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

Lund reports on atomic physics

Laser Stabilisation Using a Slow Light Cavity

Teodor Strömberg

Published Jan 1, 2015• 0 citations
OpenAlex

Abstract

In this thesis the application of slow light effects to the area of laser stabilisation is investigated. The frequency stability of lasers locked to external cavities is limited by the stability of the modes in the reference cavity. By using dispersive slow light effects the effective length of a cavity can be increased by several orders of magnitude, without a proportional increase in the sensitivity to fluctuations in cavity length, thereby yielding a net increase in stability. The effects are achieved through spectral hole burning in cryogenically cooled rare-earth ion doped crystals. Two sets of experiments are carried out, the first focusing on hole burning and the second focusing laser locking. Linewidths and frequency drift of the cavity spectrum are studied. Feedback control using an error signal generated from the slow light cavity is demonstrated, but successfully locking the laser is still yet to be achieved.

Related papers

Optical Fiber Phase Noise Cancellation for Slow Light Crystal Cavity Locking

Mohammad Tasnimul Haque

Recent developments in the field of optical clocks and quantum information have fueled the necessity for both fiber phase noise cancellation and laser stabilisation. The Quantum Information group at Lund University is conducting research on quantum computation experiments based on rare earth ion doped crystals and also application of slow light effects induced by spectral hole burning in these rare earth ion doped crystals. Slow light effects can significantly improve laser stabilisation by increasing effective cavity length without inducing mechanical noise. In this thesis a fiber phase noise cancellation setup was designed and built. The fiber stabilisation will be used in a setup where a laser is stabilised using a slow light crystal cavity as frequency reference and a setup was designed for this application. By partially reflecting back light through a fiber and by performing a phase measurement and through feedback control, the fiber phase noise can be effectively cancelled. A method for first creating a slow light crystal cavity and then locking the laser to one of the resonance peaks of the cavity was planned and designed incorporating two fiber locking setups for phase noise cancellation. Suitable components for building the system was investigated and put together. Fiber locking experiment was then carried out.

•Jan 1, 2016•0 citations

Experimental Implementation of a Fiber Noise Cancellation System for Slow Light Laser Locking

Alexander Bengtsson

An electromagnetic wave propagating through an optical fiber is sensitive to external disturbances, such as mechanical vibrations and temperature and pressure fluctuations, which add phase noise onto the wave. For high-precision frequency-based applications this phase noise has to be removed. By partially reflecting light from the remote end of the fiber back through the fiber, and comparing it to light that has not passed through the fiber, their beat note can be phase locked to a stable reference, using an acousto-optic modulator for phase noise compensation. This effectively cancels the phase noise at the remote end of the fiber. In this project, two such fiber noise cancellation systems have been successfully assembled. The fiber noise cancellation systems will be used for laser locking to a slow light crystal cavity. Using spectral hole burning, a very low group velocity can be obtained in rare-earth-ion-doped crystals. By depositing mirrors on such a crystal, it could act as a reference cavity with a very long effective length, but without the increased difficulty of isolating the cavity from mechanical vibrations associated with a physically long cavity. By locking a laser to a slow light crystal cavity, an improved stability could potentially be achieved. A possible setup for slow light crystal cavity laser locking experiments, where the fiber noise cancellation systems have been integrated, is also presented in this thesis.

•Jan 1, 2017•0 citations

Using slow light to enable laser frequency stabilization to a short, high-Q cavity

David Gustavsson, Marcus Lindén, Kevin J. Shortiss +4 more

State-of-the-art laser frequency stabilization is limited by miniscule length changes caused by thermal noise. In this work, a cavity-length-insensitive frequency stabilization scheme is implemented using strong dispersion in a $21\,\mathrm{mm}$ long cavity with a europium-ion-doped spacer of yttrium orthosilicate. A number of limiting factors for slow light laser stabilization are evaluated, including the inhomogeneous and homogeneous linewidth of the ions, the deterioration of spectral windows, and the linewidth of the cavity modes. Using strong dispersion, the cavity modes were narrowed by a factor $1.6\cdot 10^5$, leading to a cavity linewidth of $3.0\,\mathrm{kHz}$ and a $Q$ factor of $1.7\cdot 10^{11}$. Frequency stabilization was demonstrated using a cavity mode in a spectral transparency region near the center of the inhomogeneous profile, showing an overlapping Allan deviation below $6\cdot 10^{-14}$ and a linear drift rate of $3.66\,\mathrm{Hz}/\mathrm{s}$. Considering improvements that could be implemented, this makes the europium-based slow light laser frequency reference a promising candidate for ultra-precise tabletop frequency stabilization.

arXiv:2408.11703•Aug 21, 2024•0 citations

Using slow light to enable laser frequency stabilization to a short, high-Q cavity

David Gustavsson, Marcus Lindén, Kevin J. Shortiss +4 more

State-of-the-art laser frequency stabilization is limited by miniscule length changes caused by thermal noise. In this work, a cavity-length-insensitive frequency stabilization scheme is implemented using strong dispersion in a 21 mm long cavity with a europium-ion-doped spacer of yttrium orthosilicate. A number of limiting factors for slow light laser stabilization are evaluated, including the inhomogeneous and homogeneous linewidth of the ions, the deterioration of spectral windows, and the linewidth of the cavity modes. Using strong dispersion, the cavity modes were narrowed by a factor 1.6 × 10 5 , leading to a cavity linewidth of 3.0 kHz and a Q factor of 1.7 × 10 11 . Frequency stabilization was demonstrated using a cavity mode in a spectral transparency region near the center of the inhomogeneous profile, showing an overlapping Allan deviation below 6 × 10 −14 and a linear drift rate of 3.66 Hz s −1 . Considering improvements that could be implemented, this makes the europium-based slow light laser frequency reference a promising candidate for ultra-precise tabletop frequency stabilization.

Optics Express•Nov 4, 2024•5 citations

Stabilising a Ring Dye Laser to Iodine Transitions

Robert Saers

Saturation spectroscopy of Iodine is used to lock the frequency of a Coherent 699-21 Ring Dye laser. Without an external reference the laser frequency drifts several tens of MHz per hour. With the system presented in this thesis the drift has been reduced to a maximum of ±lMHz. Theoretical description of saturation spectroscopy and hole burning is given and the experiments are presented. In preparation for future experiments in quantum computing hole burning in rare-earth-ion-doped crystals and broadening of the hole by excitation of ions at different intervals have also been studied in this master's thesis.

•Jan 1, 2002•2 citations

Spectral Hole Burning for Ultra-stable Lasers

Shuo Zhang, Nemanja Lučić, Nicolas Galland +6 more

Spectral hole burning in rare earth doped crystal can provide frequency references based on the optical transition of the dopant ions [1] . The narrow spectral patterns can be used to improve laser frequency stabilization [2] , [3] and provide a new generation of ultra-stable lasers with lower thermal noise benefiting from the cryogenic environment and better quality factor of the crystal than the amorphous glass typically used in the Fabry-Perot cavity. We utilize Europium doped yttrium silicon oxide (Eu:YSO) in our experiments, which allow realization of long lived (hours or more depending on temperature) narrow spectral holes ( kHz or less) well suited for high precision experiment applications. We will describe our novel double-heterodyne detection method [4] , used to decrease the detection noise, as well as experiments assessing quantitatively the sensitivity of the spectral pattern to crystal deformation [5] , [6] , application of electric field [7] and temperature fluctuations. We currently demonstrate a state-of-the-art laser frequency stability at 1.7 × 10 − 15 at 1s [4] , limited by the latter effect, for which improvement strategies have been demonstrated elsewhere [2] and which we are currently implementing. The other effects which we have quantitatively studied are compatible with a few 10 − 18 frequency stability at 1s time scale. This work is particularly promising in the context of optical frequency lattice clocks, for which the ultra-stable laser used for probing the clock transition is a strong limiting factor of the frequency stability.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 21, 2021•1 citation
In this thesis the application of slow light effects to the area of laser stabilisation is investigated. The frequency stability of lasers locked to external cavities is limited by the stability of the modes in the reference cavity. By using dispersive slow light effects the effective length of a cavity can be increased by several orders of magnitude, without a proportional increase in the sensitivity to fluctuations in cavity length, thereby yielding a net increase in stability. The effects are achieved through spectral hole burning in cryogenically cooled rare-earth ion doped crystals. Two sets of experiments are carried out, the first focusing on hole burning and the second focusing laser locking. Linewidths and frequency drift of the cavity spectrum are studied. Feedback control using an error signal generated from the slow light cavity is demonstrated, but successfully locking the laser is still yet to be achieved.
Recent developments in the field of optical clocks and quantum information have fueled the necessity for both fiber phase noise cancellation and laser stabilisation. The Quantum Information group at Lund University is conducting research on quantum computation experiments based on rare earth ion doped crystals and also application of slow light effects induced by spectral hole burning in these rare earth ion doped crystals. Slow light effects can significantly improve laser stabilisation by increasing effective cavity length without inducing mechanical noise. In this thesis a fiber phase noise cancellation setup was designed and built. The fiber stabilisation will be used in a setup where a laser is stabilised using a slow light crystal cavity as frequency reference and a setup was designed for this application. By partially reflecting back light through a fiber and by performing a phase measurement and through feedback control, the fiber phase noise can be effectively cancelled. A method for first creating a slow light crystal cavity and then locking the laser to one of the resonance peaks of the cavity was planned and designed incorporating two fiber locking setups for phase noise cancellation. Suitable components for building the system was investigated and put together. Fiber locking experiment was then carried out.
An electromagnetic wave propagating through an optical fiber is sensitive to external disturbances, such as mechanical vibrations and temperature and pressure fluctuations, which add phase noise onto the wave. For high-precision frequency-based applications this phase noise has to be removed. By partially reflecting light from the remote end of the fiber back through the fiber, and comparing it to light that has not passed through the fiber, their beat note can be phase locked to a stable reference, using an acousto-optic modulator for phase noise compensation. This effectively cancels the phase noise at the remote end of the fiber. In this project, two such fiber noise cancellation systems have been successfully assembled. The fiber noise cancellation systems will be used for laser locking to a slow light crystal cavity. Using spectral hole burning, a very low group velocity can be obtained in rare-earth-ion-doped crystals. By depositing mirrors on such a crystal, it could act as a reference cavity with a very long effective length, but without the increased difficulty of isolating the cavity from mechanical vibrations associated with a physically long cavity. By locking a laser to a slow light crystal cavity, an improved stability could potentially be achieved. A possible setup for slow light crystal cavity laser locking experiments, where the fiber noise cancellation systems have been integrated, is also presented in this thesis.
State-of-the-art laser frequency stabilization is limited by miniscule length changes caused by thermal noise. In this work, a cavity-length-insensitive frequency stabilization scheme is implemented using strong dispersion in a 21 mm21\,\mathrm{mm}21mm long cavity with a europium-ion-doped spacer of yttrium orthosilicate. A number of limiting factors for slow light laser stabilization are evaluated, including the inhomogeneous and homogeneous linewidth of the ions, the deterioration of spectral windows, and the linewidth of the cavity modes. Using strong dispersion, the cavity modes were narrowed by a factor 1.6⋅1051.6\cdot 10^51.6⋅105, leading to a cavity linewidth of 3.0 kHz3.0\,\mathrm{kHz}3.0kHz and a QQQ factor of 1.7⋅10111.7\cdot 10^{11}1.7⋅1011. Frequency stabilization was demonstrated using a cavity mode in a spectral transparency region near the center of the inhomogeneous profile, showing an overlapping Allan deviation below 6⋅10−146\cdot 10^{-14}6⋅10−14 and a linear drift rate of 3.66 Hz/s3.66\,\mathrm{Hz}/\mathrm{s}3.66Hz/s. Considering improvements that could be implemented, this makes the europium-based slow light laser frequency reference a promising candidate for ultra-precise tabletop frequency stabilization.
State-of-the-art laser frequency stabilization is limited by miniscule length changes caused by thermal noise. In this work, a cavity-length-insensitive frequency stabilization scheme is implemented using strong dispersion in a 21 mm long cavity with a europium-ion-doped spacer of yttrium orthosilicate. A number of limiting factors for slow light laser stabilization are evaluated, including the inhomogeneous and homogeneous linewidth of the ions, the deterioration of spectral windows, and the linewidth of the cavity modes. Using strong dispersion, the cavity modes were narrowed by a factor 1.6 × 10 5 , leading to a cavity linewidth of 3.0 kHz and a Q factor of 1.7 × 10 11 . Frequency stabilization was demonstrated using a cavity mode in a spectral transparency region near the center of the inhomogeneous profile, showing an overlapping Allan deviation below 6 × 10 −14 and a linear drift rate of 3.66 Hz s −1 . Considering improvements that could be implemented, this makes the europium-based slow light laser frequency reference a promising candidate for ultra-precise tabletop frequency stabilization.
Saturation spectroscopy of Iodine is used to lock the frequency of a Coherent 699-21 Ring Dye laser. Without an external reference the laser frequency drifts several tens of MHz per hour. With the system presented in this thesis the drift has been reduced to a maximum of ±lMHz. Theoretical description of saturation spectroscopy and hole burning is given and the experiments are presented. In preparation for future experiments in quantum computing hole burning in rare-earth-ion-doped crystals and broadening of the hole by excitation of ions at different intervals have also been studied in this master's thesis.
Spectral hole burning in rare earth doped crystal can provide frequency references based on the optical transition of the dopant ions [1] . The narrow spectral patterns can be used to improve laser frequency stabilization [2] , [3] and provide a new generation of ultra-stable lasers with lower thermal noise benefiting from the cryogenic environment and better quality factor of the crystal than the amorphous glass typically used in the Fabry-Perot cavity. We utilize Europium doped yttrium silicon oxide (Eu:YSO) in our experiments, which allow realization of long lived (hours or more depending on temperature) narrow spectral holes ( kHz or less) well suited for high precision experiment applications. We will describe our novel double-heterodyne detection method [4] , used to decrease the detection noise, as well as experiments assessing quantitatively the sensitivity of the spectral pattern to crystal deformation [5] , [6] , application of electric field [7] and temperature fluctuations. We currently demonstrate a state-of-the-art laser frequency stability at 1.7 × 10 − 15 at 1s [4] , limited by the latter effect, for which improvement strategies have been demonstrated elsewhere [2] and which we are currently implementing. The other effects which we have quantitatively studied are compatible with a few 10 − 18 frequency stability at 1s time scale. This work is particularly promising in the context of optical frequency lattice clocks, for which the ultra-stable laser used for probing the clock transition is a strong limiting factor of the frequency stability.