Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Vibration Isolation and Length Stabilization of an Open-Access Fibre Fabry–Pérot Microcavity

Yash Joshi

Published Jan 1, 2026• 0 citations
OpenAlex

Abstract

Single rare-earth ions in crystals are promising systems for quantum information experiments, but detecting the fluorescence from a single ion remains challenging. An open-access fibre Fabry–Pérot microcavity can enhance the ion–light interaction and improve photon collection, but useful operation requires the cavity length to be stabilized at the picometer scale. This thesis studies both passive and active stabilization methods for such a microcavity. The passive part of the work focused on a compact spring–Kapton foam isolation stage. Simple vibration models, mechanical simulations, and room-temperature prototype measurements were used to study the expected isolation behaviour. Efforts have been put in to properly characterise the kapton foam due to the lack of studies in the literature. The spring stage provided a low-frequency resonance in the few-hertz range and useful attenuation in the 10 Hz to 100 Hz band. Kapton was found to behave as a lossy compliant layer, mainly broadening higher-frequency features rather than acting as an ideal second isolation stage. The active stabilization part focused on optical error-signal generation using higher-order spatial modes. A spatial light modulator was used to generate Hermite–Gaussian-like and Laguerre–Gaussian-like modes, including vortex–Gaussian superpositions. These experiments showed that the SLM is a flexible tool for producing candidate locking modes. Final coupling into the microcavity from the flat-mirror side was attempted, but was limited by distorted cavity modes, poor collimation, infrared alignment difficulty, and mechanical instability. Overall, the results show that passive isolation can reduce the relevant low-frequency vibration, while SLM-generated higher-order and vortex-like modes provide a practical route for future error-signal tests. The next step is to combine the improved passive isolation stage with a cleaner cavity setup and directly measure both the error-signal slope and the locking-light leakage into the single-mode-fibre detection path.

Related papers

A highly stable and fully tunable open microcavity platform at cryogenic temperatures

Maximilian Pallmann, Timon Eichhorn, Julia Benedikter +3 more

Open-access microcavities are a powerful tool to enhance light–matter interactions for solid-state quantum and nanosystems and are key to advance applications in quantum technologies. For this purpose, the cavities should simultaneously meet two conflicting requirements—full tunability to cope with spatial and spectral inhomogeneities of a material and highest stability under operation in a cryogenic environment to maintain resonance conditions. To tackle this challenge, we have developed a fully tunable, open-access, fiber-based Fabry–Pérot microcavity platform that can be operated under increased noise levels in a closed-cycle cryostat. It comprises custom-designed monolithic micro- and nanopositioning elements with up to mm-scale travel range that achieve a passive cavity length stability at low temperature of only 15 pm rms in a closed-cycle cryostat and 5 pm in a more quiet flow cryostat. This can be further improved by active stabilization, and even higher stability is obtained under direct mechanical contact between the cavity mirrors, yielding 0.8 pm rms during the quiet phase of the closed-cycle cryocooler. The platform provides the operation of cryogenic cavities with high finesse and small mode volume for strong enhancement of light–matter interactions, opening up novel possibilities for experiments with a great variety of quantum and nanomaterials.

APL Photonics•Mar 21, 2023•22 citations

A highly stable and fully tunable open microcavity platform at cryogenic temperatures

Maximilian Pallmann, Timon Eichhorn, Julia Benedikter +3 more

Open-access microcavities are a powerful tool to enhance light-matter interactions for solid-state quantum and nano systems and are key to advance applications in quantum technologies. For this purpose, the cavities should simultaneously meet two conflicting requirements - full tunability to cope with spatial and spectral inhomogeneities of a material, and highest stability under operation in a cryogenic environment to maintain resonance conditions. To tackle this challenge, we have developed a fully-tunable, open-access, fiber-based Fabry-Pérot microcavity platform which can be operated also under increased noise levels in a closed-cycle cryostat. It comprises custom-designed monolithic micro- and nanopositioning elements with up to mm-scale travel range that achieve a passive cavity length stability at low temperature of only 15 pm rms in a closed-cycle cryostat, and 5 pm in a more quiet flow cryostat. This can be further improved by active stabilization, and even higher stability is obtained under direct mechanical contact between the cavity mirrors, yielding 0:8 pm rms during the quiet phase of the closed-cycle cryo cooler. The platform provides operation of cryogenic cavities with high finesse and small mode volume for strong enhancement of light-matter interactions, opening up novel possibilities for experiments with a great variety of quantum and nano materials.

arXiv:2212.11601•Dec 22, 2022•0 citations

A fast-tunable and stable fiber microcavity for coupling Ba+ ions in quantum networks

Fang Ding, Chenghao Zhang, Weibin Chen +4 more

We present the design, implementation, and characterization of a high-stability, fast-tunable fiber Fabry-Pérot microcavity system optimized for coupling with Ba + ions to form quantum network nodes.The microcavity system integrates multiwavelength single-mode transmission, rapid and broad-band tunability, high finesse, and exceptional passive mechanical stability.By incorporating a unique vibration isolation structure, the system enables the fiber-optic microcavity (with a finesse of 8000) to remain resonant with the laser for several minutes even without active feedback.Furthermore, we demonstrate active cavity length stabilization using the Pound-Drever-Hall method, which significantly suppresses low-frequency vibrations and enables the cavity length to remain stable for several days.Experimental results show that this fiber microcavity system offers outstanding stability and flexibility for practical quantum network applications, providing reliable technical support for the construction of large-scale quantum networks based on trapped ions.

Chinese Optics Letters•Jan 1, 2025•2 citations

High finesse optical fiber cavities: optimal alignment and robust stabilization (Conference Presentation)

Lothar Ratschbacher, Jose Gallego, Sutapa Ghosh +4 more

Fiber Fabry-Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications. Some of the most promising areas of application of these optical micro-resonators with high finesse and small mode volume are in the field of quantum communication and information. The resonator-enhanced light-matter interaction, for instance, provide basis for the realization of efficient optical interfaces between stationary matter-based quantum nodes and flying single-photon qubits. To date fiber Fabry-Perot cavities have been successfully applied in experiments interfacing single photons with a wide range of quantum systems, including cold atoms, ions and solid state emitters as well as quantum optomechanical experiments. Here we address some important practical questions that arise during the experimental implementation of high finesse fiber Fabry-Perot cavities: How can optimal fiber cavity alignment be achieved and how can the efficiency of coupling light from the optical fibers to the cavity mode and vice versa be characterized? How should optical fiber cavities be constructed and stabilized to fulfill their potential for miniaturization and integration into robust scientific and technological devices that can operate outside of dedicated laboratory environments in the future? The first two questions we answer with an analytic mode matching calculation that relates the alignment dependent fiber-to-cavity mode-matching efficiency to the easily measurable dip in the reflected light power at the cavity resonance. Our general analysis provides a simple recipe for the optimal alignment of fiber Fabry-Perot cavities and moreover for the first time explains the asymmetry in their reflective line shapes. The latter question we explore by investigating a novel, intrinsically rigid fiber cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal self-locking and external temperature tuning. The performance of this novel approach is compared to a more traditional, piezomechanically-actuated resonator that is feedback stabilized to a reference laser based on the Pound-Drever-Hall locking technique. Finally, with the application of single photon interfacing in mind we discuss the issue of fiber-generated background photons in Fiber Fabry-Perot cavities. We believe that, due to their simplicity, compactness and robustness, rigid fiber cavities could be a promising solution for miniaturized, integratable and scalable cavity quantum electrodynamic devices and further applications of FFPC with similar requirements.

•Aug 3, 2016•0 citations

High-finesse fiber Fabry–Perot cavities: stabilization and mode matching analysis

J. Gallego, S. Ghosh, Seyed Khalil Alavi +4 more

Fiber Fabry–Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications, where they typically require precise stabilization of their optical resonances. Here, we study two different approaches to construct fiber Fabry–Perot resonators and stabilize their length for experiments in cavity quantum electrodynamics with neutral atoms. A piezo-mechanically actuated cavity with feedback based on the Pound–Drever–Hall locking technique is compared to a novel rigid cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal self-locking and external temperature tuning. Furthermore, we present a general analysis of the mode matching problem in fiber Fabry–Perot cavities, which explains the asymmetry in their reflective line shapes and has important implications for the optimal alignment of the fiber resonators. Finally, we discuss the issue of fiber-generated background photons. We expect that our results contribute toward the integration of high-finesse fiber Fabry–Perot cavities into compact and robust quantum-enabled devices in the future.

arXiv:1508.05289•Applied Physics B•Mar 1, 2016•74 citations

Micro-cavity length stabilization for fluorescence enhancement using schemes based on higher-order spatial modes

Abdullah Abdelatief, Antonius. J. Renders, Mohammed K. Alqedra +4 more

We report on the experimental investigation of potential high-performance cavity length stabilization using odd-indexed higher-order spatial modes. Schemes based on higher-order modes are particularly useful for micro-cavities that are used for enhanced fluorescence detection of a few emitters, which need to minimize photons leaking from a stabilization beam. We describe the design and construction of an assembly for a microcavity setup with tunable high passive stability. In addition, different types of active stabilization techniques based on higher-order modes are then implemented and characterized based on their performance. We achieved a stability of about 0.5 pm rms, while the error photons leaking from the continuous locking beam to a fluorescence detector are suppressed by more than 100-fold. We expect these results to be important for quantum technology implementations of various emitter-cavity setups, where these techniques provide a useful tool to meet the highly challenging demands.

Review of Scientific Instruments•Apr 1, 2025•2 citations
Single rare-earth ions in crystals are promising systems for quantum information experiments, but detecting the fluorescence from a single ion remains challenging. An open-access fibre Fabry–Pérot microcavity can enhance the ion–light interaction and improve photon collection, but useful operation requires the cavity length to be stabilized at the picometer scale. This thesis studies both passive and active stabilization methods for such a microcavity. The passive part of the work focused on a compact spring–Kapton foam isolation stage. Simple vibration models, mechanical simulations, and room-temperature prototype measurements were used to study the expected isolation behaviour. Efforts have been put in to properly characterise the kapton foam due to the lack of studies in the literature. The spring stage provided a low-frequency resonance in the few-hertz range and useful attenuation in the 10 Hz to 100 Hz band. Kapton was found to behave as a lossy compliant layer, mainly broadening higher-frequency features rather than acting as an ideal second isolation stage. The active stabilization part focused on optical error-signal generation using higher-order spatial modes. A spatial light modulator was used to generate Hermite–Gaussian-like and Laguerre–Gaussian-like modes, including vortex–Gaussian superpositions. These experiments showed that the SLM is a flexible tool for producing candidate locking modes. Final coupling into the microcavity from the flat-mirror side was attempted, but was limited by distorted cavity modes, poor collimation, infrared alignment difficulty, and mechanical instability. Overall, the results show that passive isolation can reduce the relevant low-frequency vibration, while SLM-generated higher-order and vortex-like modes provide a practical route for future error-signal tests. The next step is to combine the improved passive isolation stage with a cleaner cavity setup and directly measure both the error-signal slope and the locking-light leakage into the single-mode-fibre detection path.
Open-access microcavities are a powerful tool to enhance light–matter interactions for solid-state quantum and nanosystems and are key to advance applications in quantum technologies. For this purpose, the cavities should simultaneously meet two conflicting requirements—full tunability to cope with spatial and spectral inhomogeneities of a material and highest stability under operation in a cryogenic environment to maintain resonance conditions. To tackle this challenge, we have developed a fully tunable, open-access, fiber-based Fabry–Pérot microcavity platform that can be operated under increased noise levels in a closed-cycle cryostat. It comprises custom-designed monolithic micro- and nanopositioning elements with up to mm-scale travel range that achieve a passive cavity length stability at low temperature of only 15 pm rms in a closed-cycle cryostat and 5 pm in a more quiet flow cryostat. This can be further improved by active stabilization, and even higher stability is obtained under direct mechanical contact between the cavity mirrors, yielding 0.8 pm rms during the quiet phase of the closed-cycle cryocooler. The platform provides the operation of cryogenic cavities with high finesse and small mode volume for strong enhancement of light–matter interactions, opening up novel possibilities for experiments with a great variety of quantum and nanomaterials.
Open-access microcavities are a powerful tool to enhance light-matter interactions for solid-state quantum and nano systems and are key to advance applications in quantum technologies. For this purpose, the cavities should simultaneously meet two conflicting requirements - full tunability to cope with spatial and spectral inhomogeneities of a material, and highest stability under operation in a cryogenic environment to maintain resonance conditions. To tackle this challenge, we have developed a fully-tunable, open-access, fiber-based Fabry-Pérot microcavity platform which can be operated also under increased noise levels in a closed-cycle cryostat. It comprises custom-designed monolithic micro- and nanopositioning elements with up to mm-scale travel range that achieve a passive cavity length stability at low temperature of only 15 pm rms in a closed-cycle cryostat, and 5 pm in a more quiet flow cryostat. This can be further improved by active stabilization, and even higher stability is obtained under direct mechanical contact between the cavity mirrors, yielding 0:8 pm rms during the quiet phase of the closed-cycle cryo cooler. The platform provides operation of cryogenic cavities with high finesse and small mode volume for strong enhancement of light-matter interactions, opening up novel possibilities for experiments with a great variety of quantum and nano materials.
We present the design, implementation, and characterization of a high-stability, fast-tunable fiber Fabry-Pérot microcavity system optimized for coupling with Ba + ions to form quantum network nodes.The microcavity system integrates multiwavelength single-mode transmission, rapid and broad-band tunability, high finesse, and exceptional passive mechanical stability.By incorporating a unique vibration isolation structure, the system enables the fiber-optic microcavity (with a finesse of 8000) to remain resonant with the laser for several minutes even without active feedback.Furthermore, we demonstrate active cavity length stabilization using the Pound-Drever-Hall method, which significantly suppresses low-frequency vibrations and enables the cavity length to remain stable for several days.Experimental results show that this fiber microcavity system offers outstanding stability and flexibility for practical quantum network applications, providing reliable technical support for the construction of large-scale quantum networks based on trapped ions.
Fiber Fabry-Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications. Some of the most promising areas of application of these optical micro-resonators with high finesse and small mode volume are in the field of quantum communication and information. The resonator-enhanced light-matter interaction, for instance, provide basis for the realization of efficient optical interfaces between stationary matter-based quantum nodes and flying single-photon qubits. To date fiber Fabry-Perot cavities have been successfully applied in experiments interfacing single photons with a wide range of quantum systems, including cold atoms, ions and solid state emitters as well as quantum optomechanical experiments. Here we address some important practical questions that arise during the experimental implementation of high finesse fiber Fabry-Perot cavities: How can optimal fiber cavity alignment be achieved and how can the efficiency of coupling light from the optical fibers to the cavity mode and vice versa be characterized? How should optical fiber cavities be constructed and stabilized to fulfill their potential for miniaturization and integration into robust scientific and technological devices that can operate outside of dedicated laboratory environments in the future? The first two questions we answer with an analytic mode matching calculation that relates the alignment dependent fiber-to-cavity mode-matching efficiency to the easily measurable dip in the reflected light power at the cavity resonance. Our general analysis provides a simple recipe for the optimal alignment of fiber Fabry-Perot cavities and moreover for the first time explains the asymmetry in their reflective line shapes. The latter question we explore by investigating a novel, intrinsically rigid fiber cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal self-locking and external temperature tuning. The performance of this novel approach is compared to a more traditional, piezomechanically-actuated resonator that is feedback stabilized to a reference laser based on the Pound-Drever-Hall locking technique. Finally, with the application of single photon interfacing in mind we discuss the issue of fiber-generated background photons in Fiber Fabry-Perot cavities. We believe that, due to their simplicity, compactness and robustness, rigid fiber cavities could be a promising solution for miniaturized, integratable and scalable cavity quantum electrodynamic devices and further applications of FFPC with similar requirements.
Fiber Fabry–Perot cavities, formed by micro-machined mirrors on the end-facets of optical fibers, are used in an increasing number of technical and scientific applications, where they typically require precise stabilization of their optical resonances. Here, we study two different approaches to construct fiber Fabry–Perot resonators and stabilize their length for experiments in cavity quantum electrodynamics with neutral atoms. A piezo-mechanically actuated cavity with feedback based on the Pound–Drever–Hall locking technique is compared to a novel rigid cavity design that makes use of the high passive stability of a monolithic cavity spacer and employs thermal self-locking and external temperature tuning. Furthermore, we present a general analysis of the mode matching problem in fiber Fabry–Perot cavities, which explains the asymmetry in their reflective line shapes and has important implications for the optimal alignment of the fiber resonators. Finally, we discuss the issue of fiber-generated background photons. We expect that our results contribute toward the integration of high-finesse fiber Fabry–Perot cavities into compact and robust quantum-enabled devices in the future.
We report on the experimental investigation of potential high-performance cavity length stabilization using odd-indexed higher-order spatial modes. Schemes based on higher-order modes are particularly useful for micro-cavities that are used for enhanced fluorescence detection of a few emitters, which need to minimize photons leaking from a stabilization beam. We describe the design and construction of an assembly for a microcavity setup with tunable high passive stability. In addition, different types of active stabilization techniques based on higher-order modes are then implemented and characterized based on their performance. We achieved a stability of about 0.5 pm rms, while the error photons leaking from the continuous locking beam to a fluorescence detector are suppressed by more than 100-fold. We expect these results to be important for quantum technology implementations of various emitter-cavity setups, where these techniques provide a useful tool to meet the highly challenging demands.