Juli 29, 2009
Physicists at New York University (NYU), US have developed a technique to record three-dimensional movies of microscopic systems, such as biological molecules, through holographic video. The technique, developed in the laboratory of NYU Physics Professor David Grier, is comprised of two components: making and recording the images of microscopic systems and then analyzing these images. To generate and record images, the researchers created a holographic microscope. It is based on a conventional light microscope, which uses a collimated laser beam instead of on an incandescent illuminator.
When an object is placed into path of the microscope’s beam, the object scatters some of the beam’s light into a complex diffraction pattern. The scattered light overlaps with the original beam to create an interference pattern reminiscent of overlapping ripples in a pool of water. The microscope then magnifies the resulting pattern of light and dark and records it with a conventional digital video recorder. Each snapshot in the resulting video stream is a hologram of the original object. Unlike a conventional photograph, each holographic snapshot stores information about the three-dimensional structure and composition of the object that created the scattered light field. The recorded holograms appear as a pattern of concentric light and dark rings.
For analyzing the images the researchers based their work on a quantitative theory, the Lorenz-Mie theory, which maintains that the way light is scattered can reveal the size and composition of the object that is scattering it.
The application of the technique ranges from research in fundamental statistical physics to analyzing the composition of fat droplets in milk.
In the microscope, a laser beam illuminates the sample. Light scattered by the sample creates an interference pattern which is magnified and recorded. Then measurements of the particle’s position, size, and refractive index are obtained.
Juli 6, 2009
Tomaso Zambelli, a researcher in the group led by Janos Vörös, Professor at the Institute of Biomedical Technology at ETH Zurich, Switzerland, has presented a nanosyringe for automated injection of DNA, RNA and medicines into cells without damaging them.
To create this syringe, called “fluid force microscope”, Zambelli transformed the technology of the atomic force microscope into a microinjection system. In contrast to a conventional manual system, the pressure exerted on the cell by the measuring needle is adjusted so accurately that the cell is not damaged unnecessarily. A laser is responsible for the control, recording every movement of the cantilever and adjusting the force on the cell several thousand times a second. The system also operates under water or in other liquids. To enable the injection of liquids, scientists at the Swiss Center for Electronics and Microtechnology (CSEM) in Neuchâtel installed a microchannel in the cantilever – the diameter of the opening at the needle tip is only 200 nanometers.
In addition to having biological uses, the method could also be applied in the manufacture of microelectronics or microelectromechanical systems (MEMS). The results have been published in Nano Letters.
Juli 1, 2009
Together with his research team, Professor Vasilis Ntziachristos from the Helmholtz Zentrum Munich, Germany and the Technical University Munich, Germany developed a new technology to make light audible. The technique, called multi-spectral opto-acoustic tomography (MSOT), combines light and ultrasound to visualize fluorescent proteins that are seated several centimeters deep into living tissue.
The researchers used a genetically modified adult zebra fish which carried fluorescent pigments in its tissue. They illuminated the fish from multiple angles using flashes of laser light that are absorbed by the fluorescent pigments in the fish. The pigments absorb the light, a process that causes slight local increases of temperature, which in turn result in tiny local volume expansions. This happens very quickly and creates small shock waves. In effect, the short laser pulse gives rise to an ultrasound wave that the researchers pick up with an ultrasound microphone. To analyze the resulting acoustic patterns, a computer is attached. The computer uses specially developed mathematical formulas to evaluate and interpret the specific distortions caused by scales, muscles, bones and internal organs to generate a three-dimensional image. In the future this technology may facilitate the examination of tumors or coronary vessels in humans.
Multi-spectral opto-acoustic tomography or MSOT allows the investigation of subcellular processes in live organisms.
Juni 25, 2009
With 1,040 exhibitors (2007: 1,008), the exposition LASER World of PHOTONICS 2009 (June 15-18, Munich, Germany) set a new record. The percentage of companies coming from outside Germany rose from 53% in 2007 to 57% this year. The exhibition area was expanded from three halls to four, which brought the total to 42,000 m² of floor space. This additional space particularly benefited the two largest exhibition segments, “Lasers and Optronics” and “Lasers and Laser Systems for Manufacturing.” With over 24,000 attending professionals, the trade show organizer’s expectations were exceeded by a small margin (2007: 26,655). A slight drop in the number of attendees from Germany is primarily due to the lower number of attending professionals from the industrial sector, which has been hit particularly hard by the current economic difficulties.
Mai 27, 2009
The 2009 Conference on Lasers and Electro-Optics (CLEO) and The International Quantum Electronics Conference (IQEC) will come to Baltimore Convention Center, US from May 31 to June 5, 2009. The 5-day event features high-quality, cutting-edge optics and photonics programming, tutorials, special symposia, short courses and a full program of networking and social events. PhotonXpo – the exhibit at CLEO, also debuting this year, will feature 350 participating companies showcasing every facet of the optics and photonics industry.
The Baltimore Convention Center
Mai 19, 2009
For his fundamental contributions to the field of optomechanics Prof. Tobias Kippenberg, leader of the independent Max Planck junior research group “Laboratory of Photonics and Quantum Measurements” at Max Planck Institute of Quantum Optics in Garching, Germany and tenure track assistant professor at the ETH Lausanne (EPFL) in Switzerland, is honoured with the Fresnel Prize in Fundamental Aspects of the European Physical Society (EPS). This award endowed with a prize money of €3000 is given by the “Quantum Electronics and Optics Division” of EPS biannually on the occasion of the “Conference on Lasers and Electro-Optics (CLEO) Europe”, held during the “World of Photonics” Congress in Munich, Germany. The prize for Tobias Kippenberg as well as the other EPS-awards will be presented in a ceremony on June 16, 2009.
Mai 4, 2009
Researchers at the UCLA (University of California, Los Angeles, US) Henry Samueli School of Engineering and Applied Sciences have developed the serial time-encoded amplified microscopy (STEAM) technology. It is a novel, continuously running camera that enables real-time imaging at a frame rate of more than 6 MHz and a shutter speed of less than 450ps – roughly a thousand times faster than any conventional camera. Keisuke Goda, Kevin Tsia and team leader Bahram Jalali describe a new approach that does not require a traditional CCD (charge-couples device) or CMOS (complementary metal-oxide semiconductor) video camera. The new imager operates by capturing each picture with an ultrashort laser pulse. It then converts each pulse to a serial data stream that resembles the data in a fiber optic network rather than the signal coming out of the camera. Using a technique known as amplified dispersive Fourier transform, these laser pulses, each containing an entire picture, are amplified and simultaneously stretched in time to the point that they are slow enough to be captured with an electronic digitizer. Those cameras could be used for observing high-speed events such as shockwaves, communication between cells, neural activity or laser surgery.