The Cold Atom Interference Gyroscope (CAIG) offer substantial potential for rotation measurement due to the high sensitivity and stability. The CAIG with a fountain configuration realized by 4-pulse could provide a larger interference-loop area, and enhanced performance. However, this kind of CAIG is usually much larger and higher since it requires a vacuum chamber with sufficient height to achieve a long Raman pulse interval. We demonstrate a 4-pulse CAIG based on a miniaturized vacuum chamber that enables portable and transportable rotation rate measurements. The main vacuum chamber is realized by whole glass material. The height of the vacuum unit is 0.7 m, the volume is 8.86 × 10 ⁴ cm ³ and the mass is 75 kg. Then, we estimated the performance of our portable CAIG in the environment of the underground laboratory and the fifth-floor office building. In the laboratory, the sensitivities of the homemade CAIG is 4.44 × 10 ⁻⁶ rad/s/√Hz with an interrogation time of 55 ms and an interference area of 25 mm ² . In addition, we measured the angular velocity of the Earth, the relative error is 2.4%. Furthermore, we transported the CAIG to the fifth floor of the office building, which is near the subway. Ultimately, the CAIG achieved a sensitivity of 5.47 × 10 ⁻⁴ rad/s/√Hz. Additionally, the theoretical maximum interrogation time achieved by this CAIG is 124 ms corresponding to a sensitivity of 5.62 × 10 ⁻⁸ /√Hz. Our new design of the compact CAIG could provide novel insights into the miniaturization of CAIGs, while also pointing out areas for further improvement.

High-precision rotation measurements are of great importance for the field of inertial navigation and geophysics. The cold atom interferometer gyroscope (CAIG) has no mechanical wear and can achieve a better angular random walk (ARW). Therefore, the CAIG has received wide attention in recent years. Typically, the CAIG has a complex structure, large volume, and heavy weight, especially for the CAIG based on an atomic fountain realized with four Raman pulses. Previously, we have implemented a compact CAIG and carried out the transportable experiments. In this paper, the phase shifts induced by the main noises are analyzed, including the vibration noise, the Raman phase noise, and the detection noise, which significantly limit the sensitivity of our CAIG. The vibration compensation algorithm has been utilized to suppress the vibration noise. Besides, the phase noise has been reduced with the parameter optimization of the PID controller. The polarization purification for the detection beam has been implemented by two Glan-Taylor prisms to reduce the influence of detection noise. Finally, the comprehensive analysis of these noises has been carried out so that a CAIG with a total interrogation time of 4T=400 ms and a Sagnac area of 2.27 cm² has been achieved. The estimated measurement ARW is 1.12 μrad/s/Hz^1/2, and a bias instability of about 30 nrad/s can be reached with an integration time of 2000 s. Compared with the previously reported ARW of 4.4 μrad/s/Hz^1/2, the ARW has been improved by nearly four times. The experimental results of this paper can provide an effective reference for the development of compact and transportable CAIG.

In cold atom physics, the complexity of traditional magneto-optical trap system limits the use of their associated instruments for field applications in atomic physics, such as gravity mapping, space navigation and deep space exploration. This study introduces a novel compact MOT design that addresses these issues by simplifying the structure and reducing the size. The height of the unit is 0.7 m, the volume is $6.3\times {10}^{-2}$${\mathrm{m}}^3$ and the mass is 11.32 kg. The new design utilizes a single laser to generate the two different frequencies needed for laser cooling by internally splitting the beam, shifting the frequency and then combining them, effectively controlling both the cooling and repumping beams. The compact vacuum chamber optical path, in conjunction with the magnetic field, facilitates the capture of ⁸⁷Rb atoms in an ultra-high vacuum environment. Experimental results demonstrate an atom loading rate of up to $1.79\times {10}^7$⁸⁷Rb atoms per second, confirming the system’s effectiveness in capturing and cooling ⁸⁷Rb atoms. This design provides a flexible and portable solution, offering valuable insights for the advancement of compact MOT and its applications in cold atom physics.