Four-dimensional plasma holography method and device
By interfering ionization in the background gas to generate plasma gratings, recording and extracting the spatiotemporal information of strong lasers, the problems of plasma wave instability and short existence time in the prior art are solved, and effective storage and extraction of four-dimensional plasma holographic photography is realized.
Patent Information
- Application Number
- CN202510331797.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2025-06-13
AI Technical Summary
The existing four-dimensional holographic photography technology is difficult to effectively record and extract the spatiotemporal information of strong lasers, mainly due to the instability of plasma waves and the problem of too short time.
The long-pulse main laser light and the short-pulse reference light interfere in the background gas, generate an interfering electric field ionization gas to form a plasma grating, and record the space-time information of the main laser light. Then, the stored information is extracted by the first order diffraction light using probe light incident plasma grating at the Bragg angle.
Effective storage and extraction of strong laser spatiotemporal information is achieved, the plasma wave instability and short existence problems in traditional technology are overcome, and four-dimensional plasma holographic photography is realized.
Smart Images
Figure CN120143575A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of holographic imaging technology, and particularly to a four-dimensional plasma holographic photography method and apparatus. Background Art
[0002] Since Dennis Gabor proposed holographic photography in 1948, holographic photography technology has been widely used in people's lives. Holographic photography records the light intensity and phase information of the main laser by interfering the reference light with the main laser, and finally reproduces the main laser through the diffraction of a probe light beam passing through the interference fringes. Since holographic photography contains both the light intensity and phase of the main laser, and the reproduced main laser energy can restore the three-dimensional image of the object, holographic photography can achieve three-dimensional photography of the object.
[0003] In recent years, the concept of four-dimensional holographic photography has been proposed in this field. While recording the light intensity and phase information of an object, it is also possible to record the information of how the light intensity and phase change over time. The existing implementation of four-dimensional holographic photography is mainly achieved by using a large number of two-dimensional holographic films.
[0004] When the intensity of the laser reaches a certain level, it will ionize the propagation medium. Therefore, it is difficult to perform holographic photography on high-intensity lasers using traditional methods. To overcome the problem of damage to components caused by high-intensity lasers, holographic photography based on plasma has been proposed. In 2017, A. Leblanc et al. in France first reported three-dimensional plasma holographic photography based on a solid surface. They generated a plasma grating by interfering a vortex light beam with a reference light beam on the solid surface, and then restored the spatial information of the vortex light through the first-order diffraction of another probe light beam.
[0005] To further store and extract the spatio-temporal information of high-intensity lasers, the concept of four-dimensional plasma holographic photography has been proposed. In 2002, Nat Fisch et al. at Princeton University proposed a four-dimensional holographic photography technology based on a bulk plasma grating. They proposed using a short-pulse reference light and a long-pulse main laser to interact in the plasma, and the plasma waves excited by them can record the spatio-temporal information of the long-pulse main laser. Subsequently, another short-pulse probe light beam can be used to read the spatio-temporal information of the long pulse. Since the information of the laser is engraved on a three-dimensional holographic film, this holographic photography is called bulk plasma holography. At the same time, this method records the spatio-temporal information of the laser, and is also called four-dimensional holographic photography.
[0006] However, this method is difficult to implement experimentally because the generation of plasma waves is affected by plasma instability and is difficult to control, and the existence time of plasma waves is too short to effectively record the information of long pulses. Summary of the Invention
[0007] The object of the present invention is to provide a four-dimensional plasma holographic imaging method to solve the above problems.
[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: a four-dimensional plasma holographic imaging method, the method comprising the following steps: first, a long-pulse main laser and a short-pulse reference light interfere in a background gas to generate an interference electric field, the interference electric field ionizes the background gas to form a plasma grating, and the spatio-temporal information of the long-pulse main laser is recorded; then, a probe light is incident on the plasma grating at the Bragg angle, and the spatio-temporal information of the long-pulse main laser is read through the diffraction of the probe light by the plasma grating.
[0009] As a preferred technical solution, the long-pulse main laser is one of the two lasers obtained by equally splitting an initial laser by a beam splitter.
[0010] As a preferred technical solution, the long-pulse main laser first guides the light through a light guiding mirror, then passes through a delay line, and finally is focused on the background gas by a focusing lens.
[0011] As a further preferred technical solution, there are two light guiding mirrors, namely a main laser light guiding mirror a and a main laser light guiding mirror b respectively.
[0012] As a further preferred technical solution, the short-pulse reference light is the other beam of laser light separated by the beam splitter except for the long-pulse main laser. It is first compressed by a compression grating, then frequency-doubled to obtain a frequency-doubled light and a remaining fundamental frequency light. Then the remaining fundamental frequency light is reflected by the beam splitter, passes through a delay line and then becomes the short-pulse reference light, and finally is focused on the background gas by a focusing lens.
[0013] As a further preferred technical solution, the frequency-doubled light is used as the probe light, guides the light through the light guiding mirrors in sequence and is incident on the plasma grating at the Bragg angle to form a diffracted light of the probe light, and the information of the long-pulse main laser is obtained by measuring the diffracted light.
[0014] As a further preferred technical solution, there are two light guiding mirrors, namely a probe light light guiding mirror a and a probe light light guiding mirror b respectively.
[0015] As a further preferred technical solution, the diffracted light is divided into two beams of 0th-order diffracted light and 1st-order diffracted light, and the information of the long-pulse main laser is obtained by measuring the 1st-order diffracted light.
[0016] The second object of the present invention is to provide a four-dimensional plasma holographic imaging device, comprising a beam splitter, and a main laser light guiding mirror a, a main laser light guiding mirror b, a main laser delay line and a main laser focusing lens are sequentially arranged along one of the optical paths of the beam splitter; Another optical path is sequentially provided with a pair of compression gratings, a frequency-doubling crystal, and a reference light and frequency-doubled probe light beam splitter. After the reference light and frequency-doubled probe light beam splitter, it is divided into two optical paths. One optical path is sequentially provided with a reference light delay line and a reference light focusing lens, and the other optical path is sequentially provided with a probe light guiding mirror a and a probe light guiding mirror b. A plasma grating is provided between the main laser focusing lens and the reference light focusing lens.
[0017] In the present invention, a long-pulse main laser (1 ps - 20 ps) and a compressed short-pulse reference light (30 fs - 100 fs) are used to interfere and ionize in the background gas to generate a plasma grating to record the information of the long-pulse main laser. Subsequently, the stored information is extracted through the first-order diffracted light of the probe light by the plasma grating.
[0018] Among them, the present invention uses the interference ionization method to store the information of the long-pulse main laser, which mainly includes the following content: a short-pulse reference light and a reverse long-pulse main laser are used to interfere and ionize in the background gas to generate a plasma grating. Since the modulation depth of the plasma grating is related to the laser intensity, the spatio-temporal information of the long-pulse is recorded by this method. The present invention uses the diffraction method to extract the stored spatio-temporal information, which mainly includes the following content: a probe light is incident on the plasma grating at the Bragg angle, and the stored information is extracted through the first-order diffracted light.
[0019] The interference ionization technology adopted by the present invention is realized in the following way: First, two counter-propagating lasers (long-pulse main laser and short-pulse reference light) are used to interfere in the background gas. The laser interference field forms a grid structure, and the gas is ionized by this interference field to form a plasma grating with a structure similar to the laser interference field. Since the interference field contains the time waveform and spatial intensity phase information of the laser, the generated plasma grating can also record the spatio-temporal information of the laser pulse.
[0020] The information reading technology adopted by the present invention is realized in the following way: A probe light is incident on the plasma grating at the Bragg angle, and part of the probe light will be diffracted by the plasma grating. The reflectivity is proportional to the modulation depth of the grating. Therefore, the intensity of the diffracted light is proportional to the intensity of the main laser. In this way, the spatio-temporal information of the main laser can be reproduced.
[0021] Compared with the prior art, the advantages of the present invention are as follows: The present invention solves the problems of storage and extraction of strong-field laser information. Compared with the prior art that can only store and extract the intensity and phase of strong lasers, the present invention can simultaneously store and extract the time waveform information of strong lasers, adding a dimension in time. Therefore, four-dimensional plasma holography can be realized. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 is a schematic diagram of the principle of the present invention; Figure 2 is the implementation optical path diagram of the present invention; Figure 3 are the spatio-temporal information of the main laser focus inverted at different times; In the figure: 1, main laser; 2, background gas; 3, reference light; 4, probe light; 5, plasma grating; 6, 0th-order diffracted light; 7, 1st-order diffracted light; 8, reconstructed main laser; 9, initial laser; 10, beam splitter; 11, compression grating pair; 12, frequency doubling crystal; 13, beam splitter for reference light and frequency-doubled probe light; 14, reference light delay line; 15, reference light focusing lens; 16, probe light light guide mirror a; 17, probe light light guide mirror b; 18, 1st-order diffracted light of probe light; 19, main laser light guide mirror a; 20, main laser light guide mirror b; 21, main laser delay line; 22, main laser focusing lens. Specific embodiments
[0023] The present invention will be further described below in conjunction with embodiments.
[0024] Embodiment 1:
[0025] A four-dimensional plasma holographic imaging device, see Figure 1 and Figure 2 , including a beam splitter 10, along one of the optical paths of the beam splitter 10, a main laser light guide mirror a 19, a main laser light guide mirror b 20, a main laser delay line 21 and a main laser focusing lens 22 are sequentially arranged; In the other optical path, a compression grating pair 11, a frequency doubling crystal 12 and a beam splitter 13 for reference light and frequency-doubled probe light are sequentially arranged. After the beam splitter 13 for reference light and frequency-doubled probe light, it is divided into two optical paths. In one optical path, a reference light delay line 14 and a reference light focusing lens 15 are sequentially arranged. In the other optical path, a probe light light guide mirror a 16 and a probe light light guide mirror b 17 are sequentially arranged. The main laser and the reference light are respectively focused by the main laser focusing lens 22 and the reference light focusing lens 15 to generate a plasma grating 5 at the focus; Method for performing holographic imaging using the above device: The initial laser 9 is equally divided into two beams after passing through the beam splitter 10. One of the divided beams is the main laser 1. The main laser 1 is guided by the main laser light guide mirror a 19 and the main laser light guide mirror b 20, then passes through the main laser delay line 21, and finally is focused by the main laser focusing lens 22 onto the background gas 2; Another beam splitting of the spectroscope 10 is first compressed to the transform-limited state by the compression grating pair 11, and then frequency-doubled by the frequency-doubling crystal 12 to obtain the remaining fundamental frequency light and the frequency-doubled light respectively. Among them, the remaining fundamental frequency light is reflected by the reference light and frequency-doubled probe light spectroscope 13, becomes the reference light 3 after passing through the reference light delay line 14, and finally is focused on the background gas through the reference light focusing lens 15 to interfere and ionize with the main laser 1 to generate the plasma grating 5; the frequency-doubled light is used as the probe light 4, and after being guided by the probe light light guiding mirror a 16 and the probe light light guiding mirror b 17 in sequence, it is incident on the plasma grating 5 at the Bragg angle to form the first-order diffracted light 18 of the probe light. The information of the main laser can be obtained by measuring the first-order diffracted light. It should be noted that, Figure 2 The "first-order diffracted light 18 of the probe light" in Figure 1 corresponds to Figure 2 the "first-order diffracted light 7" in Figure 1 Another beam of green light below the "first-order diffracted light 18 of the probe light" in Figure 1 corresponds to
[0026] the "zeroth-order diffracted light 6" in Figure 3 In Figure 3 , the first-order diffracted light of the probe light forms the reconstructed main laser 8.
[0027] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A four-dimensional plasma holography method, characterized in that: The method comprises the following steps: firstly, a long pulse main laser and a short pulse reference light are interfered in a background gas to generate an interference electric field, the interference electric field ionizes the background gas to form a plasma grating, and the time-space information of the long pulse main laser is recorded; then, a beam of probe light is incident on the plasma grating at a Bragg angle, and the time-space information of the long pulse main laser is read through the diffraction of the probe light by the plasma grating.
2. The four-dimensional plasma holography method according to claim 1, characterized in that: The long pulse main laser is one of two laser beams divided into equal proportions by an initial laser beam through a beam splitter.
3. The four-dimensional plasma holography method according to claim 1, characterized in that: The long pulse main laser is first guided by a light guide mirror, then passes through a delay line, and finally is focused on the background gas by a focusing lens.
4. The four-dimensional plasma holography method according to claim 3, characterized in that: There are two light guide mirrors, namely a main laser light guide mirror a and a main laser light guide mirror b.
5. The four-dimensional plasma holography method according to claim 3, characterized in that: The short pulse reference light is another laser beam separated by a spectroscope except for the long pulse main laser. It is first compressed by a compression grating pair and then frequency-doubled to obtain frequency-doubled light and remaining fundamental frequency light. The remaining fundamental frequency light is then reflected by the spectroscope and becomes a short pulse reference light after passing through a delay line. Finally, it is focused on the background gas through a focusing lens.
6. The four-dimensional plasma holography method according to claim 5, characterized in that: The frequency-doubled light is used as probe light, which is guided by light guide mirrors in turn and then incident on the plasma grating at a Bragg angle to form diffracted light of the probe light. The information of the long-pulse main laser is obtained by measuring the diffracted light.
7. The four-dimensional plasma holography method according to claim 6, characterized in that: There are two light guide mirrors, namely probe light light guide mirror a and probe light light guide mirror b.
8. The four-dimensional plasma holography method according to claim 6, characterized in that: The diffracted light is divided into two beams, namely, the 0th order diffracted light and the 1st order diffracted light. The information of the long pulse main laser is obtained by measuring the 1st order diffracted light.
9. A four-dimensional plasma holographic device, characterized in that: It comprises a beam splitter, along one of the optical paths of the beam splitter a main laser light guide mirror a, a main laser light guide mirror b, a main laser delay line and a main laser focusing lens are sequentially arranged; Another optical path is sequentially provided with a compression grating pair, a frequency doubling crystal, and a reference light and frequency doubling probe light spectroscope, and the reference light and frequency doubling probe light spectroscope is divided into two optical paths, one of which is sequentially provided with a reference light delay line and a reference light focusing lens, and the other optical path is sequentially provided with a probe light guide mirror a and a probe light guide mirror b, and a plasma grating is arranged between the main laser focusing lens and the reference light focusing lens.