Immersion grating-based and transmission grating-based morphology

Abstract

Immersion grating based and transmission grating based morphologies are disclosed. An immersion grating-based morphology includes a plurality of grating lines, an intermediate multilayer structure, and a substrate carrying the plurality of grating lines and the intermediate multilayer structure, where the intermediate multilayer structure includes a plurality of intermediate layers, and where the intermediate multilayer structure is configured to improve performance of the immersion grating based on predetermined performance criteria, the predetermined performance criteria include at least a reflection loss-based performance. A transmission grating-based morphology includes a plurality of grating lines, an intermediate multilayer structure, and a substrate carrying the plurality of grating lines and the intermediate multilayer structure, where the intermediate multilayer structure includes a plurality of intermediate layers, and where the intermediate multilayer structure is configured to improve performance of the transmission grating based on predetermined performance criteria, the predetermined performance criteria include at least a reflection loss-based performance.

Description

Technical Field

[0001] Aspects of the present disclosure relate to solutions based on optical communications. More specifically, certain implementations of the present disclosure relate to methods and systems for implementing and utilizing multi-layer dielectric coatings for efficient dielectric gratings. Background Art

[0002] By comparing such systems with certain aspects of the present disclosure as set forth in the remainder of this application with reference to the figures, the limitations and disadvantages of conventional diffraction gratings will become apparent to those skilled in the art. Summary of the invention

[0003] There is provided herein a system and method for multilayer dielectric coating of high efficiency dielectric gratings substantially as shown in at least one of the accompanying drawings and / or described in connection therewith, and as more fully set forth in the claims.

[0004] These and other advantages, aspects and novel features of the present disclosure, as well as details of illustrated embodiments thereof, will be more fully understood from the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 A cross section of an exemplary diffraction grating is shown.

[0006] Figure 2 Exemplary immersion gratings and use case scenarios associated therewith are shown.

[0007] Figure 3 An exemplary immersion grating morphology incorporating a multi-layer dielectric (MLD) structure is shown.

[0008] Figure 4 Performance graphs of exemplary immersion gratings implemented without MLD are shown.

[0009] Figure 5 Performance graph of an exemplary immersion grating implemented using MLD is shown.

[0010] Figure 6 is a graph showing the variation of zero-order reflection (R0) of an exemplary immersion grating as a function of wavelength.

[0011] Figure 7 is a graph showing the first order reflection (R1) of an exemplary immersion grating as a function of wavelength.

[0012] Figure 8 is a graph showing the zero-order reflection (R0) of an exemplary immersion grating as a function of the incident angle.

[0013] Fig. 9 is a graph showing the first order reflection (R1) of an exemplary immersion grating as a function of the angle of incidence.

[0014] Fig.10 Exemplary transmission gratings and use case scenarios associated therewith are shown.

[0015] Fig.11 An exemplary transmission grating morphology incorporating a multi-layer dielectric (MLD) structure is shown.

[0016] Fig.12 Performance graphs of exemplary transmission gratings implemented without MLD are shown.

[0017] Fig.13 Performance graphs of exemplary transmission gratings implemented using MLDs are shown.

[0018] Fig.14 is a graph showing the variation of zero-order transmittance (T0) of an exemplary transmission grating with wavelength.

[0019] Fig.15 is a graph showing the first-order transmission diffraction efficiency (T1) of an exemplary transmission grating as a function of wavelength.

[0020] Fig.16 is a graph showing the variation of zero-order reflection (R0) of an exemplary transmission grating as a function of wavelength.

[0021] Fig.17 is a graph showing the first order reflection (R1) of an exemplary transmission grating as a function of wavelength.

[0022] Fig.18 is a graph showing the variation of total reflectivity (R) of an exemplary transmission grating with wavelength.

[0023] Fig.19 is a graph showing the variation of zero-order reflection (R0) of an exemplary transmission grating with the angle of incidence.

[0024] Fig. 20 is a graph showing the first order reflection (R1) of an exemplary transmission grating as a function of the incident angle.

[0025] Fig.21 is a graph showing the variation of total reflectivity (R) of an exemplary transmission grating with the incident angle.

[0026] Fig. 22 is a graph showing the variation of zero-order transmittance (T0) of an exemplary transmission grating with incident angle.

[0027] Fig.23 is a graph showing the first-order transmission diffraction efficiency (T1) of an exemplary transmission grating as a function of the incident angle.

[0028] Fig.24is a graph showing the first order transmission diffraction efficiency (T1) performance of exemplary transmission gratings with and without MLD.

[0029] Fig.25 is a graph showing the total reflectivity (R) performance of an exemplary transmission grating with and without MLD. DETAILED DESCRIPTION

[0030] The present disclosure relates to diffraction gratings, and in particular to morphologies used therein. In this regard, a diffraction grating is an optical component having a periodic structure that is configured to resolve (e.g., angularly disperse) incident light rays of different wavelengths into several light beams traveling in different directions. Diffraction gratings can be used in different devices, systems, etc., where the use and control of light beams (e.g., lasers) may be desired or required. For example, diffraction gratings can be used in fiber-based solutions. In this regard, optical fibers carrying multiple signal wavelengths can be combined with diffraction gratings for spectral multiplexing or demultiplexing. Solutions according to the present disclosure provide enhanced diffraction gratings, and in particular, morphologies based on enhanced gratings, as described in more detail below.

[0031] Figure 1 A cross section of an exemplary diffraction grating is shown. Figure 1 Shown in FIG. 1 is a diffraction grating 100. The diffraction grating 100 includes a surface having a plurality of lines and spaces configured to facilitate a grating function. The diffraction grating 100 may be disposed on a substrate layer configured to carry a grating.

[0032] The diffraction grating 100 may have a repeating structure consisting of, for example, periodic lines and spaces (i.e., lines that are close, equidistant, and parallel) and separated by corresponding close, equidistant, and parallel spaces. In other words, the diffraction grating 100 may have lines of equal size separated by equal size spaces. Such a repeating structure (especially when the materials used therein are appropriately selected) can resolve incident light in a particular manner. Nevertheless, in some cases, the grating lines may have non-periodic spacing (e.g., chirped gratings) and curved profiles. Different profiles of different shapes and / or variable spacing can still maintain the grating function, but add the additional benefits of aberration control or modification of the incident wavefront (e.g., focusing or collimation).

[0033] In various implementations based on the present disclosure, new morphologies may be used for manufacturable high performance diffraction gratings. Such morphologies may be used for different types of diffraction gratings, such as immersion gratings and transmission gratings. In this regard, a transmission grating (or transmission grating) is a diffraction grating that is typically used in transmission, and which operates to angularly disperse incident light into a spectrum. As used therein, a transmission grating is a phase grating that modifies the phase of the incident light (rather than an amplitude grating, which modifies the amplitude of the incident light in a periodic function), and can therefore theoretically be up to 100% efficient. Immersion gratings are similar to transmission gratings in that they also change the phase of the incident light, but operate in a total internal reflection regime, i.e., the incident angle is greater than the critical angle at the interface containing the grating wires. In the case of an immersion grating, typically the light is incident on the grating surface from inside the medium supporting the grating wires.

[0034] Solutions based on the present disclosure can improve the performance of diffraction gratings while also solving or mitigating some of the problems or limitations associated with conventional solutions. In this regard, an important limiting factor in the performance of diffraction gratings is reflection losses. Reflections between the substrate and the grating structure can limit the amount of power delivered to the grating structure (e.g., when illuminated from the substrate side as in an immersion grating configuration). For transmission gratings, reflections between the grating structure and the substrate limit the transmittance (e.g., efficiency to the desired output order) and result in a redistribution of power to other orders. As such, in either type, limiting reflections at the interface can lead to improved performance.

[0035] In a solution based on the present disclosure, an intermediate layer structure may be introduced / added between the grating structure and the substrate layer carrying the grating structure. The intermediate layer structure may be adaptively configured—i.e., based on the selection of materials used therein, their arrangement, etc.—to improve the performance of the diffraction grating, such as by providing anti-reflection behavior based on predetermined criteria. For example, the predetermined criteria may include achieving a specific percentage (e.g., 5%, 10%, etc.) of improvement over a specific performance aspect or parameter (e.g., reflection loss) of a grating having a similar structure but without the intermediate layer structure. In addition to the anti-reflection benefit, the intermediate layer structure provides additional benefits, such as improved overlap functionality (e.g., with respect to polarization components), as described in more detail below. The intermediate layer structure may include an arrangement based on multiple layers. For example, in different implementations, the intermediate layer structure may include a structure based on a multilayer dielectric (MLD), which is adaptively configured to provide anti-reflection behavior as described herein. In this regard, in some instances, the first layer of the MLD stack closest to the grating lines can beneficially act as an etch stop layer, thereby providing the functionality and benefits attributed thereto, as described in U.S. patent application serial number __ / ___,___ (Agent Case No.: 67055US06), filed on the same date herewith, the entire contents of which are incorporated herein by reference.

[0036] In various exemplary embodiments, an improved grating morphology may be used that includes at least: 1) grating lines that include one or more dielectric layers; 2) a multi-layer dielectric (MLD) structure or coating that provides increased diffraction efficiency by impedance matching between the substrate and the grating - thus, providing improved anti-reflection behavior; and 3) a substrate that carries these layers / structures. Such morphologies may provide various benefits compared to conventional morphologies (if any), including at least: 1) improved performance due to the MLD structure, which is configured to provide minimum reflectivity; and 2) improved overlap between ideal morphologies for different polarization components (e.g., s-polarization components and p-polarization components). Exemplary embodiments involving immersion gratings and transmission gratings are described in more detail below.

[0037] Figure 2 Exemplary immersion gratings and use case scenarios associated therewith are shown. Figure 2 Shown in FIG. 1 is an immersion grating 200 and a use case scenario associated therewith, such as during a grating operation using the immersion grating 200 .

[0038] As shown, the immersion grating 200 includes a grating structure including a repeating structure having a surface with close, equidistant and parallel lines separated by corresponding close, equidistant and parallel intervals, the surface being configured to resolve an incident light signal. The grating structure is disposed on top of a material (e.g., glass) 220. Nevertheless, the present disclosure is not limited to the use of a glass substrate, and any suitable material may be used. For example, any material that is transparent to the operating range of the grating may be used. Figure 2 An exemplary grating operation using the immersion grating 200 using a single propagation order is also shown in FIG. 1 . To this end, an input beam (incident light) is applied to the immersion grating 200, wherein the input beam strikes the immersion grating 200 from the bottom side (i.e., from within the material 220 (e.g., glass) below the grating structure), thereby generating a plurality of corresponding outputs. Further, while the immersion grating 200 is shown with air outside of it (above and outside the grating structure), the present disclosure is not limited to this design, and in some exemplary implementations, other gases, liquids, or materials that meet certain criteria (e.g., having a lower refractive index than the grating layer and / or substrate material) may be used in addition to air.

[0039] like Figure 2 As shown, the allowed output orders generated by applying an input beam to an immersion grating 200 include zero-order reflection (R0) and first-order reflection (R1) outputs. It is desirable to maximize the R1 output to optimize the performance of the grating. Figure 2In the exemplary case shown, an input beam is applied to the immersion grating 200 at an incident angle exceeding the critical angle of the grating. In addition, the grating period can be set so that diffraction into the surrounding medium (air) is not allowed. As such, all transmission diffraction orders (zero and non-zero) can be prohibited. In this regard, prohibiting all transmission orders can be achieved by: 1) setting the incident angle of the input beam so that it is greater than the critical angle (total internal reflection) to prevent zero-order transmission, and 2) setting the grating period to be small enough so that diffraction to the external medium does not occur. In other words, because the refractive index (RI) of the substrate material (glass 220) and / or the grating material exceeds the RI of the surrounding medium, when the incident light is applied at an incident angle exceeding the critical angle of the grating and at a properly selected grating period, only reflection orders (e.g., R0 and R1) occur. For example, as shown, the input beam can include near-infrared light having a wavelength in the range of 1525nm to 1615nm incident on the grating surface at an incident angle θ=45.53°. In this wavelength range, the refractive index (RI) of the glass used in material 220 is about 1.8. Therefore, the R1 output represents diffraction at a wavelength of 1615 nm.

[0040] According to the present disclosure, an immersion grating (e.g., immersion grating 200) may incorporate modified / enhanced morphologies for improving its performance. In this regard, such morphologies may incorporate an intermediate layer structure between the grating structure and the substrate layer, wherein the intermediate layer structure is adaptively configured to enhance the performance, particularly with respect to the reflection loss of the grating, as described herein. Figure 3 Exemplary embodiments of immersion gratings incorporating such exemplary morphologies are shown and described in further detail.

[0041] Figure 3 An exemplary immersion grating morphology incorporating a multi-layer dielectric (MLD) structure is shown. Figure 3 Shown in FIG. 3 is an immersion grating-based form 300 (or a portion thereof). In particular, Figure 3 A cross-section of form 300 is shown in , showing the grating layer and its associated underlying layers.

[0042] like Figure 3 As shown, the form 300 includes a single layer of grating lines 310, a multilayer structure 320, and a substrate (e.g., glass-based) 330. Figure 3 In the portion of the form 300 shown, only two (2) grating lines are shown, but it should be understood that the form 300 is composed of many lines. Each grating line 310 includes a single layer composed of the same material. For example, in Figure 3In the exemplary embodiment shown, the grating lines 310 may include a single layer of silicon-based grating lines. Additionally, while the grating lines are shown as having a cross-sectional profile with a simple rectangular shape, the present disclosure is not limited to such shapes, and as such other shapes may be used if deemed appropriate—for example, the cross-sectional profile of the lines may be trapezoidal or have a curved profile and be modeled and optimized accordingly.

[0043] In addition to the materials used therein, the grating lines 310 may be characterized by one or more grating related parameters such as line height, line width, grating period, and duty cycle (DC). These parameters are Figure 3 300 relative to the grating lines 310 of the form 300. In this regard, as used herein, the duty cycle is defined as the line width (i.e., the width of each grating line 310) divided by the grating period - that is, duty cycle = line width / grating period. As such, the line width of the grating lines 310 can be simply indicated based on the duty cycle indicating the grating period. The values ​​of the grating related parameters can be set to optimize performance. For example, in the form 300, the line height can be 340nm and the grating period can be 580nm. In addition, the grating lines 310 have a duty cycle of 67% ± 2%, and therefore, with a grating period of 580nm, the line width of the grating lines 310 in the form 300 can be 388.6nm ± 11.6nm. In the case where the cross-section of the line is not rectangular (e.g., trapezoidal or has curved sidewalls), the line width and duty cycle can be determined using defined parameters, at a specific height, or as an average at different heights (i.e., averaged over multiple heights).

[0044] The multilayer structure 320 includes a set of layers that are adaptively configured (e.g., based on the selection of materials used therein, their dimensions, the arrangement of the layers, etc.) to provide a reflective performance that meets a predetermined standard. In this regard, the multilayer structure 320 can be configured to minimize reflections and for optimized performance when operating in this manner. In various exemplary embodiments, the multilayer structure 320 can include multiple dielectric layers. As such, the multilayer structure 320 (and similar structures) are referred to herein as multilayer dielectric (MLD)-based structures, MLD coatings, or simply MLDs.

[0045] For example, in form 300, multilayer structure 320 includes three (3) layers: a first dielectric layer 322, a second dielectric layer 324, and a third dielectric layer 326. In some implementations, different layers in multilayer structure 320 may include materials having different refractive indices (RI). Different layers in multilayer structure 320 may include, for example, alternating layers of different refractive index (RI) materials. In this regard, in some implementations, multilayer structure 320 may include alternating layers of high refractive index (RI) and low refractive index (RI) materials. For example, in form 300, first dielectric layer 322 may include a high RI material, and in addition to first dielectric layer 322, multilayer structure 320 may include a pair of LH-based layers. Preferably, the same material is used throughout. Thus, in Figure 3 In the exemplary embodiment shown in , the multilayer structure 320 in form 300 includes a HLH arrangement. Nevertheless, in some cases, different high RI and / or low RI materials (and layers including such materials) may be used. The materials used in the multilayer structure 320 may be selected to optimize performance.

[0046] The substrate 330 may include a suitable material and may have predetermined dimensions for optimizing performance. Figure 3 In the illustrated exemplary embodiment, substrate 330 may include a glass (eg, SiO 2 ) based substrate.

[0047] Various parameters or characteristics of at least some of the components and / or features of the morphology 300 may be adaptively selected or adjusted based on desired performance. In this regard, this may include determining absolute values, relative values ​​(e.g., the value of a parameter associated with one component or feature as a ratio of the value of a parameter associated with another component or feature), etc. For example, the thickness of a particular structure or layer may be determined as an actual value, or as a relative value (e.g., a percentage) to another structure or layer in the morphology. In some embodiments, an optimization algorithm (e.g., least squares minimization of a merit function, associated with, for example, rigorous coupled wave analysis (RCWA) of diffraction efficiency) may be used to determine at least some of these parameters or characteristics.

[0048] For example, such an optimization algorithm may be used to determine the thickness of the multilayer structure 320 as a whole, determine the number of layers and / or the thickness of each layer in the multilayer structure 320, and / or select the materials used in each layer therein. Figure 3As shown, in form 300, based on the use of such an optimization algorithm, three individual layers in multilayer structure 320 (starting with first dielectric layer 322) may have the following thicknesses: 370 nm, 120 nm, and 120 nm, respectively, where first dielectric layer 322 and third dielectric layer 326 include tantalum pentoxide (Ta2O5), and second dielectric layer 324 includes silicon dioxide (SiO2). The optimization algorithm may also be used to determine the materials selected for use in grating line 310 and / or the grating-related parameters described above. However, it should be understood that the present disclosure is not limited to such arrangements and / or materials.

[0049] The use of morphologies implemented in accordance with the present disclosure, such as morphology 300, in immersion gratings results in improved performance. Figures 4 to 9 This performance improvement is shown in Figure 1. In this regard, the performance profiles are plotted for minimum diffraction efficiency over the wavelength range of 1525nm to 1615nm at an angle of incidence of 45.5°, and the crosshairs in each figure identify the grating morphology (defined by duty cycle (DC) and line height) that has a maximum value for that minimum diffraction efficiency.

[0050] Figure 4 Performance graphs of exemplary immersion gratings implemented without MLD are shown. Figure 4 Shown are contour plots 400 and 410 that include data representing the performance of an immersion grating implemented without MLD.

[0051] In this regard, each of the diagrams 400 and 410 includes a diagram showing that MLD is not used (e.g., having a configuration similar to Figure 3 Data on the performance (minimum diffraction efficiency in %) of two polarization (i.e., p-polarization and s-polarization) components of an immersion grating having a morphology 300 but without its MLD structure - i.e., without the multilayer structure 320) as a function of the duty cycle (DC) of the grating lines (y-axis) and the line height in μm (x-axis).

[0052] like Figure 4 As shown, each of the graphs 400 and 410 includes a contour of the minimum diffraction efficiency—that is, a contour line connecting data points corresponding to a particular minimum diffraction efficiency value. For example, as used herein, the minimum diffraction efficiency corresponds to the minimum value of R1 for both polarization components at the scanning wavelength (λ). In view of this, as Figure 4 As shown, the performance profile of minimum diffraction efficiency is plotted across a specified wavelength range (e.g., 1525nm to 1615nm) with an incident angle of 45.5°. Each crosshair shown in the graph indicates that a grating morphology is selected to provide the highest possible minimum efficiency (the maximum value of the minimum diffraction efficiency of the grating morphology defined by the duty cycle and line height).

[0053] The graphs 400 and 410 (or, specifically, the counters therein) can be interpreted similarly to a topographical map. As such, each of the graphs 400 and 410 indicates a range of variation in two parameters that can be tolerated in order to achieve a particular level of performance. For example, to achieve a minimum diffraction efficiency of 75%, the two parameters must be constrained to the interior of the contour "75". In other words, the contour 75 encompasses all data points corresponding to a minimum diffraction efficiency of 75% or greater, the contour 80 encompasses all data points corresponding to a minimum diffraction efficiency of 80% or greater, and so on.

[0054] Figure 5 Performance graph of an exemplary immersion grating implemented using MLD is shown. Figure 5 Shown in FIG. 5 are contour plots 500 and 510 that include data representing the performance of an immersion grating implemented using MLD.

[0055] In this regard, each of the graphs 500 and 510 includes a graph showing the use of MLD (e.g., having a similar Figure 3 Performance (minimum diffraction efficiency in % for all wavelengths (λ)) of two polarization (i.e., p-polarization and s-polarization) components of an immersion grating of morphology 300) as a function of the duty cycle (DC) of the grating lines (y-axis) and the line height in μm (x-axis). The crosshairs indicate the grating morphology selected to provide the highest possible minimum efficiency.

[0056] like Figure 4 and Figure 5 As shown in the graphs in , in particular by comparing the corresponding polarization graphs (e.g., graph 400 compared to graph 500 for p-polarization, and graph 410 compared to graph 510 for s-polarization), the inclusion of an MLD structure (particularly as described herein (e.g., multilayer structure 320 in form 300)) produces a significant improvement. In this regard, as shown in graphs 400, 410, 500 and 510, when the MLD structure is used for both polarization components, the area corresponding to a specific minimum diffraction efficiency value (e.g., 90%) is larger. The use of the MLD structure also ensures better alignment with the maximum value for this minimum diffraction efficiency. For example, as shown in Figure 4 and 5 The graph of shows that the inclusion of the MLD structure can provide benefits in two ways: 1) the peak efficiency of both polarizations is increased, and 2) the shift of the peak position of the s-polarization results in improved overlap between the high performance regions of the p-polarization and the s-polarization.

[0057] The inclusion of the MLD structure can produce improvements in Figures 6 to 9 It is further shown in FIG. 5 , where the diffraction efficiency of an immersion grating with and without MLD is compared depending on the wavelength or the angle of incidence.

[0058] Figure 6 is a graph showing the variation of zero-order reflection (R0) of an exemplary immersion grating as a function of wavelength. Figure 6 6 are graphs 600 and 610, which include graphs showing the difference between the MLD and the MLD, respectively. Figure 3 The immersion grating implemented by the embodiment of the embodiment 300, but without its MLD structure—that is, the multilayer structure 320) and the use of MLD (for example, with similar Figure 3 300) as a function of wavelength (λ). Specifically, each of graphs 600 and 610 includes data representing the zero-order reflection (R0) of two polarization components (p-polarization and s-polarization) as a function of wavelength (λ).

[0059] Figure 7 is a graph showing the first order reflection (R1) of an exemplary immersion grating as a function of wavelength. Figure 7 , which include graphs 700 and 710, respectively, without using MLD (eg, with Figure 3 300, but without its MLD structure—i.e., multilayer structure 320) and an immersion grating implemented using MLD (e.g., having Figure 3 300) as a function of wavelength (λ). Specifically, each of graphs 700 and 710 includes data representing the first order reflection (R1) of two polarization components (p-polarization and s-polarization) as a function of wavelength (λ).

[0060] As shown in graphs 600, 610, 710, and 720, the inclusion of the MLD structure provides a reduction in R0 across a wide wavelength range that strictly complements the improvement of R1 (since there are only two possible output orders).

[0061] Figure 8 is a graph showing the zero-order reflection (R0) of an exemplary immersion grating as a function of the incident angle. Figure 8 8 are graphs 800 and 810, which include graphs showing the respective non-use of MLD (e.g., having a similar Figure 3 The immersion grating implemented by the embodiment of the embodiment 300, but without its MLD structure—that is, the multilayer structure 320) and the use of MLD (for example, with similar Figure 3 300) as a function of the incident angle (θ). Specifically, each of the graphs 800 and 810 includes data representing the zero-order reflection (R0) of two polarization components (p-polarization and s-polarization) as a function of the incident angle (θ).

[0062] Fig. 9is a graph showing the first order reflection (R1) of an exemplary immersion grating as a function of the angle of incidence. Fig. 9 9 are graphs 900 and 910, which include graphs showing the respective non-use of MLD (e.g., having a similar Figure 3 The immersion grating implemented by the embodiment of the embodiment 300, but without its MLD structure—that is, the multilayer structure 320) and the use of MLD (for example, with similar Figure 3 300) as a function of the incident angle (θ). Specifically, each of the graphs 900 and 910 includes data representing the first order reflection (R1) of two polarization components (p-polarization and s-polarization) as a function of the incident angle (θ).

[0063] For example, in Figure 8 and Fig. 9 , for a particular center wavelength (e.g., λ=1570 nm), performance can be plotted as a function of the angle of incidence. To this end, the angular range can be selected to cover a range that allows the order to be constant (e.g., below 33.74°, allowing T0, and above 71.5°, allowing T1). As shown in graphs 800, 810, 910, and 920, the inclusion of the MLD structure provides improved performance—e.g., allowing improved peak diffraction efficiency for p-polarization, weaker angular dependence for p-polarization, and similar performance for both polarizations across the explored angular range.

[0064] Fig.10 Exemplary transmission gratings and use case scenarios associated therewith are shown. Fig.10 Shown in FIG. 1 is a transmission grating 1000 and a use case scenario associated therewith, such as during a grating operation using the transmission grating 1000 .

[0065] As shown, the transmission grating 1000 includes a grating structure including a repeating structure having a surface with close, equidistant and parallel lines separated by corresponding close, equidistant and parallel intervals, the surface being configured to resolve incident light. The grating structure is disposed on top of a material 1020 (e.g., fused silica). Fig.10 An exemplary grating operation using the transmission grating 1000 using a single propagation order is also shown in FIG. 1 . In this case, an input beam (incident light) is applied to the transmission grating 1000, wherein the input beam hits the transmission grating 1000 from the top side—that is, the input beam is applied to the top of the grating structure in air or vacuum—to generate a plurality of corresponding outputs.

[0066] For example, as shown, the input beam may include near infrared light having a wavelength in the range of 1525 nm to 1615 nm (e.g., λ=1548 nm) incident on the grating surface at an incident angle θ=74.7°, wherein the transmission grating has a line density of 1229 lines / mm. In this wavelength range, the refractive index (RI) of the fused silica used in the material 1020 is about 1.45. Fig.10 As shown, under these conditions, the allowed output orders produced by applying the input light beam to the transmission grating 1000 include zero-order reflection (R0), first-order reflection (R1), zero-order transmittance (T0) and first-order transmission diffraction efficiency (T1) outputs.

[0067] According to the present disclosure, a transmission grating (e.g., transmission grating 1000) may incorporate modified / enhanced morphologies for improving its performance. In this regard, as noted, such morphologies may incorporate intermediate layer structures that may be adaptively configured to enhance performance, particularly with respect to reflection losses of the transmission grating. Fig.11 Exemplary embodiments of transmission gratings incorporating such exemplary morphologies are shown and described in further detail.

[0068] Fig.11 An exemplary transmission grating morphology incorporating a multi-layer dielectric (MLD) structure is shown. Fig.11 Shown in FIG. 1 is a transmission grating-based form 1100 (or a portion thereof). In particular, Fig.11 A cross-section of form 1100 is shown in , showing the grating layer and its associated underlying layers.

[0069] like Fig.11 As shown, the form 1100 includes a multilayer grating line 1110, a multilayer structure 1120, and a substrate (e.g., based on fused silica) 1130. In this regard, Fig.11 In the portion of the form 1100 shown in , only two (2) grating lines 1110 are shown, but it should be understood that the form 1100 is composed of many lines.

[0070] Each grating line 1110 includes multiple layers. Fig.11In the illustrated form 1100, the grating lines 1110 may include three (3) layers: a first grating layer 1112, a second grating layer 1114, and a third grating layer 1116. The grating layers may include different materials. For example, the layers used in the grating lines 1110 may include materials with different refractive indices (RI). The grating lines 1110 may include, for example, alternating layers of materials of different refractive indices (RI). In this regard, in some implementations, an arrangement including low RI materials and high RI materials may be used. Layers based on low RI materials and layers based on high RI materials may alternate. Nevertheless, the present disclosure is not limited to such a multilayer arrangement, and any other suitable arrangement may be used.

[0071] In addition to the materials used therein, the grating lines 1110 may be characterized by one or more grating related parameters such as line height, line width, grating period, and duty cycle (DC). These parameters are Fig.11 1100 relative to the grating lines 1110 of the form 1100. In this regard, as used herein, the duty cycle is defined as the line width (i.e., the width of each grating line 1110) divided by the grating period - that is, duty cycle = line width / grating period. As such, the line width of the grating lines 1110 may be simply indicated based on the duty cycle indicating the grating period. The values ​​of the grating related parameters may be set to optimize performance. For example, in the form 1100, the line height may be 863nm and the grating period may be 813.7nm. In addition, the grating lines 1110 have a duty cycle of 45% ± 2%, and therefore, with a grating period of 580nm, the line width of the grating lines 1110 in the form 1100 may be 366.16nm ± 16.27nm. Additionally, while the grating lines are shown as having a cross-sectional profile with a simple rectangular shape, the present disclosure is not limited to such shapes, and as such other shapes may be used if deemed appropriate—for example, the cross-sectional profile of the lines may be trapezoidal or have a curved profile and / or sidewalls, and be modeled and optimized accordingly. In this regard, in such cases, the line width and duty cycle may be defined as a specific height or as an average over multiple heights.

[0072] The multilayer structure 1120 includes a set of layers that are adaptively configured (e.g., based on the selection of materials used therein, their dimensions, the arrangement of the layers, etc.) to provide a reflective performance that meets a predetermined standard. In this regard, the multilayer structure 1120 can be configured to operate to reduce reflections and optimize performance when operating in this manner. In various exemplary embodiments, the multilayer structure 1120 can include multiple dielectric layers. As such, the multilayer structure 1120 (and similar structures) are referred to herein as a multilayer dielectric (MLD)-based structure, an MLD coating, or simply an MLD.

[0073] For example, in form 1100, multilayer structure 1120 includes three (3) layers: a first dielectric layer 1122, a second dielectric layer 1124, and a third dielectric layer 1126. In some implementations, different layers in multilayer structure 1120 may include materials having different refractive indices (RI). Different layers in multilayer structure 1120 may include, for example, alternating layers of different refractive index (RI) materials. In this regard, in some implementations, multilayer structure 1120 may include alternating layers of high refractive index (RI) and low refractive index (RI) materials. For example, in form 1100, first dielectric layer 1122 may include a high RI material, and in addition to first dielectric layer 1122, multilayer structure 1120 may include a pair of LH-based layers. Preferably, the same material is used throughout. Thus, in Fig.11 In the exemplary embodiment shown in , the multilayer structure 1120 in the form 1100 includes a HLH arrangement. Nevertheless, in some cases, different high RI and / or low RI materials (and layers including such materials) can be used. The materials used in the multilayer structure 1120 can be selected to optimize performance.

[0074] The substrate 1130 may include a suitable material and may have predetermined dimensions for optimizing performance. Fig.11 In the illustrated exemplary embodiment, substrate 1130 may include a fused silica based substrate.

[0075] Various parameters or characteristics of at least some of the components and / or features of the morphology 1100 may be adaptively selected or adjusted based on desired performance. In this regard, this may include determining absolute values, relative values ​​(e.g., the value of a parameter associated with one component or feature as a ratio of the value of a parameter associated with another component or feature), etc. For example, the thickness of a particular structure or layer may be determined as an actual value, or as a relative value (e.g., a percentage) to another structure or layer in the morphology. In some embodiments, an optimization algorithm (e.g., least squares minimization of a merit function, associated with rigorous coupled wave analysis (RCWA) of, for example, diffraction efficiency) may be used to determine at least some of these parameters or characteristics.

[0076] For example, such an optimization algorithm may be used to determine the thickness of the multilayer structure 1120 as a whole, determine the number of layers and / or the thickness of each layer in the multilayer structure 1120, and / or select the materials used in each layer therein. Fig.11As shown, in form 1100, based on the use of such an optimization algorithm, 11 individual layers in multilayer structure 1120 (starting from first dielectric layer 1122) may have the following thicknesses: 202 nm, 162 nm, and 45 nm, respectively, wherein first dielectric layer 1122 and third dielectric layer 1126 include titanium dioxide (TiO2), and second dielectric layer 1124 includes silicon dioxide (SiO2). However, it should be understood that the present disclosure is not limited to such arrangements and / or materials.

[0077] Similarly, such an optimization algorithm can be used to determine the thickness of each grating line 1110 as a whole, determine the number of layers in each grating line 1110 and / or the thickness of each layer, and / or select the material used in each layer therein. Fig.11 As shown, in form 1100, based on the use of such an optimization algorithm, in a grating line 1110 having a total bus height of 863 nm, the thicknesses of the three individual layers (starting from the first grating layer 1112) may be 356 nm, 450 nm, and 57 nm, respectively, wherein the first grating layer 1112 and the third grating layer 1116 include silicon dioxide (SiO2), and the second grating layer 1114 includes silicon (Si). The optimization algorithm may also be used to determine the materials selected for use in the grating line 1110 and / or the grating-related parameters described above. However, it should be understood that the present disclosure is not limited to such arrangements and / or materials.

[0078] The use of morphologies (such as morphology 1100) implemented in accordance with the present disclosure in transmission gratings results in improved performance. In this regard, morphology 1100 can promote improved performance for specific wavelength ranges. For example, in combination with Fig.11 The transmission grating of the form 1100 shown and described may be specifically configured for improved performance in the wavelength range of 1528 nm to 1569 nm. This performance improvement is Figures 12 to 25 , which shows the performance improvement when using a transmission grating incorporating form 1100 as described herein. In this regard, since the grating lines 1110 in form 1100 include multiple layers, the results for tuning the center layer (amorphous silicon) while keeping the top and bottom (SiO2) layer thicknesses fixed are shown. The performance contours are plotted for minimum diffraction efficiency across a wavelength range of 1528nm to 1569nm, where the angle of incidence is 74.7°, and where the crosshairs in each graph identify the grating form (defined by duty cycle (DC) and line height) that has a maximum value for that minimum diffraction efficiency.

[0079] Fig.12 Performance graphs of exemplary transmission gratings implemented without MLD are shown. Fig.12 Shown in FIG. 1 are contour plots 1200 and 1210 including data representing the performance of a transmission grating implemented without an MLD.

[0080] In this regard, each of the graphs 1200 and 1210 includes a graph representing the absence of MLD (e.g., having a value similar to Fig.11 Data on the performance (minimum diffraction efficiency, in %, for all wavelengths (λ)) of two polarization (i.e., p-polarization and s-polarization) components of a transmission grating of morphology 1100 but without its MLD structure—i.e., multilayer structure 1120) as a function of the duty cycle (DC) of the grating lines (y-axis) and the line height in μm (x-axis).

[0081] like Fig.12 As shown, each of the graphs 1200 and 1210 includes a contour of the minimum diffraction efficiency—that is, a contour line connecting data points corresponding to a particular minimum diffraction efficiency value. For example, as used herein, for both polarization components, the minimum diffraction efficiency corresponds to a minimum value over the scanned wavelength (λ). The crosshairs indicate that the grating morphology is selected to provide the highest possible minimum efficiency.

[0082] The graphs 1200 and 1210 (or, specifically, the counters therein) can be interpreted similarly to a topographic map. As such, each of the graphs 1200 and 1210 indicates a range of variation in two parameters that can be tolerated in order to achieve a particular level of performance. For example, to achieve a minimum diffraction efficiency of 75%, the two parameters must be constrained to the interior of the contour "75". In other words, the contour 75 encompasses all data points corresponding to a minimum diffraction efficiency of 75% or greater, the contour 80 encompasses all data points corresponding to a minimum diffraction efficiency of 80% or greater, and so on.

[0083] Fig.13 Performance graphs of exemplary transmission gratings implemented using MLDs are shown. Fig.13 Shown in FIG. 1 are contour plots 1300 and 1310 including data representing the performance of a transmission grating implemented using an MLD.

[0084] In this regard, each of the graphs 1300 and 1310 includes a graph showing the use of MLD (e.g., having a similar Fig.11 Data showing the performance (minimum diffraction efficiency %, in %) of two polarization (i.e., p-polarization and s-polarization) components of a transmission grating of morphology 1100 (morphology of FIG. 1100 ) as a function of the duty cycle (DC) of the grating lines (y-axis) and the line height in μm (x-axis). The crosshairs indicate the grating morphology selected to provide the highest possible minimum efficiency.

[0085] like Fig.12 and Fig.13As shown in the graphs in , in particular by comparing the corresponding polarization graphs (e.g., graph 1200 compared to graph 1300 for p-polarization, and graph 1210 compared to graph 1310 for s-polarization), the inclusion of an MLD structure (particularly as described herein (e.g., multilayer structure 1120 in form 1100)) produces a significant improvement. In this regard, as shown in graphs 1200, 1210, 1300 and 1310, when the MLD structure is used for both polarization components, the area corresponding to a specific minimum diffraction efficiency value (e.g., 90%) is larger. The use of the MLD structure also ensures better alignment with the maximum value for this minimum diffraction efficiency. For example, as shown in graphs 1200, 1210, 1300 and 1310, the area corresponding to a specific minimum diffraction efficiency value (e.g., 90%) is larger. The use of the MLD structure also ensures better alignment with the maximum value for this minimum diffraction efficiency. For example, Fig.12 and 13 The graph of φ shows that the inclusion of the MLD structure can provide benefits in two ways: 1) an overall increase in the performance level for both polarizations, and 2) better alignment of the high performance regions for the p- and s-polarizations.

[0086] The inclusion of MLD structures can produce improvements in Figures 14 to 25 It is further shown in FIG. 5 , where the diffraction efficiency of a transmission grating with and without MLD is compared depending on the wavelength or the incident angle.

[0087] Fig.14 is a graph showing the variation of the zero-order transmittance (T0) of an exemplary transmission grating with wavelength. Fig.14 1400 and 1410, which include graphs showing the respective non-use of MLD (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 1100) as a function of wavelength (λ). Specifically, each of the graphs 1400 and 1410 includes data representing how the zero-order transmittance (T0) of two polarization components (p-polarization and s-polarization) varies with wavelength (λ).

[0088] Fig.15 is a graph showing the first-order transmission diffraction efficiency (T1) of an exemplary transmission grating as a function of wavelength. Fig.15 15 is a graph 1500 and a graph 1510, which include graphs showing that MLD is not used (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11The first-order transmission diffraction efficiency (T1) of the transmission grating of the form 1100 (the form of the embodiment of the invention) varies with the wavelength (λ). Specifically, each of the graphs 1500 and 1510 includes data representing the first-order transmission diffraction efficiency (T1) of two polarization components (p-polarization and s-polarization) varies with the wavelength (λ).

[0089] Fig.16 is a graph showing the variation of zero-order reflection (R0) of an exemplary transmission grating with wavelength. Fig.16 16 is a graph 1600 and a graph 1610, which include graphs showing that MLD is not used (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 1100) as a function of wavelength (λ). Specifically, each of the graphs 1600 and 1610 includes data representing the zero-order reflection (R0) of two polarization components (p-polarization and s-polarization) as a function of wavelength (λ).

[0090] Fig.17 is a graph showing the variation of the first order reflection (R1) of an exemplary transmission grating with wavelength. Fig.17 1700 and 1710, which include graphs showing that MLD is not used (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 1100) as a function of wavelength (λ). Specifically, each of the graphs 1700 and 1710 includes data representing the first order reflection (R1) of two polarization components (p-polarization and s-polarization) as a function of wavelength (λ).

[0091] Fig.18 is a graph showing the total reflectivity (R) of an exemplary transmission grating as a function of wavelength. Fig.18 18 is a graph 1800 and a graph 1810, which include graphs showing that MLD is not used (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 The graphs 1800 and 1810 each include data showing how the total reflectivity (R) of a transmission grating (of the embodiment 1100) varies with wavelength (λ). Specifically, each of the graphs 1800 and 1810 includes data showing how the total reflectivity (R) of two polarization components (p-polarization and s-polarization) varies with wavelength (λ).

[0092] like Figures 14 to 18 As shown in the graph in , the inclusion of the MLD structure produces an improvement in the transmission grating. To this end, under the described illumination conditions, the transmission grating produces four output orders: R0, R1, T0, T1. The graph comparing each output order shows that the grating using the MLD structure exhibits a smaller total reflectivity over the entire wavelength range and for both polarizations (p-polarization and s-polarization). In addition, the grating using the MLD structure exhibits an increased T1 over the entire wavelength range and for both polarizations (p-polarization and s-polarization).

[0093] Fig.19 is a graph showing the zero-order reflection (R0) of an exemplary transmission grating as a function of the incident angle. Fig.19 1900 and 1910, which include graphs showing the respective non-use of MLD (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 1100) as a function of the incident angle (θ). Specifically, each of the graphs 1900 and 1910 includes data representing the zero-order reflection (R0) of two polarization components (p-polarization and s-polarization) as a function of the incident angle (θ).

[0094] Fig. 20 is a graph showing the first order reflection (R1) of an exemplary transmission grating as a function of the incident angle. Fig. 20 Shown in FIG. 2 are graphs 2000 and 2010, which include graphs showing the difference between the MLD and the MLD, respectively. Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 The graphs 2000 and 2010 each include data showing how the first-order reflection (R1) of a transmission grating (of the embodiment 1100) varies with the incident angle (θ). Specifically, each of the graphs 2000 and 2010 includes data showing how the first-order reflection (R1) of two polarization components (p-polarization and s-polarization) varies with the incident angle (θ).

[0095] Fig.21 is a graph showing the total reflectivity (R) of an exemplary transmission grating as a function of the incident angle. Fig.21 2100 and 2110, which include graphs showing the respective non-use of MLD (e.g., having a similar Fig.11The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 The graphs 2100 and 2110 each include data showing how the total reflectivity (R) of a transmission grating (of the embodiment 1100) varies with the incident angle (θ). Specifically, each of the graphs 2100 and 2110 includes data showing how the total reflectivity (R) of two polarization components (p-polarization and s-polarization) varies with the incident angle (θ).

[0096] Fig. 22 is a graph showing the variation of the zero-order transmittance (T0) of an exemplary transmission grating with the incident angle. Fig. 22 2200 and 2210, which include graphs showing that MLD is not used (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 The graphs 2200 and 2210 each include data showing how the zero-order transmittance (T0) of a transmission grating (the morphology of 1100) varies with the incident angle (θ). Specifically, each of the graphs 2200 and 2210 includes data showing how the zero-order transmittance (T0) of two polarization components (p-polarization and s-polarization) varies with the incident angle (θ).

[0097] Fig.23 is a graph showing the first-order transmission diffraction efficiency (T1) of an exemplary transmission grating as a function of the incident angle. Fig.23 2300 and 2310, which include graphs showing that MLD is not used (e.g., having a similar Fig.11 The transmission grating implemented in the form of the form 1100, but without its MLD structure - that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 The first-order transmission diffraction efficiency (T1) of the transmission grating (the form of 1100) varies with the incident angle (θ). Specifically, each of the graphs 2300 and 2310 includes data representing the first-order transmission diffraction efficiency (T1) of two polarization components (p-polarization and s-polarization) varies with the incident angle (θ).

[0098] like Figures 19 to 23 As shown in the graph in , including the MLD structure in the transmission grating improves the performance for both polarizations (p-polarization and s-polarization) with respect to different output orders when evaluated based on the angle of incidence.

[0099] The angular range explored and shown in the graphs is chosen to preserve the number of allowed orders. For easier comparison, the results with and without the MLD structure are plotted together for T1 and total reflectivity R, as Figure 24 to Figure 25As shown and described in relation thereto.

[0100] Fig.24 is a graph showing the first order transmission diffraction efficiency (T1) performance of exemplary transmission gratings with and without MLD. Fig.24 2400, which includes graphs showing the respective Fig.11 The transmission grating implemented in the form of 1100 but without its MLD structure—that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 Data on the first-order transmission diffraction efficiency (T1) of the transmission grating (in the form of 1100) varying with the incident angle (θ) and the first-order transmission diffraction efficiency of the two polarization components (p-polarization and s-polarization) varying with the incident angle (θ).

[0101] As shown in graph 2400, while in all cases the entry T1 efficiency decreases with increasing incident angle, the transmission grating using the MLD structure performs better over the entire angular range than a similar transmission grating (e.g., comprising similar components and structure) that does not use the MLD structure.

[0102] Fig.25 is a graph showing the total reflectivity (R) performance of an exemplary transmission grating with and without MLD. Fig.25 25 is a graph 2500 including graphs showing the respective Fig.11 The transmission grating implemented in the form of 1100 but without its MLD structure—that is, the multilayer structure 1120) and the transmission grating implemented using MLD (for example, having a structure similar to Fig.11 Data on the variation of the total reflectivity (R) of the transmission grating (in the form of 1100) with the incident angle (θ) and the variation of the total reflectivity of the two polarization components (p-polarization and s-polarization) with the incident angle (θ).

[0103] As shown in graph 2500, although in all cases the total reflection increases as the incident angle approaches 90°, over the entire angular range explored, the total reflectivity of both polarizations of the transmission grating using the MLD structure is strictly smaller than that of a similar transmission grating (e.g., comprising similar components and structure) that does not use the MLD structure.

[0104] Based on the present disclosure, an exemplary immersion grating-based morphology includes a plurality of grating lines; an intermediate multilayer structure; and a substrate carrying the plurality of grating lines and the intermediate multilayer structure; wherein the intermediate multilayer structure includes a plurality of intermediate layers; wherein at least two of the plurality of intermediate layers include different refractive index (RI) materials; and wherein the intermediate multilayer structure improves the performance of the immersion grating based on predetermined performance criteria, wherein the performance criteria include one or more parameters or conditions related to the reflection loss of the immersion grating, and wherein the one or more parameters or conditions related to the reflection loss include prohibiting at least some of the transmission orders of the input light beam applied beyond the critical angle of the substrate.

[0105] In an exemplary embodiment, the plurality of intermediate layers includes a plurality of dielectric layers.

[0106] In an exemplary embodiment, the plurality of intermediate layers includes: one or more layers including a first refractive index (RI) material and one or more layers including a second refractive index (RI) material, wherein the first refractive index (RI) material is different from the second refractive index (RI) material.

[0107] In an exemplary embodiment, the first refractive index (RI) material includes a low refractive index (RI) material and the second refractive index (RI) material includes a high refractive index (RI) material.

[0108] In an exemplary embodiment, one or more layers including a first refractive index (RI) material and one or more layers including a second refractive index (RI) material are alternately arranged.

[0109] In an exemplary embodiment, the first refractive index (RI) material includes silicon dioxide (SiO2).

[0110] In an exemplary embodiment, the second refractive index (RI) material includes tantalum pentoxide (Ta2O5).

[0111] In an exemplary embodiment, each of the plurality of grating lines comprises a single grating layer.

[0112] In an exemplary embodiment, each of the plurality of grating lines includes silicon (Si).

[0113] In an exemplary embodiment, the substrate includes a glass-based material.

[0114] In an exemplary embodiment, one or more morphology parameters or characteristics of the immersion grating based morphology are set or adjusted to meet predetermined performance criteria.

[0115] In an exemplary embodiment, the one or more morphological parameters or characteristics include one or more of the following: a line height of a plurality of grating lines, a line width of a plurality of grating lines, a period of a plurality of grating lines, a duty cycle of a plurality of grating lines, a selection of materials used in a plurality of grating lines, a number of layers in a plurality of intermediate layers, a thickness of each of a plurality of intermediate layers, and a selection of materials used in each of a plurality of intermediate layers.

[0116] Based on the present disclosure, an exemplary transmission grating-based morphology includes a plurality of grating lines; an intermediate multilayer structure; and a substrate carrying the plurality of grating lines and the intermediate multilayer structure; wherein the intermediate multilayer structure includes a plurality of intermediate layers; wherein at least two of the plurality of intermediate layers include different refractive index (RI) materials; and wherein the intermediate multilayer structure improves the performance of the transmission grating based on predetermined performance criteria, wherein the performance criteria include one or more parameters or conditions related to the reflection loss of the transmission grating, and wherein the one or more parameters or conditions related to the reflection loss include prohibiting all outputs of an input light beam applied to the transmission grating that exceed a first transmission order and a first reflection order (or, alternatively, all outputs that exceed a zero-order transmission order, a zero-order reflection order, a first transmission order, and a first reflection order).

[0117] In an exemplary embodiment, the plurality of intermediate layers includes a plurality of dielectric layers.

[0118] In an exemplary embodiment, the plurality of intermediate layers includes: one or more layers including a first refractive index (RI) material and one or more layers including a second refractive index (RI) material, wherein the first refractive index (RI) material is different from the second refractive index (RI) material.

[0119] In an exemplary embodiment, the first refractive index (RI) material includes a low refractive index (RI) material and the second refractive index (RI) material includes a high refractive index (RI) material.

[0120] In an exemplary embodiment, one or more layers including a first refractive index (RI) material and one or more layers including a second refractive index (RI) material are alternately arranged.

[0121] In an exemplary embodiment, the first refractive index (RI) material includes silicon dioxide (SiO2).

[0122] In an exemplary embodiment, the second refractive index (RI) material includes titanium dioxide (TiO2).

[0123] In an exemplary embodiment, one or more of the plurality of grating lines comprises a plurality of grating layers.

[0124] In an exemplary embodiment, the plurality of grating layers comprises: one or more layers comprising a first refractive index (RI) material and one or more layers comprising a second refractive index (RI) material, wherein the first refractive index (RI) material is different from the second refractive index (RI) material.

[0125] In an exemplary embodiment, the first refractive index (RI) material includes a high refractive index (RI) material and the second refractive index (RI) material includes a low refractive index (RI) material.

[0126] In an exemplary embodiment, one or more layers including a first refractive index (RI) material and one or more layers including a second refractive index (RI) material are alternately arranged.

[0127] In an exemplary embodiment, the first refractive index (RI) material includes silicon (Si).

[0128] In an exemplary embodiment, the second refractive index (RI) material includes silicon dioxide (SiO2).

[0129] In an exemplary embodiment, the substrate includes a fused silica based material.

[0130] In an exemplary embodiment, one or more morphology parameters or characteristics of the transmission grating based morphology are set or adjusted to meet predetermined performance criteria.

[0131] In an exemplary embodiment, the one or more morphological parameters or characteristics include one or more of the following: a line height of a plurality of grating lines, a line width of a plurality of grating lines, a period of a plurality of grating lines, a duty cycle of a plurality of grating lines, a selection of materials used in a plurality of grating lines, a number of layers in a plurality of grating layers used in one or more grating lines, a thickness of each of a plurality of grating layers, a selection of materials used in each of a plurality of grating layers, a number of layers in a plurality of intermediate layers, a thickness of each of a plurality of intermediate layers, and a selection of materials used in each of a plurality of intermediate layers.

[0132] As used herein, "and / or" refers to any one or more of the items connected by "and / or" in a list. As an example, "x and / or y" represents any element in a three-element set {(x), (y), (x, y)}. In other words, "x and / or y" refers to "one or both of x and y". As another example, "x, y and / or z" refers to any element in a seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, "x, y and / or z" refers to "one or more of x, y and z". As used herein, the term "exemplary" refers to serving as a non-limiting example, instance or illustration. As used herein, the terms "for example" and "such as" list one or more non-limiting examples, instances or illustrations.

[0133] Although the present method and / or system has been described with reference to certain implementations, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and / or system. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the present disclosure without departing from the scope of the present disclosure. Therefore, the present method and / or system is not limited to the specific implementation disclosed, and the present method and / or system will include all implementations that fall within the scope of the appended claims.

Claims

1. A form based on immersion grating, comprising: Multiple raster lines; Intermediate multi-layer structure; as well as a substrate, the substrate carrying the plurality of grating lines and the intermediate multilayer structure; Wherein, the intermediate multi-layer structure comprises a plurality of intermediate layers; wherein at least two of the plurality of intermediate layers comprise materials of different refractive indices; and wherein the intermediate multilayer structure improves the performance of the immersion grating based on predetermined performance criteria, wherein the performance criteria include one or more parameters or conditions related to reflection losses of the immersion grating, and wherein the one or more parameters or conditions related to the reflection losses include prohibiting at least some of the transmission orders of the input light beam applied beyond the critical angle of the substrate.

2. The immersion grating-based modality of claim 1, wherein: The plurality of intermediate layers include a plurality of dielectric layers.

3. The immersion grating-based modality of claim 1, wherein: The plurality of intermediate layers include one or more layers including a first refractive index material and one or more layers including a second refractive index material, and wherein the first refractive index material is different from the second refractive index material.

4. The immersion grating-based modality of claim 3, wherein: The first refractive index material comprises a low refractive index material, and the second refractive index material comprises a high refractive index material.

5. The immersion grating based modality of claim 3, wherein: The one or more layers including the first refractive index material and the one or more layers including the second refractive index material are arranged alternately.

6. The immersion grating based modality of claim 3, wherein: The first refractive index material includes silicon dioxide.

7. The immersion grating based modality of claim 3, wherein: The second refractive index material includes tantalum pentoxide.

8. The immersion grating based modality of claim 1, wherein: Each of the plurality of grating lines includes a single grating layer.

9. The immersion grating based modality of claim 1, wherein: Each of the plurality of grating lines comprises silicon.

10. The immersion grating based modality of claim 1, wherein: The substrate includes a glass-based material.

11. The immersion grating based modality of claim 1, wherein: One or more morphological parameters or characteristics of the immersion grating based morphology are set or adjusted to meet the predetermined performance criteria.

12. The immersion grating based modality of claim 11, wherein: The one or more morphological parameters or characteristics include one or more of the following: The line heights of the plurality of grating lines, The line width of the plurality of grating lines, The period of the plurality of grating lines, The duty cycle of the plurality of grating lines, the selection of materials used in the plurality of grating lines, the number of layers in the plurality of intermediate layers, the thickness of each of the plurality of intermediate layers, and Selection of materials used in each of the plurality of intermediate layers.

13. A transmission grating-based form, comprising: Multiple raster lines; Intermediate multi-layer structure; as well as a substrate, the substrate carrying the plurality of grating lines and the intermediate multilayer structure; Wherein, the intermediate multi-layer structure comprises a plurality of intermediate layers; wherein at least two of the plurality of intermediate layers comprise materials of different refractive indices; and wherein the intermediate multilayer structure improves the performance of the transmission grating based on predetermined performance criteria, wherein the performance criteria include one or more parameters or conditions related to reflection loss of the transmission grating, and wherein the one or more parameters or conditions related to the reflection loss include prohibiting all outputs of the input light beam applied to the transmission grating beyond a first transmission order and a first reflection order.

14. The transmission grating-based modality of claim 13, wherein: The plurality of intermediate layers include a plurality of dielectric layers.

15. The transmission grating based modality of claim 13, wherein: The plurality of intermediate layers include one or more layers including a first refractive index material and one or more layers including a second refractive index material, and wherein the first refractive index material is different from the second refractive index material.

16. The transmission grating based modality of claim 15, wherein: The first refractive index material comprises a low refractive index material, and the second refractive index material comprises a high refractive index material.

17. The transmission grating based modality of claim 15, wherein: The one or more layers including the first refractive index material and the one or more layers including the second refractive index material are arranged alternately.

18. The transmission grating based modality of claim 15, wherein: The first refractive index material includes silicon dioxide.

19. The transmission grating-based modality of claim 15, wherein: The second refractive index material includes titanium dioxide.

20. The transmission grating based modality of claim 13, wherein: One or more of the plurality of grating lines includes a plurality of grating layers.

21. The transmission grating-based modality of claim 20, wherein: The plurality of grating layers include: one or more layers including a first refractive index material and one or more layers including a second refractive index material, and wherein the first refractive index material is different from the second refractive index material.

22. The transmission grating-based modality of claim 21, wherein: The first refractive index material includes a high refractive index material, and the second refractive index material includes a low refractive index material.

23. The transmission grating-based modality of claim 21, wherein: The one or more layers including the first refractive index material and the one or more layers including the second refractive index material are arranged alternately.

24. The transmission grating-based modality of claim 21, wherein: The first refractive index material includes silicon.

25. The transmission grating-based modality of claim 21, wherein: The second refractive index material includes silicon dioxide.

26. The transmission grating based modality of claim 13, wherein: The substrate includes a fused silica based material.

27. The transmission grating based modality of claim 13, wherein: One or more morphology parameters or characteristics of the transmission grating-based morphology are set or adjusted to meet the predetermined performance criteria.

28. The transmission grating based modality of claim 27, wherein: The one or more morphological parameters or characteristics include one or more of the following: The line heights of the plurality of grating lines, The line width of the plurality of grating lines, The period of the plurality of grating lines, The duty cycle of the plurality of grating lines, the selection of materials used in the plurality of grating lines, the number of layers in the plurality of grating layers used in the one or more grating lines, the thickness of each of the plurality of grating layers, the selection of materials used in each of the plurality of grating layers, the number of layers in the plurality of intermediate layers, the thickness of each of the plurality of intermediate layers, and Selection of materials used in each of the plurality of intermediate layers.

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