Terahertz intensity probe and packaging method and receiving light path design thereof

Abstract

The invention discloses a terahertz intensity probe and a packaging method and receiving light path design thereof, and belongs to the field of terahertz radiation intensity detection.The terahertz intensity probe comprises a lens layer, an adhesive layer, a device silicon substrate layer and a receiving light layer, and the first surface of the adhesive layer is connected with the light emitting face of the lens layer in an adhesive mode; the second surface of the adhesive layer is connected with the incident surface of the device silicon substrate layer in an adhesive manner; and the light emitting surface of the device silicon substrate layer is connected with the light receiving layer. According to the terahertz intensity probe, the packaging method thereof and the design of the receiving light path, the technical problem that the measurement precision and accuracy are affected due to serious total reflection loss of terahertz light waves on an interface in the prior art can be solved, the receiving rate of the terahertz waves capable of being received is effectively improved, and the measurement accuracy is improved. And the signal-to-noise ratio and the measurement precision of the terahertz intensity probe are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of terahertz radiation intensity detection, and more particularly to a terahertz intensity probe, its packaging method, and the design of its receiving optical path. Background Technology

[0002] Terahertz (THz) light radiation typically refers to electromagnetic waves with frequencies between 0.1 and 10 THz (corresponding to a terahertz wavelength range of 3000 μm to 30 μm). Currently, direct measurement of terahertz light radiation intensity across a wide frequency range faces technical challenges. Most terahertz detectors only have efficient responses within specific frequency bands, requiring detector replacement for different frequency ranges. A single terahertz probe is insufficient for direct measurement of terahertz light radiation intensity across a wide frequency range (0.1–10 THz). Furthermore, direct measurement of terahertz radiation intensity is generally hampered by the relatively weak radiant energy of the terahertz light waves themselves, significant absorption of terahertz light waves by moisture in the air, and extremely low detector sensitivity, resulting in low signal-to-noise ratios when measuring weak terahertz signals. Therefore, reducing various attenuations of weak terahertz signals and improving detector response sensitivity are particularly important.

[0003] Meanwhile, current terahertz radiation intensity measurement probes generally employ reflective or transmissive receiving optical paths to focus the terahertz beam onto the detector's receiving surface (photosensitive surface). Reflective receiving optical paths often use multiple off-axis parabolic mirrors (OPAs), but these generally suffer from drawbacks such as high cost, complex optical path, large size, and difficult assembly and adjustment. Transmissive receiving optical paths, on the other hand, often use a single high-resistivity silicon lens. While transmissive receiving optical paths offer advantages such as low cost, simple optical path, small size, and easy assembly and adjustment, making them more suitable for terahertz radiation intensity probes, the refractive index n of the high-resistivity silicon lens in the terahertz band... 硅 The refractive index is 3.418–3.45. This excessively high refractive index causes the critical angle θ for total internal reflection when terahertz light waves transmit from an optically denser medium (high-resistivity silicon) into an optically less dense medium (such as air). c The range is 16.8°–17.01°, which causes the incident terahertz light wave to easily undergo total internal reflection at the light-emitting surface of the high-resistivity silicon lens, preventing transmission through the dense / sparse medium interface. This severe interface reflection loss significantly reduces the signal-to-noise ratio and affects measurement accuracy. Therefore, a new receiving optical path and packaging method for a terahertz light radiation intensity probe is needed. This method should not only meet the requirements for direct measurement of terahertz light radiation intensity over a wide spectral range but also solve the problem of low-cost loss due to the refractive index n of the high-resistivity silicon lens material. 硅 The technical challenge is that excessively high values ​​cause severe loss due to total internal reflection at the interface, and it is also necessary to adapt to the packaging processes of most existing terahertz intensity probes to facilitate their widespread application. Summary of the Invention

[0004] This invention discloses a terahertz intensity probe and its packaging method and receiving optical path design, which can solve the technical problem in the prior art where the severe loss of terahertz light waves due to total internal reflection at the interface affects the measurement accuracy and precision. It effectively improves the reception rate of terahertz waves, thereby effectively improving the signal-to-noise ratio and measurement accuracy of the terahertz intensity probe.

[0005] This invention provides a terahertz intensity probe, comprising a lens layer, an adhesive layer, a device silicon substrate layer, and a light-receiving layer, wherein:

[0006] The first surface of the adhesive layer is bonded to the light-emitting surface of the lens layer;

[0007] The second surface of the adhesive layer is bonded to the incident surface of the silicon substrate layer of the device.

[0008] The light-emitting surface of the silicon substrate of the device is connected to the light-receiving layer.

[0009] This invention provides a terahertz intensity probe that uses an adhesive layer to tightly bond the light-emitting surface of the lens layer to the incident surface of the silicon substrate layer of the device, forming a back-facing encapsulation design. Utilizing the principle that the refractive index of the adhesive layer is greater than that of air, the critical angle for total internal reflection at this incident interface is increased, thereby reducing the interface total internal reflection loss that occurs when the incident terahertz light wave passes through the light-emitting surface of the lens layer. Simultaneously, it can also increase the allowable incident field of view, effectively improving the signal-to-noise ratio and measurement accuracy of the terahertz intensity probe during the measurement process. The adhesive layer is disposed on the first surface of the silicon substrate layer of the device, while the light-receiving layer is disposed on the second surface of the silicon substrate layer of the device. This avoids optical contamination of the light-receiving layer of the terahertz intensity probe by the adhesive, as well as negative effects such as aging, yellowing, and corrosion, while ensuring the stability of the probe's optical performance and extending its service life.

[0010] Furthermore, the lens layer uses a high-resistivity silicon lens.

[0011] In the above scheme, the design requirements of portable, small size and low cost of terahertz intensity probe are achieved by using a high-resistivity silicon lens.

[0012] Furthermore, the incident surface of the lens layer is a convex arc shape, while the light-emitting surface of the lens layer is a plane.

[0013] In the above scheme, by making the incident surface of the lens layer a convex arc shape and the light-emitting surface of the lens layer a plane, the focusing effect of the terahertz beam is achieved, the field of view is increased, and the terahertz beam is directly focused onto the adhesive layer by using a high-resistivity silicon lens to form a transmission receiving optical path.

[0014] Furthermore, the light-emitting surface of the lens layer includes a focusing region, and the lens layer is bonded to the first surface of the adhesive layer through the focusing region.

[0015] In the above scheme, the lens layer is bonded to the first surface of the adhesive layer through the focusing area, which facilitates integrated design, reduces the contact area between the light-emitting surface of the lens layer and the adhesive layer, reduces the number of additional optical interfaces introduced by the adhesive layer, thereby improving structural stability and avoiding optical performance degradation.

[0016] Furthermore, the adhesive layer uses a high-refractive-index adhesive, which has a refractive index greater than that of air.

[0017] Furthermore, the high-refractive-index adhesive employs a filled polymer adhesive.

[0018] In the above scheme, a high refractive index adhesive is selected as the adhesive layer, and a filled polymer adhesive is selected, which has a high refractive index, high transmittance and low absorption rate for terahertz waves, so as to effectively improve the incident angle and the reception rate of terahertz waves.

[0019] This invention provides a terahertz intensity probe that uses an adhesive to bond the light-emitting surface of a high-resistivity silicon lens to the silicon substrate of a detector. Utilizing the adhesive's higher refractive index than air, the critical angle for total internal reflection is increased, thereby reducing interface total internal reflection loss when incident terahertz light waves pass through the light-emitting surface of the high-resistivity silicon lens and increasing the allowable incident field of view, effectively improving the signal-to-noise ratio and measurement accuracy. Simultaneously, the tight bonding of the lens's light-emitting surface to the detector's silicon substrate achieves an adhesive back-mount method, avoiding negative impacts such as optical contamination, aging, yellowing, and corrosion of the detector's receiving layer by the adhesive, thus ensuring stable optical performance and extending the probe's lifespan. This effectively solves the technical problems of severely limited incident light angle, low transmittance leading to severe optical loss, low signal-to-noise ratio, and low measurement accuracy when measuring the intensity of broadband terahertz electromagnetic waves. It also features a compact structure, small size, integrability, and low cost.

[0020] This invention provides a packaging method for a terahertz intensity probe, used to realize the aforementioned terahertz intensity probe, comprising:

[0021] Determine the silicon substrate layer of the device, and set a light-receiving layer on the light-emitting surface of the silicon substrate layer of the device;

[0022] An adhesive is applied to the incident surface of the device's silicon substrate to form an adhesive layer;

[0023] The lens layer is determined, and the light-emitting surface of the lens layer is bonded to the first surface of the adhesive layer to complete the encapsulation.

[0024] This invention provides a packaging method for a terahertz intensity probe, which implements a back-facing packaging method using adhesive. The light-emitting surface of a high-resistivity silicon lens is bonded to the silicon substrate layer of the detector using adhesive. Utilizing the fact that the refractive index of the adhesive is greater than that of air, the critical angle for total internal reflection is increased, thereby reducing the interface total internal reflection loss that occurs when the incident terahertz light wave passes through the light-emitting surface of the high-resistivity silicon lens, and increasing the allowable incident field of view, effectively improving the signal-to-noise ratio and measurement accuracy. Simultaneously, the tight bonding between the lens's light-emitting surface and the detector's silicon substrate avoids negative impacts such as optical contamination, aging, yellowing, and corrosion of the detector's receiving layer by the adhesive, thus ensuring stable optical performance of the probe and extending its service life. This effectively solves the technical problems of severely limited incident light angle, low transmittance leading to severe optical loss, low signal-to-noise ratio, and low measurement accuracy when measuring the intensity of broadband terahertz electromagnetic waves.

[0025] Furthermore, the adhesive is a high-refractive-index adhesive, the refractive index of which is greater than that of air. Specifically, a high-refractive-index adhesive is obtained by filling the epoxy resin with a high-refractive-index filler.

[0026] In the above scheme, a high refractive index filler is used to fill epoxy resin to obtain a high refractive index adhesive, which achieves refractive index matching between the lens layer and the adhesive layer, reduces reflection loss and optical path offset, improves optical efficiency and focusing accuracy, and has high refractive index, high transmittance and low absorption for terahertz waves, so as to effectively improve the incident angle and the reception rate of terahertz waves.

[0027] Furthermore, determining the lens layer includes: designing the incident surface of the lens layer as a convex arc shape and designing the light-emitting surface of the lens layer as a plane, in order to determine the lens layer.

[0028] In the above scheme, by making the incident surface of the lens layer a convex arc shape and the light-emitting surface of the lens layer a plane, the focusing effect of the terahertz beam is achieved, the field of view is increased, and the terahertz beam is directly focused onto the adhesive layer by using a high-resistivity silicon lens to form a transmission receiving optical path.

[0029] This invention provides a packaging method for a terahertz intensity probe, which realizes a back-facing packaging method based on an adhesive layer. The light-emitting surface of a high-resistivity silicon lens is bonded to the silicon substrate of the detector. The refractive index of the adhesive is greater than that of air to increase the critical angle of total internal reflection, thereby reducing the interface total internal reflection loss when the incident terahertz light wave passes through the light-emitting surface of the high-resistivity silicon lens and increasing the allowable incident field of view, thus effectively improving the signal-to-noise ratio and measurement accuracy. At the same time, it avoids the negative effects of adhesive on the optical contamination, aging, yellowing, corrosion and other adverse effects on the receiving light layer of the detector, thereby ensuring the stability of the probe's optical performance and extending its working life.

[0030] This invention also provides a receiving optical path design for a terahertz intensity probe, implemented using the aforementioned terahertz intensity probe, for transmitting the terahertz electromagnetic wave to be measured to the receiving optical layer of the terahertz intensity probe, comprising:

[0031] A focused optical path is formed on the incident surface of the lens layer of the terahertz intensity probe to transmit terahertz electromagnetic waves to the first surface of the adhesive layer of the terahertz intensity probe.

[0032] A refracted optical path is formed on the first surface of the adhesive layer of the terahertz intensity probe to transmit terahertz electromagnetic waves to the incident surface of the silicon substrate layer of the terahertz intensity probe.

[0033] A transmission optical path is formed on the incident surface of the silicon substrate layer of the device to transmit terahertz electromagnetic waves to the receiving optical layer of the terahertz intensity probe.

[0034] The present invention provides a receiving optical path design for a terahertz intensity probe, which effectively reduces the loss of total internal reflection light, increases the incident angle of the terahertz wave that can be received, and improves the terahertz wave reception rate. It effectively solves the technical problems existing in measuring the intensity of broadband terahertz electromagnetic waves, such as severely limited incident light angle, low transmittance leading to severe light loss, low signal-to-noise ratio, and low measurement accuracy. Attached Figure Description

[0035] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a terahertz intensity probe provided in this embodiment;

[0037] Figure 2 This is a schematic diagram of a method for fabricating a terahertz intensity probe provided in this embodiment.

[0038] Figure 3 This is a schematic diagram of the transmission optical path of incident light from an optically denser to an optically less dense medium, provided in this embodiment;

[0039] Figure 4 This embodiment provides a schematic diagram of a single-field-of-view receiving optical path for a hollow terahertz probe with a forward-encapsulated air layer.

[0040] Figure 5 This embodiment provides a schematic diagram of a multi-field-of-view receiving optical path for a hollow terahertz probe with a forward-encapsulated air layer.

[0041] Figure 6This is a schematic diagram of a single field-of-view receiving optical path for a terahertz probe with a back-facing adhesive layer provided in this embodiment;

[0042] Figure 7 This is a schematic diagram of a multi-field-of-view receiving optical path for a terahertz probe with a back-facing adhesive layer provided in this embodiment;

[0043] Figure 8 This is a schematic diagram of a simulation analysis result provided in this embodiment;

[0044] In the diagram: 1. Lens layer; 2. Adhesive layer; 3. Device silicon substrate layer; 4. Light receiving layer; 31. Hollow lens layer; 32. Air layer; 33. Hollow light receiving layer; 34. Hollow device silicon substrate layer; 35. Hollow incident ray; 36. Middle part of hollow incident ray; 37. Side parts of hollow incident ray; 41. First multi-angle incident ray; 42. Total internal reflection part of the first multi-angle incident ray; 43. Refraction part of the first multi-angle incident ray; 51. Second single field-of-view incident ray; 52. Second single field-of-view transmitted ray; 61. Second multi-angle incident ray; 62. Second multi-angle transmitted ray; 71. Middle adhesive backing (n) 胶2 =1.9) received energy curve; 72, medium adhesive backing (n 胶1 =1.4) received energy curve; 73, hollow upright (n 空 =1.0) received energy curve; A, hollow lens section; B, hollow device section. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0046] Furthermore, features specified with "first" or "second" for descriptive purposes only should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features specified with "first" or "second" may explicitly or implicitly include at least one of the specified features. The description of "multiple" generally means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0048] Example 1:

[0049] This embodiment provides a terahertz intensity probe, such as Figure 1 As shown, it includes a lens layer 1, an adhesive layer 2, a device silicon substrate layer 3, and a light-receiving layer 4, wherein:

[0050] The first surface of the adhesive layer 2 is bonded to the light-emitting surface of the lens layer 1;

[0051] The second surface of the adhesive layer 2 is bonded to the incident surface of the device silicon substrate layer 3;

[0052] The light-emitting surface of the silicon substrate layer 3 of the device is connected to the light-receiving layer 4.

[0053] This embodiment provides a terahertz intensity probe that uses an adhesive layer 2 to tightly bond the light-emitting surface of the lens layer 1 to the incident surface of the silicon substrate layer 3 of the device, forming a back-facing encapsulation design. Utilizing the principle that the refractive index of the adhesive layer 2 is greater than that of air, the critical angle for total internal reflection at this incident interface is increased, thereby reducing the interface total internal reflection loss that occurs when the incident terahertz light wave passes through the light-emitting surface of the lens layer 1. Simultaneously, it can also increase the allowable incident field of view, effectively improving the signal-to-noise ratio and measurement accuracy of the terahertz intensity probe during the measurement process. The adhesive layer 2 is disposed on the first surface of the silicon substrate layer 3 of the device, while the light-receiving layer 4 is disposed on the second surface of the silicon substrate layer 3 of the device. This avoids optical contamination of the light-receiving layer 4 of the terahertz intensity probe by the adhesive, as well as negative effects such as aging, yellowing, and corrosion, and ensures the stability of the probe's optical performance, extending its working life.

[0054] Optionally, lens layer 1 may be a high-resistivity silicon lens.

[0055] In the specific implementation process, the design requirements of portability, small size and low cost of terahertz intensity probe were achieved by using a high-resistivity silicon lens.

[0056] Optionally, the incident surface of lens layer 1 is a convex arc shape, and the light emitting surface of lens layer 1 is a plane.

[0057] In the specific implementation process, by making the incident surface of the lens layer 1 a convex arc shape and the light-emitting surface of the lens layer 1 a plane, the focusing effect of the terahertz beam is achieved, the field of view is increased, and the terahertz beam is directly focused onto the adhesive layer 2 by using a high-resistivity silicon lens to form a transmission receiving optical path.

[0058] Optionally, the light-emitting surface of the lens layer 1 includes a focusing area, and the lens layer 1 is bonded to the first surface of the adhesive layer 2 through the focusing area.

[0059] In the specific implementation process, the lens layer 1 is bonded to the first surface of the adhesive layer 2 through the focusing area, which facilitates the integrated design, reduces the contact area between the light-emitting surface of the lens layer 1 and the adhesive layer 2, reduces the number of additional optical interfaces introduced by the adhesive layer 2, thereby improving structural stability and avoiding optical performance degradation.

[0060] Optionally, the adhesive layer 2 may be made of a high refractive index adhesive, the refractive index of which is greater than that of air.

[0061] Optionally, high-refractive-index adhesives may be filled polymer adhesives.

[0062] In the specific implementation process, a high refractive index adhesive is selected as the adhesive layer 2, and a filled polymer adhesive is selected, which has a high refractive index, high transmittance and low absorption rate for terahertz waves, so as to effectively improve the incident angle and the reception rate of terahertz waves.

[0063] This embodiment provides a terahertz intensity probe that uses an adhesive to bond the light-emitting surface of a high-resistivity silicon lens to the silicon substrate layer 3 of the detector. Utilizing the fact that the refractive index of the adhesive is greater than that of air, the critical angle for total internal reflection is increased, thereby reducing the interface total internal reflection loss that occurs when the incident terahertz light wave passes through the light-emitting surface of the high-resistivity silicon lens, and increasing the allowable incident field of view, effectively improving the signal-to-noise ratio and measurement accuracy. Simultaneously, the light-emitting surface of the lens is tightly bonded to the silicon substrate surface of the detector, achieving a back-mounted adhesive bonding method. This back-mounting process is not only suitable for wide-spectrum terahertz radiation intensity acquisition, but also easily adaptable to the packaging and mass automated production of most existing terahertz intensity meter probes. It also solves the application technical problem at low cost that the high refractive index of the silicon lens (3.45) in the terahertz band easily leads to severe total internal reflection light loss, thus greatly reducing the signal-to-noise ratio and measurement accuracy. This packaging method also avoids the negative impacts of adhesive on the detector's receiving layer, such as optical contamination, aging yellowing, and corrosion, thereby ensuring stable optical performance and extending the working life of the probe. Furthermore, the selection of the adhesive... The preferred method uses an adhesive with high refractive index, high transmittance, and low absorptivity in the 0.1–10 THz band, which greatly increases the critical angle for total internal reflection of terahertz waves at the transmission surface of the high-resistivity silicon lens, thereby improving the incident angle and the reception rate of terahertz waves. This effectively solves the technical problems existing in measuring the intensity of broadband terahertz electromagnetic waves, such as severely limited incident light angle, low transmittance leading to severe optical loss, low signal-to-noise ratio, and low measurement accuracy. The fabricated terahertz intensity probe has the advantages of compact structure, small size, integrability, and low cost.

[0064] Example 2:

[0065] This embodiment provides a packaging method for a terahertz intensity probe, such as... Figure 2 As shown, a terahertz intensity probe for achieving the above-mentioned function includes:

[0066] S1. Determine the silicon substrate 3 of the device, and set the light receiving layer 4 on the light emitting surface of the silicon substrate 3 of the device.

[0067] S2. Apply adhesive to the incident surface of the device silicon substrate 3 to form adhesive layer 2;

[0068] S3. Determine the lens layer 1, and adhere the light-emitting surface of the lens layer 1 to the first surface of the adhesive layer 2 to complete the encapsulation.

[0069] This embodiment provides a packaging method for a terahertz intensity probe, which implements a back-facing packaging method using adhesive. The light-emitting surface of a high-resistivity silicon lens is bonded to the silicon substrate layer 3 of the detector using adhesive. By utilizing the fact that the refractive index of the adhesive is greater than that of air, the critical angle for total internal reflection is increased, thereby reducing the interface total internal reflection loss that occurs when the incident terahertz light wave passes through the light-emitting surface of the high-resistivity silicon lens, and increasing the allowable incident field of view, effectively improving the signal-to-noise ratio and measurement accuracy. At the same time, the lens light-emitting surface is tightly bonded to the silicon substrate surface of the detector, avoiding the negative impacts of adhesive on the optical contamination, aging, yellowing, corrosion, etc. of the detector's receiving light layer 4, thus ensuring the stability of the probe's optical performance and extending its working life. This effectively solves the technical problems of severely limited incident light angle, low transmittance leading to severe light loss, low signal-to-noise ratio, and low measurement accuracy when measuring the intensity of broadband terahertz electromagnetic waves.

[0070] In existing technologies, portable intensity meter probes that directly measure the intensity of terahertz light radiation across a wide frequency band of 0.1–10 THz typically employ a transmission-type receiving optical path composed of a single high-resistivity silicon lens to focus the terahertz beam onto the detector's photosensitive surface. This transmission-type receiving optical path usually uses a forward-mounted method with an air gap (hereinafter referred to as "air-gap forward mounting"), where the emitting surface of the single high-resistivity silicon lens is assembled face-up to the detector's photosensitive surface, with an air gap between them. For example... Figure 3 The critical angle for total internal reflection shown is θ c The schematic diagram shows that the refractive index of the first medium is n1, the refractive index of the second medium is n2, and n1 > n2. When the incident angle of the first incident ray 21 is the critical angle θ... c When the incident ray 22 is incident along the interface direction, the refraction angle is 90°; when the incident angle of the second incident ray 23 is greater than the critical angle θ c When the light ray undergoes total internal reflection at the interface, it produces a total internal reflection ray 24; when the incident angle θ1 of the third incident ray 25 is less than the critical angle θ c At that time, its light rays are refracted at the interface, and the angle of refraction of the refracted ray 24 is θ2. Because

[0071] If n1 > n2, then θ1 < θ2. Therefore, the larger n2 is, the closer it is to n1, the closer θ1 < θ2 becomes. This means the critical angle for total internal reflection is larger, and total internal reflection is less likely to occur. This is because the refractive index n of a high-resistivity silicon lens in the terahertz band... 硅 With a refractive index of 3.418–3.45, the excessively high refractive index causes the critical angle θ for total internal reflection when terahertz light waves are transmitted from an optically denser medium (high-resistivity silicon lens) into an optically less dense medium (such as air). cThe range is 16.8° to 17.01°, which makes it easy for the incident terahertz light wave to undergo total internal reflection at the light-emitting surface of the high-resistivity silicon lens and thus cannot be transmitted through the dense / sparse medium interface, resulting in severe terahertz light wave interface reflection loss.

[0072] In practical applications, due to the high-resistivity silicon lens's refractive index n in the terahertz light band... 硅 The refractive index n is as high as 3.45, which is too high. 硅 This causes terahertz light waves to refract from an optically denser medium (such as high-resistivity silicon) into an optically less dense medium (such as an air layer, n 空气 The critical angle for total internal reflection θ = 1) c With an angle of only 16.8°, the incident terahertz light wave is prone to total internal reflection at the light-emitting surface of the high-resistivity silicon lens and cannot transmit through the dielectric interface, resulting in severe interface total internal reflection loss of the terahertz light wave. This significantly reduces the signal-to-noise ratio, measurement accuracy, and precision of the terahertz light radiation intensity measuring instrument. A hollow terahertz probe with a forward-encapsulated design in a medium air layer, such as... Figure 4 As shown, the hollow terahertz probe, in accordance with the direction of the receiving optical path, includes a hollow lens section A and a hollow device section B. Hollow lens section A includes a hollow lens layer 31, and hollow device section B includes an air layer 32, a hollow receiving light layer 33, and a hollow device silicon substrate layer 34. The receiving optical path of the terahertz probe is divided as follows: Figure 4 (a) shows the optical receiving path of the hollow lens layer 31 and as shown in the figure. Figure 4 (b) shows the optical path of the hollow device section B. In this path, the hollow lens layer 31 directly converges the terahertz wave incident light, i.e., the hollow incident light 35, at the light-emitting surface of the hollow lens layer 31 to the hollow receiving light layer 33 of the hollow device section B. The middle portion 36 of the hollow incident light 35 is refracted at the light-emitting surface of the hollow lens layer 31 and passes through to the hollow receiving light layer 33. The two side portions 37 of the hollow incident light 35 undergo total internal reflection due to the large incident angle. The transmission situation of multi-field-of-view incident light in the forward encapsulation of the hollow air layer is as follows... Figure 5 As shown, Figure 5 (a) represents the multi-field-of-view receiving optical path of the hollow lens layer. Figure 5 (b) represents the multi-field-of-view receiving optical path of the device portion, wherein in the first multi-angle incident light 41, blue indicates an incident light field-of-view angle of 0°, yellow indicates an incident light field-of-view angle of 10°, and pink indicates an incident light field-of-view angle of 20°. Figure 5 (b) The first multi-angle incident light 41 in the first multi-angle incident light total reflection portion 42 in the dashed box undergoes total reflection, and the first multi-angle incident light 41 in the first multi-angle incident light refraction portion 43 in the solid box undergoes refraction and is transmitted into the hollow light receiving layer 33.

[0073] Optionally, a high-refractive-index adhesive is used, wherein the refractive index of the high-refractive-index adhesive is greater than that of air, wherein a high-refractive-index filler is used to fill the epoxy resin to obtain the high-refractive-index adhesive.

[0074] In the specific implementation process, a high-refractive-index filler is used to fill epoxy resin to obtain a high-refractive-index adhesive, achieving refractive index matching between lens layer 1 and adhesive layer 2. This reduces reflection loss and optical path offset, improves optical efficiency and focusing accuracy, and provides high refractive index, high transmittance, and low absorptivity for terahertz waves, effectively improving the incident angle and receiver rate of terahertz waves. When selecting the adhesive, it is preferable to use an adhesive with high refractive index, high transmittance, and low absorptivity in the 0.1–10 THz band. In this embodiment, a filled polymer adhesive (e.g., high-refractive-index filler filled into epoxy resin) is preferred to effectively improve the incident angle and receiver rate of terahertz waves.

[0075] Optionally, defining the lens layer 1 includes: designing the incident surface of the lens layer 1 as a convex arc shape and designing the light-emitting surface of the lens layer 1 as a plane, thereby defining the lens layer 1.

[0076] In the specific implementation process, by making the incident surface of the lens layer 1 a convex arc shape and the light-emitting surface of the lens layer 1 a plane, the focusing effect of the terahertz beam is achieved, the field of view is increased, and the terahertz beam is directly focused onto the adhesive layer 2 by using a high-resistivity silicon lens to form a transmission receiving optical path.

[0077] In the specific implementation process, in order to solve the problem of the refractive index n of the high-resistivity silicon lens material 硅 To address the technical challenge of severe total internal reflection loss at the interface caused by excessively high resistance, this embodiment provides a back-facing packaging method based on an adhesive layer (hereinafter referred to as "mid-adhesive back-facing"). An adhesive is used to bond the light-emitting surface of the high-resistivity silicon lens to the silicon substrate of the detector chip. The high refractive index n of the adhesive is utilized... 胶 >n 空气 Increase the critical angle θ of total internal reflection c This reduces the total internal reflection loss at the interface when incident terahertz light waves pass through the emitting surface of the high-resistivity silicon lens, and increases the allowable incident field of view, thereby effectively improving the signal-to-noise ratio and measurement accuracy of the terahertz probe. Furthermore, this mid-adhesion back-mounting method using a high-refractive-index adhesive can also be adapted for direct measurement of terahertz wave intensity across a wide spectrum of 0.1–10 THz (wavelength range 3000–30 μm), without significant reduction in anti-reflection effect due to wavelength changes. This embodiment provides a transmission situation for a single field of view incident light with a back-mounted mid-adhesion layer, as shown below. Figure 6 As shown, where, Figure 6 (a) indicates that the second single field-of-view incident light ray 51 in the adhesive back-facing package is converged to the adhesive layer 2 through the lens layer 1. Figure 6In (b), the second single field-of-view transmitted ray 52 within the frame indicates that the second single field-of-view incident ray 51 is completely refracted at the interface between the light-emitting surface of the lens layer 1 and the first surface of the adhesive layer 2, and transmitted to the second surface of the adhesive layer 2; and refracted and transmitted to the receiving light layer 4 at the incident surface between the second surface of the adhesive layer 2 and the silicon substrate layer 3 of the device. The transmission situation of multi-field-of-view incident light in the back-facing package of the adhesive layer is as follows: Figure 7 As shown, where, Figure 7 (a) indicates that the second multi-angle incident light 61 in the adhesive back-facing package is converged into the adhesive layer 2 through the lens layer 1. In the second multi-angle incident light 61, blue indicates an incident light field of view of 0°, yellow indicates an incident light field of view of 10°, and pink indicates an incident light field of view of 20°. Figure 7 In (b), the second multi-angle transmitted ray 62 within the frame indicates that the second multi-angle incident ray 61 is completely refracted at the interface between the light-emitting surface of the lens layer 1 and the first surface of the adhesive layer 2, and transmitted to the second surface of the adhesive layer 2; and refracted at the incident surface between the second surface of the adhesive layer 2 and the silicon substrate layer 3 of the device, and transmitted to the receiving light layer 4. Compared with the forward packaging method with a neutral air layer, the back packaging method provided in this embodiment allows for an increased incident field of view, effectively reducing the interface total internal reflection loss that occurs when the incident terahertz light wave passes through the light-emitting surface of the high-resistivity silicon lens, thereby effectively improving the signal-to-noise ratio and measurement accuracy.

[0078] This embodiment provides a packaging method for a terahertz intensity probe, which realizes a back-facing packaging method based on adhesive layer 2. The light-emitting surface of the high-resistivity silicon lens is bonded to the silicon substrate of the detector. The refractive index of the adhesive is greater than that of air to increase the critical angle of total internal reflection, thereby reducing the interface total internal reflection loss when the incident terahertz light wave passes through the light-emitting surface of the high-resistivity silicon lens, and increasing the allowable incident field of view, thereby effectively improving the signal-to-noise ratio and measurement accuracy. At the same time, it avoids the negative effects of adhesive on the optical contamination, aging, yellowing, corrosion and other adverse effects on the light-receiving layer 4 of the detector, thereby ensuring the stability of the probe's optical performance and extending its working life.

[0079] Example 3:

[0080] This embodiment also provides a receiving optical path design for a terahertz intensity probe, implemented using the aforementioned terahertz intensity probe, for transmitting the terahertz electromagnetic wave to be measured to the receiving optical layer 4 of the terahertz intensity probe, including:

[0081] A focusing optical path is formed on the incident surface of the lens layer 1 of the terahertz intensity probe to transmit terahertz electromagnetic waves to the first surface of the adhesive layer 2 of the terahertz intensity probe.

[0082] A refracting optical path is formed on the first surface of the adhesive layer 2 of the terahertz intensity probe to transmit terahertz electromagnetic waves to the incident surface of the device silicon substrate layer 3 of the terahertz intensity probe.

[0083] A transmission optical path is formed on the incident surface of the silicon substrate layer 3 of the device to transmit terahertz electromagnetic waves to the receiving optical layer 4 of the terahertz intensity probe.

[0084] This embodiment provides a receiving optical path design for a terahertz intensity probe, which effectively reduces total internal reflection light loss, increases the incident angle of the terahertz wave that can be received, and improves the terahertz wave reception rate. It effectively solves the technical problems existing in measuring the intensity of broadband terahertz electromagnetic waves, such as severely limited incident light angle, low transmittance leading to severe light loss, low signal-to-noise ratio, and low measurement accuracy.

[0085] In specific implementation, to measure terahertz electromagnetic waves across a wide frequency band (0.1–10 THz), this embodiment preferably employs a high-resistivity silicon lens directly facing away from the silicon substrate of the detector chip to form a transmission-type receiving optical path. A high-refractive-index adhesive is used to tightly bond the light-emitting surface of the high-resistivity silicon lens to the detector chip substrate, thereby significantly increasing the critical angle for total internal reflection at the interface. In practical application, during measurement, the terahertz intensity probe utilizes its converging receiving optical path to focus the incident terahertz light wave onto the receiving surface behind the detector's device substrate, thus directly measuring the terahertz light radiation intensity.

[0086] This embodiment provides a novel optical path design and packaging method for a terahertz intensity probe. By designing the optical path and using back-to-back adhesive packaging, it efficiently and cost-effectively solves the technical problems existing in measuring the intensity of terahertz electromagnetic waves in a wide frequency range (0.1–10 THz), such as severely limited incident light angle, low transmittance leading to severe optical loss, low signal-to-noise ratio, and low measurement accuracy. This embodiment also provides a novel terahertz intensity probe with advantages such as compact structure, small size, integrability, and low cost.

[0087] Example 4:

[0088] This embodiment provides a simulation experiment scheme for a terahertz intensity probe to verify the design effect of the terahertz intensity probe and its receiving optical path. The receiving optical path and detector module of the terahertz intensity probe were designed and simulated using optical design software as follows:

[0089] First, the relevant design simulation parameters are set as follows: The lens layer uses a silicon lens, which is a plano-convex lens with a thickness of 20mm and a refractive index of n. 硅 =3.45; the air layer thickness is set to 0.1mm, n 空气 =1; Set the adhesive layer thickness to 0.1mm, n 胶1 =1.4 or n 胶2 =1.9; Set the thickness of the detector's receiving layer to 0.1 mm, n 光敏=2; The thickness of the silicon substrate layer of the detector is set to 0.4 mm, n 硅 =3.45.

[0090] Next, using the above simulation parameters, a lens layer, a hollow air layer, an adhesive layer, a light-receiving layer, and a device silicon substrate layer are formed to create a hollow front-mounted and a hollow adhesive back-mounted (n) assembly. 胶1 =1.4) and medium adhesive backing (n 胶2 =1.9) Simulation of three packaging methods, and comparison of received energy of hollow front package, medium adhesive back package and medium adhesive back package by diffraction circle energy analysis;

[0091] Simulation analysis results are as follows Figure 8 As shown, 71 represents the medium adhesive backing (n 胶2 =1.9) received energy curve, where 72 represents the medium adhesive backing (n 胶1 =1.4) received energy curve, where 73 represents the hollow positive assembly (n 胶2 =1.9) received energy curve, the horizontal axis corresponds to the radial distance from the center of mass in micrometers (μm), and the vertical axis corresponds to the energy fraction circled.

[0092] In practical implementation, the simulation results show that adhesives with high refractive index, high transmittance, and low absorptivity can effectively improve the incident angle and the reception rate of terahertz waves. This also demonstrates that the novel terahertz intensity probe receiving optical path and packaging method provided by this invention can not only meet the direct measurement requirements of terahertz light radiation intensity over a wide frequency range, but also solve the problem caused by the low refractive index n of the high-resistivity silicon lens material. 硅 Excessive levels of light cause severe loss due to total internal reflection at the interface.

[0093] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A terahertz intensity probe, characterized in that, It includes a lens layer, an adhesive layer, a device silicon substrate layer, and a light-receiving layer, wherein: The first surface of the adhesive layer is bonded to the light-emitting surface of the lens layer; The second surface of the adhesive layer is bonded to the incident surface of the silicon substrate layer of the device. The light-emitting surface of the silicon substrate layer of the device is connected to the light-receiving layer.

2. The terahertz intensity probe as described in claim 1, characterized in that, The lens layer is made of high-resistivity silicon lens.

3. A terahertz intensity probe as described in claim 1, characterized in that, The incident surface of the lens layer is a convex arc shape, and the light-emitting surface of the lens layer is a plane.

4. A terahertz intensity probe as described in claim 3, characterized in that, The light-emitting surface of the lens layer includes a focusing area, and the lens layer is bonded to the first surface of the adhesive layer through the focusing area.

5. A terahertz intensity probe as described in claim 1, characterized in that, The adhesive layer uses a high refractive index adhesive, the refractive index of which is greater than that of air.

6. A terahertz intensity probe as described in claim 5, characterized in that, The high refractive index adhesive is a filled polymer adhesive.

7. A packaging method for a terahertz intensity probe, characterized in that, For implementing a terahertz intensity probe as described in any one of claims 1 to 6, comprising: Determine the silicon substrate layer of the device, and provide a light-receiving layer on the light-emitting surface of the silicon substrate layer of the device; An adhesive is applied to the incident surface of the silicon substrate layer of the device to form an adhesive layer; The lens layer is determined, and the light-emitting surface of the lens layer is bonded to the first surface of the adhesive layer to complete the encapsulation.

8. A terahertz intensity probe as described in claim 7, characterized in that, The adhesive is a high refractive index adhesive, the refractive index of which is greater than that of air, wherein the high refractive index adhesive is obtained by filling epoxy resin with a high refractive index filler.

9. A terahertz intensity probe as described in claim 7, characterized in that, The process of determining the lens layer includes: designing the incident surface of the lens layer as a convex arc shape and designing the light-emitting surface of the lens layer as a plane, thereby determining the lens layer.

10. A receiving optical path design for a terahertz intensity probe, characterized in that, Implemented using a terahertz intensity probe as described in any one of claims 1 to 6, for transmitting the terahertz electromagnetic wave to be measured to the receiving optical layer of the terahertz intensity probe, comprising: A focused optical path is formed on the incident surface of the lens layer of the terahertz intensity probe to transmit the terahertz electromagnetic wave to the first surface of the adhesive layer of the terahertz intensity probe. A refracting optical path is formed on the first surface of the adhesive layer of the terahertz intensity probe to transmit the terahertz electromagnetic wave to the incident surface of the silicon substrate layer of the device of the terahertz intensity probe. A transmission optical path is formed on the incident surface of the silicon substrate layer of the device to transmit the terahertz electromagnetic wave to the receiving optical layer of the terahertz intensity probe.

Images