What factors are related to the success of holographic photography

Choose the right angle and coherent laser.

Holographic** is a method of recording interference patterns to reproduce the photographed object, so how to clearly record interference fringes is the key to success

1.The resolution of the recording material should be high, preferably 3000 line pairs of millimeters, but the sensitivity of the silver salt photosensitive material with such a high resolution is very low, and it takes a long time. Other photosensitive materials have lower sensitivity and require tens of minutes of ** time.

2.Due to the need for a long time, the stability requirements are very high, and it should be carried out on an optical platform with shock absorption to reduce the interference of air flow, the vibration of sound waves, and the thermal expansion of the photograph, optical devices and photosensitive materials caused by temperature changes in the process, because as long as the displacement of 1 4 wavelengths occurs, the interference pattern is completely destroyed!

3.A single longitudinal mode laser is required, i.e., there is only one wavelength of laser output, rather than multiple multimode laser outputs that are very close to each other. Only such a laser with its coherent length is long enough.

4.The power of the laser should be as large as possible, but the high-power single longitudinal mode laser is very expensive, and the laser is needed to shoot holograms, but not all lasers are applicable, and the phenomenon of "slicing bread" will occur in multi-longitudinal mode laser shooting. A single-longitudinal mode high-power pulsed laser can take portraits.

5.There is an optimal value for the amount of recorded material, and the diffraction efficiency has a functional relationship with the amount of material, which needs to be considered comprehensively according to the light intensity and the sensitivity of the recorded material. If the diffraction efficiency is too high and the less ** is under**.

6.The optical path of the object light and the reference light reaching the holographic recording material should be as equal as possible.

In short, holographic photography is a comprehensive application of physical and chemical knowledge, and in addition to theory, it also requires high experimental skills. People who want to get answers are not there to cope with exams, but for science.

A biochemist who works in holographic photography.

The difference between the two: ordinary photography can only store the spatial distribution of the light intensity of the photographed object, which cannot meet the requirements of people who want to perceive the real 3D scene in a specific environment; Holographic photography is to record the interference fringes of the object light wave and the corresponding reference light wave irradiating the object, so as to record all the light field information including the object amplitude (light intensity) and phase, so it is called "holographic".

<> In order to achieve holography, the experimental setup must meet the following three basic conditions:

1) A good coherent light source, that is, the reference beam and the object beam must be coherent light (so the laser needs to be used as the photographic light source, and the object optical path is generally equivalent to the reference optical path). Cavity.

2) A seismic table with good stability, that is, the optical system must have sufficient mechanical stability.

3) A high-resolution photosensitive negative.

4) Understand and use development, fixing, processing, and other related photography.

Holographic** and ordinary popular science** is not the same, under the appropriate lighting, the scene displayed on the holographic ** is three-dimensional, and all sides of the scene can be seen.

The difference between the full smile and the conventional photography is that the conventional photography only records the change of the light intensity on the surface of the photographed object, that is, only the amplitude of the light is recorded; Whereas, holograms record all the information of the light waves, and in addition to the amplitude, they also record the phase of the light waves. In this way, all the information about the light wave field of the space object is stored and recorded. Then use the diffraction of holographic ** to a specific wavelength monochromatic illumination light to reveal the original space scene.

It can "resurrect" a "frozen" scene and appear in front of people's eyes.

Ordinary photography can only store the spatial distribution of the light intensity of the photographed object, which cannot meet the requirements of people who want to be able to perceive the real 3D scene in a specific environment. Holographic photography is to record the interference fringes of the object light wave and the corresponding reference light wave of the irradiated object, so as to record all the light field information including the object amplitude (light touch circle beat intensity) and phase, so it is called "holographic".

Compared with the traditional optical holography, the computational holography has the following advantages: (1) The introduction of computer technology and digital image processing technology can easily introduce digital processing methods to eliminate the adverse effects of aberration, noise and nonlinearity of the photosensitivity characteristic curve of the recording medium, and improve the quality of the hologram.