Metacavity surface emitting lasers

Abstract

A vertical cavity surface emitting laser component is provided, including a light emitting structure configured to emit a light of a frequency, a dielectric layer on or above the light emitting structure; at least one mirror structure on or above the dielectric layer, and an encapsulation layer. The mirror structure includes a plurality of optical nano- elements. An interspace is formed between adjacent optical nano-elements. Any one of a structure of the optical nano- elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the plurality of nano-elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure. The encapsulation layer is formed at least in the interspace between the plurality of optical nano-elements.

Description

[0001]2023P00335 - 1 – METACAVITY SURFACE EMITTING LASERS Description This disclosure generally relates to vertical cavity surface emitting laser (VCSEL) components. In VCSELs, Distributed Bragg Reflectors (DBR) on both sides of the VCSEL component create a resonant cavity in the VCSEL component and achieve lasing. However, in Indium-Gallium- Nitride (InGaN) based VCSELs, e.g. for emitting light of blue or green wavelength, it is difficult to achieve high- reflectivity and high-quality DBRs due to absorption and low refractive index contrast between layers of Aluminium Indium Nitride (AlInN) and Gallium Nitride (GaN) of DBRs. It is an objective of the invention to provide a VCSEL component having improved optical characteristics. In one aspect, a vertical cavity surface emitting laser, VCSEL, component, includes a light emitting structure configured to emit a light of a frequency, a dielectric layer on or above the light emitting structure; and at least one mirror structure on or above the dielectric layer, wherein the mirror structure includes a plurality of optical nano- elements, wherein an interspace is formed between adjacent optical nano-elements, wherein any one of a structure of the optical nano-elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the plurality of nano-elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure; and an encapsulation layer is formed at least in the interspace between the plurality of optical nano-elements. Note that the VCSEL component, e.g. having a metasurface instead of a DBR, may not be limited to light of blue or 2023P00335 - 2 – green wavelength. In other words, the VCSEL component can be configured to operate at any wavelength in the visible, infrared, far-infrared and microwave spectrum, etc. by scaling the geometrical parameters of the optical nano- elements, e.g. pitch, height, diameter etc. of the metasurface. Further, the encapsulation layer may form a mechanical protection and a stabilization of the optical nano-elements. Illustratively, all-dielectric metasurfaces as formed by the dielectric layer and the mirror structure, having high- reflectivity instead of DBRs of the VCSEL component provide a resonant metacavity exhibiting a high quality (Q) factor resonance which can be controlled by the thickness of the dielectric layer or epitaxial layer thickness, e.g. the layer thickness of the light emitting structure. In other words, the resonant cavity of the VCSEL component includes two all-dielectric lossless metasurfaces as opposite mirrors of the optical cavity (also denoted as metacavity). This way, a surface emitting laser at blue or green blue or green wavelength without DBRs, e.g., made of AlInN and GaN layers, can be provided. The resonance frequency of each metasurface can define the operation wavelength of the VCSEL and thus the metacavity surface emitting laser can operate in single mode regime for metasurfaces which operate at the Γ-point. Note that each metasurface can have a high-reflectivity (R> 99.9%) which ensures lasing as well as low lasing threshold. In another aspect, a method for manufacturing a vertical cavity surface emitting laser, VCSEL, component is provided. The method includes: forming a light emitting structure configured to emit a light of a frequency, forming a dielectric layer on or above the light emitting structure; and forming at least one mirror structure on or above the dielectric layer. The mirror structure includes a plurality of optical nano-elements, wherein an interspace is formed 2023P00335 - 3 – between adjacent optical nano-elements. Any one of a structure of the optical nano-elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the plurality of nano-elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure. The method further including forming an encapsulation layer at least in the interspace between the plurality of optical nano-elements. Note that the arrangement of the arrangement positions of the optical nano-elements refers to the spatial distribution of the optical nano-elements in a shared (2-dimensional) plane. The spatial distribution may be a regular pattern, e.g. an array of arrangement positions. The invention is set out in the appended set of claims. The provided VCSEL component is scalable and suitable for mass production. In the drawings, like reference characters generally refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various aspects of the invention are described with reference to the following drawings, in which: FIG.1A shows a schematic cross-sectional side view of a VCSEL component; FIG.1B shows a schematic cross-sectional top view of a VCSEL component; FIG.2 shows a schematic cross-sectional side view of a VCSEL component; 2023P00335 - 4 – FIG.3A to FIG.3F show diagrams illustrating a VCSEL component; FIG.4A and FIG.4B show schematic perspective views illustrating a mirror structure for a VCSEL component; FIG.5 is a flow diagram of a method to manufacture a VCESL component; and FIG.6A to FIG.6B show a schematic cross-sectional side view of a VCSEL component. The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and aspects in which the disclosure may be practiced. One or more aspects are described in sufficient detail to enable those skilled in the art to practice the disclosure. Other aspects may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the disclosure. The various aspects described herein are not necessarily mutually exclusive, as some aspects can be combined with one or more other aspects to form new aspects. Various aspects are described in connection with methods and various aspects are described in connection with devices. However, it may be understood that aspects described in connection with methods may similarly apply to the devices, and vice versa. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. Throughout the drawings, it should be noted that proportions are not necessary to scale and that the size of features may be emphasized for ease of illustration. Achieving a high reflective mirror structure for a blue or green blue or green or green light emitting VCSEL is 2023P00335 - 5 – challenging when using DBR mirrors due to absorption and low refractive index contrast between AlInN and GaN layers of the DBR. Illustratively, a VCSEL component having at least one metasurface mirror (a mirror including a plurality of optical nano-elements) is provided. Single mode operation occurs when metasurfaces are designed to operate at the Γ-point. The VCSEL component may provide a single mode operation over a larger range of aperture sizes and refractive indices by the utilization of a metasurface based cavity (metacavity). In other words, the range of suitable aperture sizes or wavelengths in which a single mode operation is possible can be increased. The range may depend on the linewidth of the metasurface resonance and the free spectral range of the cavity mode. The metacavity do not involve any DBR and thus avoiding low-quality DBRs caused by absorption and low refractive index contrast between AlInN and GaN layers of the DBR which is a problem associated to DBRs in VCSELs emitting blue or green blue or green or green light. The metacavity formed by metasurface mirrors is based on bound states in the radiation continuum resonances. The metasurface mirrors enable VCSEL components, e.g. for a visible wavelength range, without DBRs, and thus provides more compact VCSEL device architecture. As an example, the VCSEL component having the metacavity using the metasurfaces as mirror structures provide a much thinner than DBR-based VCSELs. The resonance linewidth of a metacavity can be easily tuned by controlling the thickness of any one of the Epi layer(s) and the dielectric layer thus ensuring a mode selective operation (a single mode operation) around the design wavelength of metacavity (metasurfaces) regardless of aperture size in a straightforward manner. The wavelength of operation of metacavity can flexibly be tuned by scaling the dimension of the individual optical nano-elements forming the metasurface and their periodicity thus simplifying design 2023P00335 - 6 – process. One of the features of the VCSEL component is that it is able to emit light in both directions (up and down). However, it is possible to have an emission also in one direction by using non-identical mirror structures with slightly detuned resonant frequencies and thus making one of the mirrors more transparent (less reflective) to ensure one side emission. The mirror structure(s) in the metacavity, e.g., all- dielectric metasurfaces, can be made in a rectangular unit cell in order to reflect only x- polarization light (or y- polarization light). Thus, the VCSEL component allows to control the polarization of the emitted laser light. FIG.1A shows a schematic cross-sectional side view of a VCSEL component. FIG.1B shows a schematic cross-sectional top view of a VCSEL component. The vertical cavity surface emitting laser, VCSEL, component 100 may include a light emitting structure 190 configured to emit a light 180 of a frequency, a dielectric layer 104 on or above the light emitting structure; and at least one mirror structure 110 on or above the dielectric layer 104. The light emitting structure 190, the mirror structure 110, and the dielectric layer 104 may be integrated on a shared semiconductor substrate (not illustrated). Note, the dielectric layer 104 is transparent for the light 180 emitted by the light emitting structure 190. The plurality of optical nano-elements 102-i may be formed directly on a surface of the dielectric layer 104. The mirror structure 110 includes a plurality of optical nano-elements 102-i (with i being an integer). An arrangement of optically coupled optical nano-elements 102-i, e.g. pillars, has a resonance frequency (or resonance wavelength) in the pillar library depending among others on the size 106 (e.g. diameter), the height 114 and the pitch 108 of the 2023P00335 - 7 – pillars forming the arrangement. Optically coupled may be understood that the optical nano-elements 102-i may cause an optical resonance in the optical spectrum. Thus, the arrangement of optically coupled optical nano-elements 102-i may reflect light 180 of the light source 190 corresponding in its frequency to the resonance frequency of the arrangement of optically coupled optical nano-elements 102-i, as illustrated in FIG.3A. The resonance may not be caused by the geometry of a single pillar, but it is a collective phenomenon of optically coupled optical nano-elements 102-i in the arrangement of optically coupled optical nano-elements 102-i. Any one of a structure of the optical nano-elements 102-i and an arrangement of the arrangement positions of the optical nano-elements 102-i may be configured such that the plurality of optical nano-elements 102-i may include an optical resonance frequency corresponding to the frequency of the light 180 emitted by the light emitting structure 190. The optical resonance frequency of the plurality of optical nano- elements 102-i corresponds to any one of a lateral extension 106 optical nano-elements 102-i, a tapering angle “a” of the optical nano-elements 102-i, a lateral distance 108 (pitch) of adjacent optical nano-elements 102-i (e.g. center-to- center, or sidewall-to-sidewall; also denoted as pitch), a height 114 optical nano-elements 102-i, a shape of the optical nano-elements 102-i (e.g. any one of a circular cross sectional shape, an ellipsoidal cross sectional shape, a linear cross sectional shape, a square cross sectional shape and a rectangular cross sectional shape), a material (e.g. refractive index) of the plurality of optical nano-elements 102-i, an arrangement of the plurality of optical nano- elements 102-i, an incident angle of the light 180 on the plurality of optical nano-elements 102-i, or any combination thereof. The optical nano-elements 102-i may be spaced apart by a distance 108 in a range from about 100 nm to about 1000 nm, e.g. in a range from about 200 nm to about 600 nm, e.g. 2023P00335 - 8 – in a from about 250 nm to about 500 nm. The optical nano- elements 102-i may have a height 114 in a range from about 10 nm to about 10000 nm, e.g. in a range from about 200 nm to about 1600 nm, e.g. in a from about 450 nm to about 800 nm. The optical nano-elements 102-i may have a lateral extension 106 in a range from about 10 nm to about 1000 nm, e.g. in a range from about 50 nm to about 700 nm, e.g. in a from about 100 nm to about 350 nm. The optical nano-elements 102-i may have a tapering angle “a” in a range from about 80 ° to about 90 °, e.g. in a from about 82 ° to about 90°, e.g. in a from about 85 ° to about 88°. The plurality of optical nano-elements 102-i may be configured as metastructure for the light emitted from the VCSEL component 100. For example, the plurality of optical nano-elements 102-i of at least a subset of the plurality of optical nano-elements 102-i may be optically coupled in a lateral direction. The plurality of the nano-elements may be arranged in a regular pattern. The arrangement of the arrangement positions of the optical nano-elements may correspond to a regular grid of positions, wherein each arrangement position corresponds to a grid position. The regular grid may be any one of a monoclinic grid, an orthorhombic grid, a tetragonal grid and a hexagonal grid. The mirror structure 110 having the plurality of optical nano-elements 102-i can have a high reflectivity and low transmission for light having a frequency corresponding to the optical resonance frequency of the plurality of optical nano-elements 102-i. This way, the mirror structure 110, and hence the VCSEL component 100, may be free of a Distributed Bragg Reflecting, DBR, mirror as mirror structure. The VCSEL component 100 may further include an encapsulation layer 112 on or above the plurality of optical nano-elements 102-i. The encapsulation layer 112 may be further formed in the interspace between adjacent optical nano-elements 102-i. 2023P00335 - 9 – The encapsulation layer 112 can protect the plurality of optical nano-elements 102-i from physical damage and as dust interaction protection. Alternatively, or in addition, the encapsulation layer 112 can provide a surface having a lower roughness (e.g. root mean square roughness (RMS)) than the surface of the dielectric layer 104 having the plurality of optical nano-elements 102-i. However, the encapsulation layer 112 can be optional depending on the application of the VCSEL component 100. Thus, a surface of the mirror structure 110 may include or correspond to an emission surface of the VCSEL component 100 to emit light emitted in the light emitting structure 190 to an environment of the VCSEL component 100. FIG.2 shows a schematic cross-sectional side view of a VCSEL component. The light emitting structure 190 may have a first side and a second side opposite to the first side. The mirror structure 110 may be a first mirror structure 110-1 arranged at the first side of the light emitting structure 190. The VCSEL component 100 may further include a second mirror structure 110-2 arranged at the second side of the light emitting structure 190. The second mirror structure 110-2 may be configured corresponding to the first mirror structure 110-1. Alternatively, the plurality of optical nano-elements 102-i of the first mirror structure 110-1 may differ in at least one characteristic from the plurality of optical nano- elements 102-i of the second mirror structure 110-2. The characteristic may be any one of a distance between adjacent nano-optical elements, a lateral extension of the nano- optical elements, a shape of nano-optical elements, and a tapering angle of the nano-optical elements of the subset. As another example, and as illustrated in FIG.4A and FIG.4B showing schematic perspective views, the plurality of optical nano-elements 102-i of the first mirror structure 110-1 may be configured as pillar-shaped structures (see FIG.4A) and the plurality of optical nano-elements 102-i of the second mirror structure 110-2 may be configured as straight-line structures (see FIG.4B). Note, pillar-shaped optical nano- 2023P00335 - 10 – elements 102-i may have a reflectivity in-plane (Rx, Ry) of the light emitted by the light emitting structure in z- direction corresponding in its frequency to the optical resonance frequency of the plurality of nano-optical elements close to 1 (Rx~Ry~1). Straight-line shaped optical nano- elements 102-i may have a reflectivity in-plane (Rx, Ry) of the light emitted by the light emitting structure in z- direction corresponding in its frequency to the optical resonance frequency of the plurality of nano-optical elements in a first direction close to 1 (Rx~1) and in a second direction close to 0 (Ry~0). Thus, the straight-line shaped optical nano-elements may be transparent in one polarization direction, and thus, may provide linear polarized light in an easy manner. Illustratively, the plurality of nano-optical elements (metasurface) illustrated in FIG.4B may only reflect x- polarized light and may be transparent for y-polarized light, the plurality of nano-optical elements (metasurface) illustrated in FIG.4A may reflect x-polarized light and y- polarized light. Further, as illustrated in FIG.2, the light emitting structure 190 may include a p-contact semiconductor layer 206, an n-contact semiconductor layer 204 and an active region 202 arranged between the p-contact semiconductor layer 206 and the n-contact semiconductor layer 204. A transparent contact layer 210, e.g. formed from a transparent conductive oxide (TCO), may be formed on the p-contact semiconductor layer 206. An electrical current aperture structure 208 may be formed between the p-contact semiconductor layer 206 and the transparent contact layer 210. The VCSEL component 100 may include an optical cavity, e.g. formed by the layers of the light emitting structure 190, the dielectric layer(s) 104, the mirror structure(s) 110-1, 110- 2, and the (optional) embedding layer(s) 112. The optical 2023P00335 - 11 – cavity, e.g. by design of the layer thickness, e.g. of the dielectric layer(s) 104, may be configured to support at least one node of a standing wave of the light 180 emitted from the light emitting structure 190. The mirror structure 110 may be arranged in the optical cavity at about a position of the optical node in the optical cavity respectively. A material of the plurality of optical nano-elements 102-i has a first refractive index and the material of the dielectric layer 104 has a second refractive index smaller than the first refractive index. The difference between the first refractive index and the second refractive index may be at least 1.2 for the frequency of the light 190. For example, optical nano-elements 102-i may be formed of TiO2 having a refractive index of about 2.6, the dielectric layer 104 may be formed of SiO2 having a refractive index of about 1.45. The contact layer 210 may be formed of indium tin oxide (ITO) and the electrical current aperture structure 208 may be formed of a dielectric material, e.g. an oxide, e.g. silicon dioxide (SiO2). The p-contact semiconductor layer 206 may be formed of p-GaN and the n-contact semiconductor layer 204 may be formed of n-GaN having a refractive index of about 2.5 respectively. In other words, FIG.2 illustrates a metacavity surface emitting laser based on all-dielectric metasurface mirrors. Both metasurface mirrors 110-1, 110-2 may be periodic. Alternatively, or in addition, the dimension of the unit cells of the metasurface mirrors 110-1, 110-2 may be identical. FIG.3A shows a transmission “T” and reflection “R” of a metasurface as a function of wavelength for a given epitaxial layer thickness. FIG.3B shows a transmission “T” and 2023P00335 - 12 – reflection “R” of the metacavity as a function of wavelength for a given epitaxial layer thickness. FIG.3C shows a normalized metacavity linewidth as a function of Epi layer thickness. The reflectivity of a single metasurface above a GaN substrate separated by SiO2 dielectric layer 104 illustrated in FIG.3A shows that a single metasurface can fully reflect a linearly polarized impinging light. A metacavity surface emitting laser, as illustrated in FIG.2 may be formed by the first mirror structure 110-1 and the second mirror structure 110-2 forming an optical resonator (also denoted as optical cavity or metacavity) of the VCSEL component 100. The reflection “R” and transmission “T” of the metacavity when illuminated by a linearly polarized plane wave (light 190) is shown in FIG.3B. The metacavity can fully transmit an impinging linearly polarized light (see Fig. 3B) and its linewidth can be obtained from Γ±,metacavity=Γmetasurface∙[1±cos(k0∙nEpi∙tEpi+2k0∙nSiO2∙tspacer+2φmetasurface)] (1) where Γmetasurfaceis the linewidth of a single metasurface (see FIG.1 and FIG.3A), Γmetacavityis the linewidth of metacavity (see FIG.3B), nEpiand tEpiare the effective refractive index of Epi layers 202, 204, 206 and its overall thickness, nSiO2and tspacerare the refractive index and thickness of a SiO2 dielectric layer 104, φmetasurfaceis the phase of a single metasurface mirror, and “±” corresponds to symmetric / antisymmetric modes of the metacavity. Based on equation (1), the linewidth of the metacavity can be controlled by adjusting the thickness of Epi layers or the thickness of the dielectric layer SiO2, as illustrated in FIG.3C for the EPI layer thickness. For example, FIG.3D-FIG.3F illustrate the reflectivity R and transmission T as function of wavelength 330 for different thickness of the thickness of the epitaxial grown layer thickness of the light emitting structure – FIG.3D 2023P00335 - 13 – illustrates the a linewidth for an epi layer thickness of 720 nm, FIG.3E illustrates the a linewidth for an epi layer thickness of 730 nm, and FIG.3F illustrates the a linewidth for an epi layer thickness of 745 nm. Note that the position of the optical resonance in the spectrum (330) and the linewidth of the reflectivity R and transmission T at the resonance frequency changes depending on the thickness of the epi layer. Thus, a zero or close to zero linewidth (infinite quality factor, also called bound state in continuum resonances) for an all-dielectric metacavity (e.g. based on using the mirror structure on the dielectric layer) can be achieved in theory, as illustrated in FIG.3F. However, for practical reasons, the linewidth may be limited considering that the epitaxial layers have absorption losses as well as scattering losses due to nanofabrication imperfection. For example, the thickness of the dielectric layer tSiO2may be about 500nm. The refractive index of the layers may be assumed to be nSiO2=1.45, nTiO2=2.6, and nnGaN=2.5. The height the optical nano-elements shaped as nanopillars may be about 350 nm and the radius (lateral extension) may be about 100 nm. The periodicity array (pitch or distance) may be about 400nm such that the metasurface is subwavelength (e.g. supports only zero order diffraction). Note that the thickness of the EPI layers tEpiis assumed to be about 745 nm. The transmission T and reflection R of a metasurfaces is a function of frequency as illustrated in FIG.3A. It can be seen that the metasurface with dielectric layer SiO2 (500nm) can fully reflect a linearly polarized impinging light. Calculation may be performed using a rigorous coupled wave analysis (RCWA) code. 2023P00335 - 14 – FIG.3B shows the transmission T and the reflection R of the metacavity surface emitting laser as a function of wavelength shown in smaller wavelength ranges. Note that by changing the thickness of the dielectric layer or the thickness 300 of the epitaxial (Epi) layers, the linewidth 302 of the metacavity structure can be easily adjusted. Thus, FIG.3C illustrates a Normalized metacavity linewidth 302 as a function of Epi layer thickness 302 based on Eq. 1 for Γ+304 and Γ- 306. Note that the metasurfaces, e.g. the optical nano-elements, may be formed of high-index refractive index materials, e.g. TiO2. The high-index material may support any one of electric resonance and magnetic resonance. These resonances are also known as Mie resonances and provide complete reflection of impinging light 180 at a desire operation wavelength. A low-index dielectric layer, e.g. made from SiO2, as a substrate spacer below for all-dielectric metasurfaces may provide highly reflective Mie resonances. Thus, using rigorous coupled-wave analysis (RCWA), the VCSEL component can provide a transmission of light at a desired wavelength by adjusting the thickness of the dielectric layer and of the epitaxial layer. Moreover, the linewidth of the metacavity can be tuned by varying the thickness of the dielectric spacer or the epitaxial layer. Note that the linewidth of metacavity can vanish to zero when using lossless metacavity and epitaxial layer. The underlying physics of vanishing linewidth (high-Q resonance) of the metacavity can be explained by using the concept of bound states in the radiation continuum resonances. The linewidth of the metacavity may be limited by absorption losses of epitaxial (epi) layers as well as scattering losses due to surface roughness in the optical nano-elements. 2023P00335 - 15 – FIG.5 is a flow diagram of a method for manufacturing a VCESL component. The method 500 includes comprising forming 502 a light emitting structure configured to emit a light of a frequency, forming 504 a dielectric layer on or above the light emitting structure; and forming 506 at least one mirror structure on or above the dielectric layer. The mirror structure includes a plurality of optical nano-elements. Any one of a structure of the optical nano-elements and an arrangement of the arrangement positions of the optical nano- elements are configured such that the plurality of nano- elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure. The method may further include any feature as described for the device above. FIG.6A to FIG.6B show a schematic cross-sectional side views of a VCSEL component. In various embodiments one of the first mirror structure 110-1 and the second mirror structure 110-2 may include a first subset 602 of optical nano-elements and a second subset 604 of optical nano-elements, as illustrated in FIG.6A. The optical nano-elements of the first subset 602 and of the second subset 604 may be configured to differ in their dimensions, e.g., thickness, width, length or periodicity. Thus, by controlling the dimensions of the first subset 602 and the second subset 604, the losses of the higher order transverse modes of the VCSEL may be adjusted, e.g. increased. This way, a single transverse mode lasing may be achieved. The optical nano-elements of the first subset 602 of the first mirror structure 110-1 and of the second mirror structure 110-2 may correspond to each other, as illustrated in FIG.6A. 2023P00335 - 16 – The second subset 604 may be arranged on or above the current aperture 208, as illustrated in FIG.6a and FIG.6B. The first subset 602 may be arranged in an optical channel defined by the current aperture 208, as illustrated in FIG.6a and FIG.6B. Alternatively, or in addition, as illustrated in FIG.6B, each of the first mirror structure 110-1 and the second mirror structure 110-2 may include a first subset 602 of optical nano-elements and a second subset 604 of optical nano- elements, The optical nano-elements of the first subsets 602 and optical nano-elements of the second subsets 604 of the first mirror structure 110-1 and the second mirror structure 110-2 may correspond to each other, as illustrated in FIG.6B. In the following some examples are described, which relate to what is described herein and shown in the figures. Example 1 is a vertical cavity surface emitting laser, VCSEL, component, including: a light emitting structure configured to emit a light of a frequency, a dielectric layer on or above the light emitting structure; and at least one mirror structure on or above the dielectric layer, wherein the mirror structure includes a plurality of optical nano- elements, wherein an interspace is formed between adjacent optical nano-elements, wherein any one of a structure of the optical nano-elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the plurality of nano-elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure; and an encapsulation layer is formed at least in the interspace between the plurality of optical nano-elements. 2023P00335 - 17 – In Example 2, the subject matter of Example 1 can optionally include that the plurality of optical nano-elements are formed directly on a surface of the dielectric layer. In Example 3, the subject matter of Example 2 can optionally include that a material of the plurality of optical nano- elements has a first refractive index and the material of the dielectric layer has a second refractive index smaller than the first refractive index. In Example 4, the subject matter of Example 3 can optionally include that the difference between the first refractive index and the second refractive index is at least 1.2 for the frequency of the light. In Example 5, the subject matter of any one of Examples 1 to 4 can optionally include that the plurality of optical nano- elements are configured as metastructure for the light emitted from the VCSEL component. In Example 6, the subject matter of any one of Examples 1 to 5 can optionally include that the plurality of optical nano- elements of at least a subset of the plurality of optical nano-elements are optically coupled in a lateral direction. In Example 7, the subject matter of any one of Examples 1 to 6 can optionally include that the light emitting structure includes a p-contact semiconductor layer, an n-contact semiconductor layer and an active region arranged between the p-contact semiconductor layer and the n-contact semiconductor layer. In Example 8, the subject matter of any one of Examples 1 to 7 can optionally include that the light emitting structure, the mirror structure, and the dielectric layer are integrated on a shared semiconductor substrate. 2023P00335 - 18 – In Example 9, the subject matter of any one of Examples 1 to 8 can optionally include that the light emitting structure has a first side and a second side opposite to the first side. The mirror structure is a first mirror structure arranged at the first side of the light emitting structure, and the VCSEL component further includes a second mirror structure arranged at the second side of the light emitting structure, wherein the second mirror structure is configured corresponding to the first mirror structure. In Example 10, the subject matter of Example 9 can optionally include that the plurality of optical nano-elements of the first mirror structure differ in at least one characteristic from the plurality of optical nano-elements of the second mirror structure. In Example 11, the subject matter of Example 10 can optionally include that the characteristic is any one of a distance between adjacent nano-optical elements, a lateral extension of the nano-optical elements, a shape of nano- optical elements, and a tapering angle of the nano-optical elements of the subset. In Example 12, the subject matter of any one of Examples 9 to 11 can optionally include that the plurality of optical nano- elements of the first mirror structure are configured as pillar structures and the plurality of optical nano-elements of the second mirror structure are configured as straight- line structures. In Example 13, the subject matter of any one of Examples 1 to 12 can optionally further include a glass cover on or above the plurality of optical nano-elements. In Example 14, the subject matter of Example 13 can optionally include that the glass cover is spaced apart from the mirror structure. 2023P00335 - 19 – In Example 15, the subject matter of any one of Examples 1 to 14 can optionally include that the VCSEL component includes an optical cavity configured to support at least one node of a standing wave of the light emitted from the light emitting structure, wherein the mirror structure is arranged in the optical cavity at about a position of the optical node in the optical cavity. In Example 16, the subject matter of any one of Examples 1 to 15 can optionally include that the mirror structure is free of a Distributed Bragg Reflecting, DBR, mirror. In Example 17, the subject matter of any one of Examples 1 to 16 can optionally include that a surface of the mirror structure includes an emission surface of the VCSEL component to emit light emitted in the light emitting structure to an environment of the VCSEL component. In Example 18, the subject matter of any one of Examples 1 to 17 can optionally include that the plurality of the nano- elements are arranged in a regular pattern. In Example 19, the subject matter of Example 18 can optionally include that the arrangement of the arrangement position correspond to a regular grid of positions, wherein each arrangement position corresponds to a grid position. In Example 20, the subject matter of Example 19 can optionally include that the regular grid is any one of a monoclinic grid, an orthorhombic grid, a tetragonal grid and a hexagonal grid. In Example 21, the subject matter of any one of Examples 1 to 20 can optionally include that the plurality of nano-elements include ellipsoidal pillar shaped nano-elements including a first axis and a second axis orthogonal to the first axis, wherein the extension of the ellipsoidal pillar in the 2023P00335 - 20 – direction of the second axis is shorter than the extension of the ellipsoidal pillar in the direction of the first axis. In Example 22, the subject matter of any one of Examples 1 to 20 can optionally include that the encapsulation layer laterally encapsulates the optical nano-elements. In Example 23, the subject matter of any one of Examples 1 to 20 can optionally include that the encapsulation layer is formed as a continuous layer. In Example 24, the subject matter of any one of Examples 1 to 20 can optionally include that the encapsulation layer is formed connecting adjacent optical nano-elements. In Example 25, the subject matter of any one of Examples 1 to 20 can optionally include that the encapsulation layer has a third refractive index, wherein the third refractive index is lower than the first refractive index In Example 26, the subject matter of any one of Examples 1 to 20 can optionally include that the encapsulation layer is extending over a top surface of the optical nano-elements, and wherein the encapsulation layer is further formed on the optical nano-elements. Example 27 is a method for manufacturing a vertical cavity surface emitting laser, VCSEL, component, the method including: forming a light emitting structure configured to emit a light of a frequency, forming a dielectric layer on or above the light emitting structure; and forming at least one mirror structure on or above the dielectric layer. The mirror structure includes a plurality of optical nano-elements, wherein an interspace is formed between adjacent optical nano-elements. Any one of a structure of the optical nano- elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the 2023P00335 - 21 – plurality of nano-elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure. The method further including forming an encapsulation layer at least in the interspace between the plurality of optical nano-elements. In Example 28, the subject matter of Example 22 can optionally include that any one of a thickness of the light emitting structure and the thickness of the dielectric layer is set to adjust a linewidth of the light emitted from the VCSEL component corresponding to a predetermined linewidth value. The method may further include any feature as described for the device above. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any example or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other examples or designs. The words “plurality” and “multiple” in the description or the claims expressly refer to a quantity greater than one. The terms “group (of)”, “set [of]”, “collection (of)”, “series (of)”, “sequence (of)”, “grouping (of)”, etc., and the like in the description or in the claims refer to a quantity equal to or greater than one, i.e. one or more. Any term expressed in plural form that does not expressly state “plurality” or “multiple” likewise refers to a quantity equal to or greater than one. The term “connected” can be understood in the sense of a (e.g. mechanical, optical and / or electrical), e.g. direct or indirect, connection and / or interaction. For example, several elements can be connected together mechanically such that they are physically retained (e.g., a plug connected to a socket) and electrically such that they have an electrically 2023P00335 - 22 – conductive path (e.g., signal paths exist along a communicative chain). While the above descriptions and connected figures may depict optical device components as separate elements, skilled persons will appreciate the various possibilities to combine or integrate discrete optical functions into a single element. Such may include combining two or more components from a single component. Conversely, skilled persons will recognize the possibility to separate a single element into two or more discrete elements, such as splitting a single component into two or more separate component. It is appreciated that implementations of methods detailed herein are exemplary in nature, and are thus understood as capable of being implemented in a corresponding device. Likewise, it is appreciated that implementations of devices detailed herein are understood as capable of being implemented as a corresponding method. It is thus understood that a device corresponding to a method detailed herein may include one or more components configured to perform each aspect of the related method. All acronyms defined in the above description additionally hold in all claims included herein. While the disclosure has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims. The scope of the disclosure is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced. 2023P00335 - 23 – Reference Numeral List a tapering angle R reflectivity T Transmission 100 VCSEL 102-i, optical nano-element (e.g. pillar) 104 dielectric layer 106 lateral extension of optical nano-element (e.g. diameter of pillar) 108 distance, pitch 110, 110-1, 110-2 mirror structure 112 embedding layer 120 grid position 180 light of light emission structure 190 light emission structure 202 active region 204 n-contact layer 206 p-contact layer 208 current aperture 210 transparent contact layer 300 Epi layer thickness 302 relative linewidth 304, 306 linewidth 330 wavelength 500, 502, 504, 506 method and method steps 602, 604 subset

Claims

2023P00335 - 24 – CLAIMS What is claimed is:

1. A vertical cavity surface emitting laser, VCSEL, component, comprising: a light emitting structure configured to emit a light of a frequency, the light emitting structure having a first side and a second side opposite to the first side, a dielectric layer on or above the light emitting structure; and a first mirror structure on or above the dielectric layer at the first side of the light emitting structure, wherein the mirror structure comprises a plurality of optical nano-elements, wherein an interspace is formed between adjacent optical nano-elements and an encapsulation layer is formed at least in the interspace between the plurality of optical nano-elements, wherein any one of a structure of the optical nano-elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the plurality of nano-elements comprises an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure; and a second mirror structure arranged at the second side of the light emitting structure, wherein the second mirror structure is configured corresponding to the first mirror structure.

2. The VCSEL component of claim 1, wherein the plurality of optical nano-elements are formed directly on a surface of the dielectric layer.

3. The VCSEL component of claim 1 or 2, wherein a material of the plurality of optical nano- elements has a first refractive index and the material2023P00335 - 25 – of the dielectric layer has a second refractive index smaller than the first refractive index.

4. The VCSEL component of claim 3, wherein the difference between the first refractive index and the second refractive index is at least 1.2 for the frequency of the light.

5. The VCSEL component of any one of claims 1 to 4, wherein the encapsulation layer laterally encapsulates the optical nano-elements.

6. The VCSEL component of any one of claims 1 to 5, wherein the encapsulation layer is formed as a continuous layer.

7. The VCSEL component of any one of claims 1 to 6, wherein the encapsulation layer is formed connecting adjacent optical nano-elements.

8. The VCSEL component of any one of claims 1 to 7, wherein the encapsulation layer has a third refractive index, wherein the third refractive index is lower than the first refractive index 9. The VCSEL component of any one of claims 1 to 8, wherein the encapsulation layer is extending over a top surface of the optical nano-elements, and wherein the encapsulation layer is further formed on the optical nano-elements.

10. The VCSEL component of any one of claims 1 to 9, the light emitting structure comprising a p-contact semiconductor layer, an n-contact semiconductor layer and an active region arranged between the p-contact semiconductor layer and the n-contact semiconductor layer.2023P00335 - 26 – 11. The VCSEL component of any one of claims 1 to 10, wherein the first mirror structure and the second mirror structure are configured free of distributed Bragg reflector, DBR.

12. The VCSEL component of any one of claims 1 to 11, wherein the plurality of optical nano-elements of the first mirror structure differs in at least one characteristic from the plurality of optical nano- elements of the second mirror structure.

13. The VCSEL component of claim 12, wherein the characteristic is any one of a distance between adjacent nano-optical elements, a lateral extension of the nano-optical elements, a shape of nano- optical elements, and a tapering angle of the nano- optical elements of the subset.

14. The VCSEL component of any one of claims 1 to 13, wherein the plurality of optical nano-elements of the first mirror structure are configured as pillar structures and the plurality of optical nano-elements of the second mirror structure are configured as straight- line structures.

15. The VCSEL component of any one of claims 1 to 14, wherein the VCSEL component comprises an optical cavity configured to support at least one node of a standing wave of the light emitted from the light emitting structure, wherein the mirror structure is arranged in the optical cavity at about a position of the optical node in the optical cavity.2023P00335 - 27 – 16. The VCSEL component of any one of claims 1 to 15, wherein the optical nano-elements of any one of the first mirror structure and the second mirror structure are formed from dielectric material.

17. The VCSEL component of any one of claims 1 to 16, wherein a surface of the mirror structure comprises an emission surface of the VCSEL component to emit light emitted in the light emitting structure to an environment of the VCSEL component.

18. The VCSEL component of any one of claims 1 to 17, wherein the plurality of the nano-elements are arranged in a regular pattern, wherein the arrangement of the arrangement position correspond to a regular grid of positions, wherein each arrangement position corresponds to a grid position.

19. A method for manufacturing a vertical cavity surface emitting laser, VCSEL, component, the method comprising: forming a second mirror structure; forming a light emitting structure configured to emit a light of a frequency, the light emitting structure having a first side and a second side opposite to the first side, wherein the second mirror structure is arranged at the second side; forming a dielectric layer on or above the light emitting structure; and forming a first mirror structure on or above the dielectric layer at the first side of the light emitting structure, wherein the first mirror structure comprises a plurality of optical nano-elements, wherein an interspace is formed between adjacent optical nano-elements, wherein any one of a structure of the optical nano-elements and an arrangement of the arrangement positions of the optical nano-elements are configured such that the2023P00335 - 28 – plurality of nano-elements includes an optical resonance frequency corresponding to the frequency of the light emitted by the light emitting structure; and forming an encapsulation layer at least in the interspace between the plurality of optical nano- elements; and wherein the second mirror structure is configured corresponding to the first mirror structure.

20. The method of claim 19, wherein any one of a thickness of the light emitting structure and the thickness of the dielectric layer is set to adjust a linewidth of the light emitted from the VCSEL component corresponding to a predetermined linewidth value.

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