A portable sub Hertz ultra-stable laser over 1700km highway transportation

TL;DR

This paper reports the development and successful transportation of a portable ultrastable laser with sub-Hz linewidth over 1700 km of highway travel, demonstrating robustness and high stability suitable for precision applications.

Contribution

It introduces a compact, robust ultrastable laser system capable of maintaining sub-Hz linewidth and stability after long-distance road transportation, with validated experimental performance.

Findings

Laser linewidth median ~0.78 Hz

Fractional frequency instability <3E-15 at 1-10 s

Maintains stability after 1700 km transportation

Abstract

We present a subHz linewidth portable ultrastable laser with the mass and volume of are 40kg and 400mm*280mm*450mm, respectively, that meets the requirements of automatic frequency locking and road transportation. A dynamic analytical model of the physical parts of ultrastable laser is established, and the first order resonance frequency is determined by FEA and well agrees with the experimentally measured result. To verify the transport performance of the portable ultrastable laser, it is tested for 100 km actual road transportation and 60 min continuous vibration, corresponding to 1700 km road transportation. The success of the test demonstrated that the portable ultrastable laser was very robust. Meanwhile, the portable ultrastable lasers shows that the median of the linewidth distribution is approximately 0.78 Hz, and the fractional frequency instability is less than 3E-15 at 1 to 10 s averaging time. This value approaches the total noise of 2.0E-15 including thermal noise and residual amplitude modulation. The robust suggested that the portable ultrastable laser might be a good candidate such as optical frequency transfer and metrological systems.