149 results about "Ferroelectric crystal" patented technology

A system for generating signals for Raman vibrational analysis, particularly for a CARS microscope or spectroscope of an external specimen, the system comprising a a laser source apt to emit at least one fundamental optical pulse in a first band of fundamental frequencies comprising at least one first (ω_f1) and one second (ω_f2) fundamental frequencies; a second-harmonic (SH) generating system comprising at least one nonlinear optical crystal for converting said at least one fundamental optical pulse into at least two second-harmonic optical pulses, i.e. a first second-harmonic pulse at a first second-harmonic frequency (ω_p) of the first fundamental frequency (ω_f1) and a second second-harmonic pulse at a second second-harmonic frequency (ω_s) of the second fundamental frequency (ω_f2), said second second-harmonic frequency being other than the first second-harmonic frequency, and a Raman vibrational analysis apparatus apt to receive said first and second second-harmonic pulses and direct them toward said specimen.

According to an embodiment, the SH system comprises two nonlinear optical crystals, each including a ferroelectric crystal with periodic space-modulation of the sign of the optical susceptibility.

In a different embodiment, the SH system comprises a ferroelectric crystal with aperiodic space-modulation of the sign of nonlinear optical susceptibility, with a period varying along the optical path of said at least one fundamental optical pulse, said crystal being apt to generate said first and second second-harmonic pulses.

A method of producing a device with a ferroelectric crystal thin film on a first substrate including the steps of providing a ferroelectric crystal, of irradiating a first surface of the ferroelectric crystal with ions so that a damaged layer is created underneath the first surface, of bonding a block of material including the first substrate to the ferroelectric crystal to create a bonded element, wherein an interface is formed between the first surface and a second surface of the block, and of heating the bonded element and separating it at the damaged layer, so that a ferroelectric crystal layer remains supported by the first substrate. By this method, very thin films—down to thicknesses of a fraction of a micrometer—of ferroelectric crystals may be fabricated without jeopardizing the monocrystalline structure.

Logic data is written in a memory having a first word line and a first bit line, with the memory including a first memory cell having a first ferroelectric transistor. The first ferroelectric transistor includes a layer of ferroelectric material and has a first conduction terminal coupled to the first bit line, and a control terminal coupled to the first word line. The logic data is written based on biasing the control terminal of the first ferroelectric transistor at a first biasing value, biasing the first conduction terminal of the first ferroelectric transistor at a second biasing value different from the first biasing value, and generating a stable variation of the state of polarization of the layer of ferroelectric material of the first ferroelectric transistor to write the logic data in the first memory cell.

The invention discloses a domain wall-based nonlinear impulse autocorrelation measuring method and a measuring device in the field of optical impulse characteristic measurement. The method comprises the following steps of dividing a light beam to be measured into two beams, delaying one of the two beams, focusing the two beams of light on a domain wall of a periodically polarized nonlinear ferroelectric crystal to generate corresponding Cerenkov radiation frequency multiplication, ensuring that time domain overlapped sections of the two paths of Cerenkov radiation frequency multiplication generate autocorrelation signals, adjusting the delay of one of the light beams, and measuring a relation between the change of the autocorrelation signals and the change of the delay to obtain an autocorrelation curve so as to obtain the impulse time domain width of the light beam to be measured. By the method and the device, the nonlinear conversion efficiency is improved and the stronger autocorrelation signals are generated.

The invention provides a preparation apparatus and method of a lithium niobate crystal nano domain structure and is intended to solve the difficulty of the prior polarization technology in preparing a nano domain structure in lithium niobate crystal; the preparation apparatus and method are suitable for the preparation of nano domain structures in the field of ferroelectric crystal nano domain engineering, particularly for Z-tangential congruent lithium niobate crystal, magnesium-doped lithium niobate crystal and the like. The preparation method comprises the steps of first, constructing a domain wall structure in lithium niobate crystal; second, thermally treating a sample; third, secondarily polarizing the sample. By changing thermal treatment temperature and thermal treatment time, it is possible to prepare nano domain structures different in size; the size of the domain structures is generally of hundred nanometers level, and the depth thereof is of hundred micrometers level; by using the method, it is possible to prepare high-quality nano domain structures hundred micrometers in length; the method has the advantages that the method is simple to perform and is suitable for preparing nano domain structures in batch on a large scale.

A laser light source includes a fundamental laser generator that generates a fundamental laser light, a wavelength conversion element that is made of a ferroelectric crystal with a periodically poled structure and converts the fundamental laser light to a laser light having a different wavelength, a holding member that holds at least a part of an element surface of the wavelength conversion element that crosses a polarization direction of the periodically poled structure, and an insulation layer that is provided between the holding member and the element surface. Electric resistivity of the insulation layer is 1×10⁸ Ω·cm or higher.

An arrayed wavelength converter comprises a demultiplexing section that demultiplexes an input WDM signal light to output the demultiplexed lights, and a multiple wavelength conversion waveguide array in which the optical signals of respective wavelengths output from the demultiplexing section are given respectively to a plurality of waveguides formed in parallel on a substrate made of ferroelectric crystal. The multiple wavelength conversion waveguide array has a periodic polarization structure formed by periodically providing polarization inversion regions in which a polarization direction of the substrate is inversed, in a direction approximately perpendicular to a traveling direction of lights being propagated along the respective waveguides, and this is set such that a period of the periodic polarization structure is made different for each waveguide. As a result, it becomes possible to perform wavelength conversion of a plurality of optical signals at high efficiency with a simple structure.

The capacitor forming method utilizes a plurality of metal sheet manipulating rollers and a glass supply, which, in combination, make a metal-glass laminate and glass or devitrifying glass dielectric to form a capacitor. Several embodiments of the method manufacture ferroelectric crystal dielectrics by utilizing heat-treatment and annealing to form and devitrify glass while the glass is in a metal-glass spool or flat form.

A ferroelectric thin-film production method produces a ferroelectric crystal thin film by using a ferroelectric crystal having first and second surfaces opposed to each other and having an etching rate of the first surface greater than that of the second surface and etching the first surface of the ferroelectric crystal. While etching, a predetermined voltage is applied to the ferroelectric crystal. When the etching progresses and the thickness of the ferroelectric crystal reaches a target value, the direction of polarization of the ferroelectric crystal are inverted and the progress of the etching automatically stops. Consequently, a ferroelectric crystal thin film extremely thin and uniform in thickness over a wide area can be produced.

The invention relates to a device for detecting domain modulation of ferroelectric crystals in real time, and the device comprises a helium-neon laser, a filter, a collimating device, a first totally-reflection mirror, a second total-reflection mirror, a beam splitter prism, an imaging lens, a charge couple device (CCD) coupler and a computer. The device is contactless and free from damage and has high resolution ratio, not only can the dynamic variation of a domain structure be monitored in real time and quantitatively analyzed, but also the static response of the domain structure for an external electric field can be detected, and two-dimensional information and three-dimensional information of the reversal domain structure can be obtained.

A photonic chip based on periodical poling and waveguides circuits in ferroelectric crystals, the method is based on the integration of waveguide circuits, periodical poling and electro-optic modulator (EOM). The chip is illustrated by FIG. 1. The waveguide circuits guide the photons and makes linear operations like the beam splitting, filtering etc. on the photons. The periodical poling enables the efficient spontaneous parametric down conversion (SPDC), resulting the generation of entangled photons. The EOM controls the phase of photons dynamically. The following directional coupler distributes the entangled photons and the quantum interference takes place, resulting different types of path-entangled states by controlling the voltage of EOM insides the chip.

There is provided a manufacturing method of a ferroelectric crystal film in which an orientation of a seed crystal film is transferred preferably and a film deposition rate is suitable for volume production.

A seed crystal film is formed on a substrate in epitaxial growth by a sputtering method, an amorphous film including ferroelectric material is formed over the seed crystal film by a spin-coat coating method, the seed crystal film and the amorphous film are heated in an oxygen atmosphere for oxidation and crystallization of the amorphous film, and thereby a ferroelectric coated-and-sintered crystal film is formed.

The invention relates to an integrated photovoltaic electric field sensor based on a periodically polarized ferroelectric crystal and belongs to the electric field measurement technology field. The integrated photovoltaic electric field sensor based on the periodically polarized ferroelectric crystal comprises a periodically polarized ferroelectric crystal with electro-optic effect, and an optical waveguide which is formed within one or more polarized periods on the surface of the crystal along the direction parallel to a domain wall and has a Mach-Zehnder interferometer structure; the optical waveguide comprises an input section, an output section and a middle section which is formed by two parallel arms; and the two arms of the optical waveguide are respectively positioned in an area with the polarization direction opposite in one or more polarized periods. In the periodically polarized ferroelectric crystal, the polarized periods are distributed on the whole chip. The invention can significantly improve the temperature stability of the existing integrated photovoltaic electric field sensor, further reduces the influence of the electric field sensor on the electric field to be measured, and simultaneously combines all the other advantages of the existing integrated photovoltaic electric field sensor.

The invention discloses a polarizing electrode for polarizing a ferroelectric crystal material, which is used for preparing small-period and quasiperiodic periodically-reverse ferroelectric crystals and comprises a comb-shaped optical grating polarization electrode with a plurality of comb-shaped optical grating electrode bars and strip-shaped rectangular electrodes arranged between the comb-shaped optical grating electrode bars between the comb-shaped optical grating polarization electrode and with width smaller than intervals between the comb-shaped optical grating electrode bars. The small-period and quasiperiodic periodically-reverse ferroelectric crystal material can be prepared by means of the method of additional electric field polarization, periodic polarization of the small-period and quasiperiodic periodically-reverse ferroelectric crystal material with a period smaller than 5 mum, and the small-period and quasiperiodic periodically-reverse ferroelectric crystals can be prepared.

The invention provides a device for generating visible to infrared band ultra-wideband ultra continuous laser. The device includes a pump light source and a non-linear laser crystal. The device is characterized in that the pump light source is an intermediate infrared femtosecond pulse laser source and the frequency of femtosecond pulse laser provided by the pump light source covers an intermediate infrared section. Besides, the femtosecond pulse laser has a characteristic of high peak value power. The non-linear laser crystal is made of ferroelectric crystal material. The non-linear laser crystal includes a series of cells. The length of the series of cells in light propagation direction varies along the light propagation direcrion according to a continuous chirp change rule. The device can produce visible laser to ultra-continuous and complete relevant laser of an infrared 400 to 2200nm waveband. The device has advantages of controllable structure, convenient preparation and flexible design. The device is high in energy conversion efficiency, small in size and produces ultra-wideband and ultra continuous laser.

The ferroelectric substrate 11 of ferroelectric crystals, while being supported by the support plate 14 which is thicker than the ferroelectric substrate 11, is integrated with the support plate 14 by letting the junction 13 mediate between one major surface S1A of the ferroelectric substrate 11 and one major surface S1B of the support plate 14, and therefore, it is possible through the flat surface polishing to perform thinning of the ferroelectric substrate 11, namely, the ferroelectric crystals, and as a result, it is possible to obtain the thin periodically poled structure. By the voltage application method, the domain inverted region is formed in the ferroelectric substrate 11 which is made thin.

A fast ferroelectric transistor memory based on two-dimensional organic molecule semiconductors is prepared in a way that heavily doped p-type silicon is taken as a substrate and 50-250 nm silicon dioxide is grown and used as an insulating layer; a layer of 20-50 nm gold is prepared on the silicon dioxide by thermal evaporation and used as the gate, and then a layer of ferroelectric polymer material, poly (vinylidene fluoride-trifluoroethylene), is spin-coated on the gate; and a layer of untrathin polymethyl methacrylate (PMMA) with thickness of 2-10 nm and a dioctyl benzothiophene benzothiophene semiconductor layer (C8-BTBT) with thickness of 5-10 nm are grown respectively on P (VDF-TrFE) by the floating coffee effect and the phase separation method, wherein the passivation layer PMMA is under the two-dimensional semiconductor layer C8-BTBT, gold is deposited on the semiconductor layer as a source and a drain to prepare a two-dimensional organic molecular semiconductor ferroelectric transistor memory having a bottom gate top contact structure.

In the method, ferroelectric nonocrystal is distributed uniformly in transparent film polymer as ferroelectric material is made from strontium barium niobate, lead zirconate titanate, lanthanum doped lead zirconate titanate, BaTiO3, LiNbO3, or LiTaO3 with nanocrystal particle diameter of 20-80 nm; polymer base material is made from polymethyl methyl acrylate, polycarbonate, polyimide sort and thermoplastic polyamic acid. The prepare process includes polymerizing ferroelectric nanocrystal in the polymer in polymerization procedure of dissolving nanocrystal and polymer in polar solvent and depositing film by soaking or spinning.

The invention relates to a device for inducing the periodical domain reversal of a ferroelectric crystal by laser interference. A periodical structure is realized by using an interference method of two light beams, a polarization electric field is realized by using quartz windows and electrolyte electrodes, laser coherence irradiation is performed simultaneously, and thus, the laser-induced periodical domain reversal is realized. The device can be applied to the periodical domain reversal of the ferroelectric crystal with a fine structure in the micro scales of micron and submicron dimensions, finer and more complex all-optical microstructural devices can be manufactured, and the device can be widely applied to multiple key fields of quasi-phase-matching non-linear optics, novel optical devices and the like. The device is applicable to multi-wavelength induction light, can not be limited by an induction light source and the size of a mask, and can greatly reduce the polarization electric filed of the ferroelectric domain. The invention has more flexible manufacture, more perfect periodical structure, easy operation, accurate size, reliable principle and no damage.

The invention provides a side suppression neuron circuit based on a ferroelectric transistor FeFET. The side suppression neuron circuit comprises a capacitor, a reset tube, a positive feedback tube, atwo-stage series inverter and a ferroelectric transistor. The capacitor is used for simulating cell membrane capacitance of biological neurons and accumulating charges brought by input post-synapticcurrent; the reset tube is an N-type MOSFET device and provides a reset path for charges accumulated on the capacitor. The positive feedback tube is a P-type MOSFET device, and charges are supplemented to the capacitor when the input of the first-stage inverter is close to the logic threshold level of the first-stage inverter; the two-stage series inverter consists of two groups of complementary CMOS (Complementary Metal-Oxide-Semiconductor Transistor) and plays a role in amplifying the voltage change of the input end, and pulses are generated at the output end of the two-stage series inverter; the ferroelectric transistor is an N-type FeFET device and is used for simulating a side inhibition function of a biological neuron. According to the invention, hardware overhead can be significantly reduced; meanwhile, the basic characteristics and advanced functions of biological neurons are highly simulated.