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Khabarova, K. Yu.

Publications and source records attributed to Khabarova, K. Yu..

18 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Compact ultrastable laser system for spectroscopy of {sup 2}S{sub 1/2} → {sup 2}D{sub 3/2} quadrupole transition in {sup 171}Yb{sup +} ion

We report the results of studying a compact laser system designed for manipulating a quantum state of the optical qubit based on the {sup 2}S{sub 1/2} → {sup 2}D{sub 3/2} quadrupole transition in the {sup 171}Yb{sup +} ion at a wavelength of 435.5 nm. An emission power of the laser system reaches 500 μW at λ = 435.5 nm and the relative frequency instability of at most 3 × 10{sup −15} is achieved at averaging intervals from 0.5 to 50 s with a subtracted linear frequency drift. The compactness of the developed system makes it possible to employ it in transportable systems including optical clocks. (laser spectroscopy)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Detection of the clock transition in thulium atoms by using repump laser radiation

A population transfer from the upper level of the clock transition in thulium atoms to the ground level is demonstrated by using radiation with a wavelength of 402 nm. The method for detecting the clock transition excitation that is not affected by technical fluctuations of the number of atoms in an optical lattice is investigated. The hyperfine splitting of the |4f{sup 12}({sup 3}F{sub 2})5d{sub 5/2} 6s{sup 2}; J = 7/2〉 level in the thulium atom is measured to be 1480(9) MHz. The suggested method for population transfer can be applied to both the hyperfine components of the clock transition intended for compensating Zeeman effect in a thulium optical clock. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Compensation of residual amplitude modulation fluctuations in an optoelectronic system for laser radiation frequency stabilisation

Fluctuations of residual amplitude modulation in a scheme of laser frequency stabilisation by a Fabry – Perot cavity reduce the frequency stability of the laser systems intended for interrogating clock transitions of atoms and ions. The dependences of the residual amplitude modulation on a temperature of the waveguide-based electro-optical modulator used for modulating the radiation phase and on polarisation of the radiation are measured. The parameters are found, at which the influence of the residual amplitude modulation on the frequency stability is minimal. A system for active compensation is created, which reduces the contribution of fluctuations of residual amplitude modulation to the instability down to 2.1 × 10{sup −16}, which makes it possible to reach the thermal noise limit of a silicon cryogenic cavity. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Rabi spectroscopy of the clock transition in thulium atoms in a one-dimensional optical lattice

The clock transition at a wavelength of 1.14 μm in thulium atoms in an optical lattice in the Lamb – Dick regime is studied. The capture of thulium atoms makes it possible to suppress completely both the transition broadening due to the first-order Doppler effect and the shift of the transition frequency caused by the recoil effect. The excitation spectra of sideband oscillation frequencies and Rabi oscillations of population between the clock transition levels upon resonance excitation are investigated. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Magic wavelengths near 800 nm for precision spectroscopy of an inner-shell transition in thulium atoms

Differential dynamic polarisability of the inner-shell clock transition at a wavelength of 1.14 μm in the thulium atom is measured by the method of precision laser spectroscopy in the spectral range of 800 – 860 nm. Experimental data approximated by a theoretical model yield the probability of the transition at λ = 809.5 nm: A{sub 809.5} = 460(70) s{sup −1}. The values of two magic wavelengths are obtained experimentally, namely, λ{sub m1} = 807.727(18) nm and λ{sub m2} = 813.3(2) nm, the wavelength of λ{sub m1} being determined for the first time. Main parameters of an optical lattice at these wavelengths are compared and a conclusion is made that trapping thulium atoms in an optical lattice at λ{sub m2} is preferable for optical clock operation. (laser frequency standards)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Optical pumping of ultracold thulium atoms to a lower level of the clock transition and study of their depolarisation

The atomic energy levels corresponding to states with the zero projection of the total angular momentum have a weak sensitivity to certain sources of shifts and, therefore, are widely used in precision spectroscopy. The optical pumping of ultracold thulium atoms to the ground state level with the zero projection of the total angular momentum is described. The population dynamics of this state due to magnetic dipole − dipole interaction in an external magnetic field is studied. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Temperature drift contribution to frequency instability of silicon Fabry – Perot cavities

A contribution of a temperature drift near the silicon thermal expansion coefficient zero point to the fractional frequency instability of a silicon cavity is analysed. The thermal expansion coefficient of silicon is measured by an optical method near the zero point T{sub 0} = 123 K. It is shown that the frequency instability due to cavity temperature drifts observed in an experiment does not exceed a thermal noise limit at averaging intervals of up to 20 s. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

On the thermal noise limit of ultrastable optical cavities

We consider two methods of lowering thermal noise, which limits the attainable frequency stability of lasers stabilised to a high-Q external Fabry – Perot cavity. These are cavity lengthening and use of high-Q mechanical materials in the production of its constituent parts. The results of numerical simulation are outlined for the horizontal and vertical suspension systems of the cavity body and its sensitivity to vibrations in these cases. The progress in the development of ultrastable laser systems using cryogenic silicon cavities is also discussed. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Trapping of thulium atoms in a cavity-enhanced optical lattice near a magic wavelength of 814.5 nm

A cavity-enhanced optical lattice at a wavelength of 814.5 nm for thulium atoms is designed and its characteristics are investigated. The parametric resonances at the vibrational frequencies of the trap are measured. The enhancement cavity will be applied to search for the magic wavelength of the clock transition at 1.14 μm in thulium atoms. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Short-haul fibre-optic communication link with a phase noise compensation system for optical frequency signal transmission

A 5-m-long fibre link with a phase noise compensation system for optical frequency signal transmission at a wavelength of 1.14 μm is demonstrated. The stability of the noise compensation system in the presence of harmonic mechanical perturbations is assessed and the relative transmitted signal frequency instability is shown to be 3.8 × 10{sup −15} at an averaging time of 1 s and 3.5 × 10{sup −20} over 850 s. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Methods for determining the polarisability of the fine structure levels in the ground state of the thulium atom

We have calculated the scalar and tensor parts of the polarisabilities of the fine-structure sublevels J = 7/2 and 5/2 of the thulium atom ground state. The static polarisabilities are in a good agreement with the values known from the literature. We also present experimental techniques for measuring the dynamic scalar polarisabilities of these levels at a wavelength of 532 nm. The measured values agree with our calculations within the errors. The results of this work can be used for designing an optical frequency standard based on laser-cooled thulium atoms. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Ultrastable laser system for spectroscopy of the {sup 1}S{sub 0}–{sup 3}P{sub 0} clock transition in Sr atoms

A laser system with a spectral linewidth less than 1 Hz for spectroscopy of the {sup 1}S{sub 0}–{sup 3}P{sub 0} clock transition in strontium atoms has been demonstrated. A semiconductor laser emitting at a wavelength of 698 nm was stabilised to an external high-finesse Fabry–Perot cavity with vibration and temperature compensation near the zero expansion point. After laser cooling to a temperature below 3 μK, {sup 88}Sr atoms were loaded into an optical lattice at a magic wavelength of 813 nm. The laser system was used to characterise the {sup 88}Sr clock transition by magnetically induced spectroscopy. The resonance spectral width was determined to be 130 ± 17 Hz, which corresponds to a quality factor of 3 × 10{sup 12}. (paper)

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2017

Frequency standards based on ultracold atoms in tests of general relativity, navigation and gravimetry

Research and development in the field of optical clocks based on ultracold atoms and ions have enabled the relative uncertainty in frequency to be reduced down to a few parts in 10{sup 18}. The use of novel, precise frequency comparison methods opens up new possibilities for basic research (sensitive tests of general relativity, a search for a drift of fundamental constants and a search for ‘dark matter’) as well as for state-of-the-art navigation and gravimetry. We discuss the key methods that are used in creating precision clocks (including transportable clocks) based on ultracold atoms and ions and the feasibility of using them in resolving current relativistic gravimetry issues. (paper)

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

A new generation of cryogenic high- Q Fabry–Perot resonators for ultrastable lasers

We have performed a comparative analysis of the characteristics of laser resonators fabricated from various materials. The greatest attention is paid to the problem of Brownian noise leading to fluctuations in the resonator length and limitation of the frequency stability of a laser actively stabilised by the transmission peak of a high- Q Fabry–Perot resonator. A possibility of designing new-generation ultrastable laser systems based on cryogenic crystalline resonators is shown. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Trapping, retention and laser cooling of Th{sup 3+} ions in a multisection linear quadrupole trap

A multisection linear quadrupole trap for Th{sup 3+} ions is described. Multiply charged ions are obtained by the laser ablation method. The possibility of trapping and retention of ∼10{sup 3} ions is demonstrated in macroscopic time scales of ∼30 s. Specific features of cooling Th{sup 3+} ions on the electron transitions with wavelengths of 1088, 690 and 984 nm in Th{sup 3+} ion are discussed; a principal scheme of a setup for laser cooling is presented. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Microwave frequency standard on {sup 25}Mg{sup +} ions: expected characteristics and prospects

A scheme of the new frequency standard is reported based on a microwave transition between hyperfine components of the ground state in {sup 25}Mg{sup +} ions. It is proposed to capture ions into a linear quadrupole Paul trap and to perform the laser cooling, as well as to prepare the particle ensemble and to implement detection by using a single laser system based on a semiconductor laser. Characteristics of the suggested frequency standard are estimated. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Multiparticle losses in a linear quadrupole Paul trap

A linear quadrupole Paul trap is fabricated for capturing magnesium and aluminium ions. An experimental cycle performed has demonstrated ion capture and holding in a trap with an average ion lifetime of 1.7 s. Modelling of ion dynamics in the trap shows that the main mechanism responsible for losses of hot ions is multiparticle interaction, which results in that a kinetic energy of some ions increases and they leave the trapping zone. This mechanism is completely suppressed if ions are cooled. Another mechanism is the charge exchange; however, it is not substantial at a high average energy of ions produced in the result of an electron impact. Parameters of the trap allow one to perform precision spectroscopic measurements and to control ion quantum states. (laser cooling)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗