3 results about "Polar crystal" patented technology

This invention provides a method for preparing PVDF-based piezoelectric products using a micro-injection molding process based on anti-chain relaxation. The method involves melt-blending 94–98.5 parts by weight of PVDF, 1–5 parts by weight of ionic liquid, and 0.5–1 parts by weight of one-dimensional / two-dimensional carbon-based conductive filler to obtain a polyvinylidene fluoride composite material. This material is then injected into a mold for the desired piezoelectric product using a micro-injection molding machine, resulting in the PVDF-based piezoelectric product. This method utilizes the strong shear field involved in the micro-injection molding process to promote the orientation of PVDF molecular chains. Combined with the introduction of ionic liquid to induce the formation of polar crystals in the PVDF piezoelectric material and suppress the local thermal relaxation behavior of the PVDF molecular chains, this significantly reduces PVDF chain relaxation, facilitating the formation of a highly oriented β-polar phase and substantially improving the piezoelectric performance of PVDF-based piezoelectric devices.

The application belongs to the technical field of middle infrared thermal emission control, and more particularly relates to a method and device for electrically driving narrow-band middle infrared thermal emission controlled by a polar substrate. The method provided by the application completely abandons the dependence on the design and processing of complex micro-nano structures, and only uses the intrinsic phonon properties of the polar crystal substrate and the electro-thermal effect of the low-dimensional material to achieve narrow-band and polarized emission, thereby greatly simplifying the implementation path, reducing the process cost and being conducive to large-scale preparation. In addition, the method creatively applies an electric signal as a core driving step, instead of traditional overall thermal heating, so that the intensity of thermal emission can be modulated in real time, quickly and programmably. While obtaining structural simplicity, the method first gives high-speed dynamic electric control capability to the thermal emission source without micro-nano structures, and solves the long-standing technical contradiction.

The application relates to the technical field of strong laser nonlinear frequency conversion, in particular to a method for generating ultra-wideband mid-infrared laser in a single piece of polarized crystal. The method uses laser with a wavelength of 800 nm as pump light, laser with a wavelength of 0.95-1.6 microns as signal light, and a difference frequency conversion process occurs in the polarized crystal, thereby generating mid-infrared laser with a wavelength of 1.6-5 microns. In the method, a polarized crystal with a chirped period structure is used, that is, the polarization period of the crystal continuously changes with the position in the crystal. The polarized crystal is a 5% magnesium oxide doped chirped period lithium niobate crystal. The application utilizes quasi-phase matching technology, can use the maximum effective nonlinear coefficient of the chirped period lithium niobate crystal, and does not need to change the crystal angle or the polarization of the laser when the pump light is at different wavelengths. The application overcomes the shortcoming that the wavelength of the current mid-infrared band laser is difficult to expand due to the limitation of the gain medium.