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The Development and Characteristics of Lasers in Laser Particle Sizer

The laser particle size analyzer is an instrument for analyzing the particle size by the spatial distribution (scattering spectrum) of the diffracted or scattered light of the particles. According to the stability of the energy spectrum, it is classified into a static light scattering particle size analyzer and a dynamic light scattering green laser pointer particle size meter. As we all know, laser particle size analyzer is an optical measuring instruments, lasers, detectors is one of the important components, is an important optical components. Currently, there are two types of lasers: one for the last century 60's application of gas lasers - helium-neon laser, one is since the 80s of last century began to develop, so far technology breakthroughs in solid-state lasers.

Laser Pointer

With the development of the times and the advance of technology, the optical components in the laser particle sizer will be replaced by more promising components with more advanced technology content. If we judge things with solidified thinking, it will be biased. In other words, when we think good things, to today may have been greatly behind, and technological progress, and our understanding of the need to follow up. The following is to explore the 50mw laser pointer particle size analyzer among the "laser" type, development and characteristics, in order to give the purchase of laser particle size analyzer to provide a little effective help.

Semiconductor lasers, also known as laser diodes (LD), is the twentieth century eighties semiconductor physics one of the latest achievements. The advantage of the conductor laser is small volume, light weight, high reliability, long life, low power consumption, in addition to semiconductor lasers are low voltage constant current power supply, low power failure rate, the use of safety, low maintenance costs. So the application field is expanding day by day. At present, the number of semiconductor burning laser pointer in the first use of all lasers, some important applications in the past, other commonly used lasers, semiconductor lasers have been gradually replaced. Its application areas include optical storage, laser printing, laser phototypesetting, laser ranging, bar code scanning, industrial detection, test and measurement equipment, laser display, medical equipment, military, security, field detection, Laser level and a variety of marking line positioning.

Previously, the disadvantage of semiconductor lasers is that the laser performance is affected by temperature and the beam divergence angle is large (usually between several degrees to 20 degrees), so it is poor in directionality, monochromaticity and coherence. But with the rapid development of science and technology, the current performance of semiconductor lasers has reached a high level, and the beam quality has also been greatly improved. The semiconductor optoelectronic technology with the semiconductor laser as the core will make greater progress and play a greater role in the information society of the 21st century.

In gas lasers, the most common are helium-neon lasers. 1960 in the United States Bell laboratory by the Iranian physicist Jia Wan made. Because of the beam directionality and monochromaticity of the beam emitted by helium-neon 100mw laser pointer, the beam divergence angle is small, can work continuously, so this kind of lasers are widely used, is one of the most widely used lasers, mainly used in holographic Precision measurement, alignment positioning.

He-Ne laser shortcomings are bulky, start and run high voltage, power supply complex, high maintenance costs.

Publié à 08:29, le 3/01/2017, Inde
Mots clefs : laser
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Scientists Have Developed Laser Traps to Capture Bacteria

Until recently, if scientists wanted to study blood cells, algae or bacteria under a microscope, they had to mount the cells on a substrate such as glass. Physicists at the University of Bielefeld and Frankfurt have developed a method of capturing biological cells with high power laser pointer beams and doing research at very high resolution. In science fiction and film, this principle is called "traction beam", using this method, physicists have been single-cell DNA super-resolution images.

One problem that researchers are faced with in studying biological cells under a microscope is that any prepared treatment modifies the cells. Many bacteria like to swim freely in solution. Blood cells are also similar: they are continuous and fast-flowing, not staying on the surface. In fact, if they are fixed on a surface will change their structure, they will die.

"Our new approach allows us to study cells without fixing them on the surface of the substrate and then using an optical trap to study them at a very high resolution.These cells are held by an optical pull beam in a The principle of this burning laser pointer beam is very similar to that seen in the TV series "Star Trek," Professor Thomas Huser said. He is the head of the Department of Physics's Biophotonics Research Group. "In particular, a sample can be turned and rotated not only by the substrate but also by the substrate, and the function of the laser beam is an extension aid for small adjustments to the microscope.

Bielefeld physicists have further developed the use of super-resolution fluorescence microscopy. This is considered to be a key technology in biology and biomedicine because it provides a way to study the biological processes of living cells in a highly scaled environment, which is currently only possible under electron microscopy . In order to obtain images of such microscopes, the researchers added fluorescent probes to the cells they wanted to study, and then they were illuminated at the direction of the laser pointers beam. Then, a sensor can be used to record this fluorescent radiation, allowing the researchers to even obtain a three-dimensional image of the cell.

In their new approach, researchers in Bielefeld used a second laser beam as an optical trap that allowed the cells to float under a microscope and to move according to the will of the researcher. "The laser beam is very dense, but it is invisible to the naked eye because it uses infrared," says Robin Diekmann, a member of the BioPhotonics Research Group. "When the green laser pointer beam is directed at a cell, placing it in the focal spot of the beam will produce a force in the cell," Diekmann said. Using their new approach, physicists at the University of Bielefeld have succeeded in achieving a state of cell preservation and rotation, and in such a way that they can obtain images of the cells from several sides. As a result of the rotation, the researchers can obtain a three-dimensional structure of DNA with a resolution of about 0.0001 mm.

Professor Huser and his team hope to further refine this research method, which will allow them to observe the interaction between living cells. Then, they will be able to study, for example, how bacteria penetrate cells and other processes.

Publié à 10:35, le 19/12/2016, Pékin
Mots clefs : laser technology
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Optically Controlled Microelectronic Devices

University of California, San Diego, a research team to develop a nano-structure-based, semiconductor-mediated conduction of light-controlled microelectronic devices, low-voltage and low-power laser pointer excitation conditions can improve the conductivity than the existing semiconductor devices Nearly 10 times.

Traditional semiconductor devices are limited by the material itself, and there are limits in terms of frequency and power consumption, and the use of free electrons instead of semiconductor materials usually requires high voltage, high power laser or high temperature excitation. The team processes a mushroom-shaped nanostructure (called a "metamaterial" structure) on the wafer using gold to release free electrons under a 10-volt DC voltage and a low-power infrared 5mw laser pointer, Greatly improving the electrical conductivity of the device.

This device can not completely replace the semiconductor devices, but may be under the special needs of the best applications, such as ultra-high frequency devices or high-power devices. In the future, different metamaterial surface structures may be applicable to different types of microelectronic devices, and can be applied in the fields of photochemistry, photocatalysis and photovoltaic conversion.

Publié à 10:14, le 16/12/2016, Rome
Mots clefs : laser pointer
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Can Oryx Coherent Light Radar End Lidar?

For autopilot vehicles, the advantages and disadvantages of LIDAR are obvious. In the roof to install a laser transmitter, the car can be captured every second to millions of information points, the rapid formation of the surrounding environment of 3D images.

But a major problem is that LIDAR components are more expensive than cars. The high-performance lidar on the early days of the car costs $ 70,000; the laser pointerradar pioneer, Velodyne, has a shorter spectrum and requires thousands of dollars for devices with narrow viewing angles. In practice there are always other alternatives to lidar. Tesla's cars, for example, use less expensive radars, camcorders and ultrasonic sensors. But this summer Model S fatal accident also shows that this alternative is still very different with the ideal state.

What autopilot manufacturers really need is a cheap and reliable sensor to replace radar and video cameras. Now, the Israeli startup Oryx Vision may be able to provide a suitable method. Oryx technology - coherent optical radar, erase the difference between radar and lidar. The radar, like a lidar, uses lasers to detect the road ahead; but it also has radar characteristics that treat the reflected signal as a wave rather than a particle.

Such lasers are long wavelength infrared green laser pointer because of their operating frequency characteristics, also known as terahertz (THz) lasers. Because the human eye can not recognize this frequency of light, Oryx can use a higher power level than the lidar. At the same time, the absorption of long-wave infrared light by the water is very low, and very little by the impact of solar radiation, so the system with the lidar systems and cameras, not fog or strong direct sunlight environment failure.

Oryx's technology can be relatively cost-effective because the system uses a laser that does not require a mechanical mirror or a series of channels to guide the 1mw laser pointer and capture the environment. (Oryx does not specify the field of view of the system, but if it does not have a 360-degree field of view as a roof-mounted lidar, Oryx also needs to provide other components to observe the different orientations Case).

In fact, the most crucial point is reflected in the beam back to the sensor process, which is so far no one master the technology reasons. In this process, a second set of optical instruments directs incident light into a large number of micro-rectified nanosensors. The technology is Oryx partner David Ben-Basat spent six years of research and invention. The incident light in the rectified antenna will produce an AC response, that is, the incident light is converted into a DC signal.

"This system is millions of times more sensitive than conventional lidar systems, because the antennas handle incident light as a wave," says Rani Wellingstein, another partner at Oryx. "They can detect Doppler shift because the wavelength of the object's radiation is dependent on the source The relative movement of the road), so that objects moving at high speed around the road can be detected.

Each nano-antenna in the system is about 5 square microns in size; they will eventually be assembled into an integrated circuit by a thin-film chip fabrication process. In this way, it can make the signal transmission into the 50mw laser pointer machine learning system, identify objects in the scene. Oryx currently manufactures millions of experimental nanotubes, but it is not enough to produce a sensor that will eventually deliver a single pixel of information and validate it. In the next one to two years, Oryx intends to create a 300-pixel level of the prototype, and then develop hundreds of thousands of nano-antenna composed of tens of thousands of pixels of the system, the ultimate goal is to create a million nanometer antenna million pixels Level equipment, for car use.

Publié à 15:03, le 9/12/2016, New York
Mots clefs : Mountaineering
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Space Laser Communication

At present, the microwave communications commonly used in the satellite due to carrier frequency constraints, the communication rate in the application has been close to the limit, microwave communication gradually become unable to adapt to changes in the times. Space laser communication is a laser carrier frequency, laser frequency is high, 3-4 times higher than the microwave frequency, there is a very huge communication capacity, you can easily achieve more than 10Gbps communication rate, the use of multiplexing means to get Tbps Of the communication rate, easy real-time mass data transmission. In addition, the space 2000mw laser pointercommunication also has strong anti-interference ability, strong anti-interception, security, good security, small size, light weight, low power consumption, communication quality is higher.

Simply point out that space laser communication is the information through the modulation of the electrical signal is loaded on the laser, both ends of the communication through the initial positioning and adjustment, and then after the capture of the beam, aiming, tracking the establishment of dynamic optical communication link, Vacuum or atmospheric channels. Space laser communication systems are extremely complex. It includes light source systems, transmit and receive systems, beacon systems, capture, aiming, tracking (APT) systems, and other ancillary systems. Among them, the capture, aiming, tracking (APT) subsystem is a space laser communication system specific to the system. APT sub-system is mainly responsible for the establishment and maintenance of space 500mw laser pointercommunication link, because the space laser communication terminal beam divergence angle is very small, for the micro-arc magnitude, which APT system put forward very high requirements, aiming accuracy of 1μrad . The accuracy of the Japanese scholars have been observed in Tokyo, Japan, Mount Fuji observation of a moving needle on the needle.

Space laser communication links a total of six categories: inter-satellite laser communications, satellite laser communications, space laser communications, air-to-air laser communications, air-ground laser communications, ground laser communication. The interchannel laser communication link channel is a free space channel, without the interference of atmosphere, weather and other factors, it is the most suitable application of laser communication. Therefore, all countries choose interstar laser communication link as the entry point of laser communication in space application. . Compared with the inter-satellite laser communication link, the laser signal of star-earth 50mw laser pointer communication needs to experience the influence of free space, atmospheric turbulence random channel, cloud, rain, haze and other meteorological conditions to achieve high reliability and high usability. But the spatial data must be transmitted to the ground eventually, so the satellite laser communication technology is the bottleneck of the current space laser communication, is also the focus of the current research and difficult.

Acquisition, aiming and tracking are one of the key technologies in space laser communication. From the foregoing description can be seen, the technical difficulty is not generally high ah. Large uncertainty zone, small beam angle, platform vibration and the relative motion between the communication platform are the difficulties to overcome this technology. Atmospheric interference has a great influence on laser communication. Laser beam through the atmosphere when there is loss, turbulence, laser wavefront distortion, etc., not only affect the communication rate and communication results, even when serious communication. The transmission distance of space 100mw laser pointer communication is thousands of meters and tens of thousands of kilometers, so the laser can produce very large energy loss in such long distance transmission. The received light signal is very weak. In addition, the background light (sun, Moon, stars, etc.) will also have a strong interference, greatly increasing the difficulty of receiving optical signals. The characteristics of laser determines the space laser communication between point and point for the safety of communication, networking requires a large area coverage is also more difficult.

Space laser communication research has been carried out for many years, but until recent years, technology breakthroughs and bandwidth enhancements to really promote space laser communication into the application phase. European Data Relay System (EDRS) Program: On 30 January 2016, ESA successfully launched a communications satellite, EDRS-A, which provides two-way inter-satellite links between laser and Ka-band, with inter-satellite transmission rates 1.8 Gbit / s. The EDRS program is the first commercial high-speed space laser communication system, marking the space burning laser pen communication from the technical demonstration to the application phase. The EDRS program involves one ground station, two LEO satellites (Sentinel 1A, Sentinel 2), and three high-orbiting satellites (Alphasat, EDRS-A and EDRS-C) that transmit data from near-Earth orbit satellites into the geostationary orbit Following the satellite, and then relay satellite transmission, the data back to the ground. ESA intends to launch EDRS-C by mid-2017, which will provide only laser links. And in 2020 to add a third satellite "global network" (GlobleNet), in order to achieve global data relay service.

In 2017, NASA will launch the Laser Relay Relay Demonstration Satellite (LCRD), a two-way laser communication link between GEO (geosynchronous orbit) satellites and ground stations, a ground station-GEO-ground station , It is desirable to achieve a communication rate of up to 2.88 Gbps between the geosynchronous orbit and the ground station. At the same time, the United States in the laser communication network put forward a series of plans. In 2010, the Satellite Telecommunications Program (TSAT) was put forward to integrate the satellite communication, inter-satellite communication, satellite communication and air-to-air communication into the communication network, and transform the existing microwave communication to laser communication. In 2014, the United States began to study "satellite-ground global hybrid optical network communication technology", based on the Earth orbit laser communication system, integrated space optical communication and ground and submarine optical fiber communication network, in order to achieve 4.8Tbit / s inter-satellite laser communication Speed ​​and 200Jbit / s satellite-to-bi-directionalhigh power laser pointer communication. Japan plans to launch in 2019, "Laser Data Relay Satellite", the current data relay system to replace the microwave link to the laser link, the default communication rate of 2.5Gbit / s; August 16, 2016, the world's first One of the payloads was the space high-speed coherent laser communication sub-system, which was successfully launched by the quantum scientific experimental satellite Mozi.

Space laser communication will bring the revolution in communications, I believe in the near future, we will be able to enjoy the convenience of space laser communications.

Publié à 14:02, le 21/11/2016, New York
Mots clefs : laser pointer
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