LED lighting requires red, green and blue primary colors to converge into white light. Red LEDs and green LEDs were born in the 1960s and 1970s, and the development of blue LEDs has been stuck. It was Chisaki and Amano who had broken the shell. They broke through the bottleneck and invented the blue LED for the first time. Subsequently, Nakamura Shuji developed a technology for producing high-efficiency blue LEDs, and the collection of the three primary colors completed the era of “new light”.
What does LED lighting mean? We can calculate a data account like this. The total annual consumption of electricity is about 200 billion kWh, 19% of which is used for lighting. If all lighting fixtures are replaced with LED energy-saving lamps, then at least 152 billion kWh of electricity is saved worldwide each year. These savings are equivalent to reducing coal consumption by at least 500 million tons, reducing carbon dioxide emissions by 1.3 billion tons, and reducing sulfur dioxide emissions by 4.2 million tons.
The blue LED has achieved a gorgeous turn of LED lighting in 20 years, and now it is widely used. It uses mobile phones to chat, use computers to work, and use TV to have fun. Incandescent lamps light up the 20th century, and the 21st century will be lit by LED lights.
2009 Nobel Prize in Physics
Optical fiber: a new era of communication
For centuries, scientists have long been working on how to deliver information faster and farther. From telegrams to wired telephones to the widespread use of cables, advances in technology have allowed us to know the world without leaving home.
In the 1960s, the Chinese scientist Gao Song proposed the idea of replacing the current with light and replacing the wire with glass fiber. In 1966, he published the epoch-making paper "Dielectric fiber surface waveguide for light wave transmission", which theoretically analyzed this. The feasibility of "Arabian Nights". In 1970, Corning developed a fiber with a loss of 20dB/km, which made it possible to carry out long-distance transmission of light in the fiber. The new era of fiber-optic communication has kicked off since then, and the "father of fiber" sorghum has also stood on 2009. The Nobel Prize in Physics for the year.
"Fiber" is a full-length "optical fiber" made of transparent optical material such as quartz or glass. It is a cylindrical optical waveguide for transmitting light. Its typical structure consists of a core and a cladding. When light is incident from one end and its angle with the axis is less than a certain value, the core has a relatively high refractive index and the cladding refractive index is relatively low. Total reflection occurs at the interface with the cladding so that light can be tortuous in the core without penetrating the cladding. At this point, if we add information to the light, it is transmitted with the light to the other end, and the information is transmitted.
We can compare the two sets of data: First, the current stage of fiber-optic communication can achieve the transmission of 240,000 channels at the same time, its capacity is increased by a thousand times than microwave communication; Second, under the premise of ensuring communication quality, ordinary cable or microwave communication The relay distance is 1.5 to 60 kilometers, and the current stage of fiber can achieve 2000 to 5000 kilometers of non-relay transmission.
Nobel Prize in Physics, 1971
Holography: also true and illusory
The 3D sand table in the movie "Avatar" makes the landscape of Pandora's planet unobstructed. It is so cool that there are no friends! But this technology is not far away from us. The holography invented by Professor Dennis Gable in 1947 has already been This magic shines into reality, and he won the 1971 Nobel Prize in Physics.
Compared to traditional photographic techniques, holographic technology creatively records the spatial position of points on an object, breaking through the limitations of two dimensions in one fell swoop, so that people can see realistic three-dimensional objects through holograms.
When making a hologram, two lasers are needed, one laser is irradiated on the object, reflected by the surface of the object, and the other laser is the reference light. Similar to water wave contact, they also superimpose when they meet in space, forming a strip of bright and dark stripes, and the positional information of each point on the object is encoded in these stripes.
Place the holographic bottom plate where the two beams meet and capture the stripes. After a series of processing of the holographic substrate after the filming, we completed the recording of the hologram.
By illuminating the hologram with the reference light generated by the laser, the object light can be created again, as if the three-dimensional image of the object is actually popped up in the hologram.
Imagine that in the near future, with the continuous development of holographic technology, movies can get rid of the constraints of screens and 3D glasses and perform in the air; architects can walk around in the imaginary building, and customers can watch the comment simultaneously. A doctor thousands of miles away can check the patient's physical condition. I believe that day is not far away!
Nobel Prize in Physics, 1908
Interfere with color photography: record colorful
The 1908 Nobel Prize in Physics was awarded to French physicist Gabriel Lippmann, who invented the interferometric color photography technique to make the photo perfectly reproduce the color, causing a great sensation.
At that time, the camera used film to record grayscale images. The principle is very simple. The film contains a kind of cool photosensitive material, silver halide, which reacts with light and turns into black silver particles. The stronger the light, the more silver particles, and the image projected on the film is recorded.
The world is colorful, how can people be willing to record only black and white? At that time, most people chose to use colored glass or colored particles to add color to the photos, but the photos obtained were not lack of detail or color distortion, and the effect was not satisfactory. Gabriel Lippmann took a different approach and made a small treatment on black and white film, which achieved amazing results.
How did he do it? Since different colors of light have different wavelengths, the film remembers the wavelength of the light and can leave the color on it. In order to keep the film from losing memory, Lippmann applied a layer of mercury on the back of the film as a mirror. What is the magic effect of the mercury mirror? For example, this is the wavelength of blue light. After the blue light passes through the photosensitive layer and is reflected back on the mercury, the incident light and the light reflected by the mercury “interference phenomenon”, forming a half interval in the film. Interference fringes of wavelength. These stripes leave the characteristics of blue light. When the film is illuminated with white light, they are like a sieve that sifts out other colors of light and reflects only the blue light. Every point on the film reflects only the color of those records, so that a color photo is born.
Nobel Prize in Physics, 1901
X-ray: a world that is invisible to the naked eye
In 1901, the world's first Nobel Prize in Physics, awarded the German physicist William Roentgen, rewarded him for discovering X-rays.
On November 8, 1895, Roentgen wrapped the discharge tube with black paper and prepared for cathode ray research. A strange phenomenon caught his attention: at a distance of one meter from the discharge tube, a green light appeared on the screen plated with iridium-platinum cyanide crystals. The transmission distance of the cathode ray is clearly no more than a few centimeters. What is this green light? The roentgen calls this unknown ray X-ray. The experiment found that X-rays can penetrate a few centimeters of hard rubber skin and 15 micron aluminum plates. Using the characteristics of X-rays, Roentgen photographed the world's first X-ray photograph of the lady, whose hands and their wedding rings were clearly visible.
Both X-rays and visible light are electromagnetic waves, but their wavelengths are only 0.01 to 10 nanometers. X-CT can quickly and accurately check the condition; X-knife can accurately eliminate the tumor; X-ray crystal diffraction has become a weapon to understand the atomic world; it is also used for metal flaw detection, measuring the thickness of metal and so on. In fact, every time you go in and out of the security check, your luggage is in close contact with it. Of course, X-rays will also cause problems for us while benefiting human beings. Excessive X-ray exposure can cause diseases such as leukemia and cancer, so be careful when using X-rays.
In fact, the Nobel Prize related to optical research is far more than the five items listed above, and the science and technology related to optics has profoundly changed our lives.
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