We show that an optical transparency can be obtained by using only one single magneto-optical ring resonator. This effect is based on the splitting of counterclockwise and clockwise modes in the ring resonator. Within...We show that an optical transparency can be obtained by using only one single magneto-optical ring resonator. This effect is based on the splitting of counterclockwise and clockwise modes in the ring resonator. Within a proposed resonator-waveguide configuration the superposition between the two degeneracy broken modes produces a transparency window,which can be closed, open, and modified by tuning the applied magnetic field. This phenomenon is an analogue of Autler–Townes splitting, and the magnetic field is equivalent to the strong external pump field. We provide a theoretic analysis on the induced transparency, and numerically demonstrate the effect using full-wave simulation. Feasible implication of this effect and its potential applications are also discussed.展开更多
We experimentally demonstrate high optical quality factor silica microdisk resonators on a silicon chip with large wedge angles by reactive ion etching. For 2-μm-thick microresonators, we have achieved wedge angles o...We experimentally demonstrate high optical quality factor silica microdisk resonators on a silicon chip with large wedge angles by reactive ion etching. For 2-μm-thick microresonators, we have achieved wedge angles of 59°, 63°,70°, and 79° with optical quality factors of 2.4 × 10~7, 8.1 × 10~6, 5.9 × 10~6, and 7.4 × 10~6, respectively, from ~80 μm diameter microresonators in the 1550 nm wavelength band. Also, for 1-μm-thick microresonators, we have obtained an optical quality factor of 7.3 × 10~6 with a wedge angle of 74°.展开更多
In this paper, we design and fabricate a silicon integrated optical filter consisting of two cascaded micro-ring resonators and two straight waveguides. Two micro-heaters are fabricated on the top of two micro-rings r...In this paper, we design and fabricate a silicon integrated optical filter consisting of two cascaded micro-ring resonators and two straight waveguides. Two micro-heaters are fabricated on the top of two micro-rings respectively, which are employed to modulate the micro-rings to perform the function of a tunable optical filter by the thermo–optic effect. The static response test indicates that the extinction ratio and 3-d B bandwidth are 29.01 d B and 0.21 nm respectively, the dynamic response test indicates that the 10%–90% rise and 90%–10% fall time of the filter are 16 μs and 12 μs, respectively,which can meet the requirements of optical communication and information processing. Finally, the power consumption of the device is also characterized, and the total power consumption is about 9.43 m W/nm, which has been improved efficiently.展开更多
A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator (SO1) substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavel...A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator (SO1) substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavelength de- multiplexer is improved, such as 3 dB bandwidth and channel crosstalk. Based on the transform matrix theory, a four-channel wavelength de-multiplexer with average channel spacing 4.5±0.5 nm (3 dB bandwidth - 2 ± 0.5 nm) is demonstrated at telecommunication bands. For each channel, the extinction at the adjacent channel is below -39dB and the out-of-band rejection ratio is up to 40dB. The channel dropping loss is below 5dB in the five FSR spectral response periods (near 100 nm).展开更多
<div style="text-align:justify;"> We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber re...<div style="text-align:justify;"> We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber resonator. The optical phase-locked loop is established with a differential frequency-modulation module consists of a pair of acousto-optic modulators. The resonance-tracking loop is derived with the Pound-Drever-Hall technique for locking the heterodyne frequency of the OPLL on the frequency difference between adjacent resonance modes. A stable locking accuracy of about 7 × 10<sup>?9</sup> and a dynamic locking accuracy of about 5 × 10<sup>?8</sup> are achieved with the FSR of 8.155 MHz, indicating a bias stability of the resonator fiber optic gyro of about 0.1?/h with 10 Hz bandwidth. In addition, the thermal drift coefficient of the FSR is measured as 0.1 Hz/?C. This shows remarkable potential for realizing advanced optical measurement systems, such as the resonant fiber optic gyro, and so on. </div>展开更多
A novel Smith-Purcell (S-P) free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the charac...A novel Smith-Purcell (S-P) free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the characteristics of this device by theoretical analysis and particle-in-cell simulation method. Results indicate that tunable coherent S-P radiation with a high output peak power at millimeter wavelengths can be generated by adjusting the length of the grating period, or adjusting the voltage of the electron beam. The present scheme has the following advantages: the semi-elliptical resonator can reflect all radiation with the emission angle {? and random azimuthal angles, back onto the electron beam with same-phase and causes the electrons to be modulated, so the output power and efficiency are improved.展开更多
We report a low noise continuous-wave (CW) single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator (SRO) based on periodically poled lithium niobate (PPLN). The SRO was ...We report a low noise continuous-wave (CW) single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator (SRO) based on periodically poled lithium niobate (PPLN). The SRO was pumped by a CW single-frequency Nd:YVO4 laser at 1.06μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±l.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit (SNL) at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz.展开更多
We demonstrate a high-emciency mid-infrared picosecond optical parametric oscillator (OPO) based on MgO doped periodically poled lithium niobate (MgO:PPLN) with a laser diode array (LDA) pumped Innoslab amplifi...We demonstrate a high-emciency mid-infrared picosecond optical parametric oscillator (OPO) based on MgO doped periodically poled lithium niobate (MgO:PPLN) with a laser diode array (LDA) pumped Innoslab amplifier as the pumping source. Under a 16 W synchronously pumping power, 4.5 W of idler light at 2896nm is obtained. A tuning range of idler light from 2688nm to 3016nm is achieved, within which the highest optical-optical conversion ettlciency from pump power to OPO output is 35.1%. Moreover, a signal light of -500mW from 1644 to 1700nm with a repetition rate of 233.8 MHz is generated.展开更多
A symmetric plasmonie structure consisting of metal-insulator metal waveguide, groove studied, which supports double Fano resonances deriving from two different mechanisms and slot cavities is One of the Fano resonanc...A symmetric plasmonie structure consisting of metal-insulator metal waveguide, groove studied, which supports double Fano resonances deriving from two different mechanisms and slot cavities is One of the Fano resonances originates from the interference between the resonances of groove and slot cavities, and the other comes from the interference between slot cavities. The spectral line shapes and the peaks of the double Fano resonances can be modulated by changing the length of the slot cavities and the height of the groove. Furthermore, the wavelength of the resonance peak has a linear relationship with the length of the slot cavities. The proposed plasmonic nanosensor possesses a sensitivity of 800nm/RIU and a figure of merit of 3150, which may have important applications in switches, sensors, and nonlinear devices.展开更多
The magneto-optical Kerr effect of the HfO2/Co/HfO2/A1 multilayer structure is investigated in this work, and an ob- vious cavity enhancement of the Kerr response for the HfO2 semiconductor is found both theoretically...The magneto-optical Kerr effect of the HfO2/Co/HfO2/A1 multilayer structure is investigated in this work, and an ob- vious cavity enhancement of the Kerr response for the HfO2 semiconductor is found both theoretically and experimentally. Surprisingly, a maximum value of about -3 of the polar Kerr rotation for s-polarized incident light is observed in our experiment. We propose that this improvement on the Kerr effect can be attributed to the multiple reflection and optical interference in the cavity, which can also be proved by simulation using the finite element method.展开更多
Double resonance optical pumping spectroscopy has an outstanding advantage of high signal-to-noise ratio, thus having potential applications in precision measurement. With the counter propagated 780nm and 776nm laser ...Double resonance optical pumping spectroscopy has an outstanding advantage of high signal-to-noise ratio, thus having potential applications in precision measurement. With the counter propagated 780nm and 776nm laser beams acting on a rubidium vapor cell, the high resolution spectrum of 5S1/2 - 5P3/2 - 5D5/2 ladder-type transition of ST Rb atoms is obtained by monitoring the population of the 5S1/2 ground state. The dependence of the spectroscopy lineshape on the probe and coupling fields are comprehensively studied in theory and experiment. This research is helpful for measurement of fundamental physical constants by high resolution spectroscopy.展开更多
The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the n...The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.展开更多
To enhance the coherence and reliability of the double-ended tuning fork (DETF) resonator, a measurement system of resonator vibration is presented to check its dynamic characteristics. Laser Doppler techniques are ...To enhance the coherence and reliability of the double-ended tuning fork (DETF) resonator, a measurement system of resonator vibration is presented to check its dynamic characteristics. Laser Doppler techniques are utilized and the relation between DETF vibration velocity and output current of photodetector is obtained. Resonator vibration equation is also analyzed and its driving power only depends on the direct current bias voltage and the amplitude of alternative voltage. Furthermore, a special resonator driving control circuit based on measurement is designed. The amplitude and frequency of circuit is controlled by a computer so that highly stable and strong driving signal can be output. Experiments on driving and measuring double-ended tuning fork have been done, The frequency of driving signal is 8 kHz and the peak-to-peak value of driving voltage is 140 V. Experimental results indicate resonator can be drived stably by driving control circuit and dynamic characteristics of DETF may be measured in real time.展开更多
A model of an optical pumping nuclear magnetic resonance system rotating in a plane parallel to the quantization axis is presented. Different coordinate frames for nuclear spin polarization vector are introduced, and ...A model of an optical pumping nuclear magnetic resonance system rotating in a plane parallel to the quantization axis is presented. Different coordinate frames for nuclear spin polarization vector are introduced, and theoretical calculation is conducted to analyze this model. We demonstrate that when the optical pumping nuclear magnetic resonance system rotates in a plane parallel to the quantization axis, it will maintain a steady state with respect to the quantization axis which is independent of rotational speed and direction.展开更多
Sensors based on optical resonators often have their measurement range limited by their cavity linewidth,particularly in the measurement of time-varying signals.This paper introduces a method for optical frequency shi...Sensors based on optical resonators often have their measurement range limited by their cavity linewidth,particularly in the measurement of time-varying signals.This paper introduces a method for optical frequency shift detection using multiple harmonics to expand the dynamic range of sensors based on optical resonators.The proposed method expands the measurement range of optical frequency shift beyond the cavity linewidth while maintaining measurement accuracy.The theoretical derivation of this method is carried out based on the equation of motion for an optical resonator and the recursive relationship of the Bessel function.Experimental results show that the dynamic range is expanded to 4 times greater than the conventional first harmonic method while still maintaining accuracy.Furthermore,we present an objective analysis of the correlation between the expansion factor of the method and the linewidth and free spectrum of the optical resonator.展开更多
Integrated optical gyroscopes(IOGs)have been an efficient tool for numerous applications in various fields,including inertial navigation,flight control,and earthquake monitoring.Here,we review the progress of integrat...Integrated optical gyroscopes(IOGs)have been an efficient tool for numerous applications in various fields,including inertial navigation,flight control,and earthquake monitoring.Here,we review the progress of integrated optical gyroscopes based on two categories of integrated interferometric optical gyroscopes(IIOGs)and integrated resonant optical gyroscopes(IROGs).展开更多
The transverse construction of optical modes in the wiggler is calculated and the numerical simulations of the free-electron laser hole-coupled resonator are carried out.These 3D-simulations include optical amplitude ...The transverse construction of optical modes in the wiggler is calculated and the numerical simulations of the free-electron laser hole-coupled resonator are carried out.These 3D-simulations include optical amplitude distributions,modes evolvement of optical field and the influence of hole-radius on the distributing of modes.The nu-merical simulations confirm that the fraction of the even-order modes increase in the start-up stage and then decreases in the exponential gain stage.Moreover,it is found that the fundamental mode is dominant in the saturate stage.Based on this observa-tion,we estimate the optical output coupling by using the the fundamental mode.It is found that the numerical results and the first-order estimate are in good agreement for a range of the hole size.展开更多
We experimentally demonstrate 10-Gb/s format conversion from non-return-to-zero (NRZ) to alternatemark-inversion (AMI) using the linear filtering effect of silicon microring resonator. Our discussion and analysis ...We experimentally demonstrate 10-Gb/s format conversion from non-return-to-zero (NRZ) to alternatemark-inversion (AMI) using the linear filtering effect of silicon microring resonator. Our discussion and analysis in simulation further show that a 10-Gb/s AMI signal with good quality can be obtained by a resonator with a notch depth larger than 25 dB when the 3-dB bandwidth is 0.4 nm.展开更多
The physical properties of light fields at the subwavelength scale have emerged as extensively pursued objectives in nano-optics,photonics,and plasmonics.Here,we report that in the paraxial regime,the spectral density...The physical properties of light fields at the subwavelength scale have emerged as extensively pursued objectives in nano-optics,photonics,and plasmonics.Here,we report that in the paraxial regime,the spectral density and the spectral axial coherence(z-coherence)structures in a submicron range can be generated by employing a light beam with a suitably chosen spatial coherence state in a counter-propagating configuration,in an open-end cavity.It is established that while the spectral density forms an optical standing wave,the z-coherence state depends on the symmetry of the selected point pair and in particular,the phenomenon termed as periodical coherence switch is found.Our findings shed new light on the discussion of the role of spatial coherence in the photonic cavities,possibly inspiring further studies in the field of enhanced light-nanomaterials interactions by optical cavity.This provides a versatile framework for tailoring coherence in subwavelength space with promising applications in metrology and imaging.展开更多
We demonstrate a tunable optical parametric oscillator in a periodically poled congruently grown lithium tantalite whispering gallery mode resonator. The resonator is mechanically polished to millimeter size, and the ...We demonstrate a tunable optical parametric oscillator in a periodically poled congruently grown lithium tantalite whispering gallery mode resonator. The resonator is mechanically polished to millimeter size, and the quality factor is approximately 107 at 1064 nm. Our experiments show that this kind of resonator is capable of reaching a very low threshold and having a wide tuning range. Combined with its narrow resonant linewidth,it is potentially used as a compact, widely tunable, and narrow-linewidth infrared to mid-infrared laser source.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 12104227)the Scientific Research Foundation of Nanjing Institute of Technology (Grant No. YKJ202021)the Guizhou Provincial Science and Technology Projects (Grant No. ZK [2022] general 035)。
文摘We show that an optical transparency can be obtained by using only one single magneto-optical ring resonator. This effect is based on the splitting of counterclockwise and clockwise modes in the ring resonator. Within a proposed resonator-waveguide configuration the superposition between the two degeneracy broken modes produces a transparency window,which can be closed, open, and modified by tuning the applied magnetic field. This phenomenon is an analogue of Autler–Townes splitting, and the magnetic field is equivalent to the strong external pump field. We provide a theoretic analysis on the induced transparency, and numerically demonstrate the effect using full-wave simulation. Feasible implication of this effect and its potential applications are also discussed.
基金supported by the National Basic Research Program of China (Nos. 2012CB921804 and 2011CBA00205)the National Natural Science Foundation of China (Nos. 61435007 and 11321063)
文摘We experimentally demonstrate high optical quality factor silica microdisk resonators on a silicon chip with large wedge angles by reactive ion etching. For 2-μm-thick microresonators, we have achieved wedge angles of 59°, 63°,70°, and 79° with optical quality factors of 2.4 × 10~7, 8.1 × 10~6, 5.9 × 10~6, and 7.4 × 10~6, respectively, from ~80 μm diameter microresonators in the 1550 nm wavelength band. Also, for 1-μm-thick microresonators, we have obtained an optical quality factor of 7.3 × 10~6 with a wedge angle of 74°.
基金Project supported by the National Natural Science Foundation of China(Grant No.61405082)the Fundamental Research Funds for the Central Universities
文摘In this paper, we design and fabricate a silicon integrated optical filter consisting of two cascaded micro-ring resonators and two straight waveguides. Two micro-heaters are fabricated on the top of two micro-rings respectively, which are employed to modulate the micro-rings to perform the function of a tunable optical filter by the thermo–optic effect. The static response test indicates that the extinction ratio and 3-d B bandwidth are 29.01 d B and 0.21 nm respectively, the dynamic response test indicates that the 10%–90% rise and 90%–10% fall time of the filter are 16 μs and 12 μs, respectively,which can meet the requirements of optical communication and information processing. Finally, the power consumption of the device is also characterized, and the total power consumption is about 9.43 m W/nm, which has been improved efficiently.
基金Supported by the National High Technology Research and Development Program of China under Grant No 2015AA016904the National Key Research and Development Plan of China under Grant No 2016YFB0402502the National Natural Science Foundation of China under Grant No 61275065
文摘A four-channel integrated optical wavelength de-multiplexer is experimentally illustrated on a silicon-on-insulator (SO1) substrate. With the aid of cascaded micro-ring resonators, the whole performance of the wavelength de- multiplexer is improved, such as 3 dB bandwidth and channel crosstalk. Based on the transform matrix theory, a four-channel wavelength de-multiplexer with average channel spacing 4.5±0.5 nm (3 dB bandwidth - 2 ± 0.5 nm) is demonstrated at telecommunication bands. For each channel, the extinction at the adjacent channel is below -39dB and the out-of-band rejection ratio is up to 40dB. The channel dropping loss is below 5dB in the five FSR spectral response periods (near 100 nm).
文摘<div style="text-align:justify;"> We propose a novel scheme, based on digital-heterodyne optical phase-locked loop with whole-fiber circuit, to dynamically measure the free-spectral-range of a fiber resonator. The optical phase-locked loop is established with a differential frequency-modulation module consists of a pair of acousto-optic modulators. The resonance-tracking loop is derived with the Pound-Drever-Hall technique for locking the heterodyne frequency of the OPLL on the frequency difference between adjacent resonance modes. A stable locking accuracy of about 7 × 10<sup>?9</sup> and a dynamic locking accuracy of about 5 × 10<sup>?8</sup> are achieved with the FSR of 8.155 MHz, indicating a bias stability of the resonator fiber optic gyro of about 0.1?/h with 10 Hz bandwidth. In addition, the thermal drift coefficient of the FSR is measured as 0.1 Hz/?C. This shows remarkable potential for realizing advanced optical measurement systems, such as the resonant fiber optic gyro, and so on. </div>
基金Project supported by the National Natural Science Foundation of China (Grant No. 60871047)the Natural Science Foundation of Liaocheng University of China (Grant No. X0810018)
文摘A novel Smith-Purcell (S-P) free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the characteristics of this device by theoretical analysis and particle-in-cell simulation method. Results indicate that tunable coherent S-P radiation with a high output peak power at millimeter wavelengths can be generated by adjusting the length of the grating period, or adjusting the voltage of the electron beam. The present scheme has the following advantages: the semi-elliptical resonator can reflect all radiation with the emission angle {? and random azimuthal angles, back onto the electron beam with same-phase and causes the electrons to be modulated, so the output power and efficiency are improved.
基金supported by the National Natural Science Foundation of China(Grant No.60878003)the Science Fund for Excellent Research Team of the National Natural Science Foundation of China(Grant No.60821004)the National Basic Research Program of China(Grant No.2010CB923101)
文摘We report a low noise continuous-wave (CW) single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator (SRO) based on periodically poled lithium niobate (PPLN). The SRO was pumped by a CW single-frequency Nd:YVO4 laser at 1.06μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±l.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit (SNL) at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61275142,61308042,and 51321091the National Key Scientific Instrument and Equipment Development Project under Grant No 2011YQ030127the China Postdoctoral Science Foundation under Grant No 2014T70633
文摘We demonstrate a high-emciency mid-infrared picosecond optical parametric oscillator (OPO) based on MgO doped periodically poled lithium niobate (MgO:PPLN) with a laser diode array (LDA) pumped Innoslab amplifier as the pumping source. Under a 16 W synchronously pumping power, 4.5 W of idler light at 2896nm is obtained. A tuning range of idler light from 2688nm to 3016nm is achieved, within which the highest optical-optical conversion ettlciency from pump power to OPO output is 35.1%. Moreover, a signal light of -500mW from 1644 to 1700nm with a repetition rate of 233.8 MHz is generated.
基金Supported by the Ministry of Science and Technology of China under Grant No 2016YFA0301300the National Natural Science Foundation of China under Grant Nos 11374041 and 11574035the State Key Laboratory of Information Photonics and Optical Communications
文摘A symmetric plasmonie structure consisting of metal-insulator metal waveguide, groove studied, which supports double Fano resonances deriving from two different mechanisms and slot cavities is One of the Fano resonances originates from the interference between the resonances of groove and slot cavities, and the other comes from the interference between slot cavities. The spectral line shapes and the peaks of the double Fano resonances can be modulated by changing the length of the slot cavities and the height of the groove. Furthermore, the wavelength of the resonance peak has a linear relationship with the length of the slot cavities. The proposed plasmonic nanosensor possesses a sensitivity of 800nm/RIU and a figure of merit of 3150, which may have important applications in switches, sensors, and nonlinear devices.
基金supported by the National Key Project of Fundamental Research of China(Grant Nos.2012CB932304 and 2010CB923404)the National Natural Science Foundation of China(Grant Nos.50971070 and U1232210)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The magneto-optical Kerr effect of the HfO2/Co/HfO2/A1 multilayer structure is investigated in this work, and an ob- vious cavity enhancement of the Kerr response for the HfO2 semiconductor is found both theoretically and experimentally. Surprisingly, a maximum value of about -3 of the polar Kerr rotation for s-polarized incident light is observed in our experiment. We propose that this improvement on the Kerr effect can be attributed to the multiple reflection and optical interference in the cavity, which can also be proved by simulation using the finite element method.
基金Supported by the National Key R&D Program of China under Grant No 2017YFA0304203the National Natural Science Foundation of China under Grant Nos 61575116,61705122,61728502,91736209 and 11434007+2 种基金the Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China under Grant No IRT13076the Program for Sanjin Scholars of Shanxi Province,the Applied Basic Research Project of Shanxi Province under Grant No 201701D221004the Fund for Shanxi ‘1331 Project’ Key Subjects Construction
文摘Double resonance optical pumping spectroscopy has an outstanding advantage of high signal-to-noise ratio, thus having potential applications in precision measurement. With the counter propagated 780nm and 776nm laser beams acting on a rubidium vapor cell, the high resolution spectrum of 5S1/2 - 5P3/2 - 5D5/2 ladder-type transition of ST Rb atoms is obtained by monitoring the population of the 5S1/2 ground state. The dependence of the spectroscopy lineshape on the probe and coupling fields are comprehensively studied in theory and experiment. This research is helpful for measurement of fundamental physical constants by high resolution spectroscopy.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274302,11474276 and 11674240
文摘The third-order nonlinear optical properties of water-soluble Cu Se nanocrystals are studied in the near infrared range of 700-980 nm using a femtosecond pulsed laser by the Z-scan technique. It is observed that the nonlinear optical response of Cu Se nanocrystals is sensitively dependent on the excitation wavelength and exhibits the enhanced nonlinearity compared with other selenides such as ZnSe and CdSe. The W-shaped Z-scan trace, a mixture of the reversed saturated absorption and saturated absorption, is observed near the plasmon resonance band of Cu Se nanocrystals, which is attributed to the state-filling of free carriers generated by copper vacancies (self-doping effect) of Cu Se nanocrystals as well as the hot carrier thermal effect upon intense femtosecond laser excitation. The large nonlinear optical response and tunable plasmonic band make Cu Se nanocrystals promising materials for applications in ultra-fast all-optical switching devices as well as nonlinear nanosensors.
基金This project is supported by National Natural Science Foundation of China (No.50275108).
文摘To enhance the coherence and reliability of the double-ended tuning fork (DETF) resonator, a measurement system of resonator vibration is presented to check its dynamic characteristics. Laser Doppler techniques are utilized and the relation between DETF vibration velocity and output current of photodetector is obtained. Resonator vibration equation is also analyzed and its driving power only depends on the direct current bias voltage and the amplitude of alternative voltage. Furthermore, a special resonator driving control circuit based on measurement is designed. The amplitude and frequency of circuit is controlled by a computer so that highly stable and strong driving signal can be output. Experiments on driving and measuring double-ended tuning fork have been done, The frequency of driving signal is 8 kHz and the peak-to-peak value of driving voltage is 140 V. Experimental results indicate resonator can be drived stably by driving control circuit and dynamic characteristics of DETF may be measured in real time.
基金Project supported by the National Natural Science Foundation of China(Grant No.61475192)
文摘A model of an optical pumping nuclear magnetic resonance system rotating in a plane parallel to the quantization axis is presented. Different coordinate frames for nuclear spin polarization vector are introduced, and theoretical calculation is conducted to analyze this model. We demonstrate that when the optical pumping nuclear magnetic resonance system rotates in a plane parallel to the quantization axis, it will maintain a steady state with respect to the quantization axis which is independent of rotational speed and direction.
基金supported by the National Natural Science Foundation of China(NSFC)(No.52305621)Foundation Research Project of Shanxi Province(No.202203021212156)Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement(No.201905D121001002)。
文摘Sensors based on optical resonators often have their measurement range limited by their cavity linewidth,particularly in the measurement of time-varying signals.This paper introduces a method for optical frequency shift detection using multiple harmonics to expand the dynamic range of sensors based on optical resonators.The proposed method expands the measurement range of optical frequency shift beyond the cavity linewidth while maintaining measurement accuracy.The theoretical derivation of this method is carried out based on the equation of motion for an optical resonator and the recursive relationship of the Bessel function.Experimental results show that the dynamic range is expanded to 4 times greater than the conventional first harmonic method while still maintaining accuracy.Furthermore,we present an objective analysis of the correlation between the expansion factor of the method and the linewidth and free spectrum of the optical resonator.
文摘Integrated optical gyroscopes(IOGs)have been an efficient tool for numerous applications in various fields,including inertial navigation,flight control,and earthquake monitoring.Here,we review the progress of integrated optical gyroscopes based on two categories of integrated interferometric optical gyroscopes(IIOGs)and integrated resonant optical gyroscopes(IROGs).
文摘The transverse construction of optical modes in the wiggler is calculated and the numerical simulations of the free-electron laser hole-coupled resonator are carried out.These 3D-simulations include optical amplitude distributions,modes evolvement of optical field and the influence of hole-radius on the distributing of modes.The nu-merical simulations confirm that the fraction of the even-order modes increase in the start-up stage and then decreases in the exponential gain stage.Moreover,it is found that the fundamental mode is dominant in the saturate stage.Based on this observa-tion,we estimate the optical output coupling by using the the fundamental mode.It is found that the numerical results and the first-order estimate are in good agreement for a range of the hole size.
基金supported by the National Natural Science Foundation of China(No.60777040)the National"863"Project of China(No.2006AA01Z255)+1 种基金Shanghai Rising Star Program PhaseⅡ(No.07QH14008)the Fok Ying Tung Fund(No.101067)
文摘We experimentally demonstrate 10-Gb/s format conversion from non-return-to-zero (NRZ) to alternatemark-inversion (AMI) using the linear filtering effect of silicon microring resonator. Our discussion and analysis in simulation further show that a 10-Gb/s AMI signal with good quality can be obtained by a resonator with a notch depth larger than 25 dB when the 3-dB bandwidth is 0.4 nm.
基金supported by the National Natural Science Foundation of China(Grant Nos.11874321,and 12174338)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(Grant No.20204BCJ22012)the UM for Copper Fellowship support。
文摘The physical properties of light fields at the subwavelength scale have emerged as extensively pursued objectives in nano-optics,photonics,and plasmonics.Here,we report that in the paraxial regime,the spectral density and the spectral axial coherence(z-coherence)structures in a submicron range can be generated by employing a light beam with a suitably chosen spatial coherence state in a counter-propagating configuration,in an open-end cavity.It is established that while the spectral density forms an optical standing wave,the z-coherence state depends on the symmetry of the selected point pair and in particular,the phenomenon termed as periodical coherence switch is found.Our findings shed new light on the discussion of the role of spatial coherence in the photonic cavities,possibly inspiring further studies in the field of enhanced light-nanomaterials interactions by optical cavity.This provides a versatile framework for tailoring coherence in subwavelength space with promising applications in metrology and imaging.
基金supported by the International Science and Technology Cooperation Program of China (ISTCP) (No.2014DFT50230)the National Key Scientific Instrument and Equipment Development Project (No.2011YQ030127)
文摘We demonstrate a tunable optical parametric oscillator in a periodically poled congruently grown lithium tantalite whispering gallery mode resonator. The resonator is mechanically polished to millimeter size, and the quality factor is approximately 107 at 1064 nm. Our experiments show that this kind of resonator is capable of reaching a very low threshold and having a wide tuning range. Combined with its narrow resonant linewidth,it is potentially used as a compact, widely tunable, and narrow-linewidth infrared to mid-infrared laser source.