In the second room, the screen on the opposite wall has some circular stripes. There are some reflecting mirrors and vertical boards with round holes in the middle.
Maybe turn the mirror so that the light source shines on it. Light is reflected in another direction. Find another mirror, catch this beam of light, and reflect it again. If the light shines on the wall, there will only be a spot on the wall. After several reflections from the mirror, it is transmitted to the opposite direction. Finally, guide the light to shine on the screen, allowing the door to open to enter.
There are 10 different light sources here. 500
m-700
m.
There are 10 different round hole diameters.
0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, .1mm, 1.2mm, 1.3mm, 1.4mm.
The distance between the circular hole and the screen can be set to different distances.
Looking behind, there is also a screen on the upper rear wall with circular stripes. It is different from the stripes in the previous room. Here there are circular stripes on the back and front.
Put a light source, the light source emits light, passes through the round hole, and forms circular stripes on the screen, but they are inconsistent with the stripes on the wall.
"These circular fringes are probably diffraction fringes," Hessing said.
Geometric optics based on the law of linear propagation of light cannot explain the diffraction phenomenon of light. The explanation of this phenomenon depends on wave optics. The first person to successfully use the principle of wave optics to explain diffraction phenomena was Fresnel. After the emergence of the electromagnetic theory of light, people knew that light is an electromagnetic wave, so the diffraction problem of light waves passing through small holes should be treated as a boundary value problem of the electromagnetic field. The diffraction theories actually used are some approximate solutions.
An opaque screen with a circular hole in the middle is placed between the monochromatic point light source and the screen. If you carefully observe the edges of the projection, you will find that light enters the geometric shadow area and some light and dark stripes appear.
The occurrence of the diffraction phenomenon was initially thought to be due to the fact that the free light wave encountered obstacles such as slits and holes when propagating in space. The wave surface or wave front was restricted and divided by the obstacles, causing the wave surface to be damaged. In fact, any deformation of the wave surface or Any spatial modulation of the complex amplitude distribution of the light field on the wave surface (wavefront) will lead to the occurrence of diffraction, which will redistribute the complex amplitude of the light field after passing through the obstacle.
In order to explain the mechanism of gradual propagation of waves at various points in space, Huygens once proposed a hypothesis: every point on the wave surface (wave front) can be regarded as a secondary disturbance center emitting spherical wavelets. At the latter moment, these The envelope surface of the wavelet is the new wave surface at that time. Because the normal direction of the wave surface is the propagation direction of the light wave, the propagation of the light wave from one moment to another can be determined by applying Huygens' principle.
When the spherical wave emitted by the monochromatic point light source reaches the edge of the circular hole, only part of the wave surface is exposed within the scope of the circular hole, and the remaining part is blocked by the light screen. According to Huygens' principle, each point on the wave surface exposed within the circular hole can be regarded as a secondary disturbance center, emitting spherical wavelets, and the envelope surfaces of these wavelets determine the new wave surface after the circular hole. The light wave outside the cone no longer propagates along the original light wave direction.
An ideal Fraunhofer diffraction system functions as a spatial frequency analyzer. When a monochromatic light wave is incident on the image to be analyzed, through Fraunhofer diffraction, information of a certain spatial frequency is transported out by plane diffracted waves in a certain specific direction. These diffracted waves are intertwined with each other in the near field, and they are separated from each other in the far field, thereby achieving the purpose of frequency division. A commonly used far-field frequency dividing device is a lens: it converges plane waves in different directions to different points on the back focal plane to form diffraction spots. These diffraction spots correspond to the spatial frequency of the image one-to-one, and the back focal plane is the spectral plane of the image, which is called the Fourier surface. Fraunhofer diffraction spots are called spectral spots.
Xiang Yu said: "There are three robots here, and they are also replacing the light source, round holes, and reflectors. The opposite circular striped screen needs to be illuminated before they are assembled."
He Xin said: "The division of labor is still similar to the previous room. I will replace the light source, Xiangyu will replace the round hole, and Instant Frequency will replace the reflector."
After He Xin changed the light source, the opposite robot A1 also changed the light source. After Xiang Yu replaced the round hole, the opposite robot A2 also replaced the round hole. After replacing the reflector instantly, the opposite robot A3 also replaced the reflector.
The segment resides at the moving hole distance. The opposite round hole bracket is in automatic movement distance.
The light source here reaches the reflector through the round hole, is reflected back, passes through other round holes, and reaches the screen behind. The light source on the opposite side reaches the reflector through the circular hole, is reflected back, passes through other circular holes, and reaches the screen in front.
Even without robot interference, there are nearly 1,000 combinations of light sources, circular holes, and distances. This is equivalent to a three-digit combination lock. There are 1,000 combinations, and currently I don’t know how to make the light exactly consistent with the stripes.
Shunpin said: "Similar to the previous room, if you see that the stripes are inappropriate, such as being too large or too small, you can know how to adjust the stripes."
Based on the wavelength, distance, and hole diameter, the width of the stripes can be obtained. But the stripe width is too large or too small. I don't know which parameter to adjust.
However, the parameters adjusted by the opposite robot may prevent us from adjusting in the right direction.
Xiang Yu said: "In other words, the robot opposite has made the round hole smaller, so we should make the round hole bigger."
He Xin said: "We are doing the opposite of adjusting the robot on the opposite side, gradually adjusting three parameters."
When it is close to the appropriate value, the round hole is too large, and it is adjusted down one gear.
During the adjustment process, the robot's light source also shines and is aimed at the wall above the back. If the stripes match properly, Party A loses.
Several people from Party A also have to use baffles and reflectors to block the light from the robot's light source or reflect it in other directions.
Shunfen said: "The spacing between the stripes above us and on the opposite side are about the same width."
He Xin said: "Then the parameters used by the opposite robot are standard values."
Xiang Yu said: "Use this value to configure the combination of light source, circular hole, and distance."
Finally, we selected a wavelength of 589 nanometers, a circular hole of 1.1 mm, and a distance of 1.5 meters to obtain a suitable circular stripe width. But it was blocked by the reflector of the opposite robot and reflected back. Instantly replace the reflector and continue to reflect it back.
At the same time, in the second empty space next to him, He Xin was changing the light source, Xiang Yu was changing the round hole, and Duan was moving the distance between the round hole, and continued to emit diffraction spots to the opposite screen. Robots A1, A2, and A3 also changed the light sources and round holes in the second space, and projected them on the screen behind them, causing interference to Party A's light spot.
Instantaneous said: "Is this okay? If it causes interference, the door cannot be opened?"
Xiang Yu said: "We also illuminate the screens behind us, causing interference to them."
Party A changed the light source and round hole in the third space and projected it onto the screen behind them, causing interference to Team A's light spot. Team A fires a diffraction spot toward the opposite screen.
He Xing said: "What should we do? Our optical devices cannot be put there. What should we do if their light causes interference there?"
Duan Zhu said: "Look at the round holes on the ground?"
There is a button in the control box next to the wall. I don't know what it does. He Xin opened a button next to the wall, and some pillars appeared on the round hole. Blocking the light from Team A in the second position. Team A's light spot is projected onto the opposite wall, consistent with the circular stripes, and triggers the photoelectric switch. The door opened.
