Dr. Tiantian Shi

Co-authors

Following

Followers

Research Focus & Metrics

Explore full metrics on Scilit

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications

11 August 2022 in Physical Review Applied

Journal Article

Compact 459-nm Cs Cell Optical Frequency Standard with

2.1 \times 10^{- 13} / \sqrt{τ}

We achieve a compact optical frequency standard with an extended cavity diode laser locked to the 459-nm

6 S_{1 / 2}

7 P_{1 / 2}

transition of thermal

^{133} Cs

atoms in a

ϕ 10 mm \times 50 mm

glass cell, using modulation transfer spectroscopy (MTS). The self-estimated frequency stability of this laser is

1.4 \times 10^{- 14} / \sqrt{τ}

. With heterodyne measurement, we verify the linewidth-narrowing effect of MTS locking and measure the frequency stability of the locked laser. The linewidth of each laser is reduced from the free-running 69.6 to 10.3 kHz after MTS stabilization, by a factor of 6.75. The Allan deviation measured via beat detection is

2.1 \times 10^{- 13} / \sqrt{τ}

for each MTS-stabilized laser. In addition, we measure the hyperfine structure of the

7 P_{1 / 2}

energy level based on the heterodyne measurements, and calculate the magnetic dipole constant A of the Cs

7 P_{1 / 2}

level to be 94.38(6) MHz, which agrees well with previous measurements. This compact optical frequency standard can also be used in other applications that require high-stability lasers, such as laser interferometry, laser cooling, geodesy, and so on.

22 July 2019 in Optics Express

Journal Article

Realization of phase locking in good-bad-cavity active optical clock

Tiantian Shi

Duo Pan

Jingbiao Chen

The residual cavity-pulling effect limits further narrowing of linewidth in dual-wavelength (DW) good-bad-cavity active optical clocks (AOCs). In this paper, we for the first time experimentally realize the cavity-length stabilization of the 1064/1470 nm DW-AOCs by utilizing the phase locking technique of two independent 1064 nm good-cavity lasers. The frequency tracking accuracy between the two main-cavities of DW-AOCs is better than 3 × 10-16 at 1 s, and can reach 1 × 10-17 at 1000 s. Each 1470 nm bad-cavity laser achieves a most probable linewidth of 53 Hz, which is about a quarter of that without phase locking. The influence of the asynchronous cavity-lengths variation between two DW laser systems is suppressed.

13 September 2024 in npj Quantum Information

Journal Article

An extremely bad-cavity laser

Jianxiang Miao

Lasing in the bad-cavity regime has promising applications in quantum precision measurement and frequency metrology due to the reduced sensitivity of the laser frequency to cavity-length fluctuations. Thus far, relevant studies have been mainly focused on conventional cavities whose finesse is high enough that the resonance linewidth is sufficiently narrow compared to the cavity’s free spectral range, though still in the bad-cavity regime. However, lasing output from the cavity whose finesse is close to the limit of 2 has never been experimentally accessed. Here, we demonstrate an extremely bad-cavity laser, analyze the physical mechanisms limiting cavity finesse, and report on the worst-ever laser cavity with finesse reaching 2.01. The optical cavity has a reflectance close to zero and only provides weak optical feedback. The laser power can be as high as tens of μW and the spectral linewidth reaches a few kHz, over one thousand times narrower than the gain bandwidth. In addition, the measurement of cavity pulling reveals a pulling coefficient of 0.0148, the lowest value ever achieved for a continuous-wave laser. Our findings open up an unprecedentedly innovative perspective for future new ultra-stable lasers, which could possibly trigger future discoveries in optical clocks, cavity QED, continuous-wave superradiant laser, and explorations of quantum many-body physics.

15 November 2022 in IEEE Photonics Journal

Journal Article

Frequency Stabilization of a Cesium Faraday Laser With a Double-Layer Vapor Cell as Frequency Reference

Hangbo Shi

Pengyuan Chang

Zhiyang Wang

Zijie Liu

Tiantian Shi

Jingbiao Chen

We implement a compact optical frequency standard at the wavelength of 852 nm by the modulation transfer spectroscopy (MTS) technique, using a Faraday laser as the local oscillator and a double-layer cesium vapor cell to provide frequency reference. The vacuum space between the two quartz glass layers of the double-layer atomic vapor cell can effectively suppress the temperature fluctuations inside the internal atomic vapor cell. The influences of probe and pump laser powers, modulation frequency, and vapor cell temperature on the slope of the MTS error signal are measured. Utilizing the self-estimation method, we evaluate the frequency stability of the laser system, which can be up to $\bf {5.8\times 10^{-15}/\sqrt{\tau }}$ at short term, dropping to $\bf {2.0\times 10^{-15}}$ at 50 s. This result is obviously superior to that using single-layer vapor cell as the frequency reference. Such an ultrastable laser source can be widely used in the fields of optical metrology and precision measurement.

2 July 2020 in IEEE Photonics Journal

Journal Article

A Dual-Frequency Faraday Laser

The Faraday laser, with Faraday anomalous dispersion optical filter (FADOF) as frequency-selection element, is a natural narrow-bandwidth light source for laser physic experiments. In this work, a dual-frequency (DF) Faraday laser is demonstrated for the first time on Cs D2 line at 852 nm. The frequencies of the two modes of DF Faraday laser hinge on the peak transition frequencies of 852 nm FADOF transmittance spectrum corresponding to the ground state F = 4 and F = 3. The frequency difference between the two modes is tunable over a range of 1.4 GHz with the temperature of Cs vapor cell inside the FADOF. The linewidth of each laser mode is less than 33 kHz. Furthermore, the most probable linewidth of the beat-note spectra between the two modes is 902.95 Hz at different vapor-cell temperatures. Such a DF Faraday laser has many potential applications in atomic physics, such as sub-Doppler spectroscopy and coherent population trapping atomic clocks.

24 April 2023 in AAPPS Bulletin

Journal Article

The development of active optical clock

The atomic clocks, whether operating at optical or microwave region, can be divided into two categories according to their working mode, namely the passive clocks and active clocks. The passive clocks, whose standard frequency is locked to an ultra-narrow atomic spectral line, such as laser cooled Cs beam or lattice trapped Sr atoms, depend on the spontaneous emission line. On the contrary, the active clocks, in which the atoms are used as the gain medium, are based on the stimulated emission radiation, their spectrum can be directly used as the frequency standard. Up to now, the active hydrogen maser has been the most stable microwave atomic clocks. Also, the Sr superradiant active atomic clock is prospects for a millihertz-linewidth laser. Moreover, the optical clocks are expected to surpass the performance of microwave clocks both in stability and uncertainty, since their higher working frequency. The active optical clock has the potential to improve the stability of the best clocks by 2 orders of magnitude. In this work, we introduce the development of active optical clocks, and their types is classified according to the energy-level structure of atoms for stimulated radiation.

About Me

Dr. Tiantian Shi received her B.E. degree in Xidian University, Xian, China, in 2016, and the Ph.D degree in Electronic Science and Technology from the Peking University. Since Jul. 2021, Dr. Shi has been in School of Electronics, Peking University, as a postdoc, and since Oct. 2023, Dr. Shi has been in School of Integrated Circuits, Peking University, as a Research Assistant Professor. Dr. Shi focuses on the research of atomic clocks and laser physics. She recent research interests include: ultra-stable laser system, Faraday laser, active atomic clock, laser cooling atomic clocks, etc. Since 2018, Dr. Shi has published 50 peer-reviewed technical SCI/EI papers in international journals, such as, npj Quantum information, Communication Physics, Photonics Research, Physical Review Applied, Applied Physics Letter, Optics Express, etc. She is a member IEEE and served as a reviewer of several international journals. Dr. Shi has published two monographs titled "Faraday Laser" in both Chinese and English. She was a recipient of two Finalist of Best Paper Awards at the Joint Conference of the IEEE International Frequency Control Symposium & IEEE International Symposium on Applications of Ferroelectrics. Dr. Shi was also awarded the Beijing Outstanding Graduates, and China Postdoctoral Science Foundation, which recognized her achievement as one of the most highlighting research outputs done by postgraduates within Peking University in 2021.

Dr. Tiantian Shi

Dr. Tiantian Shi

Research Focus & Metrics

Academic Career Length

Publication Type Breakdown

Representative Publications

About Me