Imra America, Inc.

University System of Maryland

Makoto Murakami

Yong Che

Bing Liu

Zhendong Hu

Wei Qian

Jingzhou Xu

Zhenlin Liu

Yuki Ichikawa

Ichiro Takeuchi

Wei Guo

Fujino Shigehiro

Sung Hwan Lim

Daisuke Kan

Yuzuru Uehara

In the present invention, a method of producing stable bare colloidal gold nanoparticles is disclosed. The nanoparticles can subsequently be subjected to partial or full surface modification. The method comprises preparation of colloidal gold nanoparticles in a liquid by employing a top-down nanofabrication method using bulk gold as a source material. The surface modification of these nanoparticles is carried out by adding one or multiple types of ligands each containing functional groups which exhibit affinity for gold nanoparticle surfaces to produce the conjugates. Because of the high efficiency and excellent stability of the nanoparticles produced by this method, the fabricated gold nanoparticle conjugates can have surface coverage with functional ligands which can be tuned to be any percent value between 0 and 100%.

Stable colloidal gold nanoparticles with controllable surface modification and functionalization

A method for generating nanoparticles in a liquid comprises generating groups of ultrafast laser pulses, each pulse in a group having a pulse duration of from 10 femtoseconds to 200 picoseconds, and each group containing a plurality of pulses with a pulse separation of 1 to 100 nanoseconds and directing the groups of pulses at a target material in a liquid to ablate it. The multiple pulse group ablation produces nanoparticles with a reduced average size, a narrow size distribution, and improved production efficiency compared to prior pulsed ablation systems.

Nanoparticle production in liquid with multiple-pulse ultrafast laser ablation

An device for Raman spectroscopy such as surface enhanced Raman spectroscopy (SERS) is disclosed herein. Various embodiments may be utilized to prepare a SERS substrate using several deposition techniques such as pulsed laser deposition. Some embodiments optimize coverage, volume, or elements of SERS active metals. The method is a single step inexpensive method for preparing a SERS active substrate. In some embodiments a coating layer underneath the SERS active metals is utilized for additional enhancements.

Method and apparatus to prepare a substrate for molecular detection

A composite nanoparticle, for example a nanoparticle containing one or a plurality of cores embedded in another material. A composite nanoparticle can be formed by a one step process that includes: ejecting material from a bulk target material using physical energy source, with the bulk target material disposed in a liquid. Composite nanoparticles are formed by cooling at least a portion of the ejected material in the liquid. The composite fine particles may then be collected from the liquid. A product that includes composite fine particles may be formed with laser ablation, and ultrashort laser ablation may be utilized so as to preserve composite nanoparticle stoichiometry. For applications of the composite fine particles, optical properties and/or magnetic properties may be exploited for various applications.

Composite nanoparticles and methods for making the same

A method of forming patterns on transparent substrates using a pulsed laser is disclosed. Various embodiments include an ultrashort pulsed laser, a substrate that is transparent to the laser wavelength, and a target plate. The laser beam is guided through the transparent substrate and focused on the target surface. The target material is ablated by the laser and is deposited on the opposite substrate surface. A pattern, for example a gray scale image, is formed by scanning the laser beam relative to the target. Variations of the laser beam scan speed and scan line density control the material deposition and change the optical properties of the deposited patterns, creating a visual effect of gray scale. In some embodiments patterns may be formed on a portion of a microelectronic device during a fabrication process. In some embodiments high repetition rate picoseconds and nanosecond sources are configured to produce the patterns.

Pulsed laser micro-deposition pattern formation

Various embodiments include a method of producing chemically pure and stably dispersed metal and metal-alloy nanoparticle colloids with ultrafast pulsed laser ablation. A method comprises irradiating a metal or metal alloy target submerged in a liquid with ultrashort laser pulses at a high repetition rate, cooling a portion of the liquid that includes an irradiated region, and collecting nanoparticles produced with the laser irradiation and liquid cooling. The method may be implemented with a high repetition rate ultrafast pulsed laser source, an optical system for focusing and moving the pulsed laser beams, a metal or metal alloy target submerged in a liquid, and a liquid circulating system to cool the laser focal volume and collect the nanoparticle products. By controlling various laser parameters, and with optional liquid flow movement, the method provides stable colloids of dispersed metal and metal-alloy nanoparticles. In various embodiments additional stabilizing chemical agents are not required.

Production of metal and metal-alloy nanoparticles with high repetition rate ultrafast pulsed laser ablation in liquids

The present invention relates to lead-free piezoelectric ceramic materials comprising crystalline (and preferably perovskite crystalline) structures of the formula Bi(RE)FeO, where RE is one or more of La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and 0&#x2266;x&#x2266;0.3. The materials are at or near the morphotropic phase boundary and display enhanced piezoelectric and dielectric properties.

Growing community of inventors

Ann Arbor, MI, United States of America

Makoto Murakami