl-3-(2-(quinolin) vinyl)-carbazole) is a good candidate as a promising recording material for super-high-density two-photon absorption (TPA) three-dimensional (3D) optical data storage. The influence of chemical structure of the materials on the optical properties is discussed.
A nickel(II) hydrazone complex was synthesized in order to obtain a suitable optical recording medium for the new
generation recordable blu-ray disk. Smooth thin films of the nickel(II) hydrazone complex were prepared by using the
spin-coating method. Absorption and reflectance spectra of the thin films were evaluated in the wavelength 300-700 nm.
Thermal properties of the nickel(II) complex were investigated by thermogravimetry (TG) and differential scanning
calorimetry (DSC). Optical constants (complex refractive indices N=n+ik) and thickness of the thin film, prepared on
single-crystal silicon substrate, were investigated on a rotating analyzer-polarizer scanning ellipsometer in the
wavelength 285-705 nm. In addition, in order to examine its possible use as a blu-ray recording medium, the spin-coated
film of the nickel(II) complex was prepared on K9 glass substrate with a silver reflective layer, and was studied by static
optical recording testing system with a 406.7 nm laser. It is found that the absorption spectra of the thin film has an
strong absorption band in the wavelength region 360-420 nm and a moderate absorbance at the 405 nm side, which
indicates that the absorption of the film is well matched with the laser wavelength of the 405 nm. The reflectance spectra
show that a high reflectivity of the thin film at 405 nm wavelength can be obtained by an optimum film thickness and an
appropriate metal reflective layer. The thin film of the nickel(II) complex gives a high n value of 1.62 and a low k value
of 0.33, corresponding to the wavelength of the blue laser of 405 nm. Measurements of the thermal properties show that
the nickel(II) complex holds a high thermal stability (~ 300 °C) and a sharp weight loss which are helpful to fabricate a
small and sharp recording mark edge. The results of the static optical recording test, using the nickel(II) complex thin
film as the recording layer, demonstrate that high reflectivity contrast (>50 %) can be obtained at an optimum laser
writing power and pulse width. In addition, the recording marks are durable even after 20000 times readout. These
preliminary results indicate that the nickel(II) hydrazone complex has great potential application for high-density discrecordable
system at wavelength of the 405 nm.
A micro high-speed 1×2 magneto-optic switch, which is used in high-speed all-optical network (AON), is designed and analyzed. The theoretical and experimental analysis of the micro high-speed magneto-optic switch mainly involves the parts of optical route, nanosecond impulser and high-speed magnetic field etc. The study of optical route covers design scheme of polarization optical route in the optical switch, the performance analysis of magneto-optic crystal by using Faraday Effect. The research of nanosecond impulser involves the design, simulation and test of electronic circuit diagram of nanosecond pulse. The analysis of high-speed magnetic field consists of magnetic path design in Faraday rotator and analysis of high-speed magnetic field etc. The nanosecond current pulse transient from nanosecond impulser is used to switch the magnetization of the magneto-optic crystal, which propagates a 1550nm optical beam. The experiment results state that nanosecond impulser can output the current pulse with impulse amplitude 10~60V and impulse width 10~ 100ns. The optical beam can be stably switched and the switching time is less than 1μs currently.
A novel type of 2×2 polarization independent magneto-optic switch with low Insertion Loss, nanosecond order switching time is designed and analyzed. The study of the magneto-optic switch involves two main parts: Faraday rotator assembly and optical route design. In faraday rotator design, magneto-optic crystal comparison and selection, two types of Faraday rotator assembly schemes design and analysis; high speed magnetic field simulation and generation; nanosecond trigger signal generator design, simulation and experiment are involved. Within optical router design, a simple but effective optical router with 2×2 mode is introduced. The nanosecond trigger signal supply to the Faraday rotator assembly is 12ns. The key characteristics, insertion loss, far-end crosstalk, switching time of magneto-optic switch that developed at a wavelength of 1550nm have been tested and root causes analyzed.
An all-fiber magneto-optic switch is designed in this paper, which makes use of Faraday Effect, fiber-type polarizing beam splitter/combiner (PBS/PBC), magneto-optic crystal fiber, nanosecond impulser and high-speed magnetic field control technology. The design scheme uses magneto-optic crystal fiber instead of bulky magneto-optic crystal. The optical route design includes linear layout of magneto-optic crystal fiber, the optical route design of polarized light in fiber PBS/PBC, magnetic route design and analysis of linear solenoid, etc. A solenoid which is driven by nanosecond current and can generate high-speed magnetic field is designed and manufactured. The result analysis shows that pulse signal can be greatly strengthened by impressed-bias static magnetic field which is perpendicular to transmission direction of light beam. Static magnetic field insures the intensity of induced magnetization where the light passes come back to original value, so that it can offer high-extent magnetization equality. The intensity of magnetic field can be improved to two orders when the length ratio of magneto-optic crystal fiber to solenoid is increased eight times. When the diameter of magneto-optic crystal and solenoid is decreased from three millimeters to one millimeter, the intensity of magnetic field can be improved to one order. The all fiber magneto-optic switch is slim in structure, flexible, easy to high-density integration and expansion, so there are many integration methods to design all-fiber magneto-optic switch array, which is characterized of smaller bulk, higher magnetic field usage, lower consumption and driving voltage, etc.
In the paper, a high speed magneto-optic switch based on the Faraday Effect is designed and analyzed. The optic switch adopts Faraday rotator, nanosecond impulser, and high speed magnetic field, so it is characterized by no moving parts, low transmission loss and polarization insensitive, low optical insertion loss etc. Using the polarization and Faraday Effect of magneto-optic crystal, the magneto-optic switch can hold the function of all-optical switching, which is needed in all-optical communication networks. As the first part of this paper, a design scheme of optical route in high speed magneto-optic switch and its experiment analysis will be discussed. Good avalanche effect of transistor 2N5551 is adopted to generate nanosecond pulse signal and then to drive the high speed magnetic field. Shown by the experiment data, the rising time of the impulse about 10ns, the amplitude of the impulse about 10~60V are available on the Output end from the nanosecond impulser, which can be used as driving current pulse of Faraday rotator. By using the relationship between the polarization plane rotate direction of polarization light and magnetic direction, the Faraday rotator is designed. It's unique double magnetic field and externally applied static magnetic design can greatly speed the excitation time of the internal inductive magnetic field and shorten the switching time of magneto-optic switch.
Magneto-optic switch has been widely researched due to its capabilities handling large beam cross sections, operating at low voltages, featured as low insertion loss and intrinsic non-reciprocity. However, the switching speed is rather slow: switching time of available magneto-optics switches are of hundreds microseconds. Previously, we developed a novel type high speed magneto-optic switch based on Faraday rotation effect of light in yttrium-iron-garnet (YIG). The switch shows its good performance and high reliabilities. However, it had some disadvantages: 1) Although it was polarization independently designed for the insertion loss, some dependence about 0.5dB was observed due to the components' misalignments since it has many components and adjustment points; 2) Faraday rotator assembly designed by using double YIG rods with diameter 3 mm require much higher switching current to rotate the light by 90°. And the heat generated when operating may also affect the YIG performance. 3) The narrow and sharp pulse width of nanosecond trigger impulse signal generated with short duration can't accumulate the high speed switching magnetic field large enough to drive the YIG reach saturation magnetic field within a trigger period. In this paper, we mainly devote to design an improved switch featured as compact optical route, much more effective Faraday rotator assembly and nanosecond trigger impulse signal with wider pulse width.
A novel micro high-speed 2x2 magneto-optic switch and its optical route, which is used in high-speed all-optical communication network, is designed and analyzed in this paper. The study of micro high-speed magneto-optic switch mainly involves the optical route and high-speed control technique design. The optical route design covers optical route design of polarization in optical switch, the performance analysis and material selection of magneto-optic crystal and magnetic path design in Faraday rotator. The research of high-speed control technique involves the study of nanosecond pulse generator, high-speed magnetic field and its control technique etc. High-speed current transients from nanosecond pulse generator are used to switch the magnetization of the magneto-optic crystal, which propagates a 1550nm optical beam. The optical route design schemes and electronic circuits of high-speed control technique are both simulated on computer and test by the experiments respectively. The experiment results state that the nanosecond pulse generator can output the pulse with rising edge time 3~35ns, voltage amplitude 10~90V and pulse width 10~100ns. Under the control of CPU singlechip, the optical beam can be stably switched and the switching time is less than 1μs currently.