A terahertz scalar vortex quantum cascade laser and its fabrication method

Abstract

The present invention relates to a terahertz scalar vortex quantum cascade laser, comprising a substrate and a bonding metal layer located above the substrate, wherein a seed laser region, a gradual amplification region, an insulating region, and an emission region are arranged in sequence along the length direction of the laser above the bonding metal layer, a first absorption region is provided on the side of the seed laser region opposite to the gradual amplification region, and a second absorption region is provided on the surrounding side of the emission region; the width of the gradual amplification region gradually increases from the seed laser region to the insulating region, and the width of the insulating region gradually increases from the gradual amplification region to the emission region. The present invention also provides a method for preparing a terahertz scalar vortex quantum cascade laser, which can directly emit a terahertz scalar vortex laser with a high mode purity, can realize a hollow annular far-field light spot, and the phase is spirally carried with orbital angular momentum, can realize a specific topological charge, and has linear polarization characteristics, high stability, high excitation efficiency, narrow line width, and high side mode suppression ratio.

Description

Technical Field

[0001] The present invention relates to the field of terahertz quantum cascade lasers, and more specifically to a terahertz scalar vortex quantum cascade laser and a preparation method thereof. Background Art

[0002] Terahertz (THz) quantum cascade lasers (QCL) have become a highly potential coherent light source in the range of 2-5 THz due to their high energy conversion efficiency, small size, easy integration, and electric pumping. They have important applications in imaging, material detection, and communications. For example, in imaging and material detection, because the intrinsic vibrational energy levels of a large number of molecules and clusters are in the THz band, this band is also called the fingerprint spectrum of molecules. The THz imaging technology using this characteristic has been applied in the fields of molecular spectroscopy, biomedicine, security, and non-destructive testing. In terms of communications, THz wireless communications have the advantages of wide bandwidth, high confidentiality, and the ability to penetrate plasma layers, and can become another important communication frequency band after microwave and optical communications.

[0003] by (l is the topological charge, i is the imaginary unit, Electromagnetic waves with phase distribution in the form of angular coordinates have orbital angular momentum. Due to its spiral wavefront, it is called vortex light. Vortex light is used in STED technology, which can break the diffraction limit and reduce the resolution to the nanometer level. In addition, through the encoding and multiplexing of orbital angular momentum, an unlimited number of channels can be added at the same communication frequency in theory. Vortex light can be divided into scalar vortex light and vector vortex light. The polarization of the scalar vortex field is uniform and the same everywhere in space, while the polarization of the vector vortex field changes with the spatial position.

[0004] At present, vortex light is mostly generated by discrete devices, which has the disadvantage of unstable optical path assistance. Integrated vortex light emitters are concentrated in the visible light and communication bands, and there is no laser that can directly generate vortex light in the terahertz band. Therefore, there is an urgent need for a laser that can vortex-control the phase of the terahertz wave to directly generate a stable scalar vortex terahertz wave. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a terahertz scalar vortex quantum cascade laser and a preparation method thereof, which can directly emit scalar vortex terahertz waves and has the advantage of high stability, so that the emitted scalar vortex terahertz waves have high mode purity.

[0006] A terahertz scalar vortex quantum cascade laser provided by the present invention comprises a substrate and a bonding metal layer located above the substrate, wherein a seed laser region, a gradual amplification region, an insulating region and an emission region are arranged in sequence along the length direction of the laser above the bonding metal layer, a first absorption region is provided on a side of the seed laser region opposite to the gradual amplification region, and a second absorption region is provided on a peripheral side of the emission region; wherein the width of the gradual amplification region gradually increases from the seed laser region to the insulating region, and the width of the insulating region gradually increases from the gradual amplification region to the emission region.

[0007] Furthermore, the seed laser region includes a first active region and a first top metal layer from bottom to top, and the first active region has a periodic grating structure.

[0008] Furthermore, the periodic grating structure is composed of a number of long strip gratings of the same size, and the long strip gratings are equidistantly spaced.

[0009] The gradual amplification region has a first starting side and a first terminating side, the insulating region has a second starting side and a second terminating side, the width of the first starting side matches the width of the seed laser region, the first terminating side matches the width of the second starting side, and the width of the second terminating side matches the width of the emission region.

[0010] Furthermore, the gradient enlargement region includes a second active region and a second top metal layer from bottom to top, and the second active region and the second top metal layer are in a trapezoidal shape.

[0011] Furthermore, the insulating region includes a third active region, an insulating layer and a third top metal layer in sequence from bottom to top, and the third active region, the insulating layer and the third top metal layer are in a trapezoidal shape.

[0012] Furthermore, the emission region includes, from bottom to top, a fourth active region and a fourth top metal layer, and a portion of the fourth top metal layer has a fork-shaped grating structure.

[0013] Further, the portion of the fourth top metal layer having the fork-shaped grating structure is formed as a fork-shaped grating region, and the portion without the fork-shaped grating structure is formed as a lead region.

[0014] The present invention also provides a method for preparing a terahertz scalar vortex quantum cascade laser, comprising:

[0015] Step S1, preparing an active region material having a bonding metal layer.

[0016] Step S2, forming an absorption edge pattern on the active region material having the bonding metal layer.

[0017] Step S3, forming a periodic grating pattern on the surface of the active region layer in the absorption edge pattern region, and etching the active region layer having the periodic grating pattern to obtain periodic grating slits.

[0018] Step S4, growing insulating material on the surface of the active region layer after performing step S3, forming an insulating layer pattern on a portion of the surface of the active region layer, and then removing the insulating material in areas other than the insulating layer pattern.

[0019] Step S5, making an electrode pattern on the surface of the active region layer after the step S4, and growing metal on the pattern obtained by photolithography, and forming a top metal layer after peeling.

[0020] Step S6, using the photoresist as a mask for the top metal layer, etching the area of ​​the active region layer not covered by the photoresist to expose the bonding metal layer.

[0021] Step S7, thinning the substrate after step S6, and growing metal behind the thinned substrate.

[0022] Furthermore, the step S1 comprises:

[0023] Step S11, preparing a first substrate having a first metal layer; including: providing a first substrate, epitaxially growing a corrosion barrier layer on the surface of the first substrate, epitaxially growing an upper contact layer on the corrosion barrier layer, epitaxially growing an active area layer on the upper contact layer, epitaxially growing a lower contact layer on the active area layer, and then forming a first metal layer on the lower contact layer.

[0024] Step S12, preparing a second substrate having a second metal layer; comprising: providing a second substrate, and forming a second metal layer on a surface of the second substrate.

[0025] Step S13: bonding the first metal layer and the second metal layer together to form a bonding metal layer.

[0026] Step S14, corroding the first substrate to expose the corrosion barrier layer, and then removing the corrosion barrier layer, and the second substrate serves as the substrate.

[0027] The present invention can directly emit terahertz scalar vortex laser with high mode purity through electric pumping, can realize a hollow annular far-field light spot, the phase is spiral, carries orbital angular momentum, can realize a specific topological charge, and has linear polarization characteristics. It has the advantages of high stability, high excitation efficiency, narrow linewidth, and high side mode suppression ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of a terahertz scalar vortex quantum cascade laser according to the present invention.

[0029] Figure 2 is along Figure 1 Section view taken along the midline AA.

[0030] Figure 3 yes Figure 1 Schematic diagram of the structure of the seed laser region.

[0031] Figure 4 yes Figure 1 Schematic diagram of the structure of the gradual enlargement area in the middle.

[0032] Figure 5 yes Figure 1 Schematic diagram of the structure of the middle insulation zone.

[0033] Figure 6 yes Figure 1 Schematic diagram of the structure of the middle emission area.

[0034] Figure 7 The present invention is a flowchart of a method for preparing a terahertz scalar vortex quantum cascade laser.

[0035] Figure 8 This is the LIV test result of the terahertz scalar vortex quantum cascade laser according to the present invention.

[0036] Fig. 9 It is a spectrum diagram of the terahertz scalar vortex quantum cascade laser under different pump currents according to the present invention.

[0037] Fig.10 It is a mode purity diagram of the topological charge of vortex light emitted by the terahertz scalar vortex quantum cascade laser according to the present invention.

[0038] Fig.11 It is a polarization diagram of vortex light emitted by the terahertz scalar vortex quantum cascade quantum level laser according to the present invention. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0040] like Figure 1 and Figure 2 As shown, the terahertz scalar vortex quantum cascade laser provided by the present invention adopts a bimetallic waveguide structure, including a substrate 1, a bonding metal layer 2 is provided above the substrate 1, a seed laser region 3, a gradual amplification region 4, an insulating region 5 and an emission region 6 are arranged in sequence along the length direction of the laser above the bonding metal layer 2, a first absorption region 7 is provided on the side of the seed laser region 3 opposite to the gradual amplification region 4, and a second absorption region 8 is provided on the peripheral side of the emission region 6 not connected to the insulating region 5.

[0041] The seed laser region 3 is rectangular in shape as a whole. Figure 3 As shown, it includes a first active area 31 and a first top metal layer 32 from bottom to top. The first active area 31 has a periodic grating structure 311, which is composed of a number of long strip gratings of the same size, and these long strip gratings are equidistantly spaced. The periodic grating structure 311 is formed by first etching a number of grating slits of the same size in the first active area 31, and then growing metal on the surface of the first active area 31. When growing metal, the metal enters the grating slits to form the grating structure 311, and the remaining metal that does not enter the grating slits grows on the surface of the first active area 31 as the first top metal layer 32. The number of long strip gratings in the periodic grating structure 311 is 60-100, the spacing between two adjacent long strip gratings is 8μm-22μm, the length of each long strip grating is 150μm-300μm, the width is 4μm-10μm, and the height (i.e., the corrosion depth of the first active area 13) is 200nm-2000nm. If the vortex light frequency excited by the laser of the present invention is designed to be 3.45THz, the number of long strip gratings is designed to be 60, the spacing between two adjacent long strip gratings is designed to be 12.1um, the length of each long strip grating is designed to be 250μm, the width is designed to be 8μm, and the height is designed to be 600nm. At the same time, adding a π phase shift of one quarter of the wavelength of the vortex light at the center of the grating can improve the Q value of the distributed feedback structure, so that the frequency of the lasing works at the forbidden center of the photon energy band and maintains the single-mode characteristic.

[0042] Reference again Figure 1 , the width of the gradual enlargement zone 4 gradually expands from the seed laser zone 3 to the insulating zone 5, and has a first starting side 41 and a first terminating side 42. The width of the first starting side 41 matches the width of the seed laser zone 3 (that is, the widths of the two are equal), and the first terminating side 42 matches the width of the second starting side 51 of the insulating zone 5. The gradual expansion distance of the gradual enlargement zone 4 is 1000μm-1600μm, that is, the distance between the first starting side 41 and the first terminating side 42 is 1000μm-1300μm. Taking the width of the seed laser zone 3 as 250μm as an example, the gradual enlargement zone 4 gradually expands from 250μm to 1000μm-1300μm to the insulating zone 5. The specific structure of the gradual enlargement zone 4 is as follows Figure 4 As shown, from bottom to top, it includes a second active area 43 and a second top metal layer 44. The second active area 43 and the second top metal layer 44 are in a trapezoidal shape, and their short sides together constitute the first starting side 41, and their long sides together constitute the first terminating side 42.

[0043] Similar to the gradual enlargement region 4, the width of the insulating region 5 gradually increases from the gradual enlargement region 4 to the emission region 6, and has a second starting side 51 and a second ending side 52 (see Figure 1). The width of the second starting side 51 matches the width of the first terminating side 42, and the width of the second terminating side 52 matches the width of the emitting region 6. The distance of the insulating region 5 gradually widens is 400 μm-700 μm, that is, the distance between the second starting side 51 and the second terminating side 52 is 400 μm-700 μm. The specific structure of the insulating region 5 is as follows Figure 5 As shown, from bottom to top, it includes a third active region 53, an insulating layer 54, and a third top metal layer 55. The third active region 53, the insulating layer 54, and the third top metal layer 55 are in a trapezoidal shape, and their short sides together constitute the second starting side 51, and their long sides together constitute the second terminating side 52. In this way, the waveguide is gradually expanded from the width of the seed laser region 3 to the width of the emission region 6 through the gradual amplification region 4 and the insulating region 5.

[0044] The first top metal layer 32, the second top metal layer 44 and the third top metal layer 55 are connected for wiring to provide electrical pumping for the seed laser region 3 and the gradient amplification region 4. Since the pumping current and pumping voltage required for electrical pumping exceed the output upper limit of the current power supply, the insulating layer 54 and the bottom surface of the second active region 43 are set at the same height, and the third top metal layer 55 is higher than the second top metal layer 44 by the thickness of the insulating layer 54, so that the insulating layer 54 of the insulating region 5 electrically insulates a part of the active region to reduce the electrical pumping area, reduce the working current of the device, and thus reduce the working voltage of the pump power supply. In this way, after the seed laser region 1 generates a seed laser of a fixed frequency, the adiabatic change of the mode is realized through the gradient amplification region 4 and the insulating region 5 to keep the fundamental mode of the waveguide unchanged during the transmission process, thereby ensuring the uniformity of the electromagnetic field when the laser reaches the emission region 6.

[0045] The emission area 6 is rectangular in shape as a whole. Figure 2 and Figure 6 As shown, it includes a fourth active area 61 and a fourth top metal layer 62 from bottom to top. Among them, a part of the fourth top metal layer 62 has a fork-shaped grating structure, and the grating depth of the fork-shaped grating structure penetrates the fourth top metal layer 62. The part with the fork-shaped grating structure is formed as a fork-shaped grating area 63, which is used to invert scalar vortex light. The other part of the fourth top metal layer 62 that does not have a fork-shaped grating structure is formed as a lead area 64 for lead. The fork-shaped grating structure is composed of a number of long strips of gratings, and these gratings are distributed to form a fork-shaped pattern. Specifically, the method of forming the fork-shaped grating structure is: using the principle of computer holography, the laser waveguide mode E generated by the seed laser area 3 is r (x r ,y r , z r )=u r (x r ,y r , z r)exp(ikz r ) and target vortex light Interference is performed, and a fork-shaped interference pattern is formed after interference; the fork-shaped interference pattern is made on the photolithography mask in the semiconductor processing technology, and a fork-shaped grating structure is formed by photolithography. According to the diffraction principle, when the grating in the fork-shaped grating structure is a long strip, the waveguide mode intensity near the center of the grating can be made relatively uniform, thereby improving the mode purity of the outgoing vortex light.

[0046] The first absorption region 7 includes the fifth active region, and the second absorption region 8 includes the sixth active region. The absorption region 7 is used to absorb the laser generated by the left end face of the seed laser region 3, and the absorption region 8 is used to absorb the laser passing through the fork grating structure to avoid the interference of reflection on the fork grating mode. It should be noted that the first active region 31, the second active region 43, the third active region 53, the fourth active region 61, the fifth active region and the sixth active region are the same active region, which are prepared in one step. The first top metal layer 32, the second top metal layer 44, the third top metal layer 55 and the fourth top metal layer 62 are also the same metal layer, which are prepared in one step. For the convenience of explanation, they are distinguished.

[0047] The method for preparing the above-mentioned terahertz scalar vortex quantum cascade laser is described below.

[0048] like Figure 7 As shown, the method for preparing the terahertz scalar vortex quantum cascade laser provided by the present invention comprises the following steps:

[0049] Step S1, preparing a substrate 1 having a bonding metal layer 2 and an active region layer. The process comprises:

[0050] Step S11, preparing a first substrate having a first metal layer: providing a first substrate, epitaxially growing a corrosion barrier layer on the surface of the first substrate, epitaxially growing an upper contact layer on the corrosion barrier layer, epitaxially growing an active region layer on the upper contact layer, epitaxially growing a lower contact layer on the active region layer, and then forming a first metal layer on the lower contact layer. The active region layer comprises 90 periodically repeated modules, each module comprising 9 overlapping layers of GaAs potential wells and 9 layers of Al 0.15 Ga 0.85 The thickness of the As barrier starting from GaAs is: 11.4, 2.0, 12.0, 2.0, 12.2, 1.8, 12.8, 1.5, 15.8, 0.6, 9.0, 0.6, 14.0, 3.8, 11.6, 3.5, 11.3, 2.7 (nm). The first two layers of GaAs are doped layers with an n-type doping concentration of 10 16 cm -3 .

[0051] Step S12, preparing a second substrate having a second metal layer: providing a second substrate, and forming a second metal layer on a surface of the second substrate.

[0052] Step S13, bonding the first metal layer and the second metal layer together to form a bonding metal layer. The bonding metal layer obtained at this time corresponds to the bonding metal layer 2 mentioned above.

[0053] Step S14, the first substrate is corroded to expose the corrosion barrier layer, and then the corrosion barrier layer is removed with an acid solution (such as HF acid or concentrated hydrochloric acid). At this time, the second substrate with the second metal layer is retained to form the above-mentioned substrate 1, and the substrate 1 with the bonding metal layer 2 and the active area layer is prepared.

[0054] Step S2, an absorption edge pattern is produced on the substrate 1 having the bonding metal layer 2 and the active region layer. The absorption edge pattern is the region formed by the periphery of the seed laser region 3, the gradual amplification region 4, the electrical insulation region 5, the emission region 6, the first absorption region 7 and the second absorption region 8. Thus, the boundaries of the seed laser region 3, the gradual amplification region 4, the electrical insulation region 5, the emission region 6, the first absorption region 7 and the second absorption region 8 are formed.

[0055] Step S3, using photolithography technology to produce a periodic grating pattern on the surface of the active area layer in the absorption edge pattern area, and using a sulfuric acid system etching solution to etch the active area layer with the periodic grating pattern to obtain periodic grating slits. At this time, the active area with the periodic grating slits corresponds to the first active area 31. The etching depth is calibrated by a step profiler. After the etching is completed, the photoresist on the surface of the active area layer needs to be removed.

[0056] Step S4, based on step S3, continues to grow insulating material on the surface of the active area layer, uses photolithography technology to make an insulating layer pattern on part of the surface of the active area layer, and then uses hydrofluoric acid etching solution to remove the insulating material in the area outside the insulating layer pattern. At this time, the insulating material retained on the surface of the active area layer corresponds to the insulating layer 54 of the above-mentioned electrical insulation area 5. In this embodiment, the insulating material is silicon dioxide with a thickness of about 200nm. After the etching is completed, the photoresist on the surface of the active area layer needs to be removed.

[0057] Step S5, using photolithography technology to make an electrode pattern on the surface of the active area layer having periodic grating slits and an insulating layer, and using electron beam evaporation, magnetron sputtering or thermal evaporation to grow metal on the photolithographic electrode pattern, and form a top metal layer after peeling. The top metal layer at this time corresponds to the first top metal layer 32, the second top metal layer 44, the third top metal layer 55 and the fourth top metal layer 62. Among them, the fourth top metal layer 62 has a fork grating structure.

[0058] Step S6, using the photoresist as a mask for the top metal layer, etching the area of ​​the active layer not covered by the photoresist to expose the bonding metal layer. It should be noted that the photoresist used as a mask is 5um wider than the top metal layer and the absorption edge area in step S2 to protect the top metal layer and the absorption edge. After etching is completed, the photoresist on the surface of the active layer needs to be removed.

[0059] Step S7, thinning the substrate after step S6 to about 200 μm by mechanical polishing, and then growing metal behind the thinned substrate to improve heat dissipation.

[0060] By utilizing the present invention, a terahertz scalar vortex laser with high mode purity can be obtained. The performance of the laser of the present invention is described in detail below through experimental results.

[0061] Figure 8 The LIV test results of a laser with a topological charge of 1 under different pumping conditions are shown. The results were measured in a pulse mode with a repetition frequency of 10kHz and a pulse width of 1μs. Different pump voltages were provided to the fork grating in the test to study the laser characteristics under different gains. As can be seen from the figure, the maximum output power of the above device is 17.1mW when the grating voltage is equal to 13V.

[0062] Fig. 9 The test results of the spectral characteristics of the laser with a topological charge equal to 1 of the present invention are shown. The left figure shows that the pump voltage of the fork grating is kept constant at 10.5V, and the right figure shows that the pump voltage of the fork grating is kept constant at 9V, and the pump current of the distributed feedback laser and the amplification area is gradually changed. The pulse mode has a repetition frequency of 10kHz and a pulse width of 1μs. The test temperature is 77K. It can be seen from the figure that the laser starts from the threshold current and maintains a single-mode characteristic as the current increases until a multi-mode characteristic appears at the peak current. The single-mode characteristic of the laser does not change with the change of the grating voltage. The central frequency of the laser lasing is f=3.4275THz.

[0063] Fig.10 The diagram shows the mode purity of the topological charge of the vortex light emitted by the laser. The results were obtained in a pulse mode at 77K, a repetition frequency of 10kHz, and a pulse width of 1μs. Among them, the pumping conditions of the laser with a topological charge of 1 are: the pumping current of the distributed feedback laser and the amplification area is 5.15A, and the pumping voltage of the fork grating is 10.5V. The pumping conditions of the laser with a topological charge of 2 are: the distributed feedback laser, the amplification area, and the emission area are pumped together, and the pumping current is 6.19A. It can be seen that the mode purity of the lasers with topological charges of 1 and 2 are as high as 84.58% and 89.25% respectively.

[0064] Fig.11The polarization test diagram of the vortex light emitted by the laser is shown. It can be seen that in the vertical direction, the intensity appears to be maximum and minimum, which indicates that the emitted vortex light is linearly polarized light.

[0065] It can be seen that the present invention can realize a hollow annular far-field light spot, the phase is a spiral carrying orbital angular momentum, a specific topological charge can be realized, the polarization characteristics are linear, and it has the characteristics of high excitation efficiency, narrow linewidth, and high side mode suppression ratio.

[0066] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A terahertz scalar vortex quantum cascade laser, comprising a substrate and a bonding metal layer located above the substrate, characterized in that: A seed laser region, a gradual amplification region, an insulating region and an emission region are arranged in sequence along the length direction of the laser above the bonding metal layer, a first absorption region is provided on the side of the seed laser region opposite to the gradual amplification region, and a second absorption region is provided on the peripheral side of the emission region; wherein the width of the gradual amplification region gradually increases from the seed laser region to the insulating region, and the width of the insulating region gradually increases from the gradual amplification region to the emission region.

2. The terahertz scalar vortex quantum cascade laser according to claim 1, characterized in that: The seed laser region comprises a first active region and a first top metal layer from bottom to top, and the first active region has a periodic grating structure.

3. The terahertz scalar vortex quantum cascade laser according to claim 2, characterized in that: The periodic grating structure is composed of a plurality of long strip gratings of the same size, and the long strip gratings are equidistantly spaced.

4. The terahertz scalar vortex quantum cascade laser according to claim 1, characterized in that: The gradual amplification region has a first starting side and a first terminating side, the insulating region has a second starting side and a second terminating side, the width of the first starting side matches the width of the seed laser region, the first terminating side matches the width of the second starting side, and the width of the second terminating side matches the width of the emission region.

5. The terahertz scalar vortex quantum cascade laser according to claim 1, characterized in that: The gradient enlarged region includes a second active region and a second top metal layer from bottom to top, and the second active region and the second top metal layer are in a trapezoidal shape.

6. The terahertz scalar vortex quantum cascade laser according to claim 1, characterized in that: The insulating region includes a third active region, an insulating layer and a third top metal layer in sequence from bottom to top, and the third active region, the insulating layer and the third top metal layer are in a trapezoidal shape.

7. The terahertz scalar vortex quantum cascade laser according to claim 1, characterized in that: The emission region includes a fourth active region and a fourth top metal layer from bottom to top, and a portion of the fourth top metal layer has a fork-shaped grating structure.

8. The terahertz scalar vortex quantum cascade laser according to claim 7, characterized in that: The portion of the fourth top metal layer having the fork-shaped grating structure is formed as a fork-shaped grating region, and the portion without the fork-shaped grating structure is formed as a lead region.

9. A method for preparing a terahertz scalar vortex quantum cascade laser, characterized in that: include: Step S1, preparing a substrate having a bonding metal layer and an active area layer; Step S2, forming an absorption edge pattern on a substrate having a bonding metal layer and an active region layer; Step S3, making a periodic grating pattern on the surface of the active region layer in the absorption edge pattern area, and etching the active region layer with the periodic grating pattern to obtain a periodic grating slit; Step S4, growing insulating material on the surface of the active region layer after performing step S3, and after forming an insulating layer pattern on a portion of the surface of the active region layer, removing the insulating material in the area outside the insulating layer pattern; Step S5, making an electrode pattern on the surface of the active area layer after the step S4, and growing metal on the photolithographic electrode pattern, and forming a top metal layer after peeling; Step S6, using the photoresist as a mask for the top metal layer, etching the area of ​​the active area layer not covered by the photoresist to expose the bonding metal layer; Step S7, thinning the substrate after step S6, and growing metal behind the thinned substrate.

10. The method for preparing a terahertz scalar vortex quantum cascade laser according to claim 1, characterized in that: The step S1 comprises: Step S11, preparing a first substrate having a first metal layer; comprising: providing a first substrate, epitaxially growing a corrosion barrier layer on a surface of the first substrate, epitaxially growing an upper contact layer on the corrosion barrier layer, epitaxially growing an active region layer on the upper contact layer, epitaxially growing a lower contact layer on the active region layer, and then forming a first metal layer on the lower contact layer; Step S12, preparing a second substrate having a second metal layer; comprising: providing a second substrate, and forming a second metal layer on a surface of the second substrate; Step S13, bonding the first metal layer and the second metal layer together to form a bonding metal layer; Step S14, corroding the first substrate to expose the corrosion barrier layer, and then removing the corrosion barrier layer, and the second substrate serves as the substrate.

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