Research Projects

An atomic clock is a highly precise timekeeping device that relies on the oscillations of atoms to measure time with exceptional accuracy. Atoms are excellent natural oscillators, exhibiting both microwave and optical transitions that span a wide frequency range, from the gigahertz (GHz) scale to several hundred terahertz (THz). Various types of atoms are used in atomic clocks, including alkali atoms (87 Rb, 133 Cs), alkaline-earth atoms (88 Sr), and rare-earth atoms (173 Yb). The accuracy of an atomic clock is measured by the Allan deviation, which is proportional to ∆ν/ν₀ , where ∆ν is the measured linewidth of the clock transition, and ν₀ is the measured frequency of the clock transition. A smaller Allan deviation indicates better performance and higher accuracy of the atomic clock. Microwave atomic clocks operate at frequencies like 9.19GHz (Cs) and 6.83GHz (Rb), whereas optical clocks use much higher frequencies 10^(14) Hz, enabling significantly improved time resolution and stability. Laser-cooled single-ion clocks and optical lattice clocks with neutral atoms utilize optical transitions to achieve exceptional precision. However, these traditional cold-atom based atomic clocks are bulky and not easily portable, restricting their practical deployment. This makes the miniaturization of atomic clocks a key requirement for real-world applications. We plan to develop a portable atomic clock based on coherent population trapping (CPT). The proposed CPT-based portable atomic clock is expected to demonstrate excellent frequency stability and low power consumption in a compact form factor. To enhance the clock’s performance, we aim to use a custom-designed vapor cell filled with 1000 torr of buffer gas. The presence of buffer gas significantly reduces wall-atom and atom-atom collisions, enabling the generation of a sub-kHz CPT resonance signal. Short-term frequency stability on the order of 10^(−12) at 1 second averaging time is anticipated, driven by the narrow linewidth and high signal-to-noise ratio. The use of a buffer gas and magnetic shielding will enhance coherence time and signal contrast. The system is designed to operate at room temperature, minimizing the need for thermal control and contributing to overall power efficiency. Power consumption is expected to remain below 1 W, making the clock suitable for battery-powered and remote applications. The complete setup, including optics, electronics, and shielding, will be housed in a compact and robust enclosure, targeting a volume of just a hundred cubic centimeters. The key innovation of this proposal is the integration of high stability, low power consumption, and portability. Moreover, the development and deployment of this miniaturized quantum technology for applications in geodesy, GPS navigation, and space exploration are well aligned with the goals of India’s National Quantum Mission (NQM).