A wavelength tunable saturable absorber mirror

Abstract

The utility model relates to a kind of wavelength tunable saturable absorption mirror. Including: substrate;Buffer layer, located on the substrate;Bragg reflection layer, located on the buffer layer;Quantum dot absorption layer, located on the Bragg reflection layer;Cap layer, located on the quantum dot absorption layer;The thickness of gradually changing wavelength tuning layer, located on the cap layer;Wherein, the wavelength tuning layer is dielectric constant near zero material layer, the optical Stark effect of the quantum dot absorption layer and the light field localization characteristic of the interaction of the dielectric constant near zero material layer, so that the saturable absorption mirror has wavelength tunable nature.Based on the above wavelength tunable saturable absorption mirror, by introducing the interaction of dielectric constant near zero material layer and quantum dot absorption layer, the precise, flexible tuning of working wavelength is realized, and the wide application requirement of different laser systems is met.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, and in particular to a wavelength-tunable saturable absorber mirror. Background Technology

[0002] Saturable absorber mirrors are key optical devices widely used in passive mode-locked lasers, ultrashort pulse lasers, and high-power fiber lasers. They achieve selective absorption of light through nonlinear optical effects, thereby modulating and stabilizing laser output.

[0003] Existing saturable absorber mirrors are mainly based on the following materials and structures: quantum dot materials, quantum well materials, carbon nanotubes (CNTs), and graphene. Currently, the wavelength tuning range of existing saturable absorber mirrors is limited, making it difficult to meet the wavelength requirements of different laser systems. Utility Model Content

[0004] The present invention provides a wavelength-tunable saturable absorber mirror, which at least solves the problem that the wavelength tuning range of saturable absorber mirrors in related technologies is limited and it is difficult to meet the wavelength requirements of different laser systems for saturable absorber mirrors.

[0005] According to an embodiment of the present invention, a wavelength-tunable saturable absorber mirror is provided, comprising:

[0006] Substrate;

[0007] A buffer layer is located on the substrate;

[0008] A Bragg reflector layer is located on the buffer layer;

[0009] A quantum dot absorption layer is located on the Bragg reflector layer;

[0010] A capping layer is located on the quantum dot absorption layer;

[0011] A wavelength tuning layer with a gradually varying thickness is located on the capping layer;

[0012] The wavelength tuning layer is a material layer with a near-zero dielectric constant. The interaction between the optical Stark effect of the quantum dot absorption layer and the optical field localization characteristics of the material layer with a near-zero dielectric constant enables the saturable absorption mirror to have wavelength tunability.

[0013] Preferably, the near-zero dielectric constant material layer includes an indium tin oxide layer, a zinc oxide layer, or a vanadium oxide layer.

[0014] Preferably, the optical band gap of the indium tin oxide layer is 0.7 eV to 1.2 eV; the optical band gap of the zinc oxide layer is 3.2 eV to 3.3 eV; and the optical band gap of the vanadium oxide layer is 0.7 eV to 1.0 eV.

[0015] Preferably, the thickness of the wavelength tuning layer ranges from 25 nanometers to 130 nanometers, and the thickness variation gradient of the wavelength tuning layer is from 0.5% to 2% per nanometer.

[0016] Preferably, the substrate is made of gallium arsenide, silicon, or indium phosphide, and the substrate thickness is between 300 micrometers and 700 micrometers.

[0017] Preferably, the material of the buffer layer includes gallium arsenide, aluminum gallium arsenide, indium phosphide, or gallium nitride, and the thickness of the buffer layer includes 50 nanometers to 500 nanometers.

[0018] Preferably, the Bragg reflector layer comprises at least 20 layers of mixed materials, wherein the mixed materials comprise a mixed material composed of gallium arsenide and aluminum gallium arsenide, a mixed material composed of silicon oxide and silicon nitride, or a mixed material composed of indium phosphide and indium gallium phosphide.

[0019] Preferably, the quantum dot absorption layer comprises a mixed material composed of indium arsenide and gallium arsenide, a mixed material composed of indium gallium arsenide and gallium arsenide, or a mixed material composed of indium arsenide and indium phosphide or indium phosphide and gallium phosphide, and the thickness of the quantum dot absorption layer comprises 5 nanometers to 20 nanometers.

[0020] Furthermore, the quantum dot density in the quantum dot absorption layer is 10 per square centimeter. 10 One to 10 11 indivual.

[0021] Preferably, the material of the capping layer includes gallium arsenide, indium phosphide, indium gallium arsenide, or gallium nitride, and the thickness of the capping layer includes 10 nanometers to 200 nanometers.

[0022] This invention provides a wavelength-tunable saturable absorber mirror, comprising a substrate; a buffer layer on the substrate; a Bragg reflector layer on the buffer layer; a quantum dot absorption layer on the Bragg reflector layer; a capping layer on the quantum dot absorption layer; and a wavelength-tuning layer with a gradually varying thickness on the capping layer. The wavelength-tuning layer is a material layer with a near-zero dielectric constant. The interaction between the optical Stark effect of the quantum dot absorption layer and the optical field localization characteristics of the near-zero dielectric constant material layer enables the saturable absorber mirror to have wavelength tunability. This invention provides a wavelength-tunable saturable absorber mirror that achieves precise tuning of the operating wavelength by introducing a wavelength-tuning layer with a gradually varying thickness. The wavelength-tuning layer, made of a material layer with a near-zero dielectric constant, utilizes its unique optical field localization characteristics to significantly enhance the optical Stark effect of the quantum dot absorption layer, thereby achieving flexible wavelength adjustment. Specifically, the near-zero dielectric constant material layer possesses a near-zero dielectric constant within a specific wavelength range. This means that light travels at extremely low speeds within this layer, resulting in a strong optical field localization effect both on the material's surface and within its interior. When laser light irradiates the near-zero dielectric constant material layer, the optical field is localized, leading to a significant increase in light intensity in localized regions. This enhanced optical field interacts with the optical Stark effect in the quantum dot absorption layer, causing a change in the quantum dot's absorption spectrum and thus enabling tuning of the operating wavelength. Simultaneously, the gradually varying thickness of the near-zero dielectric constant material layer allows different thicknesses to correspond to different wavelength tuning ranges, achieving broadband tuning. This enables the saturable absorber mirror to adapt to the needs of various laser systems, providing more flexible and broader application scenarios. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a wavelength-tunable saturable absorber mirror provided for an embodiment of the present invention.

[0025] In the figure, 1 is the substrate; 2 is the buffer layer; 3 is the Bragg reflector layer; 4 is the quantum dot absorption layer; 5 is the capping layer; and 6 is the wavelength tuning layer. Detailed Implementation

[0026] Embodiments of this embodiment will now be described in more detail with reference to the accompanying drawings. While some embodiments of this embodiment are shown in the drawings, it should be understood that this embodiment can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this embodiment. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this embodiment.

[0027] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings. Where there is no conflict between the embodiments, the following embodiments and features can be combined with each other. Furthermore, the timing of the steps in the following method embodiments is merely an example and not a strict limitation.

[0028] Saturable absorber mirrors (SAMs) are indispensable optical components in laser technology, widely used in passively mode-locked lasers, ultrashort pulse lasers, and high-power fiber lasers. They achieve selective absorption of light through nonlinear optical effects, thereby effectively modulating and stabilizing laser output. Currently, SAMs are mainly based on several materials and structures: quantum dots, quantum wells, carbon nanotubes (CNTs), and graphene. Quantum dots, with their unique quantum confinement effect and optical nonlinear properties, are often deposited on Bragg mirrors to enhance their absorption and reflection performance. Carbon nanotubes and graphene, due to their excellent optical nonlinear properties and ultrafast carrier dynamic response, are widely used for integration with optical fibers or other optical components to achieve effective modulation of laser pulses.

[0029] Despite the significant success of these existing saturable absorber mirrors in many applications, they still face a number of technical problems and challenges. First, the wavelength tuning range of existing saturable absorber mirrors is limited, making it difficult to meet the diverse wavelength requirements of different laser systems, especially in multi-wavelength and broadband laser applications. Second, the absorption characteristics of materials such as quantum dots, quantum wells, carbon nanotubes, and graphene are limited by the inherent properties of the materials and their fabrication processes, making it difficult to maintain consistent absorption efficiency over a wide wavelength range. This is particularly true in high-power laser applications, where the nonlinear absorption characteristics of existing materials are insufficient to meet high power demands.

[0030] Meanwhile, high-power lasers place higher demands on the thermal stability and long-term reliability of saturable absorber mirrors. Existing materials and structures are prone to performance degradation and thermal damage under prolonged high-power laser irradiation, affecting the stable operation of the laser. Finally, the complexity of existing saturable absorber mirror materials and fabrication processes leads to high production costs, limiting their widespread adoption in cost-sensitive applications. In summary, existing saturable absorber mirror technology still faces significant technical challenges in terms of wavelength tunability, absorption characteristic optimization, fabrication process complexity, thermal stability and reliability, and cost, requiring further technological improvements and innovations to promote its wider application.

[0031] To address the aforementioned issues, this utility model provides a wavelength-tunable saturable absorber mirror, resolving the problem that the wavelength tuning range of saturable absorber mirrors in related technologies is limited, making it difficult to meet the wavelength requirements of different laser systems.

[0032] To better understand the technical solution of this utility model, the terms involved in the embodiments of this utility model will be explained in detail first.

[0033] The optical Stark effect is an inelastic light scattering phenomenon that typically occurs when a strong light field interacts with matter. When the light field intensity is sufficiently high, it can directly disturb the electronic energy levels within the matter, causing minute shifts in these levels. In quantum dots, due to the quantum confinement effect, the energy levels of electrons are quantized, meaning even small changes in energy can lead to significant changes in the spectrum. Therefore, the optical Stark effect is particularly pronounced in quantum dots and has a significant impact on optoelectronics and quantum optics.

[0034] Near-zero dielectric (ENZ) materials: These are materials whose dielectric constant is very close to zero within a specific frequency range. At the interface between ENZ and non-ENZ materials, the abrupt change in dielectric constant can create a strong electromagnetic field localization phenomenon. This localization effect can significantly enhance the interaction between light and the surrounding nonlinear medium (such as quantum dots, dye molecules, etc.), providing new possibilities for optical manipulation and sensor applications.

[0035] Figure 1 This is a schematic diagram of a wavelength-tunable saturable absorber mirror provided for an embodiment of this utility model. (See attached diagram.) Figure 1 As shown, the wavelength-tunable saturable absorber mirror includes a substrate 1, a buffer layer 2, a Bragg reflector layer 3, a quantum dot absorber layer 4, a capping layer 5, and a wavelength tuning layer 6.

[0036] Among them, buffer layer 2 is located on substrate 1; Bragg reflector layer 3 is located on buffer layer 2; quantum dot absorption layer 4 is located on Bragg reflector layer 3; capping layer 5 is located on quantum dot absorption layer 4; and wavelength tuning layer 6 with gradually varying thickness is located on capping layer 5.

[0037] In this embodiment, the wavelength tuning layer 6 is a material layer with a near-zero dielectric constant. The interaction between the optical Stark effect of the quantum dot absorption layer 4 and the optical field localization characteristics of the material layer with a near-zero dielectric constant enables the saturable absorption mirror to have wavelength tunability.

[0038] In this embodiment of the invention, the wavelength-tunable saturable absorber mirror achieves precise tuning of the operating wavelength by introducing a wavelength tuning layer 6 with a gradually varying thickness. The wavelength tuning layer 6 is made of a material with a near-zero dielectric constant. Utilizing its unique optical field localization characteristics, it significantly enhances the optical Stark effect of the quantum dot absorption layer 4, thereby enabling flexible wavelength adjustment.

[0039] Specifically, the near-zero dielectric constant material layer has a near-zero dielectric constant within a specific wavelength range. This means that light travels at extremely low speeds within this layer, resulting in a strong localization effect of the optical field both on and inside the material. When a laser beam irradiates the near-zero dielectric constant material layer, the optical field is localized, causing a significant increase in light intensity in localized regions. This enhanced optical field interacts with the optical Stark effect in the quantum dot absorption layer 4, causing a change in the absorption spectrum of the quantum dot, thereby enabling tuning of the operating wavelength.

[0040] Furthermore, the near-zero dielectric constant material layer with gradually varying thickness allows for different wavelength tuning ranges corresponding to different thicknesses, thus achieving broadband tuning. In summary, saturable absorber mirrors can adapt to different laser system requirements, providing more flexible and broader application scenarios.

[0041] In this embodiment, substrate 1 can be used to provide support and serve as a base for other layers. Optionally, the material of substrate 1 includes gallium arsenide, silicon, or indium phosphide, and the thickness of substrate 1 can include 300 micrometers to 700 micrometers.

[0042] The buffer layer 2 is located on the substrate 1 and can be used to mitigate lattice mismatch between different materials, providing a smooth transition layer. Optionally, the material of the buffer layer 2 may include gallium arsenide, aluminum gallium arsenide, indium phosphide, or gallium nitride, and the thickness of the buffer layer 2 may include 50 nanometers to 500 nanometers.

[0043] The Bragg reflector layer 3 is located on the buffer layer 2 and is composed of multiple layers of hybrid materials, which can be used to provide high reflectivity. Optionally, the material of the Bragg reflector layer 3 includes at least 20 layers of hybrid materials, including a hybrid material composed of gallium arsenide and aluminum gallium arsenide, a hybrid material composed of silicon oxide and silicon nitride, or a hybrid material composed of indium phosphide and indium gallium phosphide.

[0044] The quantum dot absorption layer 4 is located on the Bragg reflector layer 3 and can achieve nonlinear optical absorption using the quantum confinement effect. Optionally, the quantum dot absorption layer 4 may comprise a mixed material composed of indium arsenide and gallium arsenide, a mixed material composed of indium gallium arsenide and gallium arsenide, or a mixed material composed of indium arsenide and indium phosphide or indium phosphide and gallium phosphide. The thickness of the quantum dot absorption layer 4 includes 5 nanometers to 20 nanometers. Furthermore, the quantum dot density in the quantum dot absorption layer 4 can be 102 per square centimeter. 10

[0045] One to 10 11 indivual.

[0046] The capping layer 5 is located on the quantum dot absorber layer 4 and can be used to protect the quantum dot absorber layer 4 and provide interface stability. Optionally, the material of the capping layer 5 may include gallium arsenide, indium phosphide, indium gallium arsenide, or gallium nitride, and the thickness of the capping layer 5 may include 10 nanometers to 200 nanometers.

[0047] Wavelength tuning layer 6 is located on capping layer 5, with a gradually varying thickness, and is a near-zero dielectric (ENZ) material layer. Optionally, the near-zero dielectric material layer may include an indium tin oxide layer, a zinc oxide layer, or a vanadium oxide layer. Further optionally, the optical bandgap of the indium tin oxide layer includes 0.7 eV to 1.2 eV; the optical bandgap of the zinc oxide layer includes 3.2 eV to 3.3 eV; and the optical bandgap of the vanadium oxide layer includes 0.7 eV to 1.0 eV.

[0048] In one alternative embodiment, the thickness of the wavelength tuning layer 6 ranges from 25 nanometers to 130 nanometers, and the thickness variation gradient of the wavelength tuning layer 6 is from 0.5% to 2% per nanometer.

[0049] The wavelength-tunable saturable absorber mirror described in the above embodiments can be fabricated using the following method: Specifically, it includes the following steps:

[0050] Step 1: Preparation of substrate 1.

[0051] In this embodiment, an appropriate material can be selected as substrate 1; then substrate 1 is cleaned and treated to make its surface clean and have appropriate surface flatness and lattice structure.

[0052] Optionally, the substrate 1 material includes gallium arsenide, silicon, or indium phosphide; the thickness of the substrate 1 is between 300 micrometers and 700 micrometers.

[0053] Step 2, Growth of buffer layer 2.

[0054] In this embodiment, a buffer layer 2 is grown on the substrate 1. Specifically, molecular beam epitaxy (MBE) or metal-organic chemical vapor deposition (MOCVD) techniques can be used to grow the buffer layer 2 to ensure high-quality lattice matching and a smooth surface.

[0055] Optionally, the material of buffer layer 2 includes gallium arsenide, aluminum gallium arsenide, indium phosphide, or gallium nitride; the thickness of buffer layer 2 is between 50 nanometers and 500 nanometers.

[0056] In an alternative embodiment, the substrate 1 can be treated with a standard cleaning process, and then the buffer layer 2 can be grown using molecular beam epitaxy to ensure good lattice matching and quality between layers.

[0057] Step 3: Preparation of Bragg reflector layer 3.

[0058] In this embodiment, a Bragg reflector layer 3 is deposited on the buffer layer 2. This layer consists of at least 20 layers of hybrid material. Specifically, the high reflectivity of the Bragg reflector layer 3 is ensured through precise control of the thickness of each layer.

[0059] Alternatively, the mixed material layer may be composed of gallium arsenide and aluminum gallium arsenide, silicon oxide and silicon nitride, or indium arsenide and indium phosphide, or indium phosphide (InP) and indium gallium phosphide (InGaP).

[0060] In an alternative embodiment, a high-reflectivity Bragg reflective layer 3 can be deposited layer by layer using metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) techniques, ensuring precise control of the thickness and material composition of each layer to achieve the desired reflective properties.

[0061] Step 4: Growth of quantum dot absorption layer 4.

[0062] In this embodiment, a quantum dot absorption layer 4 is grown on the Bragg reflector layer 3, which can utilize the quantum confinement effect to achieve nonlinear optical absorption.

[0063] Optionally, the quantum dot absorber layer 4 can be made of indium arsenide and gallium arsenide, indium gallium arsenide and gallium arsenide, indium arsenide and indium phosphide, or indium phosphide (InP) and gallium phosphide. The thickness of the quantum dot absorber layer 4 is between 5 nanometers and 20 nanometers, and the quantum dot density should be 102 per square centimeter. 10 One to 10 11 indivual.

[0064] In an alternative embodiment, the quantum dot absorption layer 4 can be deposited using molecular beam epitaxy or chemical vapor deposition techniques, and the thickness and quantum dot density of the layer can be controlled to achieve the desired absorption characteristics and nonlinear optical performance.

[0065] Step 5: Deposition of cap layer 5.

[0066] In this embodiment, a capping layer 5 is deposited on the quantum dot absorption layer 4 to protect the quantum dot absorption layer 4 and provide interface stability.

[0067] Optionally, the capping layer 5 may be made of gallium arsenide, indium phosphide, indium gallium arsenide, or gallium nitride. The thickness of the capping layer 5 may be between 10 nanometers and 200 nanometers.

[0068] In an alternative embodiment, the same technique as that used for the quantum dot absorber layer 4 can be used to deposit the capping layer 5 to ensure protection of the quantum dot absorber layer 4 and provide a stable interface.

[0069] Step 6: Fabrication of wavelength tuning layer 6.

[0070] In this embodiment, a wavelength tuning layer 6 with a gradually varying thickness is deposited on the capping layer 5. The wavelength tuning layer 6 is a material layer with a near-zero dielectric constant.

[0071] Optionally, the material of the wavelength tuning layer 6 may include indium tin oxide, zinc oxide, or vanadium oxide. The thickness of the wavelength tuning layer 6 ranges from 25 nanometers to 130 nanometers, with a thickness variation gradient of 0.5% to 2% per nanometer.

[0072] In an optional embodiment, physical vapor deposition or chemical vapor deposition techniques can be used to deposit a wavelength tuning layer 6 with a near-zero dielectric constant, and by controlling the deposition rate and thickness variation gradient, a thickness gradient structure can be achieved to realize broadband wavelength tuning.

[0073] The wavelength-tunable saturable absorber mirror provided in this embodiment of the invention is composed of a multi-layer structure. The working principle and function of each layer are explained below:

[0074] Substrate 1: Used to provide mechanical support and a basic platform to support the multi-layered structure of the entire mirror.

[0075] As a base material, it can provide the necessary physical and chemical properties to ensure that other layers can grow stably on it.

[0076] Buffer layer 2: Used to mitigate lattice mismatch between different materials and provide a smooth transition layer.

[0077] By growing the buffer layer 2, the lattice mismatch between the transition substrate 1 and the upper material is smoothed, avoiding defects and stress caused by differences in lattice constants, thereby improving the crystal quality and optical performance of the entire structure.

[0078] Bragg reflector layer 3: Used to provide a highly reflective mirror surface to enhance the intensity of reflected light.

[0079] The Bragg reflector layer 3 utilizes the principle of light interference, forming a highly reflective mirror surface through alternating layers of materials with different refractive indices. The thickness of each layer is precisely designed to match the wavelength of the incident light, maximizing the reflectivity within a specific wavelength range and thus enhancing the reflection effect.

[0080] Quantum dot absorption layer 4: Nonlinear optical absorption can be achieved by utilizing the quantum confinement effect.

[0081] The quantum dot absorption layer 4, through the quantum confinement effect, forms an electron and hole energy level structure within the quantum dot, giving it a strong absorption capability for light of specific wavelengths. The optical Stark effect further enhances this property, resulting in the quantum dot absorption layer 4 exhibiting a significant saturable absorption effect under high-intensity light irradiation, thus possessing saturable absorption characteristics under high-intensity light.

[0082] Capping layer 5: Used to protect quantum dot absorption layer 4 and provide interface stability.

[0083] The capping layer 5 provides a protective film to prevent the quantum dot absorption layer 4 from being damaged in subsequent processes, while ensuring interface stability and material compatibility, which helps maintain the optical performance and physical stability of the quantum dot absorption layer 4.

[0084] Wavelength tuning layer 6: Used to achieve tuning of the working wavelength, so that the saturable absorber mirror has wavelength tunability.

[0085] Materials with near-zero dielectric constants exhibit an almost zero dielectric constant within a specific wavelength range, resulting in extremely low light propagation speeds and strong localization effects of the light field both on the material's surface and within its interior. When a laser beam irradiates a layer of material with near-zero dielectric constant, the light field is localized, and the local light intensity increases significantly. This enhanced light field interacts with the optical Stark effect of quantum dot absorption layer 4, causing a change in the absorption spectrum of quantum dot absorption layer 4, thereby enabling tuning of the operating wavelength. The gradually varying thickness structure allows different thicknesses to correspond to different wavelength tuning ranges, achieving broadband tuning.

[0086] Through the synergistic effect of the above layers, the wavelength-tunable saturable absorber mirror can achieve precise and flexible wavelength tuning in different laser systems, meet a variety of application requirements, and provide efficient and stable optical performance.

[0087] It should be noted that the term "comprising" and its variations used in the embodiments of this utility model are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of this utility model are illustrative and not restrictive. Those skilled in the art should understand that, unless explicitly indicated otherwise in the context, they should be understood as "one or more".

[0088] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this utility model embodiment are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of related data must comply with the relevant laws, regulations and standards of relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0089] The steps described in the method embodiments provided by this utility model can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of this utility model is not limited in this respect.

[0090] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0091] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the scope of protection of this utility model. Therefore, the scope of protection of this utility model should be determined by the appended claims.

Claims

1. A wavelength-tunable saturable absorber mirror, characterized in that, include: The substrate, as a base, provides support; A buffer layer is located on the substrate; A Bragg reflector layer is located on the buffer layer; A quantum dot absorption layer is located on the Bragg reflector layer; A capping layer is located on the quantum dot absorption layer; A wavelength tuning layer with a gradually varying thickness is located on the capping layer, and the wavelength tuning layer is a material layer with a near-zero dielectric constant; The interaction between the optical Stark effect of the quantum dot absorption layer and the optical field localization characteristics of the near-zero dielectric constant material layer enables the saturable absorption mirror to have wavelength tunability.

2. The saturable absorber mirror according to claim 1, characterized in that, The near-zero dielectric constant material layer includes an indium tin oxide layer, a zinc oxide layer, or a vanadium oxide layer.

3. The saturable absorber mirror according to claim 2, characterized in that, The optical band gap of the indium tin oxide layer is 0.7 eV to 1.2 eV; the optical band gap of the zinc oxide layer is 3.2 eV to 3.3 eV; and the optical band gap of the vanadium oxide layer is 0.7 eV to 1.0 eV.

4. The saturable absorber mirror according to claim 1, characterized in that, The thickness of the wavelength tuning layer ranges from 25 nanometers to 130 nanometers, and the thickness variation gradient of the wavelength tuning layer ranges from 0.5% to 2% per nanometer.

5. The saturable absorber mirror according to claim 1, characterized in that, The substrate is made of gallium arsenide, silicon, or indium phosphide, and the thickness of the substrate ranges from 300 micrometers to 700 micrometers.

6. The saturable absorber mirror according to claim 1, characterized in that, The buffer layer is made of gallium arsenide, aluminum gallium arsenide, indium phosphide, or gallium nitride, and the thickness of the buffer layer ranges from 50 nanometers to 500 nanometers.

7. The saturable absorber mirror according to claim 1, characterized in that, The Bragg reflector layer comprises at least 20 layers of mixed materials, including a mixed material composed of gallium arsenide and aluminum gallium arsenide, a mixed material composed of silicon oxide and silicon nitride, or a mixed material composed of indium phosphide and indium gallium phosphide.

8. The saturable absorber mirror according to claim 1, characterized in that, The quantum dot absorption layer comprises a mixed material composed of indium arsenide and gallium arsenide, a mixed material composed of indium gallium arsenide and gallium arsenide, or a mixed material composed of indium arsenide and indium phosphide or indium phosphide and gallium phosphide, and the thickness of the quantum dot absorption layer ranges from 5 nanometers to 20 nanometers. Furthermore, the quantum dot density range in the quantum dot absorption layer is: 10 per square centimeter. 10 One to 10 11 indivual.

9. The saturable absorber mirror according to claim 1, characterized in that, The material of the capping layer includes gallium arsenide, indium phosphide, indium gallium arsenide, or gallium nitride, and the thickness of the capping layer ranges from 10 nanometers to 200 nanometers.

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