Stable all-optical formation of Bose–Einstein condensate using pointing-stabilized optical trapping beams

Kobayashi, Jun; Izumi, Yumiko; Kumakura, M.; Takahashi, Yoshiro

doi:10.1007/s00340-006-2140-2

Cited by 6 publications

(9 citation statements)

References 10 publications

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“…The gain inversion was caused by transient heating of the AOM crystal, resulting in index changes that shifted the diffraction angle (Dq) of the beam. Previous measurements of pointing instability after large intensity changes (almost the full range) in a different AOM crystal (germanium) have been as large as 4 mrad in just 2 s (25). In our experimental geometry, the transient pointing error was converted into a time-and history-dependent intensity error.…”

Section: Active Reduction Of Trap Laser Noisementioning

confidence: 92%

Precision Surface-Coupled Optical-Trapping Assay with One-Basepair Resolution

Carter

Seol

Perkins

2009

Biophysical Journal

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The most commonly used optical-trapping assays are coupled to surfaces, yet such assays lack atomic-scale ( approximately 0.1 nm) spatial resolution due to drift between the surface and trap. We used active stabilization techniques to minimize surface motion to 0.1 nm in three dimensions and decrease multiple types of trap laser noise (pointing, intensity, mode, and polarization). As a result, we achieved nearly the thermal limit (<0.05 nm) of bead detection over a broad range of trap stiffness (k(T) = 0.05-0.5 pN/nm) and frequency (Deltaf = 0.03-100 Hz). We next demonstrated sensitivity to one-basepair (0.34-nm) steps along DNA in a surface-coupled assay at moderate force (6 pN). Moreover, basepair stability was achieved immediately after substantial (3.4 pN) changes in force. Active intensity stabilization also led to enhanced force precision ( approximately 0.01%) that resolved 0.1-pN force-induced changes in DNA hairpin unfolding dynamics. This work brings the benefit of atomic-scale resolution, currently limited to dual-beam trapping assays, along with enhanced force precision to the widely used, surface-coupled optical-trapping assay.

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Section: Active Reduction Of Trap Laser Noisementioning

confidence: 92%

Precision Surface-Coupled Optical-Trapping Assay with One-Basepair Resolution

Carter

Seol

Perkins

2009

Biophysical Journal

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“…Many groups generating BECs in dipole traps use CO 2lasers [3,[8][9][10] in single-beam or crossed-beam configurations. Slight disadvantages result from the high power required for the laser wavelength of 10.6 µm and from the need to implement optical materials transparent at this wavelength which might complicate the optical setup.…”

Section: Introductionmentioning

confidence: 99%

Optimized Bose-Einstein-condensate production in a dipole trap based on a 1070-nm multifrequency laser: Influence of enhanced two-body loss on the evaporation process

et al. 2011

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We present an optimized strategy for the production of tightly confined Bose-Einstein condensates (BEC) of 87 Rb in a crossed dipole trap with direct loading from a magneto-optical trap. The dipole trap is created with light of a multifrequency fiber laser with a center wavelength of 1070 nm. Evaporative cooling is performed by ramping down the laser power only. A comparison of the resulting atom number in an almost pure BEC to the initial atom number and the value for the gain in phase space density per atom lost confirm that this straightforward strategy is very efficient. We observe that the temporal characteristics of evaporation sequence are strongly influenced by power-dependent two-body losses resulting from enhanced optical pumping to the higher-energy hyperfine state. We characterize these losses and compare them to results obtained with a single-frequency laser at 1030 nm.

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“…Different with the perpendicular direction, there is an attached piezoelectric transducer at one side of the diffracting direction, which can not be water-cooled. The solution is that we can control the temperature of the other side to the same temperature as the transducer side by thermal control to make an symmetry temperature distribution along the diffraction direction [6]. The result is shown in Fig.…”

Section: Reduce the Angular Driftmentioning

confidence: 99%

“…Meanwhile, slow angular drifting should also be avoided, which causes the instability of optical trapping, especially for a cross-beam ODT [5]. Previously, a large thermal effect on the diffracted beam, induced by radio-frequency (RF) driving, has been observed in many ODT experiments [6][7][8][9]. It has also been verified that the angular drift problem is more serious for the high-power applications, companying with a larger AOM crystal as well as higher RF driving power [6].…”

Section: Introductionmentioning

confidence: 99%

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Beam pointing stabilization of an acousto-optic modulator with thermal control

Zhang¹,

Chen²,

Fang³

et al. 2019

Opt. Express

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Diffraction beams generated by an acousto-optic modulator (AOM) are widely used in various optical experiments, some of which require high angular stability with the temporal modulation of optical power. Usually, it is difficult to realize both angular stability and highpower modulation in a passive setup without a servo system of radio-frequency compensation.Here, we present a method to suppress the angular drift and pointing noise only with the thermal management of the AOM crystal. We analyze the dependence of the angular drift on the refractive index variation, and find that the angular drift is very sensitivity to the temperature gradient which could induce the refractive index gradient inside the AOM crystal. It reminds us such angular drift could be significantly suppressed by carefully overlapping the zero temperature gradient area with the position of the acousto-optic interaction zone. We implement a watercooling setup, and find that the angular drift of an AOM is reduced over 100 times during the thermal transient, and the angular noise is also suppressed to 1/3 of the non-cooled case. It should be emphasized that this thermal control method is a general to suppress the beam drift in both the diffraction and the perpendicular-to-diffraction directions. The refractive index thermal coefficient of tellurium dioxide crystal at 1064 nm determined by this angular drift-temperature model is 16×10 −6 K −1 consistent with previous studies. This thermal control technique provides potential applications for optical trapping and remote sensoring that demand for intensity ramps.

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Stable all-optical formation of Bose–Einstein condensate using pointing-stabilized optical trapping beams

Cited by 6 publications

References 10 publications

Precision Surface-Coupled Optical-Trapping Assay with One-Basepair Resolution

Precision Surface-Coupled Optical-Trapping Assay with One-Basepair Resolution

Optimized Bose-Einstein-condensate production in a dipole trap based on a 1070-nm multifrequency laser: Influence of enhanced two-body loss on the evaporation process

Beam pointing stabilization of an acousto-optic modulator with thermal control

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