A simple laser system for atom interferometry

We present here a simple laser system for a laser-cooled atom interferometer, where all functions (laser cooling, interferometry and detection) are realized using only two extended cavity laser diodes, amplified by a common tapered amplifier. One laser is locked by frequency modulation transfer spectroscopy, the other being phase locked with an offset frequency determined by an field-programmable gate array-controlled direct digital synthesizer, which allows for efficient and versatile tuning of the laser frequency. Raman lasers are obtained with a double pass acoustooptic modulator. We demonstrate a gravimeter using this laser system, with performances close to the state of the art.     

Compact laser system for atom interferometry

We describe an optical bench in which we lock the relative frequencies or phases of a set of three lasers in order to use them in a cold atom interferometry experiment. As a new feature, the same two lasers serve alternately to cool atoms and to realize the atomic interferometer. This requires a fast change of the optical frequencies over a few GHz. The number of required independent laser sources is then only three, which enables the construction of the whole laser system on a single transportable optical bench. Recent results obtained with this optical setup are also presented. PACS 32.80.Pj; 42.50.Vk; 39.20.+q     

Compact and robust laser system for onboard atom interferometry

We propose a compact and robust laser system at 780 nm for onboard atomic inertial sensors based on rubidium atom interferometry. The principle of this system consists in doubling the frequency of a telecom fiber bench at 1560 nm. The same laser source is used to achieve a magneto-optical trap, matter–wave interferences, and the atomic detection. An atomic gravimeter has been realized and the laser system has been validated under hyper- and microgravity.     

Dual-wavelength laser source for onboard atom interferometry

We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components, which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto-optical trap in microgravity during parabolic flights.     

Prospects for atom interferometry

Atom interferometers were first realized ten years ago, and since then have evolved from beautiful demonstrations of quantum physics into instruments at the leading edge of precision measurement. In this article we trace the development of atom interferometry, looking at how the physical principles have been put into practice to achieve ground-breaking experiments. We also discuss new atom optical techniques that are becoming available and anticipate the ways in which the consequent improvements will provide new opportunities in metrology and the study of fundamental physics.     

Dispersion compensation for atom interferometry

A new technique for maintaining high contrast in an atom interferometer is used to measure large de Broglie wave phase shifts. Dependence of an interaction induced phase on the atoms' velocity is compensated by applying an engineered counterphase. The counterphase is equivalent to a rotation, is precisely determined by a frequency, and can be used to measure phase shifts due to interactions of unknown strength. Phase shifts of 150 rad (5 times larger than previously possible) have now been measured in an atom beam interferometer, and we suggest that this technique can enable comparisons of atomic polarizability with precision of one part in 10,000.     

适用于高精度激光测距的光学系统设计北大核心CSCD

随着激光雷达技术的发展和测距精度需求的提高,对发射和接收光学系统提出了新的要求,需具有光束可调节、测量光斑小、回波效率高等特性。设计一种工作于1550 nm光通信波段的收发一体光学系统,发射与接收模块共用部分光路,以减小接收视野盲区,同时有利于结构小型化。为解决不同测量距离、不同表面倾角造成的回波能量差异问题,将光学系统的扩束组件设计成放大倍率为2×~3.5×的连续可调结构;使用两组双胶合透镜进行色差校正,以降低光谱宽度对系统传播距离的影响。经设计优化,系统准直后的激光发散角小于0.3 mrad,出射光斑直径在6.26 mm~10.20 mm连续可调,对于50 m内的测量目标,照射光斑直径均小于20 mm,且在不同变焦位置发散角和光斑直径均满足设计要求。     

A laser system for optical waves mixing experiments

We built a neodymium glass laser delivering two simultaneous pulses having a frequency separation tunable by steps from 10 to 90 cm^-1. We used it to measure non-linear polarizabilities in glases and carbon disulfide by conventional coherent second Stokes and anti-Stokes techniques with unusual spectral filtering requirements. With the device described one can study in the 10^-13–10^-14 s range the kinetics of effects induced by the square of an electric field.     

Development of portable laser machining system for laser writing applications

This study presents a portable laser machining system that consists of a fiber-optic diode laser source with a wavelength of 808 nm, optic/opto-mechanical components, a laser scanning module, and a laser energy control module. The laser beam quality was measured at different operation frequencies during system evaluation. The experimental results of beam profile evaluation indicate that the enlarged collimated beam was the TEM₀₀ mode with a roundness of approximately of 96%. The output laser power level increased as the pulse frequency increased during laser power evaluation. To control the rotating angle of the galvanometric scanning system, the deflective angle was adjusted using a 0.192 voltage to obtain a deflective value of 1mm and the maximum scan field of 100 × 100mm². The laser source operated at different frequencies, with pulse widths ranging from 530 to 48 μs. Finally, the proposed machine can also be used for black thick paper laser writing applications.     

A simple laser pulse tailoring/synchronization system for laser plasma interaction experiments

A system is described for accurately synchronizing pulses from single longitudinal mode Q-switched Nd: YAG oscillator (QSO) with those from a passively mode-locked Nd: YAG oscillator (MLO). Single mode operation is achieved by applying external negative feedback stabilization to the QSO to bring it into quasi-CW operation before Q-switching is triggered by the pulse from the MLO. The relative jitter between the peaks of the two pulses did not exceed 1 ns.     

Light-pulse atom interferometry in microgravity

We describe the operation of a light pulse interferometer using cold ⁸⁷Rb atoms in reduced gravity. Using a series of two Raman transitions induced by light pulses, we have obtained Ramsey fringes in the low gravity environment achieved during parabolic flights. With our compact apparatus, we have operated in a regime which is not accessible on ground. In the much lower gravity environment and lower vibration level of a satellite, our cold atom interferometer could measure accelerations with a sensitivity orders of magnitude better than the best ground based accelerometers and close to proven spaced-based ones.     

Large area light-pulse atom interferometry

We report the experimental demonstration of a large area atom interferometer based on extended sequences of light pulses. We characterize the interferometer through measurement of the acceleration due to gravity and demonstrate a threefold enhancement in intrinsic acceleration sensitivity. The technique is applicable to many atom interferometer configurations, including those used for measurement of rotations, gravity gradients, and Planck's over 2pi/m.     

Precision measurement with atom interferometry

Development of atom interferometry and its application in precision measurement are reviewed in this paper. The principle, features and the implementation of atom interferometers are introduced, the recent progress of precision measurement with atom interferometry, including determination of gravitational constant and fine structure constant, measurement of gravity, gravity gradient and rotation, test of weak equivalence principle, proposal of gravitational wave detection, and measurement of quadratic Zeeman shift are reviewed in detail. Determination of gravitational redshift, new definition of kilogram, and measurement of weak force with atom interferometry are also briefly introduced.     

Phase-coherent light pulses for atom optics and interferometry

We have developed a novel source for the generation of powerful phase-coherent light pulses. Our setup uses an acousto-optic modulator (AOM) inside an external high-finesse resonator. By applying a short rf pulse to the AOM, we dump the cavity and extract a large part of the stored and enhanced power within a short optical pulse and with a controllable optical phase. In preliminary experiments we reached 100 W of peak power in a 15-ns optical pulse. The mutual phase coherence of successive light pulses is demonstrated with a molecular iodine interferometer experiment in a cell.     

Using atom interferometry to search for new forces

Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 10² and near-future advances may be able to rewrite the limits for forces with ranges from 1 mm to 100 m.     

Chirped pulse reflectivity and frequency domain interferometry in laser driven shock experiments

We show the simultaneous applicability of the frequency domain interferometry and the chirped pulse reflectometry techniques to measure shock parameters. The experiment has been realized with the laser at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) with a 550-ps pulse duration and an intensity on target approximately 5 x 10(13) W/cm(2) to produce a shock in a layered aluminum-fused silica target. A second low energy, partially compressed chirped probe beam was used to irradiate the target rear side and the reflected light has been analyzed with a spectrometer, achieving a temporal resolution of the order of 1 ps.