We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock.It is demonstrated that the intra-cavity lattice power can be increased by about 45 times,and the trap depth can be as l...We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock.It is demonstrated that the intra-cavity lattice power can be increased by about 45 times,and the trap depth can be as large as 1400Er when laser light with a power of only 0.6 W incident to the lattice cavity.Such high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to~1×10-18.By probing the ytterbium atoms trapped in the power-enhanced optical lattice,we obtain a 4.3 Hz-linewidth Rabi spectrum,which is then used to feedback to the clock laser for the close loop operation of the optical lattice clock.We evaluate the density shift of the Yb optical lattice clock based on interleaving measurements,which is-0.46(62)mHz.This result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344μm.展开更多
Two Nd：YAG lasers operating at 1064 nm are separately servo-locked to two vertically mounted ultra-stable cavities. The optical heterodyne beat between two cavity-stabilized lasers shows that the linewidth of each la...Two Nd：YAG lasers operating at 1064 nm are separately servo-locked to two vertically mounted ultra-stable cavities. The optical heterodyne beat between two cavity-stabilized lasers shows that the linewidth of each laser reaches 2 Hz and the average frequency drift reduces to less than 1 Hz/s.展开更多
We demonstrate coherent transfer of an ultra-stable optical frequency at 192.8 THz over 50-km spooled fiber. Random phase noise induced by environmental disturbance through fiber is detected and suppressed by feeding ...We demonstrate coherent transfer of an ultra-stable optical frequency at 192.8 THz over 50-km spooled fiber. Random phase noise induced by environmental disturbance through fiber is detected and suppressed by feeding a correctional signal into an acousto-optic modulator. After being compensated, the fiber-induced frequency instability is 2×10-17 at 1-s averaging time and reaches 8×10-20 after 16 h. The noise floor of the compensation system could be as low as 2×10-18 at 1-s averaging time.展开更多
An optical atomic clock with 171yb atoms is devised and tested. By using a two-stage Doppler cooling technique, the 171Yb atoms are cooled down to a temperature of 6 ± 3 μK, which is close to the Doppler limit. ...An optical atomic clock with 171yb atoms is devised and tested. By using a two-stage Doppler cooling technique, the 171Yb atoms are cooled down to a temperature of 6 ± 3 μK, which is close to the Doppler limit. Then, the cold 171Yb atoms are loaded into a one-dimensional optical lattice with a wavelength of 759 nm in the Lamb-Dicke regime. Furthermore, these cold 171yb atoms are excited from the ground-state 1S0 to the excited-state 3P0 by a clock laser with a wavelength of 578 nm. Finally, the 1S0-3P0 clock-transition spectrum of these 171yb atoms is obtained by measuring the dependence of the population of the ground-state 1 S0 upon the clock-laser detuning.展开更多
The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different support...The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different supporting positions.展开更多
A laser at 578 nm is phase-locked to an optical frequency comb（OFC） which is optically referenced to a subhertzlinewidth laser at 1064 nm. Coherence is transferred from 1064 nm to 578 nm via the OFC. By comparing wi...A laser at 578 nm is phase-locked to an optical frequency comb（OFC） which is optically referenced to a subhertzlinewidth laser at 1064 nm. Coherence is transferred from 1064 nm to 578 nm via the OFC. By comparing with a cavitystabilized laser at 578 nm, the absolute linewidth of 1.1 Hz and the fractional frequency instability of 1.3 × 10^-15 at an averaging time of 1 s for each laser at 578 nm have been determined, which is limited by the performance of the reference laser for the OFC.展开更多
We report a long-term frequency-stabilized optical frequency comb at 530–1100 nm based on a turnkey Ti:sapphire modelocked laser.With the help of a digital controller,turnkey operation is realized for the Ti:sapphire...We report a long-term frequency-stabilized optical frequency comb at 530–1100 nm based on a turnkey Ti:sapphire modelocked laser.With the help of a digital controller,turnkey operation is realized for the Ti:sapphire mode-locked laser.Under optimized design of the laser cavity,the laser can be mode-locked over a month,limited by the observation time.The combination of a fast piezo and a slow one inside the Ti:sapphire mode-locked laser allows us to adjust the cavity length with moderate bandwidth and tuning range,enabling robust locking of the repetition rate(f_(r)) to a hydrogen maser.By combining a fast analog feedback to pump current and a slow digital feedback to an intracavity wedge and the pump power of the Ti:sapphire mode-locked laser,the carrier envelope offset frequency(f_(ceo)) of the comb is stabilized.We extend the continuous frequency-stabilized time of the Ti:sapphire optical frequency comb to five days.The residual jitters of f;and f;are 0.08 m Hz and 2.5 m Hz at 1 s averaging time,respectively,satisfying many applications demanding accuracy and short operation time for optical frequency combs.展开更多
We demonstrate two ultra-stable laser systems at 1064 nm by independently stabilizing two 10-cm-long Fabry–Pérot cavities.The reference cavities are on a cubic spacer,which is rigidly mounted for both low sensit...We demonstrate two ultra-stable laser systems at 1064 nm by independently stabilizing two 10-cm-long Fabry–Pérot cavities.The reference cavities are on a cubic spacer,which is rigidly mounted for both low sensitivity to environmental vibration and ability for transportation.By comparing against an independent ultra-stable laser at 578 nm via an optical frequency comb,the 1064 nm lasers are measured to have frequency instabilities of 6×10^-16 at 1 s averaging time.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12334020 and 11927810)the National Key Research and Development Program of China(Grant No.2022YFB3904001).
文摘We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock.It is demonstrated that the intra-cavity lattice power can be increased by about 45 times,and the trap depth can be as large as 1400Er when laser light with a power of only 0.6 W incident to the lattice cavity.Such high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to~1×10-18.By probing the ytterbium atoms trapped in the power-enhanced optical lattice,we obtain a 4.3 Hz-linewidth Rabi spectrum,which is then used to feedback to the clock laser for the close loop operation of the optical lattice clock.We evaluate the density shift of the Yb optical lattice clock based on interleaving measurements,which is-0.46(62)mHz.This result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344μm.
基金Project supported by the National Natural Science Foundation of China (Grant No 60490280)the State Key Development for Basic Research Program of China (Grant Nos 2006CB806005 and 2006CB921104)+2 种基金the Science and Technology Commission of Shanghai Municipality, China (Grant Nos 06JC14026 and 07JC14019)Shanghai Pujiang Talent Program, China (Grant No 07PJ14038)the Program for Changjiang Scholars and Innovative Research Teams, China
文摘Two Nd：YAG lasers operating at 1064 nm are separately servo-locked to two vertically mounted ultra-stable cavities. The optical heterodyne beat between two cavity-stabilized lasers shows that the linewidth of each laser reaches 2 Hz and the average frequency drift reduces to less than 1 Hz/s.
基金supported by the National Natural Science Foundation of China(Grant Nos.11127405,11334002,and 11374102)the National Basic Research Program of China(Grant No.2012CB821302)
文摘We demonstrate coherent transfer of an ultra-stable optical frequency at 192.8 THz over 50-km spooled fiber. Random phase noise induced by environmental disturbance through fiber is detected and suppressed by feeding a correctional signal into an acousto-optic modulator. After being compensated, the fiber-induced frequency instability is 2×10-17 at 1-s averaging time and reaches 8×10-20 after 16 h. The noise floor of the compensation system could be as low as 2×10-18 at 1-s averaging time.
基金supported by the National Basic Research Program of China (Grant Nos. 2012CB821302 and 2010CB922903)the National Natural Science Foundation of China (Grant Nos. 11134003 and 10774044)the Shanghai Excellent Academic Leaders Program of China (Grant No. 12XD1402400)
文摘An optical atomic clock with 171yb atoms is devised and tested. By using a two-stage Doppler cooling technique, the 171Yb atoms are cooled down to a temperature of 6 ± 3 μK, which is close to the Doppler limit. Then, the cold 171Yb atoms are loaded into a one-dimensional optical lattice with a wavelength of 759 nm in the Lamb-Dicke regime. Furthermore, these cold 171yb atoms are excited from the ground-state 1S0 to the excited-state 3P0 by a clock laser with a wavelength of 578 nm. Finally, the 1S0-3P0 clock-transition spectrum of these 171yb atoms is obtained by measuring the dependence of the population of the ground-state 1 S0 upon the clock-laser detuning.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60490280 and 10774044)the NationalBasic Research Program of China (Grant No 2006CB806005)+1 种基金the Science and Technology Commission of Shanghai Municipality,China (Grant No 07JC14019)the Program for Changjiang Scholars and Innovative Research Teams and Shanghai Leading Academic Discipline Project (Grant No B408)
文摘The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different supporting positions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11334002,11374102,11104077,and 11127405)the National Basic Research Program of China(Grant No.2012CB821302)
文摘A laser at 578 nm is phase-locked to an optical frequency comb（OFC） which is optically referenced to a subhertzlinewidth laser at 1064 nm. Coherence is transferred from 1064 nm to 578 nm via the OFC. By comparing with a cavitystabilized laser at 578 nm, the absolute linewidth of 1.1 Hz and the fractional frequency instability of 1.3 × 10^-15 at an averaging time of 1 s for each laser at 578 nm have been determined, which is limited by the performance of the reference laser for the OFC.
基金supported by the National Key R&D Program of China(No.2017YFA0304403)the National Natural Science Foundation of China(Nos.11927810,11822402,and11804094)。
文摘We report a long-term frequency-stabilized optical frequency comb at 530–1100 nm based on a turnkey Ti:sapphire modelocked laser.With the help of a digital controller,turnkey operation is realized for the Ti:sapphire mode-locked laser.Under optimized design of the laser cavity,the laser can be mode-locked over a month,limited by the observation time.The combination of a fast piezo and a slow one inside the Ti:sapphire mode-locked laser allows us to adjust the cavity length with moderate bandwidth and tuning range,enabling robust locking of the repetition rate(f_(r)) to a hydrogen maser.By combining a fast analog feedback to pump current and a slow digital feedback to an intracavity wedge and the pump power of the Ti:sapphire mode-locked laser,the carrier envelope offset frequency(f_(ceo)) of the comb is stabilized.We extend the continuous frequency-stabilized time of the Ti:sapphire optical frequency comb to five days.The residual jitters of f;and f;are 0.08 m Hz and 2.5 m Hz at 1 s averaging time,respectively,satisfying many applications demanding accuracy and short operation time for optical frequency combs.
基金supported by the National Natural Science Foundation of China(Nos.11654004,11822402,91636214,and 11804094)the National Key R&D Program of China(No.2017YFA0304403)。
文摘We demonstrate two ultra-stable laser systems at 1064 nm by independently stabilizing two 10-cm-long Fabry–Pérot cavities.The reference cavities are on a cubic spacer,which is rigidly mounted for both low sensitivity to environmental vibration and ability for transportation.By comparing against an independent ultra-stable laser at 578 nm via an optical frequency comb,the 1064 nm lasers are measured to have frequency instabilities of 6×10^-16 at 1 s averaging time.
