In this study, we demonstrate the fabrication of waveguide resonators using nanoimprint technology. Without relying on traditionally costly lithography methods, such as electron-beam lithography or stepper lithography, silicon nitride (Si3N4) resonators with high-quality factors up to the order of 105 can be realized at C-band by nanoimprint lithography. In addition, by properly designing the waveguide geometry, a low-dispersive waveguide can be achieved with waveguide dispersion at around −35 ps/nm/km in the normal dispersion regime, and the waveguide dispersion can be further tuned to be 29 ps/nm/km in the anomalous dispersion regime with the polymer cladding. The tunability of nanoimprinted devices is demonstrated by the aid of microheaters, realizing on-chip optical functionalities. This work offers the potential to fabricate low-dispersive waveguide resonators for integrated modulators and filters in a significantly cost-effective and process-friendly scheme.
在这项研究中，我们展示了利用纳米压印技术制造波导谐振器的方法。在不依赖电子束光刻或步进光刻等传统昂贵光刻方法的情况下，通过纳米压印光刻技术可以在 C 波段实现质量系数高达 105 的氮化硅（Si3N4）谐振器。此外，通过适当设计波导几何形状，还可实现低色散波导，在正常色散机制下，波导色散约为-35 ps/nm/km，而在反常色散机制下，利用聚合物包层可将波导色散进一步调整为 29 ps/nm/km。借助微加热器，纳米压印器件的可调性得到了验证，从而实现了片上光学功能。这项工作为以一种极具成本效益且工艺友好的方案制造用于集成调制器和滤波器的低色散波导谐振器提供了可能性。
{"title":"Low-dispersive silicon nitride waveguide resonators by nanoimprint lithography","authors":"Pei-Hsun Wang, He-Yuan Zheng, Yuan-Hsiu Liu, Nien-Lin Hou, Chien-Hung Chen, Hung-Wen Chen, Chih-Ming Wang","doi":"10.1063/5.0204857","DOIUrl":"https://doi.org/10.1063/5.0204857","url":null,"abstract":"In this study, we demonstrate the fabrication of waveguide resonators using nanoimprint technology. Without relying on traditionally costly lithography methods, such as electron-beam lithography or stepper lithography, silicon nitride (Si3N4) resonators with high-quality factors up to the order of 105 can be realized at C-band by nanoimprint lithography. In addition, by properly designing the waveguide geometry, a low-dispersive waveguide can be achieved with waveguide dispersion at around −35 ps/nm/km in the normal dispersion regime, and the waveguide dispersion can be further tuned to be 29 ps/nm/km in the anomalous dispersion regime with the polymer cladding. The tunability of nanoimprinted devices is demonstrated by the aid of microheaters, realizing on-chip optical functionalities. This work offers the potential to fabricate low-dispersive waveguide resonators for integrated modulators and filters in a significantly cost-effective and process-friendly scheme.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"58 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This Tutorial introduces structural color in fruits as a phenomenon of diverse optical materials. Originally best known in abiotic materials and animals, structural colors are being increasingly described in plants. Structural colors have already inspired a variety of useful products, and plants are especially attractive as models to develop new bioinspired technologies thanks to the comparative ease of working with them compared with animal systems. Already, human-engineered structural colors modeled after plant cellulose-based architectures have shown promising applications in colorants and sensors. However, structural colors include a far broader group of materials and architectures beyond cellulose. Understanding the new and diverse structures that have recently been described in plants should provoke research into new bioinspired products based on plant optical structures and biomaterials. In this Tutorial, we focus on fruits as new structures have recently been discovered, leading to new opportunities for bioinspired technologies. We bring together a review of optical structures found in fruits from a physical optics perspective, with a consideration of each structure as an opportunity in bioinspired and biomimetic design.
{"title":"Structural color in fruits: Biomaterials to inspire physical optics","authors":"R. Middleton, M. Sinnott-Armstrong","doi":"10.1063/5.0208528","DOIUrl":"https://doi.org/10.1063/5.0208528","url":null,"abstract":"This Tutorial introduces structural color in fruits as a phenomenon of diverse optical materials. Originally best known in abiotic materials and animals, structural colors are being increasingly described in plants. Structural colors have already inspired a variety of useful products, and plants are especially attractive as models to develop new bioinspired technologies thanks to the comparative ease of working with them compared with animal systems. Already, human-engineered structural colors modeled after plant cellulose-based architectures have shown promising applications in colorants and sensors. However, structural colors include a far broader group of materials and architectures beyond cellulose. Understanding the new and diverse structures that have recently been described in plants should provoke research into new bioinspired products based on plant optical structures and biomaterials. In this Tutorial, we focus on fruits as new structures have recently been discovered, leading to new opportunities for bioinspired technologies. We bring together a review of optical structures found in fruits from a physical optics perspective, with a consideration of each structure as an opportunity in bioinspired and biomimetic design.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"144 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Colin J. Mitchell, Tianhui Hu, Shiyu Sun, Callum J. Stirling, Milos Nedeljkovic, Anna C. Peacock, Graham T. Reed, Goran Z. Mashanovich, David J. Rowe
Silicon photonics is one of the most dynamic fields within photonics, and it has seen huge progress in the last 20 years, addressing applications in data centers, autonomous cars, and sensing. It is mostly focused on the telecommunications wavelength range (1.3 and 1.55 µm), where silicon becomes transparent. In this range, there are excellent light sources and photodetectors, as well as optical fibers operating with extremely low losses and dispersion. It is a technology that hugely benefits from the availability of complementary metal–oxide–semiconductor (CMOS) fabrication infrastructure and techniques used for microelectronics. Silicon and germanium, as another CMOS compatible group IV material, are transparent beyond the wavelength of 2 µm. The mid-IR wavelength range (2–20 µm) is of particular importance as it contains strong absorption signatures of many molecules. Therefore, Si- and Ge-based platforms open up the possibility of small and cost-effective sensing in the fingerprint region for medical and environmental monitoring. In this paper, we discuss the current mid-IR silicon photonics landscape, future directions, and potential applications of the field.
{"title":"Mid-infrared silicon photonics: From benchtop to real-world applications","authors":"Colin J. Mitchell, Tianhui Hu, Shiyu Sun, Callum J. Stirling, Milos Nedeljkovic, Anna C. Peacock, Graham T. Reed, Goran Z. Mashanovich, David J. Rowe","doi":"10.1063/5.0222890","DOIUrl":"https://doi.org/10.1063/5.0222890","url":null,"abstract":"Silicon photonics is one of the most dynamic fields within photonics, and it has seen huge progress in the last 20 years, addressing applications in data centers, autonomous cars, and sensing. It is mostly focused on the telecommunications wavelength range (1.3 and 1.55 µm), where silicon becomes transparent. In this range, there are excellent light sources and photodetectors, as well as optical fibers operating with extremely low losses and dispersion. It is a technology that hugely benefits from the availability of complementary metal–oxide–semiconductor (CMOS) fabrication infrastructure and techniques used for microelectronics. Silicon and germanium, as another CMOS compatible group IV material, are transparent beyond the wavelength of 2 µm. The mid-IR wavelength range (2–20 µm) is of particular importance as it contains strong absorption signatures of many molecules. Therefore, Si- and Ge-based platforms open up the possibility of small and cost-effective sensing in the fingerprint region for medical and environmental monitoring. In this paper, we discuss the current mid-IR silicon photonics landscape, future directions, and potential applications of the field.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"6 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Artem Prokoshin, Weng W. Chow, Bozhang Dong, Frederic Grillot, John Bowers, Yating Wan
This paper explores the impact of gain medium on linewidth narrowing in integrated self-injection locked III–V/SiN lasers, theoretically and experimentally. We focus on the effects of carrier densities of states in zero- and two-dimensional structures due to quantum-dot and quantum-well confinement. The theoretical approach includes (a) multimode laser interaction to treat mode competition and wave mixing, (b) quantum-optical contributions from spontaneous emission, and (c) composite laser/free-space eigenmodes to describe outcoupling and coupling among components within an extended cavity. For single-cavity lasers, such as distributed feedback lasers, the model reproduces the experimentally observed better linewidth performance of quantum-dot active regions over quantum-well ones. When applied to integrated III–V/SiN lasers, our analysis indicates Hz-level linewidth performance for both quantum-dot and quantum-well gain media due to overcoming the difference in carrier-induced refractive index by incorporating a high-Q SiN passive resonator. Trade-offs are also explored between linewidth, output power, and threshold current.
{"title":"Linewidth narrowing in self-injection locked lasers: Effects of quantum confinement","authors":"Artem Prokoshin, Weng W. Chow, Bozhang Dong, Frederic Grillot, John Bowers, Yating Wan","doi":"10.1063/5.0214254","DOIUrl":"https://doi.org/10.1063/5.0214254","url":null,"abstract":"This paper explores the impact of gain medium on linewidth narrowing in integrated self-injection locked III–V/SiN lasers, theoretically and experimentally. We focus on the effects of carrier densities of states in zero- and two-dimensional structures due to quantum-dot and quantum-well confinement. The theoretical approach includes (a) multimode laser interaction to treat mode competition and wave mixing, (b) quantum-optical contributions from spontaneous emission, and (c) composite laser/free-space eigenmodes to describe outcoupling and coupling among components within an extended cavity. For single-cavity lasers, such as distributed feedback lasers, the model reproduces the experimentally observed better linewidth performance of quantum-dot active regions over quantum-well ones. When applied to integrated III–V/SiN lasers, our analysis indicates Hz-level linewidth performance for both quantum-dot and quantum-well gain media due to overcoming the difference in carrier-induced refractive index by incorporating a high-Q SiN passive resonator. Trade-offs are also explored between linewidth, output power, and threshold current.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"144 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Melton, J. F. McMillan, J. Yang, W. Wang, Y. Lai, M. Gerber, M. Rodriguez, J. P. Hubschman, K. Nouri-Mahdavi, C. W. Wong
Spectral-domain optical coherence tomography is a pervasive, non-invasive, in vivo biomedical imaging platform that currently utilizes incoherent broadband superluminescent diodes to generate interferograms from which depth and structural information are extracted. Advancements in laser frequency microcombs have enabled the chip-scale broadband generation of discrete frequency sources, with prior soliton and chaotic comb states examined in discrete spectral-domain optical coherence tomography at 1.3 μm. In this work, we demonstrate coherence tomography through Si3N4 microresonator laser frequency microcombs at 1 μm, achieving imaging qualities on-par with or exceeding the equivalent commercial optical coherence tomography system. We characterize the noise performance of our frequency comb states and additionally show that inherent comb line amplitude fluctuations in a chaotic state and the resultant tomograms can be compensated via multi-scan averaging.
{"title":"Optical coherence tomography imaging and noise characterization based on 1-μm microresonator frequency combs","authors":"T. Melton, J. F. McMillan, J. Yang, W. Wang, Y. Lai, M. Gerber, M. Rodriguez, J. P. Hubschman, K. Nouri-Mahdavi, C. W. Wong","doi":"10.1063/5.0215574","DOIUrl":"https://doi.org/10.1063/5.0215574","url":null,"abstract":"Spectral-domain optical coherence tomography is a pervasive, non-invasive, in vivo biomedical imaging platform that currently utilizes incoherent broadband superluminescent diodes to generate interferograms from which depth and structural information are extracted. Advancements in laser frequency microcombs have enabled the chip-scale broadband generation of discrete frequency sources, with prior soliton and chaotic comb states examined in discrete spectral-domain optical coherence tomography at 1.3 μm. In this work, we demonstrate coherence tomography through Si3N4 microresonator laser frequency microcombs at 1 μm, achieving imaging qualities on-par with or exceeding the equivalent commercial optical coherence tomography system. We characterize the noise performance of our frequency comb states and additionally show that inherent comb line amplitude fluctuations in a chaotic state and the resultant tomograms can be compensated via multi-scan averaging.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"165 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peijun Gong, Imogen Boman, Renate Zilkens, Chris Yeomans, Mireille Hardie, Anmol Rijhumal, Christobel M. Saunders, Brendan F. Kennedy
Mechanical load imparted to tissue, for example via handheld imaging probes, leads to tissue deformation, altering the distribution of tissue microstructure and, consequently, attenuation of light and image formation in optical imaging. In mechanically heterogeneous tissue, the load can result in spatially varying deformation and, therefore, spatially varying changes in the attenuation of light, which may provide additional image contrast. To investigate this potential, an assessment of the spatially resolved impact of mechanical deformation of the tissue on optical imaging is critical; however, it is challenging to incorporate stress mapping into optical imaging without obscuring the detection of photons. To address this, we present the novel integration of stress imaging using optical palpation with attenuation imaging based on optical coherence tomography (OCT). The method was implemented using a compliant silicone sensor incorporated into a custom handheld OCT probe, providing two-dimensional stress imaging with concurrent attenuation imaging. Attenuation imaging with varying mechanical loads was demonstrated on 19 tissue regions acquired from eight freshly excised human breast specimens. The results demonstrated distinct characteristics for different breast tissue types: benign stroma showed relatively large increases in attenuation (e.g., ∼0.3 to 0.4 mm−1/kPa) over a low stress range (∼2 to 10 kPa), while cancerous tissue showed markedly small increases in attenuation (e.g., ∼0.005 to 0.02 mm−1/kPa) mainly over a medium to high stress range (∼10 to 90 kPa). The integration of stress imaging with attenuation imaging provided a pilot assessment of the spatially resolved impact of tissue mechanical heterogeneity on optical attenuation, providing novel image contrast by encoding variations in mechanical properties on optical attenuation in tissue.
{"title":"Load-dependent optical coherence tomography attenuation imaging: How tissue mechanics can influence optical scattering","authors":"Peijun Gong, Imogen Boman, Renate Zilkens, Chris Yeomans, Mireille Hardie, Anmol Rijhumal, Christobel M. Saunders, Brendan F. Kennedy","doi":"10.1063/5.0208026","DOIUrl":"https://doi.org/10.1063/5.0208026","url":null,"abstract":"Mechanical load imparted to tissue, for example via handheld imaging probes, leads to tissue deformation, altering the distribution of tissue microstructure and, consequently, attenuation of light and image formation in optical imaging. In mechanically heterogeneous tissue, the load can result in spatially varying deformation and, therefore, spatially varying changes in the attenuation of light, which may provide additional image contrast. To investigate this potential, an assessment of the spatially resolved impact of mechanical deformation of the tissue on optical imaging is critical; however, it is challenging to incorporate stress mapping into optical imaging without obscuring the detection of photons. To address this, we present the novel integration of stress imaging using optical palpation with attenuation imaging based on optical coherence tomography (OCT). The method was implemented using a compliant silicone sensor incorporated into a custom handheld OCT probe, providing two-dimensional stress imaging with concurrent attenuation imaging. Attenuation imaging with varying mechanical loads was demonstrated on 19 tissue regions acquired from eight freshly excised human breast specimens. The results demonstrated distinct characteristics for different breast tissue types: benign stroma showed relatively large increases in attenuation (e.g., ∼0.3 to 0.4 mm−1/kPa) over a low stress range (∼2 to 10 kPa), while cancerous tissue showed markedly small increases in attenuation (e.g., ∼0.005 to 0.02 mm−1/kPa) mainly over a medium to high stress range (∼10 to 90 kPa). The integration of stress imaging with attenuation imaging provided a pilot assessment of the spatially resolved impact of tissue mechanical heterogeneity on optical attenuation, providing novel image contrast by encoding variations in mechanical properties on optical attenuation in tissue.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"29 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fanqi Meng, Zhenling Tang, Petr Ourednik, Jahnabi Hazarika, Michael Feiginov, Safumi Suzuki, Hartmut G. Roskos
Oscillators based on resonant tunneling diodes (RTDs) are able to reach the highest oscillation frequency among all electronic THz emitters. However, the emitted power from RTDs remains limited. Here, we propose linear RTD oscillator arrays capable of supporting coherent emission from both in-phase and anti-phase coupled modes. The oscillation modes can be selected by adjusting the mesa areas of the RTDs. Both the modes exhibit constructive interference at different angles in the far field, enabling high-power emission. Experimental demonstrations of coherent emission from linear arrays containing 11 RTDs are presented. The anti-phase mode oscillates at ∼450 GHz, emitting about 0.7 mW, while the in-phase mode oscillates at around 750 GHz, emitting about 1 mW. Moreover, certain RTD oscillator arrays exhibit dual-band operation: changing the bias voltage allows for controllable switching between the anti-phase and in-phase modes. Upon bias sweeping in both directions, a notable hysteresis feature is observed. Our linear RTD oscillator array represents a significant step forward in the realization of large arrays for applications requiring continuous-wave THz radiation with substantial power.
{"title":"High-power in-phase and anti-phase mode emission from linear arrays of resonant-tunneling-diode oscillators in the 0.4-to-0.8-THz frequency range","authors":"Fanqi Meng, Zhenling Tang, Petr Ourednik, Jahnabi Hazarika, Michael Feiginov, Safumi Suzuki, Hartmut G. Roskos","doi":"10.1063/5.0213695","DOIUrl":"https://doi.org/10.1063/5.0213695","url":null,"abstract":"Oscillators based on resonant tunneling diodes (RTDs) are able to reach the highest oscillation frequency among all electronic THz emitters. However, the emitted power from RTDs remains limited. Here, we propose linear RTD oscillator arrays capable of supporting coherent emission from both in-phase and anti-phase coupled modes. The oscillation modes can be selected by adjusting the mesa areas of the RTDs. Both the modes exhibit constructive interference at different angles in the far field, enabling high-power emission. Experimental demonstrations of coherent emission from linear arrays containing 11 RTDs are presented. The anti-phase mode oscillates at ∼450 GHz, emitting about 0.7 mW, while the in-phase mode oscillates at around 750 GHz, emitting about 1 mW. Moreover, certain RTD oscillator arrays exhibit dual-band operation: changing the bias voltage allows for controllable switching between the anti-phase and in-phase modes. Upon bias sweeping in both directions, a notable hysteresis feature is observed. Our linear RTD oscillator array represents a significant step forward in the realization of large arrays for applications requiring continuous-wave THz radiation with substantial power.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"74 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Hensel, Lenard Vamos, Igor Tyulnev, Ugaitz Elu, Jens Biegert
We study and describe the reshaping of ultrashort and broadband mid-IR optical pulses in an ambient atmosphere. While all pulse propagation undergoes dispersion and absorption, which causes pulse reshaping, the effects are strongly pronounced for broadband radiation in the mid-IR due to the orders of magnitude greater oscillator strengths of molecular constituents of our atmosphere. A noticeable macroscopic impact is a transition of the measured autocorrelation function from squared hyperbolic secant to Lorentzian, which we fully explain based on pulse propagation, including molecular free induction decay. Electro-optical sampling directly reveals the light wave response to atmospheric molecular free induction decay, and a Kramers–Kronig-based propagation model thoroughly explains the observation. The findings are essential for applications in sensing, standoff detection, high-energy pulse propagation, and energy delivery.
{"title":"Propagation of broadband mid-infrared optical pulses in atmosphere","authors":"Christian Hensel, Lenard Vamos, Igor Tyulnev, Ugaitz Elu, Jens Biegert","doi":"10.1063/5.0218225","DOIUrl":"https://doi.org/10.1063/5.0218225","url":null,"abstract":"We study and describe the reshaping of ultrashort and broadband mid-IR optical pulses in an ambient atmosphere. While all pulse propagation undergoes dispersion and absorption, which causes pulse reshaping, the effects are strongly pronounced for broadband radiation in the mid-IR due to the orders of magnitude greater oscillator strengths of molecular constituents of our atmosphere. A noticeable macroscopic impact is a transition of the measured autocorrelation function from squared hyperbolic secant to Lorentzian, which we fully explain based on pulse propagation, including molecular free induction decay. Electro-optical sampling directly reveals the light wave response to atmospheric molecular free induction decay, and a Kramers–Kronig-based propagation model thoroughly explains the observation. The findings are essential for applications in sensing, standoff detection, high-energy pulse propagation, and energy delivery.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"141 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuo Sun, Jin Li, Xiaoxun Li, Xiangyu Huang, Yi Zhang, Liang Chen
Holographic display is considered the holy grail of photorealistic three-dimensional (3D) visualization technology because it can provide arbitrary wavefronts related to the essential visual cues of 3D images. Metasurfaces with exceptional high-pixel light modulation capability are increasingly favored for implementing high-quality 3D holography. However, current 3D metasurface holography always has some trade-offs among lots of algorithmic data, acceptable time, image quality, and structure complexity. Therefore, the development of a high-efficiency 3D metasurface holography device is still necessary to meet the increasing high space bandwidth product (SBP) of 3D technology. Here, based on the holographic-lens (HL) computer-generated hologram (CGH) algorithm, we experimentally demonstrate a new 3D metasurface holography device that integrates the 3D image phase cues and multiple layers of virtual lenses with different focal lengths, which exhibits significant capabilities in terms of ultra-high spatial pixel modulation and the generation of high-quality 3D holography characterized by high-efficiency, broadband response, low-crosstalk, and reduced acceptable time. The HL-CGH algorithm was efficiently integrated into parameter-optimized α-Si nanopillar meta-atoms, enabling enhanced visualization of 3D clues in a lens-free system. The prepared 3D HL-metasurface holography presented the presence of multiple depths of a 3D holographic image across a broad spectral range (400–900 nm), providing enhanced 3D visual cues. Our work provides a new perspective on designing metasurface-driven high-SBP 3D holography.
全息显示被认为是逼真三维（3D）可视化技术的圣杯，因为它可以提供与 3D 图像基本视觉线索相关的任意波面。具有卓越的高像素光调制能力的元表面在实现高质量三维全息技术方面越来越受到青睐。然而，目前的三维超表面全息技术总是需要在大量算法数据、可接受时间、图像质量和结构复杂性之间进行权衡。因此，为了满足三维技术日益增长的高空间带宽积（SBP）的要求，开发一种高效的三维元面全息设备仍然是必要的。在此，我们基于全息透镜（HL）计算机生成全息图（CGH）算法，实验演示了一种新型三维元面全息设备，该设备集成了三维图像相位线索和多层不同焦距的虚拟透镜，在超高空间像素调制和生成高质量三维全息图方面表现出显著的能力，具有高效率、宽带响应、低串扰和缩短可接受时间等特点。HL-CGH 算法被有效集成到参数优化的 α-Si 纳米柱元原子中，从而在无透镜系统中增强了三维线索的可视化。制备的三维 HL-元原子表面全息图在宽光谱范围（400-900 nm）内呈现出多深度的三维全息图像，提供了增强的三维视觉线索。我们的工作为设计元表面驱动的高 SBP 三维全息技术提供了一个新的视角。
{"title":"High-efficiency, broadband, and low-crosstalk 3D holography by multi-layer holographic-lens integrated metasurface","authors":"Shuo Sun, Jin Li, Xiaoxun Li, Xiangyu Huang, Yi Zhang, Liang Chen","doi":"10.1063/5.0218862","DOIUrl":"https://doi.org/10.1063/5.0218862","url":null,"abstract":"Holographic display is considered the holy grail of photorealistic three-dimensional (3D) visualization technology because it can provide arbitrary wavefronts related to the essential visual cues of 3D images. Metasurfaces with exceptional high-pixel light modulation capability are increasingly favored for implementing high-quality 3D holography. However, current 3D metasurface holography always has some trade-offs among lots of algorithmic data, acceptable time, image quality, and structure complexity. Therefore, the development of a high-efficiency 3D metasurface holography device is still necessary to meet the increasing high space bandwidth product (SBP) of 3D technology. Here, based on the holographic-lens (HL) computer-generated hologram (CGH) algorithm, we experimentally demonstrate a new 3D metasurface holography device that integrates the 3D image phase cues and multiple layers of virtual lenses with different focal lengths, which exhibits significant capabilities in terms of ultra-high spatial pixel modulation and the generation of high-quality 3D holography characterized by high-efficiency, broadband response, low-crosstalk, and reduced acceptable time. The HL-CGH algorithm was efficiently integrated into parameter-optimized α-Si nanopillar meta-atoms, enabling enhanced visualization of 3D clues in a lens-free system. The prepared 3D HL-metasurface holography presented the presence of multiple depths of a 3D holographic image across a broad spectral range (400–900 nm), providing enhanced 3D visual cues. Our work provides a new perspective on designing metasurface-driven high-SBP 3D holography.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"33 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jasper Riebesehl, Holger R. Heebøll, Aleksandr Razumov, Michael Galili, Darko Zibar
Performing noise characterizations of lasers and optical frequency combs on sampled data offers numerous advantages compared to analog measurement techniques. One of the main advantages is that the measurement setup is greatly simplified. Only a balanced detector followed by an analog-to-digital converter is needed, allowing all the complexity to be moved to the digital domain. Secondly, near-optimal phase estimators are efficiently implementable, providing accurate phase noise estimation in the presence of measurement noise. Finally, joint processing of multiple comb lines is feasible, enabling the computation of the phase noise correlation matrix, which includes all information about the phase noise of the optical frequency comb. This tutorial introduces a framework based on digital signal processing for phase noise characterization of lasers and optical frequency combs. The framework is based on the extended Kalman filter (EKF) and automatic differentiation. The EKF is a near-optimal estimator of the optical phase in the presence of measurement noise, making it very suitable for phase noise measurements. Automatic differentiation is key to efficiently optimizing many parameters entering the EKF framework. More specifically, the combination of EKF and automatic differentiation enables the efficient optimization of phase noise measurement for optical frequency combs with arbitrarily complex noise dynamics that may include many free parameters. We show the framework’s efficacy through simulations and experimental data, showcasing its application across various comb types and in dual-comb measurements, highlighting its accuracy and versatility. Finally, we discuss its capability for digital phase noise compensation, which is highly relevant to free-running dual-comb spectroscopy applications.
{"title":"Digital signal processing techniques for noise characterization of lasers and optical frequency combs: A tutorial","authors":"Jasper Riebesehl, Holger R. Heebøll, Aleksandr Razumov, Michael Galili, Darko Zibar","doi":"10.1063/5.0212592","DOIUrl":"https://doi.org/10.1063/5.0212592","url":null,"abstract":"Performing noise characterizations of lasers and optical frequency combs on sampled data offers numerous advantages compared to analog measurement techniques. One of the main advantages is that the measurement setup is greatly simplified. Only a balanced detector followed by an analog-to-digital converter is needed, allowing all the complexity to be moved to the digital domain. Secondly, near-optimal phase estimators are efficiently implementable, providing accurate phase noise estimation in the presence of measurement noise. Finally, joint processing of multiple comb lines is feasible, enabling the computation of the phase noise correlation matrix, which includes all information about the phase noise of the optical frequency comb. This tutorial introduces a framework based on digital signal processing for phase noise characterization of lasers and optical frequency combs. The framework is based on the extended Kalman filter (EKF) and automatic differentiation. The EKF is a near-optimal estimator of the optical phase in the presence of measurement noise, making it very suitable for phase noise measurements. Automatic differentiation is key to efficiently optimizing many parameters entering the EKF framework. More specifically, the combination of EKF and automatic differentiation enables the efficient optimization of phase noise measurement for optical frequency combs with arbitrarily complex noise dynamics that may include many free parameters. We show the framework’s efficacy through simulations and experimental data, showcasing its application across various comb types and in dual-comb measurements, highlighting its accuracy and versatility. Finally, we discuss its capability for digital phase noise compensation, which is highly relevant to free-running dual-comb spectroscopy applications.","PeriodicalId":8198,"journal":{"name":"APL Photonics","volume":"79 1","pages":""},"PeriodicalIF":5.6,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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