近年來，結構光技術廣泛應用於三維感測、人臉辨識及擴增實境等領域，使投影系統朝向微型化、大照明視場角及低光斑發散角。然而，傳統結構光系統通常需要搭配繞射光學元件與準直透鏡，不僅增加系統體積與組裝複雜度，在大角度投影下亦可能產生零階光過強及繞射效率降低等問題。
本研究提出一套整合垂直共振腔面射型雷射(Vertical-Cavity Surface-Emitting Laser, VCSEL)陣列與超穎介面(Metasurface)的微型化結構光系統，使單一元件同時具備波前準直與1-to-5分光功能。超穎介面由二氧化矽基板上的非晶矽奈米柱組成，工作波長為940 nm，並利用嚴格耦合波分析法建立奈米柱尺寸與光學響應之對應關係。透過整合準直相位與偏轉相位，將光束分別導引至−40°、−19°、0°、19°及40°，並藉由權重配置補償大角度偏轉光束的效率損失。
單一光源量測結果顯示，九個不同入射位置皆能形成穩定的1-to-5分光效果，且光斑變化趨勢與模擬結果相符。整合VCSEL模組後，實際量測之水平與垂直照明視場角分別達111.1°與51.19°，圖案畸變程度介於15.63%至44.01%。由以上結果可知，本研究所提出的超穎介面可同時實現波前準直、能量分配與多點分光，具備應用於微型化結構光投影及三維感測系統的潛力。

Structured light technology has been widely applied in three-dimensional sensing, facial recognition, and augmented reality, driving the development of compact projection systems with a large field of illumination (FOI) and low beam divergence. However, conventional structured light systems generally require both diffractive optical elements and collimating lenses, increasing the system size and assembly complexity. Strong zero-order diffraction and reduced efficiency may also occur at large projection angles.
This study proposes a compact structured light system integrating a vertical-cavity surface-emitting laser (VCSEL) array with a metasurface that simultaneously provides beam collimation and five-beam splitting. The metasurface consists of amorphous silicon nanopillars on a silicon dioxide substrate and operates at a wavelength of 940 nm. Rigorous coupled-wave analysis was employed to determine the optical responses of nanopillars with different dimensions. By combining a collimation phase with five deflection phases, the incident light was directed toward −40°, −19°, 0°, 19°, and 40°. A weighting strategy was also introduced to compensate for the efficiency reduction of the large-angle diffraction channels.
Single-source measurements demonstrated stable five-beam splitting at nine different incident positions, with spot-displacement trends consistent with the simulation results. After integration with the VCSEL module, the measured horizontal and vertical FOIs reached 111.1° and 51.19°, respectively. The measured pattern distortion ranged from 15.63% to 44.01. These results demonstrate that the proposed metasurface can simultaneously achieve beam collimation, power redistribution, and five-beam splitting, indicating its potential for compact structured light projection and three-dimensional sensing systems.

[1] T. Cizmar, and K. Dholakia, "Time-of-flight 3D imaging through multimode optical fibers," Optics Express 20, 29881–29892 (2012).
[2] S. Foix, G. Alenyà, and C. Torras, "Lock-in Time-of-Flight (ToF) cameras: a survey," IEEE Sensors Journal 11, 1917–1926 (2011).
[3] H. Xie, H. Yao, S. Zhou, S. Zhang, X. Tong, and W. Sun, "Toward 3D object reconstruction from stereo images," Neurocomputing 463, 444–453 (2021).
[4] J. Geng, "Structured-light 3D surface imaging: a tutorial," Advances in Optics and Photonics 3, 130–157 (2011).
[5] F. Gu, H. Cao, Z. Song, P. Xie, J. Zhao, and J. Liu, "Dot-coded structured light for accurate and robust 3D reconstruction," Applied Optics 59, 10574–10583 (2020).
[6] L. Kang, H. Liu, Y. Zhang, H. C. Chui, and J. Yang, "Motion-induced phase shift for dynamic structured light measurement," Optics Letters 49, 6509–6512 (2024).
[7] W. C. Hsu, C. H. Chang, Y. H. Hong, H. C. Kuo, and Y. W. Huang, "Metasurface and PCSEL-Based structured light for monocular depth perception and facial recognition," Nano Letters 24, 1808–1815 (2024).
[8] C. Wu, X. Huang, Y. Ji, T. Cheng, J. Wang, N. Chi, S. Yu, and C. J. Chang-Hasnain, "Addressable structured light system using metasurface optics and an individually addressable VCSEL array," Photonics Research 12, 1129–1137 (2024).
[9] J. Yravedra, J. Aramendi, M. A. Mate-Gonzalez, L. Austin Courtenay, and D. Gonzalez-Aguilera, "Differentiating percussion pits and carnivore tooth pits using 3D reconstructions and geometric morphometrics," PLoS One 13, e0194324 (2018).
[10] J. I. Laughner, S. Zhang, H. Li, C. C. Shao, and I. R. Efimov, "Mapping cardiac surface mechanics with structured light imaging," American Journal of Physiology-Heart and Circulatory Physiology 303, 712–720 (2012).
[11] C. Schmalz, F. Forster, A. Schick, and E. Angelopoulou, "An endoscopic 3D scanner based on structured light," Medical Image Analysis 16, 1063–1072 (2012).
[12] M. Ghisoni, H. Martinsson, N. Eriksson, M. Li, L. A. Larsson, J. Bengtsson, A. Khan, and G. Parry, "4 × 4 fan-out spot generator using GaAs based VCSEL's and diffractive optical element," IEEE Photonics Technology Letters 9, 506–508 (1997).
[13] G. Kim, Y. Kim, J. Yun, S. W. Moon, S. Kim, J. Kim, J. Park, T. Badloe, I. Kim, and J. Rho, "Metasurface-driven full-space structured light for three-dimensional imaging," Nature Communications 13, 5920 (2022).
[14] Y. Ni, S. Chen, Y. Wang, Q. Tan, S. Xiao, and Y. Yang, "Metasurface for structured light projection over 120 degrees field of view," Nano Letters 20, 6719–6724 (2020).
[15] Q. H. Wang, P. N. Ni, Y. Y. Xie, Q. Kan, P. P. Chen, P. Fu, J. Deng, T. L. Jin, H. D. Chen, H. W. H. Lee, C. Xu, and P. Genevet, "On‐Chip generation of structured light based on metasurface optoelectronic integration," Laser & Photonics Reviews 15, 2000385 (2021).
[16] N. Yu, P. Genevet, M. A. Kats, F. Aieta, J.-P. Tetienne, F. Capasso, and Z. Gaburro, "Light propagation with phase discontinuities: generalized laws of reflection and refraction," Science 334, 333–337 (2011).
[17] C. L. Holloway, E. F. Kuester, J. A. Gordon, J. O'Hara, J. Booth, and D. R. Smith, "An overview of the theory and applications of metasurfaces: the two-dimensional equivalents of metamaterials," IEEE Antennas and Propagation Magazine 54, 10–35 (2012).
[18] V. G. Veselago, "The Electrodynamics of substances with simultaneously negative values of ε and μ," Soviet Physics Uspekhi 10, 509–514 (1968).
[19] R. A. Shelby, D. R. Smith, and S. Schultz, "Experimental verification of a negative index of refraction," Science 292, 77–79 (2001).
[20] X. Zhang, and Z. Liu, "Superlenses to overcome the diffraction limit," Nature Materials 7, 435–441 (2008).
[21] L. Huang, S. Zhang, and T. Zentgraf, "Metasurface holography: from fundamentals to applications," Nanophotonics 7, 1169–1190 (2018).
[22] W. Wan, J. Gao, and X. Yang, "Metasurface holograms for holographic imaging," Advanced Optical Materials 5, 1700541 (2017).
[23] X. Ni, Z. J. Wong, M. Mrejen, Y. Wang, and X. Zhang, "An ultrathin invisibility skin cloak for visible light," Science 349, 1310–1314 (2015).
[24] J. Valentine, J. Li, T. Zentgraf, G. Bartal, and X. Zhang, "An optical cloak made of dielectrics," Nature Materials 8, 568–571 (2009).
[25] A. V. Kabashin, P. Evans, S. Pastkovsky, W. Hendren, G. A. Wurtz, R. Atkinson, R. Pollard, V. A. Podolskiy, and A. V. Zayats, "Plasmonic nanorod metamaterials for biosensing," Nature Materials 8, 867–871 (2009).
[26] H. Tao, L. R. Chieffo, M. A. Brenckle, S. M. Siebert, M. Liu, A. C. Strikwerda, K. Fan, D. L. Kaplan, X. Zhang, R. D. Averitt, and F. G. Omenetto, "Metamaterials on paper as a sensing platform," Advanced Materials 23, 3197–3201 (2011).
[27] Z. A. Zaky, A. M. Ahmed, A. S. Shalaby, and A. H. Aly, "Refractive index gas sensor based on the tamm state in a one-dimensional photonic crystal: theoretical optimisation," Scientific Reports 10, 9736 (2020).
[28] K. Koshelev, and Y. Kivshar, "Dielectric resonant metaphotonics," ACS Photonics 8, 102–112 (2020).
[29] Y. K. and, and A. Miroshnichenko, "Meta-optics with Mie resonances," Optics and Photonics News 28, 24–31 (2017).
[30] S. Wang, P. C. Wu, V. C. Su, Y. C. Lai, M. K. Chen, H. Y. Kuo, B. H. Chen, Y. H. Chen, T. T. Huang, J. H. Wang, R. M. Lin, C. H. Kuan, T. Li, Z. Wang, S. Zhu, and D. P. Tsai, "A broadband achromatic metalens in the visible," Nature Nanotechnology 13, 227–232 (2018).
[31] P. Genevet, F. Capasso, F. Aieta, M. Khorasaninejad, and R. Devlin, "Recent advances in planar optics: from plasmonic to dielectric metasurfaces," Optica 4, 139–152 (2017).
[32] S. M. Kamali, E. Arbabi, A. Arbabi, and A. Faraon, "A review of dielectric optical metasurfaces for wavefront control," Nanophotonics 7, 1041–1068 (2018).
[33] L. Liu, X. Zhang, M. Kenney, X. Su, N. Xu, C. Ouyang, Y. Shi, J. Han, W. Zhang, and S. Zhang, "Broadband metasurfaces with simultaneous control of phase and amplitude," Advanced Materials 26, 5031–5036 (2014).
[34] Y. Nanfang, P. Genevet, F. Aieta, M. A. Kats, R. Blanchard, G. Aoust, J. P. Tetienne, Z. Gaburro, and F. Capasso, "Flat optics: controlling wavefronts with optical antenna metasurfaces," IEEE Journal of Selected Topics in Quantum Electronics 19, 4700423–4700423 (2013).
[35] F. Aieta, P. Genevet, M. A. Kats, N. Yu, R. Blanchard, Z. Gaburro, and F. Capasso, "Aberration-free ultrathin flat lenses and axicons at telecom wavelengths based on plasmonic metasurfaces," Nano Letters 12, 4932–4936 (2012).
[36] Z. e. Bomzon, G. Biener, V. Kleiner, and E. Hasman, "Space-variant Pancharatnam-Berry phase optical elements with computer-generated subwavelength gratings," Optics Letters 27, 1141–1143 (2002).
[37] G. Milione, H. I. Sztul, D. A. Nolan, and R. R. Alfano, "Higher-order poincare sphere, stokes parameters, and the angular momentum of light," Physical Review Letters 107, 053601 (2011).
[38] P. C. Wu, W. Y. Tsai, W. T. Chen, Y. W. Huang, T. Y. Chen, J. W. Chen, C. Y. Liao, C. H. Chu, G. Sun, and D. P. Tsai, "Versatile polarization generation with an aluminum plasmonic metasurface," Nano Letters 17, 445–452 (2017).