Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the a...Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications.展开更多
A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity d...A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity decay. Analytic expressions for the dipole force, the friction force, the optical potentials and the friction coefficient are obtained. Then the numerical and graphical methods are used to investigate the friction coefficient with the controlling parameters. It is shown that the friction coefficient is strongly dependent on the controlling parameters. The cooling rate can increase by one order of magnitude more than that of a two-level atomic system. The reason can be given using the dressed states and the Sisyphus cooling mechanism, which would stimulate further experimental investigations.展开更多
We study the features of electromagnetically induced transparency（EIT） in a single Λ-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser.Our calculations sho...We study the features of electromagnetically induced transparency（EIT） in a single Λ-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser.Our calculations show that three transparency windows appear when the pump strength is large enough.This can be explained by the residual pump in the cavity mostly resulting in energy splitting.The level ｜3 is split into four slightly different energy levels,and interference takes place between the excitation pathways.Furthermore,it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning 2,and that the reflection profile is very sensitive to the cavity field detuning △c.展开更多
CHIN A and Africa＇s top leaders have already logged an impressive number of air miles visiting each other in 2013. President Xi Jinping visited Tanzania,South Africa and the Republic of the Congo in March and Vice Pr...CHIN A and Africa＇s top leaders have already logged an impressive number of air miles visiting each other in 2013. President Xi Jinping visited Tanzania,South Africa and the Republic of the Congo in March and Vice Premier Wang Yang traveled to Zimbabwe and Ethiopia in May.In July,Nigerian President Goodluck Jonathan flew to China for a state visit,and Kenyan President Uhuru Kenyatta paid a six-day visit to China in August.In September,Zhang Dejiang,Chairman of the Standing Committee of the 12th National People＇s Congress（NPC）, China＇s parliament,will make his way to Nigeria and Kenya. The frequent exchanges between the new leadership of China and Africa are indicative of the growing trust between the two sides.展开更多
The loss of a high-finesse Fabry-Perot cavity was measured using frequency scan and cavity ring-down techniques.Different transverse modes were examined by sweeping the frequency of the laser across the corresponding ...The loss of a high-finesse Fabry-Perot cavity was measured using frequency scan and cavity ring-down techniques.Different transverse modes were examined by sweeping the frequency of the laser across the corresponding resonances.In addition,cavity ring-down technique was used to measure the loss of the Fabry-Perot cavity and a simple model was employed to remove the influence of finite response time of the optical switch and the detection circuit.展开更多
Stylistic effect of metaphor. What platitude! One may immediately feel inclined to brush aside the topic. Don’t we all know ’A metaphor enables its user to convey his meaning with force and vividness’? Yes. Unfortu...Stylistic effect of metaphor. What platitude! One may immediately feel inclined to brush aside the topic. Don’t we all know ’A metaphor enables its user to convey his meaning with force and vividness’? Yes. Unfortunately, however, such an understanding is far from enough for a true critical awareness of metaphor’s stylistic finesse. A well-wrought metaphor is not merely an ’imported device’ for purely ornamental effect; it is, in Ezra Pound’s words, ’an intellectual and emotional complex.’ As a figurative mode of expression, metaphor is marked by its ’synthetic’ power,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
基金Project supported by National Key Research and Development Program of China (Grant No.2022YFA1603403)。
文摘Finesse is a critical parameter for describing the characteristics of an optical enhancement cavity(OEC). This paper first presents a review of finesse measurement techniques, including a comparative analysis of the advantages, disadvantages, and potential limitations of several main methods from both theoretical and practical perspectives. A variant of the existing method called the free spectral range(FSR) modulation method is proposed and compared with three other finesse measurement methods, i.e., the fast-switching cavity ring-down(CRD) method, the rapidly swept-frequency(SF) CRD method, and the ringing effect method. A high-power OEC platform with a high finesse of approximately 16000 is built and measured with the four methods. The performance of these methods is compared, and the results show that the FSR modulation method and the fast-switching CRD method are more suitable and accurate than the other two methods for high-finesse OEC measurements. The CRD method and the ringing effect method can be implemented in open loop using simple equipment and are easy to perform. Additionally, recommendations for selecting finesse measurement methods under different conditions are proposed, which benefit the development of OEC and its applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.10704031)the National Science Foundation for Fostering Talents in Basic Research of the National Natural Science Foundation of China(Grant No.J0630313)+1 种基金the Fundamental Research Fund for Physics and Mathematics of Lanzhou University,China(Grant No.Lzu05001)the Natural Science Foundation of Gansu Province,China(Grant No.3ZS061-A25-035)
文摘A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity decay. Analytic expressions for the dipole force, the friction force, the optical potentials and the friction coefficient are obtained. Then the numerical and graphical methods are used to investigate the friction coefficient with the controlling parameters. It is shown that the friction coefficient is strongly dependent on the controlling parameters. The cooling rate can increase by one order of magnitude more than that of a two-level atomic system. The reason can be given using the dressed states and the Sisyphus cooling mechanism, which would stimulate further experimental investigations.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11274148 and 10704031)the Basic Scientific Research Business Expenses of the Central University,China (Grant No. lzujbky-2010-75)the Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University,China
文摘We study the features of electromagnetically induced transparency（EIT） in a single Λ-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser.Our calculations show that three transparency windows appear when the pump strength is large enough.This can be explained by the residual pump in the cavity mostly resulting in energy splitting.The level ｜3 is split into four slightly different energy levels,and interference takes place between the excitation pathways.Furthermore,it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning 2,and that the reflection profile is very sensitive to the cavity field detuning △c.
文摘CHIN A and Africa＇s top leaders have already logged an impressive number of air miles visiting each other in 2013. President Xi Jinping visited Tanzania,South Africa and the Republic of the Congo in March and Vice Premier Wang Yang traveled to Zimbabwe and Ethiopia in May.In July,Nigerian President Goodluck Jonathan flew to China for a state visit,and Kenyan President Uhuru Kenyatta paid a six-day visit to China in August.In September,Zhang Dejiang,Chairman of the Standing Committee of the 12th National People＇s Congress（NPC）, China＇s parliament,will make his way to Nigeria and Kenya. The frequent exchanges between the new leadership of China and Africa are indicative of the growing trust between the two sides.
基金Supported by Bureau of Comprehensive Planning,Chinese Academy of Sciences
文摘The loss of a high-finesse Fabry-Perot cavity was measured using frequency scan and cavity ring-down techniques.Different transverse modes were examined by sweeping the frequency of the laser across the corresponding resonances.In addition,cavity ring-down technique was used to measure the loss of the Fabry-Perot cavity and a simple model was employed to remove the influence of finite response time of the optical switch and the detection circuit.
文摘Stylistic effect of metaphor. What platitude! One may immediately feel inclined to brush aside the topic. Don’t we all know ’A metaphor enables its user to convey his meaning with force and vividness’? Yes. Unfortunately, however, such an understanding is far from enough for a true critical awareness of metaphor’s stylistic finesse. A well-wrought metaphor is not merely an ’imported device’ for purely ornamental effect; it is, in Ezra Pound’s words, ’an intellectual and emotional complex.’ As a figurative mode of expression, metaphor is marked by its ’synthetic’ power,
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.
