Research on chip-scale atomic clocks （CSACs） based on coherent population trapping （CPT） is reviewed. The back- ground and the inspiration for the research are described, including the important schemes proposed t...Research on chip-scale atomic clocks （CSACs） based on coherent population trapping （CPT） is reviewed. The back- ground and the inspiration for the research are described, including the important schemes proposed to improve the CPT signal quality, the selection of atoms and buffer gases, and the development of micro-cell fabrication. With regard to the re- liability, stability, and service life of the CSACs, the research regarding the sensitivity of the CPT resonance to temperature and laser power changes is also reviewed, as well as the CPT resonance＇s collision and light of frequency shifts. The first generation CSACs have already been developed but its characters are still far from our expectations. Our conclusion is that miniaturization and power reduction are the most important aspects calling for further research.展开更多
The physics package of a chip-scale atomic clock （CSAC） has been successfully realized by integrating vertical cavity surface emitting laser （VCSEL）, neutral density （ND） filter, λ/4 wave plate, 87Rb vapor cell...The physics package of a chip-scale atomic clock （CSAC） has been successfully realized by integrating vertical cavity surface emitting laser （VCSEL）, neutral density （ND） filter, λ/4 wave plate, 87Rb vapor cell, photodiode （PD）, and magnetic coil into a cuboid metal package with a volume of about 2.8 cm3. In this physics package, the critical component, 87Rb vapor cell, is batch-fabricated based on MEMS technology and in-situ chemical reaction method. Pt heater and thermistors are integrated in the physics package. A PTFE pillar is used to support the optical elements in the physics package, in order to reduce the power dissipation. The optical absorption spectrum of 87Rb D1 line and the microwave frequency correction signal are successfully observed while connecting the package with the servo circuit system. Using the above mentioned packaging solution, a CSAC with short-term frequency stability of about 7 × 10^-10τ-1/2 has been successfully achieved, which demonstrates that this physics package would become one promising solution for the CSAC.展开更多
We describe the microfabrication of ^85Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb. Under controlled conditions...We describe the microfabrication of ^85Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb. Under controlled conditions, the pure metallic Rb drops and buffer gases were obtained in the cells with a few mm^3 internal volumes during the cell sealing process. At an ambient temperature of 90 ℃ the optical absorption resonance of ^85Rb D1 transition with proper broadening and the corresponding coherent population trapping （CPT） resonance, with a signal contrast of 1.5% and linewidth of about 1.7 kHz, have been detected. The sealing quality and the stability of the cells have also been demonstrated experimentally by using the helium leaking detection and the after-9-month optoelectronics measurement which shows a similar CPT signal as its original status. In addition, the physics package of chip-scale atomic clock （CSAC） based on the cell was realized. The measured frequency stability of the physics package can reach to 2.1 × 10^-10 at one second when the cell was heated to 100 ℃ which proved that the cell has the quality to be used in portable and battery-operated devices.展开更多
Chip-scale quantum magnetometers featuring both ultra-high sensitivity and uniform spin polarization are highly desired for practical applications and have been diligently pursued.However,the fulfillment of such capab...Chip-scale quantum magnetometers featuring both ultra-high sensitivity and uniform spin polarization are highly desired for practical applications and have been diligently pursued.However,the fulfillment of such capabilities for quantum magnetometers typically necessitates a separate heating unit,bulky reflector,and beyond,severely impeding on-chip integration and batch fabrication of these quantum devices.Herein,we present a novel paradigm for the wafer-level fabrication of ultra-sensitive chip-scale quantum magnetometer,which is enabled by integrating a highly reflective mirror and a temperature-controlled component on the optically transparent windows of the MEMS atomic vapor cell,thereby providing a genuinely all-in-one atomic vapor cell with a temperature stability better than±5 mK at up to 200°C as well as a reflectivity of 95%at Rb D1 transition wavelength.With the as-developed on-chip atomic vapor cell with internal dimensions ofΦ3×1.5 mm^(3),we configured a chip-scale single-beam atomic magnetometer with a sensitivity floor of about 15 fT/Hz^(1/2),along with a theoretically more homogeneous spin polarization distribution.We envision that the proposed chip-scale integration solution paves a concrete route for batch manufacturing and widespread application of quantum magnetometers.展开更多
Based on a silicon platform, we design and fabricate a four-mode division(de)multiplexer for chip-scale optical data transmission in the 2 μm waveband for the first time, to the best of our knowledge. The(de)multiple...Based on a silicon platform, we design and fabricate a four-mode division(de)multiplexer for chip-scale optical data transmission in the 2 μm waveband for the first time, to the best of our knowledge. The(de)multiplexer is composed of three tapered directional couplers for both mode multiplexing and demultiplexing processes. In the experiment, the average crosstalk for four channels is measured to be less than-18 dB over a wide wavelength range(70 nm) from 1950 to 2020 nm, and the insertion losses are also assessed. Moreover, we further demonstrate stable 5 Gbit/s direct modulation data transmission through the fabricated silicon photonic devices with nonreturn-to-zero on–off keying signals. The experimental results show clear eye diagrams, and the penalties at a bit error rate of 3.8 × 10-3 are all less than 2.5 dB after on-chip data transmission. The obtained results indicate that the presented silicon four-mode division multiplexer in the mid-infrared wavelength band might be a promising candidate facilitating chip-scale high-speed optical interconnects.展开更多
As the key part of chip-scale atomic clocks(CSACs), the vapor cell directly determines the volume, stability,and power consumption of the CSAC. The reduction of the power consumption and CSAC volumes demands the manuf...As the key part of chip-scale atomic clocks(CSACs), the vapor cell directly determines the volume, stability,and power consumption of the CSAC. The reduction of the power consumption and CSAC volumes demands the manufacture of corresponding vapor cells. This overview presents the research development of vapor cells of the past few years and analyzes the shortages of the current preparation technology. By comparing several different vapor cell preparation methods, we successfully realized the micro-fabrication of vapor cells using anodic bonding and deep silicon etching. This cell fabrication method is simple and effective in avoiding weak bonding strengths caused by alkali metal volatilization during anodic bonding under high temperatures.Finally, the vapor cell D2 line was characterized via optical-absorption resonance. According to the results,the proposed method is suitable for CSAC.展开更多
On-chip spectroscopic sensors have attracted increasing attention for portable and field-deployable chemical detection applications. So far, these sensors largely rely on benchtop tunable lasers for spectroscopic inte...On-chip spectroscopic sensors have attracted increasing attention for portable and field-deployable chemical detection applications. So far, these sensors largely rely on benchtop tunable lasers for spectroscopic interrogation. Large footprint and mechanical fragility of the sources, however, preclude compact sensing system integration. In this paper, we address the challenge through demonstrating, for the first time to our knowledge, a supercontinuum source integrated on-chip spectroscopic sensor, where we leverage nonlinear Ge_(22)Sb_(18)Se_(60) chalcogenide glass waveguides as a unified platform for both broadband supercontinuum generation and chemical detection. A home-built, palm-sized femtosecond laser centering at 1560 nm wavelength was used as the pumping source. Sensing capability of the system was validated through quantifying the optical absorption of chloroform solutions at 1695 nm. This work represents an important step towards realizing a miniaturized spectroscopic sensing system based on photonic chips.展开更多
基金Project support by the National Natural Science Foundation of China(Grant No.11074012)
文摘Research on chip-scale atomic clocks （CSACs） based on coherent population trapping （CPT） is reviewed. The back- ground and the inspiration for the research are described, including the important schemes proposed to improve the CPT signal quality, the selection of atoms and buffer gases, and the development of micro-cell fabrication. With regard to the re- liability, stability, and service life of the CSACs, the research regarding the sensitivity of the CPT resonance to temperature and laser power changes is also reviewed, as well as the CPT resonance＇s collision and light of frequency shifts. The first generation CSACs have already been developed but its characters are still far from our expectations. Our conclusion is that miniaturization and power reduction are the most important aspects calling for further research.
基金supported by the Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.KGCX2-YW-143)
文摘The physics package of a chip-scale atomic clock （CSAC） has been successfully realized by integrating vertical cavity surface emitting laser （VCSEL）, neutral density （ND） filter, λ/4 wave plate, 87Rb vapor cell, photodiode （PD）, and magnetic coil into a cuboid metal package with a volume of about 2.8 cm3. In this physics package, the critical component, 87Rb vapor cell, is batch-fabricated based on MEMS technology and in-situ chemical reaction method. Pt heater and thermistors are integrated in the physics package. A PTFE pillar is used to support the optical elements in the physics package, in order to reduce the power dissipation. The optical absorption spectrum of 87Rb D1 line and the microwave frequency correction signal are successfully observed while connecting the package with the servo circuit system. Using the above mentioned packaging solution, a CSAC with short-term frequency stability of about 7 × 10^-10τ-1/2 has been successfully achieved, which demonstrates that this physics package would become one promising solution for the CSAC.
基金Project supported by National 863/973 Plans Projects (Grant Nos. 2006AA04Z361,2006CB932402)NSFC (Grant No. 60971002)
文摘We describe the microfabrication of ^85Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb. Under controlled conditions, the pure metallic Rb drops and buffer gases were obtained in the cells with a few mm^3 internal volumes during the cell sealing process. At an ambient temperature of 90 ℃ the optical absorption resonance of ^85Rb D1 transition with proper broadening and the corresponding coherent population trapping （CPT） resonance, with a signal contrast of 1.5% and linewidth of about 1.7 kHz, have been detected. The sealing quality and the stability of the cells have also been demonstrated experimentally by using the helium leaking detection and the after-9-month optoelectronics measurement which shows a similar CPT signal as its original status. In addition, the physics package of chip-scale atomic clock （CSAC） based on the cell was realized. The measured frequency stability of the physics package can reach to 2.1 × 10^-10 at one second when the cell was heated to 100 ℃ which proved that the cell has the quality to be used in portable and battery-operated devices.
基金supported by the National Key Research&Development(R&D)Program of China(Grant No.2024YFB3212500)the National Natural Science Foundation of China(Grant No.52435010)the Shaanxi Provincial Science and Technology Development Program(Grant Nos.2023-LL-QY-35,and 2024RS-CXTD-19).
文摘Chip-scale quantum magnetometers featuring both ultra-high sensitivity and uniform spin polarization are highly desired for practical applications and have been diligently pursued.However,the fulfillment of such capabilities for quantum magnetometers typically necessitates a separate heating unit,bulky reflector,and beyond,severely impeding on-chip integration and batch fabrication of these quantum devices.Herein,we present a novel paradigm for the wafer-level fabrication of ultra-sensitive chip-scale quantum magnetometer,which is enabled by integrating a highly reflective mirror and a temperature-controlled component on the optically transparent windows of the MEMS atomic vapor cell,thereby providing a genuinely all-in-one atomic vapor cell with a temperature stability better than±5 mK at up to 200°C as well as a reflectivity of 95%at Rb D1 transition wavelength.With the as-developed on-chip atomic vapor cell with internal dimensions ofΦ3×1.5 mm^(3),we configured a chip-scale single-beam atomic magnetometer with a sensitivity floor of about 15 fT/Hz^(1/2),along with a theoretically more homogeneous spin polarization distribution.We envision that the proposed chip-scale integration solution paves a concrete route for batch manufacturing and widespread application of quantum magnetometers.
基金National Natural Science Foundation of China(NSFC)(61761130082,11574001,11774116,61705072)Royal Society-Newton Advanced Fellowship+4 种基金National Program for Support of Top-notch Young ProfessionalsNatural Science Foundation of Hubei Province(2018CFA048,ZRMS2017000413)Beijing University of Posts and Telecommunications(BUPT))(IPOC2018A002)Program for HUST Academic Frontier Youth Team(2016QYTD05)Fundamental Research Funds for the Central Universities(2019kfyRCPY037)
文摘Based on a silicon platform, we design and fabricate a four-mode division(de)multiplexer for chip-scale optical data transmission in the 2 μm waveband for the first time, to the best of our knowledge. The(de)multiplexer is composed of three tapered directional couplers for both mode multiplexing and demultiplexing processes. In the experiment, the average crosstalk for four channels is measured to be less than-18 dB over a wide wavelength range(70 nm) from 1950 to 2020 nm, and the insertion losses are also assessed. Moreover, we further demonstrate stable 5 Gbit/s direct modulation data transmission through the fabricated silicon photonic devices with nonreturn-to-zero on–off keying signals. The experimental results show clear eye diagrams, and the penalties at a bit error rate of 3.8 × 10-3 are all less than 2.5 dB after on-chip data transmission. The obtained results indicate that the presented silicon four-mode division multiplexer in the mid-infrared wavelength band might be a promising candidate facilitating chip-scale high-speed optical interconnects.
基金supported by the National Key Research and Development Program of China(No.2017YFB0503200)the National Natural Science Foundation of China(Nos.61675185 and 61875250)+3 种基金the Natural Science Foundation of Shanxi Province(No.201701D121065)Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Provincethe Program for the Top Young and Middle-Aged Innovative Talents of HigherLearning Institutions of Shanxisponsored by the Fund for Shanxi ‘1331 Project’ Key Subject Construction
文摘As the key part of chip-scale atomic clocks(CSACs), the vapor cell directly determines the volume, stability,and power consumption of the CSAC. The reduction of the power consumption and CSAC volumes demands the manufacture of corresponding vapor cells. This overview presents the research development of vapor cells of the past few years and analyzes the shortages of the current preparation technology. By comparing several different vapor cell preparation methods, we successfully realized the micro-fabrication of vapor cells using anodic bonding and deep silicon etching. This cell fabrication method is simple and effective in avoiding weak bonding strengths caused by alkali metal volatilization during anodic bonding under high temperatures.Finally, the vapor cell D2 line was characterized via optical-absorption resonance. According to the results,the proposed method is suitable for CSAC.
基金National Science Foundation(NSF)(6937070)Defense Threat Reduction Agency(DTRA)(HDTRA1-13-1-0001)+1 种基金National Natural Science Foundation of China(NSFC)(61475129)Natural Science Foundation of Fujian Province,China(2017J06016)
文摘On-chip spectroscopic sensors have attracted increasing attention for portable and field-deployable chemical detection applications. So far, these sensors largely rely on benchtop tunable lasers for spectroscopic interrogation. Large footprint and mechanical fragility of the sources, however, preclude compact sensing system integration. In this paper, we address the challenge through demonstrating, for the first time to our knowledge, a supercontinuum source integrated on-chip spectroscopic sensor, where we leverage nonlinear Ge_(22)Sb_(18)Se_(60) chalcogenide glass waveguides as a unified platform for both broadband supercontinuum generation and chemical detection. A home-built, palm-sized femtosecond laser centering at 1560 nm wavelength was used as the pumping source. Sensing capability of the system was validated through quantifying the optical absorption of chloroform solutions at 1695 nm. This work represents an important step towards realizing a miniaturized spectroscopic sensing system based on photonic chips.
