Article
Engineering, Electrical & Electronic
Nobuhide Yokota, Kazuhiro Ikeda, Hiroshi Yasaka
Summary: We investigate the modulation responses of injection-locked VCSELs using optical spin-polarization modulation technique and find that weak injection locking can maintain strong resonance response at high frequencies due to the linear birefringence of VCSELs. Our simulated results based on spin-flip rate equations match well with the experimental measurements, supporting the novel applications of spin-controlled VCSELs with injection locking.
IEICE ELECTRONICS EXPRESS
(2023)
Article
Nanoscience & Nanotechnology
Tao Yang, Yan-Hui Chen, Ya-Chao Wang, Wei Ou, Lei-Ying Ying, Yang Mei, Ai-Qin Tian, Jian-Ping Liu, Hao-Chung Guo, Bao-Ping Zhang
Summary: In this study, low threshold green GaN-based VCSEL operating at room temperature was achieved by using self-formed InGaN quantum dots as the active region. The results provide important guidance for achieving high-performance GaN-based VCSELs.
NANO-MICRO LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Rami T. Elafandy, Jin-Ho Kang, Chenziyi Mi, Tae Kyoung Kim, Joon Seop Kwak, Jung Han
Summary: This paper introduces a technique using birefringent nanoporous DBRs to achieve polarization locking in GaN VCSELs, overcoming the challenge of laser polarization control, demonstrating a fully electrically injected blue VCSEL. This technique allows the definition of polarization angles in a planar array, opening up possibilities for novel applications.
Article
Optics
Dhaifallah Almutairi, Karl Johnson, Alexei Smolyaninov, Andrew Grieco, Yeshaiahu Fainman
Summary: This study proposes a novel technique for a 2D beam steering system using hybrid plasmonic phase shifters. The design facilitates a sub-wavelength spacing between individual phase shifters, resulting in an expanded field of view and side lobes suppression.
Article
Engineering, Electrical & Electronic
Kai Liu, Yun-Feng Zhong, Xiao-Wen Dong, Yong-Qing Huang, Xiao-Feng Duan, Xiao-Min Ren, Shi-Wei Cai, Qi Wang
Summary: In this article, a method is proposed to achieve single mode output by adjusting the modes of VCSEL. Simulation and experimental results demonstrate the feasibility of this approach and a single-mode VCSEL with a high side-mode suppression ratio and low threshold current is obtained.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Hongbo Zhang, Yuzhong Hu, Wen Wen, Bowen Du, Lishu Wu, Yu Chen, Shun Feng, Chenji Zou, Jingzhi Shang, Hong Jin Fan, Ting Yu
Summary: This study demonstrated lasing emission of (PEA)(2)PbI4 in a vertical microcavity under continuous pumping, overcoming the challenge of CW pumped lasing in 2D lead halide perovskites. The high crystallization, excellent thermal stability, and outstanding optical properties of the obtained (PEA)(2)PbI4 single crystal enabled robust VCSEL operation at room temperature with an ultra-low threshold.
Article
Engineering, Electrical & Electronic
Congcong Wang, Chong Li, Zhiyong Wang
Summary: This paper investigates the performance of top-surface-emitting VCSELs in terms of infrared laser output. The physical mechanism of minimum threshold current generation in oxide-confined VCSELs is revealed through theoretical and experimental studies, and the output power and power conversion efficiency of 2 x 4 VCSEL arrays are examined. The thermal properties of 2 x 2 VCSEL arrays are analyzed using numerical and experimental methods.
OPTICAL AND QUANTUM ELECTRONICS
(2022)
Article
Multidisciplinary Sciences
Young-Hoon Kim, Yaxin Zhai, Haipeng Lu, Xin Pan, Chuanxiao Xiao, E. Ashley Gaulding, Steven P. Harvey, Joseph J. Berry, Zeev Valy Vardeny, Joseph M. Luther, Matthew C. Beard
Summary: Traditional optoelectronic approaches rely on both electrical and magnetic fields to control spin, charge, and light, while the use of chiral-induced spin selectivity (CISS) technology allows for the fabrication of a spin-LED that operates at room temperature without the need for magnetic fields or ferromagnetic contacts.
Article
Engineering, Electrical & Electronic
Meng Xun, Guanzhong Pan, Zhuangzhuang Zhao, Yun Sun, Chengyue Yang, Qiang Kan, Jingtao Zhou, Dexin Wu
Summary: The output characteristics of vertical cavity surface emitting lasers arrays are influenced by temperature, and thermal properties were systematically studied in a 20-element oxide-confined VCSEL arrays through theory and experiment. Output power, conversion efficiency, and threshold current were measured depending on ambient temperatures. The relationship between wavelength shift, dissipated power, and device thermal resistance depending on ambient temperature was obtained, with the actual temperature in the active region successfully extracted. A 3-D heat diffusion model was established for accurate simulation of temperature distribution.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Optics
Lars Persson, Filip Hjort, Giulia Cardinali, Johannes Enslin, Tim Kolbe, Tim Wernicke, Michael Kneissl, Joachim Ciers, Asa Haglund
Summary: A concept for achieving a temperature-stable lasing wavelength in VCSELs is proposed and demonstrated. By incorporating a dielectric material with a negative thermo-optic coefficient in the DBRs, the positive dn/dT of the semiconductor cavity can be compensated and the redshift of the lasing wavelength can be avoided. This concept is validated for optically-pumped VCSELs emitting at 310 nm, showing a maximum blueshift of less than 0.1 nm over an 80 degrees C range.
LASER & PHOTONICS REVIEWS
(2023)
Article
Engineering, Electrical & Electronic
Zhongming Zheng, Yang Mei, Hao Long, Jason Hoo, Shiping Guo, Qingxuan Li, Leiying Ying, Zhiwei Zheng, Baoping Zhang
Summary: An optically pumped AlGaN-based VCSEL laser in the deep ultraviolet range has been demonstrated, with a lasing wavelength of 275.91 nm, threshold power density of 1.21 MW/cm(2), and linewidth of 0.78 nm. The performance of this laser is believed to be enhanced by the high IQE of the AlGaN-based MQWs and improved fabrication processes.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Physics, Applied
A. Yamada, M. Yamada, M. Honda, S. Yamada, K. Sawano, K. Hamaya
Summary: The study reports the highest two-terminal magnetoresistance ratio in semiconductor-based vertical spin-valve devices on a silicon platform. By utilizing Co2FeSi as one of the FM electrodes and a 20-nm-thick Ge intermediate layer, they achieved over 1% two-terminal MR ratios even at room temperature. It was emphasized that Co-based Heusler alloys are effective in obtaining high MR ratios at room temperature in SC-based VSV structures on Si.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Mariusz Drong, Jan Perina, Tibor Fordos, Henri Y. Jaffres, Kamil Postava, Henri-Jean Drouhin
Summary: It is found that spin-injected vertical-cavity surface-emitting lasers (spin-VCSELs) exhibit interesting functionalities when considering the linear gain anisotropy. Using the extended spin-flip model (SFM), exceptional points (EPs) are predicted in spin-VCSELs along with two interesting phenomena: polarization switching and frequency comb generation. These effects have great technological potential and are not limited to spin-VCSEL technology. The concept of anisotropy-engineered non-Hermitian microlasers and their polarization dynamics near EPs are discussed.
Article
Engineering, Electrical & Electronic
Qing Fang, Huiming Wang, Hanxu Zhou, Can Jiang, Weizheng Di, Gaofeng Xu, Tao Wang
Summary: This study provides a numerical investigation of the nonlinear dynamics of semiconductor lasers with controllable spin-polarized electron injection. The influence of noise from two polarization states is emphasized. The results show that superthermal emission properties can be generated by modifying the spin of the pump current. The noise effect on laser emission can be tuned by modifying the pump ellipticity, which is significant for laser device design and fabrication. Furthermore, the corresponding polarization dynamics characterized by the Poincare sphere is also discussed.
IEEE JOURNAL OF QUANTUM ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
M. Skontranis, G. S. Sarantoglou, A. Bogris, C. Mesaritakis
Summary: In this work, a numerical study on a time-delayed reservoir computing scheme is presented, utilizing a quantum-dot spin polarized vertical cavity surface-emitting laser (QD s-VCSEL) as the single nonlinear node. The scheme exploits the complex temporal dynamics of multiple energy states in quantum dot materials and utilizes dual emission to enhance computational efficiency.
OPTICAL MATERIALS EXPRESS
(2022)
Article
Optics
Lena Schnitzler, Krisztian Neutsch, Falk Schellenberg, Martin R. Hofmann, Nils C. Gerhardt
Summary: This paper introduces a confocal laser scanning holographic microscope for investigating buried structures, which combines high diffraction limited resolution and high signal-to-noise-ratio with phase acquisition ability. The amplitude and phase imaging capabilities are demonstrated on a test target, and an optical beam induced current modality is added for studying buried integrated semiconductor structures, providing additional structure-sensitive contrast. The performance of the multimodal system is demonstrated by imaging the buried structures of a microcontroller through the silicon backside in reflection geometry.
Article
Optics
Vira R. Besaga, Nils C. Gerhardt, Martin R. Hofmann
Summary: In this study, spatially resolved measurements of below-band-gap carrier-induced absorption and phase change in a semiconductor were achieved using transmission digital holography. The phase information enabled monitoring of excess carrier distributions, and a phase-based approach for separating carrier and heat related effects in the semiconductor optical response was discussed.
Article
Optics
Niels Heermeier, Tobias Heuser, Jan Grosse, Natalie Jung, Arsenty Kaganskiy, Markus Lindemann, Nils C. Gerhardt, Martin R. Hofmann, Stephan Reitzenstein
Summary: Spin-controlled lasers and high-beta quantum dot micropillar lasers are two fascinating photonic devices with potential applications. The experimental and predicted polarization oscillation frequencies of spin-laser effects are presented, demonstrating the possibility of developing more compact, faster, and more energy-efficient spin-lasers.
LASER & PHOTONICS REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Krisztian Neutsch, Evgeny L. Gurevich, Martin R. Hofmann, Nils C. Gerhardt
Summary: This paper demonstrates the investigation of laser-induced periodic surface structures (LIPSSs) on a polycrystalline diamond substrate using synthetic optical holography (SOH). The novel technique operates non-invasively without any processing or contact with the LIPSS sample, providing high-resolution images of the investigated sample.
Article
Engineering, Electrical & Electronic
Markus Lindemann, Natalie Jung, Nicolas Manrique-Nieto, Tobias Pusch, Rainer Michalzik, Nils C. Gerhardt, Martin R. Hofmann
Summary: Spin-polarized vertical-cavity surface-emitting lasers (spin-VCSELs) with high birefringence show great potential for optical data-transmission systems with superior performance compared to conventional direct current modulation. The birefringence in spin-VCSELs determines the resonance frequency and modulation bandwidth. This study demonstrates the polarization dynamics of a VCSEL with an integrated birefringence control mechanism using custom designed integrated surface gratings. The spin-VCSELs generated polarization oscillations with frequencies corresponding to the birefringence induced by the surface grating and exhibited polarization dynamics up to 68 GHz.
ELECTRONICS LETTERS
(2023)
Article
Physics, Multidisciplinary
G. R. M. Robb, J. G. M. Walker, G. -L. Oppo, T. A. Ackemann
Summary: A Bose-Einstein condensate (BEC) interacting with an optical field via a feedback mirror can realize the quantum Hamiltonian Mean Field (HMF) model, which is a typical model for long-range interactions in quantum systems. It has been shown that the self-structuring instability of a initially uniform BEC can evolve in accordance with the predictions of the quantum HMF model, exhibiting quasiperiodic chevron dynamics under strong driving. Under weak driving, the BEC and optical field behave as a two-state quantum system, oscillating regularly between a spatially uniform state and a spatially periodic state. This study also predicts the width of stable optomechanical droplets and their dependence on optical pump intensity.
PHYSICAL REVIEW RESEARCH
(2023)
Proceedings Paper
Engineering, Biomedical
Jens Moeller, Eveline Popanda, Iris Tischoff, Nuri H. Aydin, Hubert Welp, Carsten Brenner, Nils C. Gerhardt, Kirsten Schmieder, Dorothea Miller, Martin R. Hofmann
Summary: This work utilizes optical coherence tomography to image glioblastoma resection specimens and optimizes texture features for tissue classification. The study highlights the relationships between texture features and structural characteristics in healthy and tumor tissues.
OPTICAL COHERENCE TOMOGRAPHY AND COHERENCE DOMAIN OPTICAL METHODS IN BIOMEDICINE XXVI
(2022)
Article
Optics
T. Ackemann, G. Labeyrie, A. Costa Boquete, G. Baio, J. G. M. Walker, R. Kaiser, G-L Oppo, G. R. M. Robb
Summary: This study investigates self-organized phases in cold atoms due to light-mediated interactions with the coupling of internal spin degrees of freedom and optomechanical dynamics. The results show that the dominance of magnetic driving or optomechanical driving depends on the lattice periods, with the magnetic driving being stronger for long-period transmission gratings and the optomechanical driving being dominant at small lattice periods.
Article
Optics
J. G. M. Walker, G. R. M. Robb, G-L Oppo, T. Ackemann
Summary: In this study, we numerically investigate the properties of a one-dimensional Bose-Einstein condensate illuminated by off-resonant laser light reflected by a single feedback mirror. We find self-trapped density structures formed by the optomechanical action of the diffracted light, which are stable and exhibit Newtonian dynamics. Our results suggest the possibility of continuous, nondestructive monitoring of condensate dynamics through optical intensity measurement, and potential opportunities for optical control and transport of coherent matter through gradients in optical phase.
Article
Optics
G. Labeyrie, J. G. M. Walker, G. R. M. Robb, R. Kaiser, T. Ackemann
Summary: We investigate the interaction between two mechanisms for magnetic self-organization in a cloud of cold rubidium atoms. The transitions between different phases, induced by either a weak transverse magnetic field or laser intensity, are observed and characterized. The experimental observations are successfully compared to numerical simulations based on a spin-1 model.
Proceedings Paper
Engineering, Electrical & Electronic
Thorsten Ackemann, Thierry Guillet
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Giuseppe Baio, Gordon R. M. Robb, Thorsten Ackemann, Alison M. Yao, Gian-Luca Oppo
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Giuseppe Baio, Gordon R. M. Robb, Alison M. Yao, Gian-Luca Oppo, Thorsten Ackemann
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
J. Doogan, S. Phutthaprasartporn, E. Clarke, T. Ackemann
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Article
Optics
Giuseppe Baio, Thorsten Ackemann, Gian-Luca Oppo, Gordon R. M. Robb, Alison M. Yao
Summary: Clouds of cold neutral atoms driven by a coherent light beam in a ring cavity exhibit self-structured states transversely with respect to the beam axis due to optomechanical forces and the backaction of the atomic structures on the beam. Below the instability threshold for extended hexagonal structures, localized soliton-like excitations can be stable. Complex rotating and spiraling motion of coupled atom-light solitons, and hence, atomic transport, can be achieved via phase gradients in the input field profile. The investigations are performed in a cavity scheme but expected to apply to other longitudinally pumped schemes with diffractive coupling.
