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Construction of an External Cavity Laser and Reference Cavity for addressing Dysprosium

 Christopher Hayton

Published Jan 1, 2024• 0 citations
OpenAlex

Abstract

The goal of this Masters project is to construct a laser system to facilitate future experiments with atomic Dysprosium via the transition at 421.29 nm. Dysprosium is of interest due to its magnetic properties, namely that it is tied with Terbium as the most magnetic element. Although there have been a number of investigations into laser cooling and trapping clouds of Dysprosium atoms, we would like to (in the future) interact with and manipulate individual atoms of Dysprosium. The first step towards this is to construct a laser system capable of interacting with the atom/s. To this end, an External Cavity Diode Laser (ECDL) operating at 421.29 nm and an optical reference cavity mounted in a vacuum are designed, constructed, and implemented.

Related papers

Trapping Dysprosium in a Magnetic Optical Trap Directly from a Thermal Beam

Liam Domett-Potts

Dysprosium is the most magnetic element on the periodic table, which gives it the potential to display exotic physics. To study magnetic interacting atoms, we plan to capture single atoms of Dysprosium in optical tweezers, as done with Rubidium atoms in [1]. The first step is a 3D magneto-optical trap (MOT), which combines the optical molasses technique [2] and spatial-dependent Zeeman splitting [3] to trap a cloud of Dysprosium atoms. The MOT is inside an ultra-high vacuum (UHV) chamber and an effusion cell produces a hot beam of Dysprosium atoms, from which it loads. An amplified external cavity diode laser, locked to an optical reference cavity, generates the 421 nm light that forms the optical molasses. Water-cooled coils in a quadrupole configuration generate the magnetic fields. Our experiment is the first to load the MOT directly in the hot beam, prioritising simplicity over a large MOT population by going without a 2D MOT or Zeeman slower, used in [4] and [5]. This thesis presents our design and implementation of the simple Dysprosium MOT, shown in Fig. 1. We also show the characteristics of the MOT and atomic source. The simplification of the Dysprosium MOT is twofold: it does not require frequency doubling setups to generate the laser light [5,6] and the aforementioned pre-cooling stages [5,7]. Simplifying this process allows more laboratories worldwide to implement Dysprosium trapping and further our understanding of its exotic physics.

•Jan 24, 2025•0 citations

External Cavity Diode Laser for Ultra-cold Atom Experiments

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This thesis describes the design, construction and characterization of an external cavity diode laser (ECDL) within the context of AMO research – specifically, ultracold rubidium experiments. The main benefit over other forms of laser light is the ECDL’s low cost and narrow linewidth. Having a more narrow linewidth allows us to affect specific electron states, such as for laser cooling, more precisely than broader alternatives. We find that building such a laser in house is feasible with scan range up to 4 GHz. We also note that attention to external noise, through mechanical vibrations but more importantly through temperature drifts, is necessary to produce an ECDL with a stable optical frequency.

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Development of an external cavity diode laser for application to spectroscopy and laser cooling and trapping of rubidium

G. N. Botha

In the presented study a diode laser was characterised and used for spec- troscopy, measuring the resonance lines of atomic rubidium. The characteristics of diode lasers and external cavity diode lasers (ECDL) for the purposes of ab- sorption spectroscopy were investigated and an experimental setup for tunable diode laser spectroscopy using an ECDL was developed. In external cavity diode lasers, the advantages of low cost, small size and e ciency of a diode laser is combined with tunability and a narrow frequency bandwidth. The ECDL was applied in experimental setups for absorption spectroscopy and saturated ab- sorption spectroscopy. Measurement of the absorption of atomic rubidium's D2 line near 780 nm is discussed. The Doppler broadened, as well as the Doppler free spectrum of the ne and hyper ne structure of the D2 line were measured and is discussed. Finer control of the ECDL's stability and frequency, using a servo circuit, were investigated and tested. An overview is given of laser cool- ing and trapping of neutral rubidium atoms, which is the main application the ECDL were developed for.

•Mar 1, 2009•0 citations

Simple magneto-optical and magnetic traps for dysprosium

Liam Domett-Potts, Lucile Sanchez, Charlotte Hayton +6 more

Abstract Dysprosium (Dy) is the most magnetic element on the periodic table, making it excellent for studying dipolar atom-atom interactions. We report on a simple Dy magneto-optical trap (MOT) that captures atoms directly from the thermal beam using a single diode-laser system to generate the light. Additionally, the atoms are magnetically confined by the quadrupole magnetic field that also facilitates the MOT. The MOT loading time constant is τ b = 26 ms . Atoms can decay to a dark state that is magnetically trapped. The time constant for loading into this magnetic trap is τ d = 410 ms . The total magnetically trapped population is 1.14 × 10 5 atoms, with 85 % residing in the dark states. The magnetically trapped atoms have a temperature of 28 μ K , significantly below the Doppler limit. This population fulfills the requirements for a range of future experiments.

Journal of Physics B Atomic Molecular and Optical Physics•May 27, 2026•0 citations

Manipulation and control of ultra-cold rubidium atoms

Anna Kowalczyk

During the course of this PhD an experimental set-up has been designed and implemented to confine neutral atoms in microscopic dipole traps and to manipulate their internal states by laser excitation to Rydberg states. A lot of effort was devoted to the stabilization of the laser sources for two-photon excitation to the Rydberg states, using techniques based on modulation transfer spectroscopy and electromagnetically induced transparency (EIT). Taking advantage of the EIT spectroscopy scheme, we have measured for the first time the electric dipole moments for the transitions between the first excited 5P3/2 and Rydberg nDS/2 level of rubidium. These measurements provided benchmarking of existing theoretical models to calculate the reduced matrix elements and have helped us to identify the D'yachkov Pankratov method as a particularly reliable one. Therefore we made use of the existing code to calculate the relative radial matrix elements for bound-bound, bound-free and free-free transitions between arbitrary states of alkali atoms. Our results allowed us to identify many features of interest and several Cooper minima have been revealed for the first time. The preparation of a new apparatus required ultra-high vacuum for efficient laser cooling and trapping experiments. A unique 4-beam magneto-optical trap has been designed and implemented in our new system. The tetrahedral MOT operating at a very acute beams angle has been demonstrated for the first time. The characterisation of the basic properties of our MOT has highlighted. some interesting new cooling mechanisms that do not fully match existing theoretical models and will require further investigation. It has been demonstrated that our tetrahedral MOT is suitable to prepare cold, diluted reservoirs of atoms and therefore efficiently load our microscopic dipole trap.

•Jan 1, 2013•1 citation

Simple Magneto-Optical and Magnetic Traps for Dysprosium

Liam Domett-Potts, Lucile Sanchez, Charlotte Hayton +6 more

Dysprosium (Dy) is the most magnetic element on the periodic table, making it excellent for studying dipolar atom-atom interactions. We report on a simple Dy MOT that captures atoms directly from the thermal beam using a single diode-laser system to generate the light. Additionally, the atoms are magnetically confined by the quadrupole magnetic field that also facilitates the MOT. The MOT loading time is $τ_\text{b} = 26~\text{ms}$. Atoms can decay to a dark state that is magnetically trapped. The time constant for loading into this magnetic trap is $τ_\text{d} = 410~\text{ms}$. The total magnetically trapped population is $1.14\times10^{5}$ atoms, with $85\%$ residing in the dark states. The magnetically trapped atoms have a temperature of $28~μ\text{K}$, significantly below the Doppler limit. This population fulfills the requirements for a range of future experiments.

arXiv:2602.09403•Feb 10, 2026•0 citations
The goal of this Masters project is to construct a laser system to facilitate future experiments with atomic Dysprosium via the transition at 421.29 nm. Dysprosium is of interest due to its magnetic properties, namely that it is tied with Terbium as the most magnetic element. Although there have been a number of investigations into laser cooling and trapping clouds of Dysprosium atoms, we would like to (in the future) interact with and manipulate individual atoms of Dysprosium. The first step towards this is to construct a laser system capable of interacting with the atom/s. To this end, an External Cavity Diode Laser (ECDL) operating at 421.29 nm and an optical reference cavity mounted in a vacuum are designed, constructed, and implemented.
Dysprosium is the most magnetic element on the periodic table, which gives it the potential to display exotic physics. To study magnetic interacting atoms, we plan to capture single atoms of Dysprosium in optical tweezers, as done with Rubidium atoms in [1]. The first step is a 3D magneto-optical trap (MOT), which combines the optical molasses technique [2] and spatial-dependent Zeeman splitting [3] to trap a cloud of Dysprosium atoms. The MOT is inside an ultra-high vacuum (UHV) chamber and an effusion cell produces a hot beam of Dysprosium atoms, from which it loads. An amplified external cavity diode laser, locked to an optical reference cavity, generates the 421 nm light that forms the optical molasses. Water-cooled coils in a quadrupole configuration generate the magnetic fields. Our experiment is the first to load the MOT directly in the hot beam, prioritising simplicity over a large MOT population by going without a 2D MOT or Zeeman slower, used in [4] and [5]. This thesis presents our design and implementation of the simple Dysprosium MOT, shown in Fig. 1. We also show the characteristics of the MOT and atomic source. The simplification of the Dysprosium MOT is twofold: it does not require frequency doubling setups to generate the laser light [5,6] and the aforementioned pre-cooling stages [5,7]. Simplifying this process allows more laboratories worldwide to implement Dysprosium trapping and further our understanding of its exotic physics.
This thesis describes the design, construction and characterization of an external cavity diode laser (ECDL) within the context of AMO research – specifically, ultracold rubidium experiments. The main benefit over other forms of laser light is the ECDL’s low cost and narrow linewidth. Having a more narrow linewidth allows us to affect specific electron states, such as for laser cooling, more precisely than broader alternatives. We find that building such a laser in house is feasible with scan range up to 4 GHz. We also note that attention to external noise, through mechanical vibrations but more importantly through temperature drifts, is necessary to produce an ECDL with a stable optical frequency.
In the presented study a diode laser was characterised and used for spec- troscopy, measuring the resonance lines of atomic rubidium. The characteristics of diode lasers and external cavity diode lasers (ECDL) for the purposes of ab- sorption spectroscopy were investigated and an experimental setup for tunable diode laser spectroscopy using an ECDL was developed. In external cavity diode lasers, the advantages of low cost, small size and e ciency of a diode laser is combined with tunability and a narrow frequency bandwidth. The ECDL was applied in experimental setups for absorption spectroscopy and saturated ab- sorption spectroscopy. Measurement of the absorption of atomic rubidium's D2 line near 780 nm is discussed. The Doppler broadened, as well as the Doppler free spectrum of the ne and hyper ne structure of the D2 line were measured and is discussed. Finer control of the ECDL's stability and frequency, using a servo circuit, were investigated and tested. An overview is given of laser cool- ing and trapping of neutral rubidium atoms, which is the main application the ECDL were developed for.
Abstract Dysprosium (Dy) is the most magnetic element on the periodic table, making it excellent for studying dipolar atom-atom interactions. We report on a simple Dy magneto-optical trap (MOT) that captures atoms directly from the thermal beam using a single diode-laser system to generate the light. Additionally, the atoms are magnetically confined by the quadrupole magnetic field that also facilitates the MOT. The MOT loading time constant is τ b = 26 ms . Atoms can decay to a dark state that is magnetically trapped. The time constant for loading into this magnetic trap is τ d = 410 ms . The total magnetically trapped population is 1.14 × 10 5 atoms, with 85 % residing in the dark states. The magnetically trapped atoms have a temperature of 28 μ K , significantly below the Doppler limit. This population fulfills the requirements for a range of future experiments.
During the course of this PhD an experimental set-up has been designed and implemented to confine neutral atoms in microscopic dipole traps and to manipulate their internal states by laser excitation to Rydberg states. A lot of effort was devoted to the stabilization of the laser sources for two-photon excitation to the Rydberg states, using techniques based on modulation transfer spectroscopy and electromagnetically induced transparency (EIT). Taking advantage of the EIT spectroscopy scheme, we have measured for the first time the electric dipole moments for the transitions between the first excited 5P3/2 and Rydberg nDS/2 level of rubidium. These measurements provided benchmarking of existing theoretical models to calculate the reduced matrix elements and have helped us to identify the D'yachkov Pankratov method as a particularly reliable one. Therefore we made use of the existing code to calculate the relative radial matrix elements for bound-bound, bound-free and free-free transitions between arbitrary states of alkali atoms. Our results allowed us to identify many features of interest and several Cooper minima have been revealed for the first time. The preparation of a new apparatus required ultra-high vacuum for efficient laser cooling and trapping experiments. A unique 4-beam magneto-optical trap has been designed and implemented in our new system. The tetrahedral MOT operating at a very acute beams angle has been demonstrated for the first time. The characterisation of the basic properties of our MOT has highlighted. some interesting new cooling mechanisms that do not fully match existing theoretical models and will require further investigation. It has been demonstrated that our tetrahedral MOT is suitable to prepare cold, diluted reservoirs of atoms and therefore efficiently load our microscopic dipole trap.
Dysprosium (Dy) is the most magnetic element on the periodic table, making it excellent for studying dipolar atom-atom interactions. We report on a simple Dy MOT that captures atoms directly from the thermal beam using a single diode-laser system to generate the light. Additionally, the atoms are magnetically confined by the quadrupole magnetic field that also facilitates the MOT. The MOT loading time is τb=26 msτ_\text{b} = 26~\text{ms}τb​=26 ms. Atoms can decay to a dark state that is magnetically trapped. The time constant for loading into this magnetic trap is τd=410 msτ_\text{d} = 410~\text{ms}τd​=410 ms. The total magnetically trapped population is 1.14×1051.14\times10^{5}1.14×105 atoms, with 85%85\%85% residing in the dark states. The magnetically trapped atoms have a temperature of 28 μK28~μ\text{K}28 μK, significantly below the Doppler limit. This population fulfills the requirements for a range of future experiments.