Generation and propagation characteristics of a localized hollow beam

Xia, Meng; Wang, Zhizhang; Yin, Yin; Zhou, Qi; Xia, Yong; Yin, Jing

doi:10.1088/1555-6611/aaada7

Cited by 3 publications

(5 citation statements)

References 45 publications

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“…In recent research, a localized hollow beam by using a π-phase binary bitmap and a convergent thin lens was demonstrated experimentally. The measured beam profiles in free space agree well with the theoretical modeling from the light diffraction theory [34]. So, we compare the simulation results of the optical intensity distribution of the FHB with ones derived from the light diffraction theory, and study the influence of the discrete and continuous phases of the grating on the intensity distribution of the modulated optical field.…”

Section: Influences Of Both Discrete and Continuous Phases Of The Gra...supporting

confidence: 70%

“…The number of the phase-shifting rings is enough, so that the phase distribution of the grating is continuous. According to the light diffraction theory, the normalized amplitude distribution near the focal plane of the metasurface grating can be defined as [34,35], Here, ρ and u are the simplified radial and axial coordinates in the transmission region, respectively, r is the radial coordinate of pupil plane of figure 2(c), f j defines the phase of zone j ( = j 1, 2) on the pupil plane and r j is the radial position of each zone. The amplitude distribution of the incident laser beam is given by g r .…”

Section: Influences Of Both Discrete and Continuous Phases Of The Gra...mentioning

confidence: 99%

“…( ) Here, we choose the incident laser as the plane wave, so g r ( ) equals 1. The specific normalized amplitude distribution is given by [34], where…”

Section: Influences Of Both Discrete and Continuous Phases Of The Gra...mentioning

confidence: 99%

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Chip-scale molecule trapping by a blue-detuned metasurface hollow beam

Yu¹,

Mao²,

Li³

et al. 2020

J. Opt.

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We propose a tightly focused hollow beam to trap cold molecules by using a metasurface grating, which has a hybrid phase with focusing and completely destructive interference functions. The intensity distributions of the hollow beam in free space concerning different structural parameters of the grating are theoretically studied in detail. The influences of both the discrete and continuous phases of the grating on the intensity distribution of the modulated optical field are compared. Our theoretical study shows that such a blue-detuned beam can provide a deep potential to trap cold molecules with a low photon scattering rate and a long trap lifetime. Our studies suggest that the metasurface-based optical chip is applicable to trap molecules and can be an ideal platform for building a robust quantum laboratory.

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Section: Influences Of Both Discrete and Continuous Phases Of The Gra...supporting

confidence: 70%

Section: Influences Of Both Discrete and Continuous Phases Of The Gra...mentioning

confidence: 99%

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Chip-scale molecule trapping by a blue-detuned metasurface hollow beam

Yu¹,

Mao²,

Li³

et al. 2020

J. Opt.

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“…The exact arithmetic solution of LHB laser intensity profile is presented in [40], and the approximate analytic solution used in the simulation is ( ) e x p 2 , 0 2 2 0 2 2 where r and a are radial component and axial component, respectively, R is the ratio of the long axis to the short axis, r 0 is the radial size of LHB, w is the full width at half maximum of a single peak of radial intensity distribution at = a 0 plane. The total scattering rate P sp can be obtained, i.e.…”

Section: Dressed States and Spontaneous Transitionmentioning

confidence: 99%

“…Sub-Doppler cooling, which can be generally understood from spatially varying polarization gradients in type-I systems, such as Sisyphus (p p - The scheme to trap and cool MgF molecules using a LHB and a weak RPB is shown in figure 1. The LHB is succinctly generated by a collimated Gaussian laser beam (GLB) and a spatial light modulator (SLM) [40]. There is a non-light area at the center of the generated LHB, which is dark spot (DS).…”

Section: Introductionmentioning

confidence: 99%

A new route for laser cooling and trapping of cold molecules: Intensity-gradient cooling of MgF molecules using localized hollow beams

et al. 2020

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We propose a promising scheme to prepare ultracold MgF molecules from a slowed cold molecular beam by using three-dimensional pure intensity-gradient induced Sisyphus cooling. The cooling is based on a blue-detuned localized hollow beam and a weak repumping beam. We investigate the dynamic process in the trap with the method of the Monte-Carlo simulations, verifying the feasibility. Our results show that achieving sub-Doppler temperature should be possible in such a well-designed trap; the trapped MgF molecules with initial temperature of 1 mK can be directly cooled to the final equilibrium temperature of about m 46.5 K, well below the Doppler limit (about m 527.9 K for MgF); meanwhile, molecules with initial temperature of 14 mK can be even cooled to about m 68.7 K. + -) cooling [22,23], is totally different in type-II systems, because of the existence of the dark states. There are two main cooling mechanisms in such transitions, the gray molasses and the magnetically-assisted Sisyphus cooling, both of which are able to cool particles to below the Doppler limit [24,25]. On this basis, Truppe et al realized for the first time the cooling of molecules, well below the Doppler limit, using a three-dimensional blue-detuned molasses [26]. temperature was achieved by Λ-enhanced gray molasses and deep cooling with a single laser, both of which can cool CaF to several mK [27,28]. Besides, laser cooling and deceleration of molecules with stimulated force has also progressed a lot both theoretically and experimentally [29][30][31].As the common cooling method before molecules loaded into a type-II MOT, laser sweep slowing or whitelight slowing, both of which are used to compensate Doppler shift, are not a very efficient way for larger number of molecules. This causes the problem of the small number and the low density of trapped molecules in the type-II MOT. In order to produce a diverse set of dense, ultracold diatomic molecular species, it would be interesting and worthwhile to explore how to produce much larger numbers of trapped molecules. Here we propose a new scheme for the preparation of ultracold molecules, which consists of the Stark-decelerated molecules and a localized hollow optical trap, where sub-Doppler cooling works well. We bypass the Doppler cooling, and achieve the process from supersonic molecular beam to sub-Doppler cooling of molecules. The localized hollow optical trap has a strong cooling capacity, and it can derive ultracold trapped molecules with higher density.The cooling mechanism of a hollow optical trap is pure intensity-gradient cooling [32][33][34][35][36][37], another sub-Doppler cooling, which can also efficiently cool the molecules to the temperature of several photon recoils. The magnetic-field-assisted intensity-gradient cooling of molecules has first been observed in a one-dimensional standing wave, which have substantially reduced the transverse temperature of a SrF molecular beam [4]. Magnesium monofluoride (MgF) [38,39], due to its highly diagonal Franck-Condon factors (FCFs) and st...

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Optical Bottle Shaping Using Axicons with Amplitude or Phase Apodization

et al. 2023

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We investigate the formation of single and multiple optical bottle beams on the optical axis using a diffractive axicon with amplitude or phase apodization. The proposed approach allows one to control the location and the contrast of the boundaries of the generated dark intensity regions on the optical axis. Experimental results obtained using a spatial light modulator are in good agreement with numerically obtained ones. We successfully used the designed and experimentally formed set of three optical bottle beams for trapping light-absorbing agglomerations of carbon nanoparticles in air under the action of photophoretic forces. This confirms the efficiency of the proposed approach for optical manipulation applications.

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Generation and propagation characteristics of a localized hollow beam

Cited by 3 publications

References 45 publications

Chip-scale molecule trapping by a blue-detuned metasurface hollow beam

Chip-scale molecule trapping by a blue-detuned metasurface hollow beam

A new route for laser cooling and trapping of cold molecules: Intensity-gradient cooling of MgF molecules using localized hollow beams

Optical Bottle Shaping Using Axicons with Amplitude or Phase Apodization

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