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

Journal of Physics Conference Series

Weakly Aligned Molecules: From Molecular Detectors to Room-Temperature Tunable Masers

Colin Roy, Zorica Branković, Yuri V. Rostovtsev

Published Apr 1, 2022• 3 citations
Publisher

Abstract

Abstract We have developed and demonstrated a new mechanism of manipulation of population in molecular rotational levels in a weakly aligned molecules. The mechanism is based on an adiabatically changing electric field interacting with the molecules with dipole moments. Treating molecules as simple rotators, we have described their behavior using the density matrix taking into account the relaxation processes. We have considered the interaction of the weakly aligned molecules with a microwave field in a high finesse cavity. We have found that, on one hand, the population inversion can be reached in the ensemble of the weakly aligned molecules to be used for the maser operation at room temperature. On the another hand, we have found that the enhancement of the absorption can reach the theoretical limit and be used for gas sensing with high sensitivity and selectivity. Such sensors can efficiently analyze the multi-gas mixtures and be used for a huge range of applications – stretching from technology, sciences, control of environment, biology and medicine.

DOI
10.1088/1742-6596/2249/1/012001

Related papers

A resonant single-frequency molecular detector based on adiabatically changing electric field

Yuri V. Rostovtsev, Zorica Branković

During last decades many gas sensing mechanisms, based on different physical or chemical interactions with sensitive materials, have been developed, but the problem of precise analysis of gas mixtures still remains. New sensing mechanism has been suggested that is based on an adiabatically changing electric field interacting with the rotational structure of the molecules with dipole moments. A single low frequency gas detector, that can be used for sensing of gas mixtures with high selectivity, accuracy, and sensitivity, has been theoretically demonstrated. The enhancement of the population difference between corresponding molecular levels and reached the theoretical maximum of absorption have been shown.

Optical and Quantum Sensing and Precision Metrology•Mar 4, 2021•2 citations

A resonant single frequency molecular detector with high sensitivity and selectivity for gas mixtures

Zorica Branković, Yuri V. Rostovtsev

Air quality control is an important task in prevention of human exposure to toxic and harmful gases and requires reliable gas sensors. During last decades many gas sensing mechanisms, based on different physical or chemical interactions with sensitive materials, have been developed, but the problem of precise analysis of gas mixtures still remains. The problem can be solved by introducing new sensing mechanism based on an adiabatically changing electric field interacting with the rotational structure of the molecules with dipole moments. We have theoretically demonstrated a single low frequency gas detector that can be used for sensing of gas mixtures with high selectivity, accuracy, and sensitivity. The enhancement of the population difference between corresponding molecular levels and reached the theoretical maximum of absorption have been shown.

Scientific Reports•Jan 30, 2020•10 citations

Optical Control of Coherent Quantum Systems

Colin Dean Roy

Optical control of coherent quantum systems has many methods and applications. In this defense we will discuss the effects of an electric field interacting with molecules with dipole moments. The theoretical study of such molecules will consist of two-level atom and a three-level atom in the λ configuration. The methods that will be discussed are population trapping using both bright and dark starts obtained by both STIRAP and CHIRAP pulses. The application to be discussed is how to create a room temperature maser.

•Dec 1, 2022•0 citations

Buffer-gas Loading and Magnetic Trapping of Molecules

John M. Doyle

Ultracold and cold molecules have enormous potential for yielding a wealth of new physics and new technologies. Molecules possess several features that greatly increase the possibilities for new interactions, collective quantum states and effects, collisional processes, fundamental symmetry tests and chemical processes. This is due to 1) the strong interactions between the dipole moments of polar molecules, 2) the rotational and vibrational internal structure of all molecules, and 3) the easily orientable internal electric field of many molecules. The promise of cold and ultracold molecules will only be realized when samples can be prepared with at least the same ease in which we now prepare atomic samples. Several approaches towards trapping of molecules, the key first step toward studying ultracold molecules at high density, have already succeeded: direct cooling of molecules via a buffer gas, mechanical slowing of a pulsed molecular beam with electric fields and photoassociation of alkali atoms. In the ICAP 2002 session on molecules I described some of the current theoretical results and predictions about ultracold molecular systems. Profs. Meijer and Heinzen described results on pulsed beam slowing and photoassociation. This contribution describes some of the key results on buffer-gas loading of molecules. A.

International Conference on Atomic Physics (ICAP)•Apr 1, 2003•0 citations

Dynamics of cold molecules in electromagnetic fields

Sergey Alyabyshev

The research field of cold and ultracold atoms and molecules is rapidly growing and expanding into different areas of research such as quantum information science and condensed matter physics. The success of this field is due to the possibility of precisely controlling and manipulating atoms and molecules at low temperatures. The progress in this field relies on the development of new methods for controlling collisional dynamics and interactions of particles with electromagnetic fields. This Thesis describes research on modification of the collisional dynamics of ultracold atoms and molecules by external laser and microwave fields as well as new methods for the detection of weak electromagnetic fields. First, we study the scattering of atoms and molecules confined in a 2D geometry by optical lattices. In particular we develop a theory for scattering in 2D and derive the equations for the threshold dependence of the collision cross sections. We show that inelastic processes and chemical reactions can be suppressed under strong confinement in one dimension and can be controlled by varying the orientation of the external field with respect to the plane of confinement. Next, we present a rigorous theory of low-temperature molecular collisions in the presence of a microwave field. The microwave field can theoretically be used to trap and control polar molecules. The molecular collisions may lead to trap loss and decoherence. We develop a rigorous quantum theory for molecular scattering in the presence of microwave fields. We study inelastic, spin-changing molecular collisions and Feshbach resonances in the presence of microwave fields. We demonstrate that inelastic collisions accompanied by absorption of microwave photons can be significant. The detection of weak electromagnetic fields is very important for various applications ranging from fundamental measurements to biomagnetic imaging, and for tests of microwave chips. We present a method for the detection of weak electromagnetic fields in a wide range of frequencies from sub-kHz to THz with ultracold polar molecules. We show that using ultracold molecules one can achieve the sensitivity of two orders of magnitude larger than with a similar method based on ultracold Rb atoms.

•Jan 1, 2012•0 citations

Effect of rotational-state-dependent molecular alignment on the optical dipole force

Lee Yeong Kim, Ju Hyeon Lee, Hye Ah Kim +3 more

The properties of molecule-optical elements such as lenses or prisms based on the interaction of molecules with optical fields depend in a crucial way on the molecular quantum state and its alignment created by the optical field. Herein, we consider the effects of state-dependent alignment in estimating the optical dipole force acting on the molecules and, to this end, introduce an effective polarizability which takes proper account of molecular alignment and is directly related to the alignment-dependent optical dipole force. We illustrate the significance of including molecular alignment in the optical dipole force by a trajectory study that compares previously used approximations with the present approach. The trajectory simulations were carried out for an ensemble of linear molecules subject to either propagating or standing-wave optical fields for a range of temperatures and laser intensities. The results demonstrate that the alignment-dependent effective polarizability can serve to provide correct estimates of the optical dipole force, on which a state-selection method applicable to nonpolar molecules could be based. We note that an analogous analysis of the forces acting on polar molecules subject to an inhomogeneous static electric field reveals a similarly strong dependence on molecular orientation.

arXiv:1606.00516•Physical Review A•Jul 27, 2016•6 citations
Abstract We have developed and demonstrated a new mechanism of manipulation of population in molecular rotational levels in a weakly aligned molecules. The mechanism is based on an adiabatically changing electric field interacting with the molecules with dipole moments. Treating molecules as simple rotators, we have described their behavior using the density matrix taking into account the relaxation processes. We have considered the interaction of the weakly aligned molecules with a microwave field in a high finesse cavity. We have found that, on one hand, the population inversion can be reached in the ensemble of the weakly aligned molecules to be used for the maser operation at room temperature. On the another hand, we have found that the enhancement of the absorption can reach the theoretical limit and be used for gas sensing with high sensitivity and selectivity. Such sensors can efficiently analyze the multi-gas mixtures and be used for a huge range of applications – stretching from technology, sciences, control of environment, biology and medicine.
During last decades many gas sensing mechanisms, based on different physical or chemical interactions with sensitive materials, have been developed, but the problem of precise analysis of gas mixtures still remains. New sensing mechanism has been suggested that is based on an adiabatically changing electric field interacting with the rotational structure of the molecules with dipole moments. A single low frequency gas detector, that can be used for sensing of gas mixtures with high selectivity, accuracy, and sensitivity, has been theoretically demonstrated. The enhancement of the population difference between corresponding molecular levels and reached the theoretical maximum of absorption have been shown.
Air quality control is an important task in prevention of human exposure to toxic and harmful gases and requires reliable gas sensors. During last decades many gas sensing mechanisms, based on different physical or chemical interactions with sensitive materials, have been developed, but the problem of precise analysis of gas mixtures still remains. The problem can be solved by introducing new sensing mechanism based on an adiabatically changing electric field interacting with the rotational structure of the molecules with dipole moments. We have theoretically demonstrated a single low frequency gas detector that can be used for sensing of gas mixtures with high selectivity, accuracy, and sensitivity. The enhancement of the population difference between corresponding molecular levels and reached the theoretical maximum of absorption have been shown.
Optical control of coherent quantum systems has many methods and applications. In this defense we will discuss the effects of an electric field interacting with molecules with dipole moments. The theoretical study of such molecules will consist of two-level atom and a three-level atom in the λ configuration. The methods that will be discussed are population trapping using both bright and dark starts obtained by both STIRAP and CHIRAP pulses. The application to be discussed is how to create a room temperature maser.
Ultracold and cold molecules have enormous potential for yielding a wealth of new physics and new technologies. Molecules possess several features that greatly increase the possibilities for new interactions, collective quantum states and effects, collisional processes, fundamental symmetry tests and chemical processes. This is due to 1) the strong interactions between the dipole moments of polar molecules, 2) the rotational and vibrational internal structure of all molecules, and 3) the easily orientable internal electric field of many molecules. The promise of cold and ultracold molecules will only be realized when samples can be prepared with at least the same ease in which we now prepare atomic samples. Several approaches towards trapping of molecules, the key first step toward studying ultracold molecules at high density, have already succeeded: direct cooling of molecules via a buffer gas, mechanical slowing of a pulsed molecular beam with electric fields and photoassociation of alkali atoms. In the ICAP 2002 session on molecules I described some of the current theoretical results and predictions about ultracold molecular systems. Profs. Meijer and Heinzen described results on pulsed beam slowing and photoassociation. This contribution describes some of the key results on buffer-gas loading of molecules. A.
The research field of cold and ultracold atoms and molecules is rapidly growing and expanding into different areas of research such as quantum information science and condensed matter physics. The success of this field is due to the possibility of precisely controlling and manipulating atoms and molecules at low temperatures. The progress in this field relies on the development of new methods for controlling collisional dynamics and interactions of particles with electromagnetic fields. This Thesis describes research on modification of the collisional dynamics of ultracold atoms and molecules by external laser and microwave fields as well as new methods for the detection of weak electromagnetic fields. First, we study the scattering of atoms and molecules confined in a 2D geometry by optical lattices. In particular we develop a theory for scattering in 2D and derive the equations for the threshold dependence of the collision cross sections. We show that inelastic processes and chemical reactions can be suppressed under strong confinement in one dimension and can be controlled by varying the orientation of the external field with respect to the plane of confinement. Next, we present a rigorous theory of low-temperature molecular collisions in the presence of a microwave field. The microwave field can theoretically be used to trap and control polar molecules. The molecular collisions may lead to trap loss and decoherence. We develop a rigorous quantum theory for molecular scattering in the presence of microwave fields. We study inelastic, spin-changing molecular collisions and Feshbach resonances in the presence of microwave fields. We demonstrate that inelastic collisions accompanied by absorption of microwave photons can be significant. The detection of weak electromagnetic fields is very important for various applications ranging from fundamental measurements to biomagnetic imaging, and for tests of microwave chips. We present a method for the detection of weak electromagnetic fields in a wide range of frequencies from sub-kHz to THz with ultracold polar molecules. We show that using ultracold molecules one can achieve the sensitivity of two orders of magnitude larger than with a similar method based on ultracold Rb atoms.
The properties of molecule-optical elements such as lenses or prisms based on the interaction of molecules with optical fields depend in a crucial way on the molecular quantum state and its alignment created by the optical field. Herein, we consider the effects of state-dependent alignment in estimating the optical dipole force acting on the molecules and, to this end, introduce an effective polarizability which takes proper account of molecular alignment and is directly related to the alignment-dependent optical dipole force. We illustrate the significance of including molecular alignment in the optical dipole force by a trajectory study that compares previously used approximations with the present approach. The trajectory simulations were carried out for an ensemble of linear molecules subject to either propagating or standing-wave optical fields for a range of temperatures and laser intensities. The results demonstrate that the alignment-dependent effective polarizability can serve to provide correct estimates of the optical dipole force, on which a state-selection method applicable to nonpolar molecules could be based. We note that an analogous analysis of the forces acting on polar molecules subject to an inhomogeneous static electric field reveals a similarly strong dependence on molecular orientation.