Florian Kappe, Yusuf Karli, Grant Wilbur, Ria G. Krämer, Sayan Ghosh, René Schwarz, Moritz Kaiser, Thomas K. Bracht, Doris E. Reiter, Stefan Nolte, Kimberley C. Hall, Gregor Weihs, Vikas Remesh
Shaped laser pulses have been remarkably effective in investigating various aspects of light–matter interactions spanning a broad range of research. Chirped laser pulses exhibiting a time-varying frequency, or quadratic spectral phase, form a crucial category in the group of shaped laser pulses. This type of pulses have made a ubiquitous presence from spectroscopic applications to developments in high-power laser technology, and from nanophotonics to quantum optical communication, ever since their introduction. In the case of quantum technologies recently, substantial efforts are being invested toward achieving a truly scalable architecture. Concurrently, it is important to develop methods to produce robust photon sources. In this context, semiconductor quantum dots hold great potential, due to their exceptional photophysical properties and on-demand operating nature. Concerning the scalability aspect of semiconductor quantum dots, it is advantageous to develop a simple, yet robust method to generate photon states from it. Chirped pulse excitation has been widely demonstrated as a robust and efficient state preparation scheme in quantum dots, thereby boosting its applicability as a stable photon source in a real-world scenario. Despite the rapid growth and advancements in laser technologies, the generation and control of chirped laser pulses can be demanding. Here, an overview of a selected few approaches is presented to tailor and characterize chirped pulses for the efficient excitation of a quantum dot source. By taking the chirped-pulse-induced adiabatic rapid passage process in quantum dot as an example, numerical design examples are presented along with experimental advantages and challenges in each method and conclude with an outlook on future perspectives.
{"title":"Chirped Pulses Meet Quantum Dots: Innovations, Challenges, and Future Perspectives","authors":"Florian Kappe, Yusuf Karli, Grant Wilbur, Ria G. Krämer, Sayan Ghosh, René Schwarz, Moritz Kaiser, Thomas K. Bracht, Doris E. Reiter, Stefan Nolte, Kimberley C. Hall, Gregor Weihs, Vikas Remesh","doi":"10.1002/qute.202300352","DOIUrl":"https://doi.org/10.1002/qute.202300352","url":null,"abstract":"Shaped laser pulses have been remarkably effective in investigating various aspects of light–matter interactions spanning a broad range of research. Chirped laser pulses exhibiting a time-varying frequency, or quadratic spectral phase, form a crucial category in the group of shaped laser pulses. This type of pulses have made a ubiquitous presence from spectroscopic applications to developments in high-power laser technology, and from nanophotonics to quantum optical communication, ever since their introduction. In the case of quantum technologies recently, substantial efforts are being invested toward achieving a truly scalable architecture. Concurrently, it is important to develop methods to produce robust photon sources. In this context, semiconductor quantum dots hold great potential, due to their exceptional photophysical properties and on-demand operating nature. Concerning the scalability aspect of semiconductor quantum dots, it is advantageous to develop a simple, yet robust method to generate photon states from it. Chirped pulse excitation has been widely demonstrated as a robust and efficient state preparation scheme in quantum dots, thereby boosting its applicability as a stable photon source in a real-world scenario. Despite the rapid growth and advancements in laser technologies, the generation and control of chirped laser pulses can be demanding. Here, an overview of a selected few approaches is presented to tailor and characterize chirped pulses for the efficient excitation of a quantum dot source. By taking the chirped-pulse-induced adiabatic rapid passage process in quantum dot as an example, numerical design examples are presented along with experimental advantages and challenges in each method and conclude with an outlook on future perspectives.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"79 6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139408611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problem of implementation security in quantum key distribution (QKD) refers to the difficulty of meeting the requirements of mathematical security proofs in real-life QKD systems. Here, a succint review is provided on this topic, focusing on discrete-variable QKD setups. Particularly, some of their main vulnerabilities and comments are disscused on possible approaches to overcome them.
{"title":"Implementation Security in Quantum Key Distribution","authors":"Víctor Zapatero, Álvaro Navarrete, Marcos Curty","doi":"10.1002/qute.202300380","DOIUrl":"https://doi.org/10.1002/qute.202300380","url":null,"abstract":"The problem of implementation security in quantum key distribution (QKD) refers to the difficulty of meeting the requirements of mathematical security proofs in real-life QKD systems. Here, a succint review is provided on this topic, focusing on discrete-variable QKD setups. Particularly, some of their main vulnerabilities and comments are disscused on possible approaches to overcome them.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139398578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kazuki Hashimoto, Dmitri B. Horoshko, Maria V. Chekhova
Nonlinear interferometry with entangled photons allows for characterizing a sample without detecting the photons interacting with it. This method enables highly sensitive optical sensing in the wavelength regions where efficient detectors are still under development. Recently, nonlinear interferometry has been applied to interferometric measurement techniques with broadband light sources, such as Fourier-transform infrared spectroscopy and infrared optical coherence tomography. However, they have been demonstrated with photon pairs produced through spontaneous parametric down-conversion (SPDC) at a low parametric gain, where the average number of photons per mode is much smaller than one. The regime of high-gain SPDC offers several important advantages, such as the amplification of light after its interaction with the sample and a large number of photons per mode at the interferometer output. This work presents broadband spectroscopy and high-resolution optical coherence tomography with undetected photons generated via high-gain SPDC in an aperiodically poled lithium niobate crystal. To prove the principle, reflective Fourier-transform near-infrared spectroscopy with a spectral bandwidth of 17 THz and optical coherence tomography with an axial resolution of 11 µm are demonstrated.
{"title":"Broadband Spectroscopy and Interferometry with Undetected Photons at Strong Parametric Amplification","authors":"Kazuki Hashimoto, Dmitri B. Horoshko, Maria V. Chekhova","doi":"10.1002/qute.202300299","DOIUrl":"https://doi.org/10.1002/qute.202300299","url":null,"abstract":"Nonlinear interferometry with entangled photons allows for characterizing a sample without detecting the photons interacting with it. This method enables highly sensitive optical sensing in the wavelength regions where efficient detectors are still under development. Recently, nonlinear interferometry has been applied to interferometric measurement techniques with broadband light sources, such as Fourier-transform infrared spectroscopy and infrared optical coherence tomography. However, they have been demonstrated with photon pairs produced through spontaneous parametric down-conversion (SPDC) at a low parametric gain, where the average number of photons per mode is much smaller than one. The regime of high-gain SPDC offers several important advantages, such as the amplification of light after its interaction with the sample and a large number of photons per mode at the interferometer output. This work presents broadband spectroscopy and high-resolution optical coherence tomography with undetected photons generated via high-gain SPDC in an aperiodically poled lithium niobate crystal. To prove the principle, reflective Fourier-transform near-infrared spectroscopy with a spectral bandwidth of 17 THz and optical coherence tomography with an axial resolution of 11 µm are demonstrated.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"98 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139035157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francesco Scala, Andrea Ceschini, Massimo Panella, Dario Gerace
In classical machine learning (ML), “overfitting” is the phenomenon occurring when a given model learns the training data excessively well, and it thus performs poorly on unseen data. A commonly employed technique in ML is the so called “dropout,” which prevents computational units from becoming too specialized, hence reducing the risk of overfitting. With the advent of quantum neural networks (QNNs) as learning models, overfitting might soon become an issue, owing to the increasing depth of quantum circuits as well as multiple embedding of classical features, which are employed to give the computational nonlinearity. Here, a generalized approach is presented to apply the dropout technique in QNN models, defining and analyzing different quantum dropout strategies to avoid overfitting and achieve a high level of generalization. This study allows to envision the power of quantum dropout in enabling generalization, providing useful guidelines on determining the maximal dropout probability for a given model, based on overparametrization theory. It also highlights how quantum dropout does not impact the features of the QNN models, such as expressibility and entanglement. All these conclusions are supported by extensive numerical simulations and may pave the way to efficiently employing deep quantum machine learning (QML) models based on state-of-the-art QNNs.
{"title":"A General Approach to Dropout in Quantum Neural Networks","authors":"Francesco Scala, Andrea Ceschini, Massimo Panella, Dario Gerace","doi":"10.1002/qute.202300220","DOIUrl":"https://doi.org/10.1002/qute.202300220","url":null,"abstract":"In classical machine learning (ML), “overfitting” is the phenomenon occurring when a given model learns the training data excessively well, and it thus performs poorly on unseen data. A commonly employed technique in ML is the so called “dropout,” which prevents computational units from becoming too specialized, hence reducing the risk of overfitting. With the advent of quantum neural networks (QNNs) as learning models, overfitting might soon become an issue, owing to the increasing depth of quantum circuits as well as multiple embedding of classical features, which are employed to give the computational nonlinearity. Here, a generalized approach is presented to apply the dropout technique in QNN models, defining and analyzing different quantum dropout strategies to avoid overfitting and achieve a high level of generalization. This study allows to envision the power of quantum dropout in enabling generalization, providing useful guidelines on determining the maximal dropout probability for a given model, based on overparametrization theory. It also highlights how quantum dropout does not impact the features of the QNN models, such as expressibility and entanglement. All these conclusions are supported by extensive numerical simulations and may pave the way to efficiently employing deep quantum machine learning (QML) models based on state-of-the-art QNNs.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138562638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
María Laura Olivera-Atencio, Lucas Lamata, Jesús Casado-Pascual
Quantum machine learning (QML) is a discipline that holds the promise of revolutionizing data processing and problem-solving. However, dissipation and noise arising from the coupling with the environment are commonly perceived as major obstacles to its practical exploitation, as they impact the coherence and performance of the utilized quantum devices. Significant efforts have been dedicated to mitigating and controlling their negative effects on these devices. This perspective takes a different approach, aiming to harness the potential of noise and dissipation instead of combating them. Surprisingly, it is shown that these seemingly detrimental factors can provide substantial advantages in the operation of QML algorithms under certain circumstances. Exploring and understanding the implications of adapting QML algorithms to open quantum systems opens up pathways for devising strategies that effectively leverage noise and dissipation. The recent works analyzed in this perspective represent only initial steps toward uncovering other potential hidden benefits that dissipation and noise may offer. As exploration in this field continues, significant discoveries are anticipated that could reshape the future of quantum computing.
{"title":"Benefits of Open Quantum Systems for Quantum Machine Learning","authors":"María Laura Olivera-Atencio, Lucas Lamata, Jesús Casado-Pascual","doi":"10.1002/qute.202300247","DOIUrl":"https://doi.org/10.1002/qute.202300247","url":null,"abstract":"Quantum machine learning (QML) is a discipline that holds the promise of revolutionizing data processing and problem-solving. However, dissipation and noise arising from the coupling with the environment are commonly perceived as major obstacles to its practical exploitation, as they impact the coherence and performance of the utilized quantum devices. Significant efforts have been dedicated to mitigating and controlling their negative effects on these devices. This perspective takes a different approach, aiming to harness the potential of noise and dissipation instead of combating them. Surprisingly, it is shown that these seemingly detrimental factors can provide substantial advantages in the operation of QML algorithms under certain circumstances. Exploring and understanding the implications of adapting QML algorithms to open quantum systems opens up pathways for devising strategies that effectively leverage noise and dissipation. The recent works analyzed in this perspective represent only initial steps toward uncovering other potential hidden benefits that dissipation and noise may offer. As exploration in this field continues, significant discoveries are anticipated that could reshape the future of quantum computing.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138562629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantum metrology pursues the physical realization of higher-precision measurements to physical quantities than the classically achievable limit by exploiting quantum features, such as entanglement and squeezing, as resources. It has potential applications in developing next-generation frequency standards, magnetometers, radar, and navigation. However, the ubiquitous decoherence in the quantum world degrades the quantum resources and forces the precision back to or even worse than the classical limit, which is called the no-go theorem of noisy quantum metrology and greatly hinders its applications. Therefore, how to realize the promised performance of quantum metrology in realistic noisy situations attracts much attention in recent years. The principle, categories, and applications of quantum metrology are reviewed. Special attention is paid to different quantum resources that can bring quantum superiority in enhancing sensitivity. Then, the no-go theorem of noisy quantum metrology and its active control under different kinds of noise-induced decoherence situations are introduced.
{"title":"Quantum Metrology in the Noisy Intermediate-Scale Quantum Era","authors":"Lin Jiao, Wei Wu, Si-Yuan Bai, Jun-Hong An","doi":"10.1002/qute.202300218","DOIUrl":"https://doi.org/10.1002/qute.202300218","url":null,"abstract":"Quantum metrology pursues the physical realization of higher-precision measurements to physical quantities than the classically achievable limit by exploiting quantum features, such as entanglement and squeezing, as resources. It has potential applications in developing next-generation frequency standards, magnetometers, radar, and navigation. However, the ubiquitous decoherence in the quantum world degrades the quantum resources and forces the precision back to or even worse than the classical limit, which is called the no-go theorem of noisy quantum metrology and greatly hinders its applications. Therefore, how to realize the promised performance of quantum metrology in realistic noisy situations attracts much attention in recent years. The principle, categories, and applications of quantum metrology are reviewed. Special attention is paid to different quantum resources that can bring quantum superiority in enhancing sensitivity. Then, the no-go theorem of noisy quantum metrology and its active control under different kinds of noise-induced decoherence situations are introduced.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nitrogen-vacancy (NV) center in diamond is a unique magnetometer. Its atomic size enables integrations of a tremendous amount (nNV) of NV centers in a bulk diamond with a sensitivity scaling as . However, such a bulk sensor requires a high-power laser to polarize and read out the NV centers. The increasing thermal damage and additional noises associated with high-power lasers hinder the growth of nNV, and thus limit the sensitivity at picotesla level. Here, it shows a relaxometry-based microwave magnetometer that the power density is determined by the relaxation time T1. By cooling the diamond sensor to prolong the T1 (≈s), the required power density further reduces to , of the saturation value. This work paves the way for the utilization of large-size diamond to promote the sensitivity of diamond magnetometer to femtotesla level and beyond.
{"title":"Toward a Laser-Free Diamond Magnetometer for Microwave Fields","authors":"Pengju Zhao, Haodong Wang, Fei Kong, Zhecheng Wang, Yuhang Guo, Huiyao Yu, Fazhan Shi, Jiangfeng Du","doi":"10.1002/qute.202300191","DOIUrl":"https://doi.org/10.1002/qute.202300191","url":null,"abstract":"The nitrogen-vacancy (NV) center in diamond is a unique magnetometer. Its atomic size enables integrations of a tremendous amount (<i>n</i><sub>NV</sub>) of NV centers in a bulk diamond with a sensitivity scaling as <math altimg=\"urn:x-wiley:25119044:media:qute202300191:qute202300191-math-0001\" display=\"inline\" location=\"graphic/qute202300191-math-0001.png\">\u0000<semantics>\u0000<mrow>\u0000<mn>1</mn>\u0000<mo>/</mo>\u0000<msqrt>\u0000<msub>\u0000<mi>n</mi>\u0000<mi>NV</mi>\u0000</msub>\u0000</msqrt>\u0000</mrow>\u0000$1/sqrt {n_{rm NV}}$</annotation>\u0000</semantics></math>. However, such a bulk sensor requires a high-power laser to polarize and read out the NV centers. The increasing thermal damage and additional noises associated with high-power lasers hinder the growth of <i>n</i><sub>NV</sub>, and thus limit the sensitivity at picotesla level. Here, it shows a relaxometry-based microwave magnetometer that the power density is determined by the relaxation time <i>T</i><sub>1</sub>. By cooling the diamond sensor to prolong the <i>T</i><sub>1</sub> (≈s), the required power density further reduces to <math altimg=\"urn:x-wiley:25119044:media:qute202300191:qute202300191-math-0002\" display=\"inline\" location=\"graphic/qute202300191-math-0002.png\">\u0000<semantics>\u0000<mrow>\u0000<mn>0.077</mn>\u0000<mspace width=\"3.33333pt\"></mspace>\u0000<msup>\u0000<mi>Wcm</mi>\u0000<mrow>\u0000<mo>−</mo>\u0000<mn>2</mn>\u0000</mrow>\u0000</msup>\u0000</mrow>\u0000$0.077nobreakspace {rm Wcm^{-2}}$</annotation>\u0000</semantics></math>, <math altimg=\"urn:x-wiley:25119044:media:qute202300191:qute202300191-math-0003\" display=\"inline\" location=\"graphic/qute202300191-math-0003.png\">\u0000<semantics>\u0000<mrow>\u0000<mo>≈</mo>\u0000<mspace width=\"0.33em\"></mspace>\u0000<msup>\u0000<mn>10</mn>\u0000<mrow>\u0000<mo>−</mo>\u0000<mn>6</mn>\u0000</mrow>\u0000</msup>\u0000</mrow>\u0000$approx 10^{-6}$</annotation>\u0000</semantics></math> of the saturation value. This work paves the way for the utilization of large-size diamond to promote the sensitivity of diamond magnetometer to femtotesla level and beyond.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A fundamental concept of quantum physics, the Wigner–Yanase information, is used here as a measure of quantum coherence in spin-dependent radical-pair reactions pertaining to biological magnetic sensing. This measure is connected to the uncertainty of the reaction yields and, further, to the statistics of a cellular receptor-ligand system used to biochemically convey magnetic-field changes. Measurable physiological quantities, such as the number of receptors and fluctuations in ligand concentration, are shown to reflect the introduced Wigner–Yanase measure of singlet-triplet coherence. A quantum-biological uncertainty relation connecting the product of a biological resource and a biological figure of merit with the Wigner–Yanase coherence is arrived at. This approach can serve as a general search for quantum-coherent effects within cellular environments.
{"title":"Physiological Search for Quantum Biological Sensing Effects Based on the Wigner–Yanase Connection between Coherence and Uncertainty","authors":"Iannis K. Kominis","doi":"10.1002/qute.202300292","DOIUrl":"https://doi.org/10.1002/qute.202300292","url":null,"abstract":"A fundamental concept of quantum physics, the Wigner–Yanase information, is used here as a measure of quantum coherence in spin-dependent radical-pair reactions pertaining to biological magnetic sensing. This measure is connected to the uncertainty of the reaction yields and, further, to the statistics of a cellular receptor-ligand system used to biochemically convey magnetic-field changes. Measurable physiological quantities, such as the number of receptors and fluctuations in ligand concentration, are shown to reflect the introduced Wigner–Yanase measure of singlet-triplet coherence. A quantum-biological uncertainty relation connecting the product of a biological resource and a biological figure of merit with the Wigner–Yanase coherence is arrived at. This approach can serve as a general search for quantum-coherent effects within cellular environments.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Edgar F. Perez, Cori Haws, Marcelo Davanco, Jindong Song, Luca Sapienza, Kartik Srinivasan
Single epitaxial quantum dots (QDs) embedded in nanophotonic geometries are a leading technology for quantum light generation. However, efficiently coupling their emission into a single mode fiber or Gaussian beam often remains challenging. Here, direct laser writing (DLW) is used to address this challenge by fabricating 1 µm diameter polymer nanowires (PNWs) in-contact-with and perpendicular-to a QD-containing GaAs layer. QD emission is coupled to the PNW's waveguide mode, enhancing collection efficiency into a single-mode fiber. PNW fabrication does not alter the QD device layer, making PNWs well-suited for augmenting pre-existing in-plane geometries. Standalone PNWs and PNWs in conjunction with metallic nanoring devices that have been previously established for increasing extraction of QD emission are studied. Methods that mitigate standing wave reflections and heat, caused by GaAs's absorption/reflection of the lithography beam, and which otherwise prevent PNW fabrication, are also reported. A maximum improvement of ( in a nanoring system with a PNW compared to the same system without a PNW is observed, in line with numerical results, and highlighting the PNW's ability to waveguide QD emission and increase collection efficiency simultaneously. These results demonstrate new DLW functionality in service of quantum emitter photonics that maintains compatibility with existing top-down fabrication approaches.
{"title":"Direct-Laser-Written Polymer Nanowire Waveguides for Broadband Single Photon Collection from Epitaxial Quantum Dots into a Gaussian-like Mode","authors":"Edgar F. Perez, Cori Haws, Marcelo Davanco, Jindong Song, Luca Sapienza, Kartik Srinivasan","doi":"10.1002/qute.202300149","DOIUrl":"https://doi.org/10.1002/qute.202300149","url":null,"abstract":"Single epitaxial quantum dots (QDs) embedded in nanophotonic geometries are a leading technology for quantum light generation. However, efficiently coupling their emission into a single mode fiber or Gaussian beam often remains challenging. Here, direct laser writing (DLW) is used to address this challenge by fabricating 1 µm diameter polymer nanowires (PNWs) in-contact-with and perpendicular-to a QD-containing GaAs layer. QD emission is coupled to the PNW's <math altimg=\"urn:x-wiley:25119044:media:qute202300149:qute202300149-math-0001\" display=\"inline\" location=\"graphic/qute202300149-math-0001.png\">\u0000<semantics>\u0000<mrow>\u0000<mi>H</mi>\u0000<msub>\u0000<mi>E</mi>\u0000<mn>11</mn>\u0000</msub>\u0000</mrow>\u0000$HE_{11}$</annotation>\u0000</semantics></math> waveguide mode, enhancing collection efficiency into a single-mode fiber. PNW fabrication does not alter the QD device layer, making PNWs well-suited for augmenting pre-existing in-plane geometries. Standalone PNWs and PNWs in conjunction with metallic nanoring devices that have been previously established for increasing extraction of QD emission are studied. Methods that mitigate standing wave reflections and heat, caused by GaAs's absorption/reflection of the lithography beam, and which otherwise prevent PNW fabrication, are also reported. A maximum improvement of (<math altimg=\"urn:x-wiley:25119044:media:qute202300149:qute202300149-math-0002\" display=\"inline\" location=\"graphic/qute202300149-math-0002.png\">\u0000<semantics>\u0000<mrow>\u0000<mn>3.0</mn>\u0000<mspace width=\"3.33333pt\"></mspace>\u0000<mo>±</mo>\u0000<mspace width=\"3.33333pt\"></mspace>\u0000<mn>0.7</mn>\u0000<mo stretchy=\"false\">)</mo>\u0000<mo>×</mo>\u0000</mrow>\u0000$3.0nobreakspace pm nobreakspace 0.7)times$</annotation>\u0000</semantics></math> in a nanoring system with a PNW compared to the same system without a PNW is observed, in line with numerical results, and highlighting the PNW's ability to waveguide QD emission and increase collection efficiency simultaneously. These results demonstrate new DLW functionality in service of quantum emitter photonics that maintains compatibility with existing top-down fabrication approaches.","PeriodicalId":501028,"journal":{"name":"Advanced Quantum Technologies","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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