Related Experiment Video
Updated: Jun 20, 2026
10:00
Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 11, 2013
Spin dependence of optical dephasing in ruby: the frozen core
Optics Letters
|September 1, 2009
Summary
Optical dephasing times were measured for the (4)A(2)(-3/2) ? E(-(1/2)) transition in ruby. Frozen-core effects significantly alter the dephasing time ratio compared to predictions.
Area of Science:
- Quantum Optics
- Solid-State Physics
- Spectroscopy
Background:
- Ruby (Cr:Al2O3) is a key material in laser technology and quantum information.
- Optical dephasing times characterize the coherence of excited states, crucial for quantum applications.
- Previous studies focused on the (4)A(2)(-(1/2)) ? E(-(1/2)) transition, leaving other transitions less explored.
Purpose of the Study:
- To measure the optical dephasing time for the (4)A(2)(-3/2) ? E(-(1/2)) transition in ruby for the first time.
- To compare these measurements with the dephasing time of the previously studied (4)A(2)(-(1/2)) ? E(-(1/2)) transition.
- To investigate the influence of frozen-core effects on the ratio of dephasing times.
Main Methods:
- Optical dephasing time measurements using spectroscopic techniques.
- Comparison of experimental results with theoretical predictions based on magnetic tuning rates.
- Analysis of frozen-core effects on electron-phonon interactions.
Main Results:
- The optical dephasing time for the (4)A(2)(-3/2) ? E(-(1/2)) transition in ruby was measured.
- The ratio of dephasing times T(2)(-(1/2))/T(2)(-3/2) was found to be 1.5.
- This ratio is significantly lower than the expected value of 7.6 from simple magnetic tuning rate considerations.
Conclusions:
- Frozen-core effects play a critical role in determining the optical dephasing dynamics in ruby.
- The observed reduction in the dephasing time ratio highlights the limitations of simplified models.
- Accurate characterization of dephasing times is essential for advancing ruby-based quantum technologies.
Related Concept Videos
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:11Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
01:08Atomic Nuclei: Nuclear Spin
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
01:03Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
02:39Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...