Journals >Chinese Optics Letters
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2017
Volume: 15 Issue 9
25 Article(s)
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ADVANCES IN METASURFACES
Laser speckle imaging and wavelet analysis of cerebral blood flow associated with the opening of the blood–brain barrier by sound
O. Semyachkina-Glushkovskaya, A. Abdurashitov, A. Pavlov, A. Shirokov, N. Navolokin, O. Pavlova, A. Gekalyuk, M. Ulanova, N. Shushunova, A. Bodrova, E. Saranceva, A. Khorovodov, I. Agranovich, V. Fedorova, M. Sagatova, A. E. Shareef, C. Zhang, D. Zhu, and V. Tuchin
The cerebral blood flow (CBF) alterations related to sound-induced opening of the blood–brain barrier (BBB) in adult mice are studied using laser speckle contrast imaging (LSCI) and wavelet analysis of vascular physiology. The results clearly show that the opening of the BBB is accompanied by the changes of venous but not microvessel circulation in the brain. The elevation of the BBB permeability is associated with the decrease of venous CBF and the increase of its complexity. These data suggest that the cerebral veins rather than microvessels are sensitive components of the CBF related to the opening BBB.The cerebral blood flow (CBF) alterations related to sound-induced opening of the blood–brain barrier (BBB) in adult mice are studied using laser speckle contrast imaging (LSCI) and wavelet analysis of vascular physiology. The results clearly show that the opening of the BBB is accompanied by the changes of venous but not microvessel circulation in the brain. The elevation of the BBB permeability is associated with the decrease of venous CBF and the increase of its complexity. These data suggest that the cerebral veins rather than microvessels are sensitive components of the CBF related to the opening BBB..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090002 (2017)
Imaging the structure and organization of mouse cerebellum and brain stem with second harmonic generation microscopy
Xiuli Liu, Daozhu Hua, Ling Fu, and Shaoqun Zeng
To visualize the structure and organization of the brain is a fundamental requirement in the research of neuroscience. Here, combining with two-photon excitation fluorescence microscopy and transgenetic mouse GAD67, we demonstrate a custom-built second harmonic generation (SHG) microscope to discriminate brain layers and sub regions in the cerebellum and brain stem slices with cellular resolution. In particular, the cell densities of neurons in different brain layers are extracted due to the cell soma appearing as dark shadow on an SHG image. Further, the axon initial segments of the Purkinje cell are easily recognized without labeling, which would be useful for guiding micropipettes for electrophysiology.To visualize the structure and organization of the brain is a fundamental requirement in the research of neuroscience. Here, combining with two-photon excitation fluorescence microscopy and transgenetic mouse GAD67, we demonstrate a custom-built second harmonic generation (SHG) microscope to discriminate brain layers and sub regions in the cerebellum and brain stem slices with cellular resolution. In particular, the cell densities of neurons in different brain layers are extracted due to the cell soma appearing as dark shadow on an SHG image. Further, the axon initial segments of the Purkinje cell are easily recognized without labeling, which would be useful for guiding micropipettes for electrophysiology..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090003 (2017)
High-speed 3D imaging based on structured illumination and electrically tunable lens
Dongping Wang, Yunlong Meng, Dihan Chen, Yeung Yam, and Shih-Chi Chen
In this Letter, we present a high-speed volumetric imaging system based on structured illumination and an electrically tunable lens (ETL), where the ETL performs fast axial scanning at hundreds of Hz. In the system, a digital micro-mirror device (DMD) is utilized to rapidly generate structured images at the focal plane in synchronization with the axial scanning unit. The scanning characteristics of the ETL are investigated theoretically and experimentally. Imaging experiments on pollen samples are performed to verify the optical cross-sectioning and fast axial scanning capabilities. The results show that our system can perform fast axial scanning and three-dimensional (3D) imaging when paired with a high-speed camera, presenting an economic solution for advanced biological imaging applications.In this Letter, we present a high-speed volumetric imaging system based on structured illumination and an electrically tunable lens (ETL), where the ETL performs fast axial scanning at hundreds of Hz. In the system, a digital micro-mirror device (DMD) is utilized to rapidly generate structured images at the focal plane in synchronization with the axial scanning unit. The scanning characteristics of the ETL are investigated theoretically and experimentally. Imaging experiments on pollen samples are performed to verify the optical cross-sectioning and fast axial scanning capabilities. The results show that our system can perform fast axial scanning and three-dimensional (3D) imaging when paired with a high-speed camera, presenting an economic solution for advanced biological imaging applications..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090004 (2017)
Optical coherence tomography imaging of cranial meninges post brain injury in vivo
Woo June Choi, and Ruikang K. Wang
We report a new application of optical coherence tomography (OCT) to investigate the cranial meninges in an animal model of brain injury in vivo. The injury is induced in a mouse due to skull thinning, in which the repeated and excessive drilling exerts mechanical stress on the mouse brain through the skull, resulting in acute and mild brain injury. Transcranial OCT imaging reveals an interesting virtual space between the cranial meningeal layers post skull thinning, which is gradually closed within hours. The finding suggests a promise of OCT as an effective tool to monitor the mechanical trauma in the small animal model of brain injury.We report a new application of optical coherence tomography (OCT) to investigate the cranial meninges in an animal model of brain injury in vivo . The injury is induced in a mouse due to skull thinning, in which the repeated and excessive drilling exerts mechanical stress on the mouse brain through the skull, resulting in acute and mild brain injury. Transcranial OCT imaging reveals an interesting virtual space between the cranial meningeal layers post skull thinning, which is gradually closed within hours. The finding suggests a promise of OCT as an effective tool to monitor the mechanical trauma in the small animal model of brain injury..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090005 (2017)
Feasibility study of phase-sensitive imaging based on multiple reference optical coherence tomography
Roshan Dsouza, Hrebesh Subhash, Kai Neuhaus, Paul M. McNamara, Josh Hogan, Carol Wilson, and Martin J. Leahy
Multiple reference optical coherence tomography (MR-OCT) is a recently developed, low-cost and compact time-domain OCT solution for primary care and consumer level applications. A combination of a voice coil actuator and a partial mirror (PM) extends the scan range for imaging depths of approximately 1 mm in biological samples. Our previous research on MR-OCT is based only on intensity information obtained from the depth-resolved interference signal. In this Letter, we extract the phase information from the MR-OCT signal and, hence, provide an additional contrast modality. The phase sensitivity of the system is measured to be approximately 0.2 and 1.5 rad for the first and twelfth orders of reflection when using a mirror as the sample. This Letter describes first results of phase-sensitive data measured on a phantom obtained with MR-OCT. Data from a chick embryo chorioallantoic membrane (CAM) is used to demonstrate the feasibility of MR-OCT for in vivo phase-sensitive imaging.Multiple reference optical coherence tomography (MR-OCT) is a recently developed, low-cost and compact time-domain OCT solution for primary care and consumer level applications. A combination of a voice coil actuator and a partial mirror (PM) extends the scan range for imaging depths of approximately 1 mm in biological samples. Our previous research on MR-OCT is based only on intensity information obtained from the depth-resolved interference signal. In this Letter, we extract the phase information from the MR-OCT signal and, hence, provide an additional contrast modality. The phase sensitivity of the system is measured to be approximately 0.2 and 1.5 rad for the first and twelfth orders of reflection when using a mirror as the sample. This Letter describes first results of phase-sensitive data measured on a phantom obtained with MR-OCT. Data from a chick embryo chorioallantoic membrane (CAM) is used to demonstrate the feasibility of MR-OCT for in vivo phase-sensitive imaging..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090007 (2017)
Combination of OCT and Raman spectroscopy for improved characterization of atherosclerotic plaque depositions
Kokila Egodage, Christian Matthäus, Sebastian Dochow, Iwan W. Schie, Carmen Härdtner, Ingo Hilgendorf, and Jürgen Popp
The biochemical composition of atherosclerotic plaques is closely related to plaque stability and, therefore, to the associated risk of plaque evolution and rupture. Combinations of current imaging modalities, such as optical coherence tomography (OCT) with spectroscopic methods, therefore offer the possibility of concurrently obtaining morphological as well as chemical information. Raman spectroscopy is one of the most promising techniques that can be combined with intravascular imaging modalities. A microscopy setup merging both techniques has been applied to characterize plaque depositions of a human aorta affected by the disease. Calcified depositions were clearly identified and subsequently confirmed by histopathology.The biochemical composition of atherosclerotic plaques is closely related to plaque stability and, therefore, to the associated risk of plaque evolution and rupture. Combinations of current imaging modalities, such as optical coherence tomography (OCT) with spectroscopic methods, therefore offer the possibility of concurrently obtaining morphological as well as chemical information. Raman spectroscopy is one of the most promising techniques that can be combined with intravascular imaging modalities. A microscopy setup merging both techniques has been applied to characterize plaque depositions of a human aorta affected by the disease. Calcified depositions were clearly identified and subsequently confirmed by histopathology..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090008 (2017)
DIGITAL HOLOGRAPHY AND 3D IMAGING
Research Articles
Simultaneous electromagnetically induced transparency and absorption in thermal atomic medium
Shangqing Liang, Yunfei Xu, and Qiang Lin
A three-level lambda system driven by multicolor control, pump, and probe fields is investigated. The pump and probe fields are derived from the same laser with opposite propagating directions. Due to the Doppler effect, the zero group-velocity atoms face bichromatic fields, while other atoms face trichromatic fields. The atomic medium shows distinct characteristics and exhibits simultaneous electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) at two frequencies. EIT and EIA peaks have a fixed relationship with frequency, which is determined by the Doppler shifts.A three-level lambda system driven by multicolor control, pump, and probe fields is investigated. The pump and probe fields are derived from the same laser with opposite propagating directions. Due to the Doppler effect, the zero group-velocity atoms face bichromatic fields, while other atoms face trichromatic fields. The atomic medium shows distinct characteristics and exhibits simultaneous electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) at two frequencies. EIT and EIA peaks have a fixed relationship with frequency, which is determined by the Doppler shifts..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090201 (2017)
MULTIPHOTON PROCESSES
Research Articles
Boundary evaluation and error correction on pseudo-random spread spectrum photon counting system
Shanshan Shen, Qian Chen, Weiji He, and Yuqiang Wang
The Cramer–Rao lower bound on range error is modeled for pseudo-random ranging systems using Geiger-mode avalanche photodiodes. The theoretical results are shown to agree with the Monte Carlo simulation, satisfying boundary evaluations. Experimental tests prove that range errors caused by the fluctuation of the number of photon counts in the laser echo pulse leads to the range drift of the time point spread function. The function relationship between the range error and the photon counting ratio is determined by using numerical fitting. Range errors due to a different echo energy is calibrated so that the corrected range root mean square error is improved to 1 cm.The Cramer–Rao lower bound on range error is modeled for pseudo-random ranging systems using Geiger-mode avalanche photodiodes. The theoretical results are shown to agree with the Monte Carlo simulation, satisfying boundary evaluations. Experimental tests prove that range errors caused by the fluctuation of the number of photon counts in the laser echo pulse leads to the range drift of the time point spread function. The function relationship between the range error and the photon counting ratio is determined by using numerical fitting. Range errors due to a different echo energy is calibrated so that the corrected range root mean square error is improved to 1 cm..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090101 (2017)
OPTICAL METHODS FOR LIFE SCIENCES
Research Articles
Q-switched fiber laser using carbon platinum saturable absorber on side-polished fiber
H. Ahmad, H. Hassan, R. Safaei, K. Thambiratnam, and I. S. Amiri
A 1550 nm Q-switched fiber laser using a carbon platinum saturable absorber deposited on side-polished fiber (SPF) is proposed and demonstrated. The SPF is approximately 2 mm with a polarization-dependent loss (PDL) of 0.4 dB and an insertion loss of 2.5 dB. A stable Q-switched output spectrum is obtained at 1559.34 nm with a peak power of ～6 mW, a pulse width of 1.02 μs, pulse energy of 5.8 nJ, average output power of 0.76 mW, and a repetition rate of 131.6 kHz taken at a pump power of 230.0 mW. A signal-to-noise ratio of 49.62 dB indicates that the Q-switched pulse is highly stable.A 1550 nm
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090601 (2017)
High temperature-sensitivity sensor based on long period fiber grating inscribed with femtosecond laser transversal-scanning method
Xinran Dong, Zheng Xie, Yuxin Song, Kai Yin, Dongkai Chu, and Ji’an Duan
We propose a high temperature-sensitive long period fiber grating (LPFG) sensor fabricated by using the femtosecond laser transversal-scanning method. The femtosecond pulses scan over the whole fiber core and some part of the cladding region; the modified regions are more extended. It is found that the LPFG-I fabricated by the transversal-scanning method shows higher temperature sensitivity and better temperature uniformity than that of LPFG-II written by the femtosecond laser point-by-point method. The LPFG-I with a temperature sensitivity of 75.96 pm/°C in the range of 25°C–400°C is measured. Moreover, in the range from 400°C to 800°C, a higher temperature sensitivity of 148.64 pm/°C and good linearity of 0.99 are achieved, while the temperature sensitivity of LPFG-II is only 95.55 pm/°C. LPFG-I exhibits better temperature characteristics, which, to the best of our knowledge, has the highest sensitivity in silica fiber temperature sensors.We propose a high temperature-sensitive long period fiber grating (LPFG) sensor fabricated by using the femtosecond laser transversal-scanning method. The femtosecond pulses scan over the whole fiber core and some part of the cladding region; the modified regions are more extended. It is found that the LPFG-I fabricated by the transversal-scanning method shows higher temperature sensitivity and better temperature uniformity than that of LPFG-II written by the femtosecond laser point-by-point method. The LPFG-I with a temperature sensitivity of 75.96 pm/°C in the range of 25°C–400°C is measured. Moreover, in the range from 400°C to 800°C, a higher temperature sensitivity of 148.64 pm/°C and good linearity of 0.99 are achieved, while the temperature sensitivity of LPFG-II is only 95.55 pm/°C. LPFG-I exhibits better temperature characteristics, which, to the best of our knowledge, has the highest sensitivity in silica fiber temperature sensors..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090602 (2017)
Frequency-doubled triangular shape lightwave generation with a flexible modulation index
Jing Li, Ze Hao, Li Pei, Tigang Ning, and Jingjing Zheng
An approach for full duty frequency-doubled triangle shape lightwave generation is proposed and demonstrated. It requires a dual-parallel Mach–Zehnder modulator (DP-MZM) driven by a sinusoidal signal. A stop band filter is coupled to filter out two undesired sidebands. By tuning the bias voltage applied to the DP-MZM, the output optical intensity with a full duty cycle triangle shape profile can be obtained. It is found that the required modulation index is no longer a fixed one. It can vary within a range, without degrading the target waveform. The principle is analyzed by theory and evaluated by simulation. A proof-of-concept experiment is also conducted. Good agreements between theoretical prediction and experimental results have been found. This approach might be attractive due to the feature of a variable modulation index, which insures simple operation in practice.An approach for full duty frequency-doubled triangle shape lightwave generation is proposed and demonstrated. It requires a dual-parallel Mach–Zehnder modulator (DP-MZM) driven by a sinusoidal signal. A stop band filter is coupled to filter out two undesired sidebands. By tuning the bias voltage applied to the DP-MZM, the output optical intensity with a full duty cycle triangle shape profile can be obtained. It is found that the required modulation index is no longer a fixed one. It can vary within a range, without degrading the target waveform. The principle is analyzed by theory and evaluated by simulation. A proof-of-concept experiment is also conducted. Good agreements between theoretical prediction and experimental results have been found. This approach might be attractive due to the feature of a variable modulation index, which insures simple operation in practice..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 090603 (2017)
Research Articles
Instrumentation, measurement, and metrology
LS-SVM-based surface roughness prediction model for a reflective fiber optic sensor
Li Fu, Jun Luo, Weimin Chen, Xueming Liu, Dong Zhou, Zhongling Zhang, and Sheng Li
Reflective fiber optic sensors have advantages for surface roughness measurements of some special workpieces, but their measuring precision and efficiency need to be improved further. A least-squares support vector machine (LS-SVM)-based surface roughness prediction model is proposed to estimate the surface roughness, Ra, and the coupled simulated annealing (CSA) and standard simplex (SS) methods are combined for the parameter optimization of the mode. Experiments are conducted to test the performance of the proposed model, and the results show that the range of average relative errors is 4.232%–2.5709%. In comparison with the existing models, the LS-SVM-based model has the best performance in prediction precision, stability, and timesaving.Reflective fiber optic sensors have advantages for surface roughness measurements of some special workpieces, but their measuring precision and efficiency need to be improved further. A least-squares support vector machine (LS-SVM)-based surface roughness prediction model is proposed to estimate the surface roughness, Ra, and the coupled simulated annealing (CSA) and standard simplex (SS) methods are combined for the parameter optimization of the mode. Experiments are conducted to test the performance of the proposed model, and the results show that the range of average relative errors is 4.232 % – 2.5709 %
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 091201 (2017)
Lasers and Laser Optics
Comparison of high-energy multi-pass Ti:sapphire amplifiers with a different Ti-dopant concentration
Zebiao Gan, Xiaoyan Liang, Lianghong Yu, Jiaqi Hong, Ming Xu, Ying Hang, and Ruxin Li
We experimentally compare the output abilities of lightly and heavily doped Ti:Sapphire (Ti:S) amplifiers with diameters as large as 150 mm. Although a lightly doped Ti:S is more favorable to overcome parasitic lasing (PL) and transverse amplified spontaneous emission (TASE), the self-phase-modulation (SPM) effect becomes more pronounced when a longer crystal is used. Recompression of the amplified, stretched pulses can be seriously affected by the SPM effect. We then propose a temporal multi-pulse pump scheme to suppress PL and TASE in a thin, heavily doped Ti:S crystal. This novel temporal multi-pulse pump technique can find potential applications in 10 PW chirped-pulse amplification laser systems.We experimentally compare the output abilities of lightly and heavily doped Ti:Sapphire (Ti:S) amplifiers with diameters as large as 150 mm. Although a lightly doped Ti:S is more favorable to overcome parasitic lasing (PL) and transverse amplified spontaneous emission (TASE), the self-phase-modulation (SPM) effect becomes more pronounced when a longer crystal is used. Recompression of the amplified, stretched pulses can be seriously affected by the SPM effect. We then propose a temporal multi-pulse pump scheme to suppress PL and TASE in a thin, heavily doped Ti:S crystal. This novel temporal multi-pulse pump technique can find potential applications in 10 PW chirped-pulse amplification laser systems..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 091401 (2017)
13.5 mJ polarized 2.09 μm fiber-bulk holmium laser and its application to a mid-infrared
Encai Ji, Mingming Nie, and Qiang Liu
A high pulse repetition frequency (PRF), high energy Ho:YAG laser directly pumped by a Tm-doped fiber laser and its application to a mid-infrared ZnGeP2 (ZGP) optical parametric oscillator (OPO) is demonstrated. The maximum polarized 2.09 μm laser pulse energy is 13.46 mJ at a PRF of 1 kHz. The corresponding peak power reaches 504 kW. In a double-resonant ZGP-OPO, a maximum mid-infrared laser pulse energy of 1.25 mJ, corresponding to a peak power of 79 kW, is accomplished at a PRF of 3 kHz. The nonlinear conversion efficiency reaches 41.7%. The nonlinear slope efficiency reaches 53.3%.A high pulse repetition frequency (PRF), high energy Ho:YAG laser directly pumped by a Tm-doped fiber laser and its application to a mid-infrared ZnGeP 2
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 091402 (2017)
Narrow-spectral-span spectral beam combining with a nonparallel double-grating structure
Quan Zhou, Changhe Zhou, Na Yu, Chunlong Wei, Wei Jia, and Yancong Lu
We propose a nonparallel double-grating structure in a spectral-beam combining technique, where two gratings are placed nonparallel satisfying the Littrow mount in the focal region of the convergent lens. The most attractive advantage of this approach is that it will compress the spectral span into half of its original spectrum, which means the number of combined elements can be doubled in the gain range of diode lasers. Experimental results demonstrate that the CW output power of the combined beam is 30.9 W with a spectral span of 7.0 nm, compared with its original spectrum span of 13.6 nm, and the spectral beam combining efficiency is 70.5%. In consideration that a single grating could have a high efficiency of >97% in a bandwidth of over ten nanometers, the efficiency loss of the grating pair should be less than 6%, which is acceptable for most applications, so this method of using double gratings should be highly interesting for practical applications when a nearly doubled number of diode lasers could be combined into one single laser compared with the previous single-grating methods.We propose a nonparallel double-grating structure in a spectral-beam combining technique, where two gratings are placed nonparallel satisfying the Littrow mount in the focal region of the convergent lens. The most attractive advantage of this approach is that it will compress the spectral span into half of its original spectrum, which means the number of combined elements can be doubled in the gain range of diode lasers. Experimental results demonstrate that the CW output power of the combined beam is 30.9 W with a spectral span of 7.0 nm, compared with its original spectrum span of 13.6 nm, and the spectral beam combining efficiency is 70.5%. In consideration that a single grating could have a high efficiency of > 97 %
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 091403 (2017)
Nonlinear Optics
Multiple-mode phase matching in a single-crystal lithium niobate waveguide for three-wave mixing
Chuanyi Zhu, Yuping Chen, Guangzhen Li, Licheng Ge, Bing Zhu, Mengning Hu, and Xianfeng Chen
Developing natural “free space” frequency upconversion is essential for photonic integrated circuits. In a single-crystal lithium niobate thin film planar waveguide of less than 1 μm thickness, we achieve type I and type II mode phase-matching conditions simultaneously for this thin film planar waveguide. Finally, by employing the mode phase matching of e+e→e with d33 at 1018 nm, we successfully achieve a green second-harmonic wave output with the conversion efficiency of 0.12%/(W·cm2), which verifies one of our simulation results. The rich mode phase matching for three-wave mixing in a thin film planar waveguide may provide a potential application in on-chip frequency upconversions for integrated photonic and quantum devices.Developing natural “free space” frequency upconversion is essential for photonic integrated circuits. In a single-crystal lithium niobate thin film planar waveguide of less than 1 μm thickness, we achieve type I and type II mode phase-matching conditions simultaneously for this thin film planar waveguide. Finally, by employing the mode phase matching of e + e → e d 33 0.12 % / ( W · cm 2 )
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 091901 (2017)
Injection-seeded single frequency 2.05 μm output by ring cavity optical parametric oscillator
Xiaobing Xie, Xiaolei Zhu, Shiguang Li, Xiuhua Ma, Xiao Chen, Yanguang Sun, Huaguo Zang, Jiqiao Liu, and Weibiao Chen
An injection-seeded single-resonant optical parametric oscillator (SROPO) with single frequency nanosecond pulsed 2.05 μm wavelength output is presented. Based on two potassium titanyl phosphate crystals and pumped by a 1064 nm single frequency laser pulse, injection seeding is performed successfully by using the ramp-hold-fire technique in a ring cavity with a bow-tie configuration. The SROPO provides 2.65 mJ single frequency signal pulse output with a 17.6 ns pulse duration at a 20 Hz repetition rate. A near-diffraction-limited beam is achieved with a beam quality factor M2 of about 1.2. The spectrum linewidth of the signal pulse is around 26.4 MHz, which is almost the Fourier-transform-limited value.An injection-seeded single-resonant optical parametric oscillator (SROPO) with single frequency nanosecond pulsed 2.05 μm wavelength output is presented. Based on two potassium titanyl phosphate crystals and pumped by a 1064 nm single frequency laser pulse, injection seeding is performed successfully by using the ramp-hold-fire technique in a ring cavity with a bow-tie configuration. The SROPO provides 2.65 mJ single frequency signal pulse output with a 17.6 ns pulse duration at a 20 Hz repetition rate. A near-diffraction-limited beam is achieved with a beam quality factor M 2
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 091902 (2017)
Optical devices
Detection of low-concentration EGFR with a highly sensitive optofluidic resonator
Jianfeng Shang, Hailang Dai, Yun Zou, and Xianfeng Chen
A hollow-core metal-cladding waveguide (HCMW) optofluidic resonator that works based on a free-space coupling technique is designed. An HCMW can excite ultra-high-order modes (UOMs) at the coupled angle, which can be used as an optofluidic resonator to detect alterations of the epidermal growth factor receptor (EGFR) concentration. Theoretical analysis shows that the UOMs excited in the HCMW have a highly sensitive response to the refractive index (RI) variation of the guiding layer. An EGFR solution with a 0.2 ng/mL alteration is detected, and the RI variation caused by the concentration alteration is about 2.5×10 3.A hollow-core metal-cladding waveguide (HCMW) optofluidic resonator that works based on a free-space coupling technique is designed. An HCMW can excite ultra-high-order modes (UOMs) at the coupled angle, which can be used as an optofluidic resonator to detect alterations of the epidermal growth factor receptor (EGFR) concentration. Theoretical analysis shows that the UOMs excited in the HCMW have a highly sensitive response to the refractive index (RI) variation of the guiding layer. An EGFR solution with a 0.2 ng/mL alteration is detected, and the RI variation caused by the concentration alteration is about 2.5 × 10 3
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 092301 (2017)
Other Areas of Optics
Thermal-stable mixed-cation lead halide perovskite solar cells | Editors' Pick
Shuai Gu, Pengchen Zhu, Renxing Lin, Mingyao Tang, Shining Zhu, and Jia Zhu
As perovskite solar cells show tremendous potential for widespread applications, we find that adding inorganic thermal-stable cesium ions into MAPbI3 results in significantly improves thermal stability. For un-encapsulated perovskite devices, the energy conversion efficiency maintains about 75% of its original value (over 15%) in the MA0.85Cs0.05PbI3 device under 80 min of heating at 140°C in a dry atmosphere (RH≤30%). With significantly improved thermal stability achieved by a convenient process, it is expected that this type of mixed-cation perovskites can further facilitate large scale applications.As perovskite solar cells show tremendous potential for widespread applications, we find that adding inorganic thermal-stable cesium ions into MAPbI 3 MA 0.85 Cs 0.05 PbI 3 RH ≤ 30 %
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 093501 (2017)
Optical tug-of-war tweezers: shaping light for dynamic control of bacterial cells-corrigendum
Joshua Lamstein, Anna Bezryadina, Daryl Preece, Joseph C. Chen, and Zhigang Chen
The authors would like to apologize for an error in the paper Chinese Optics Letters vol. 15, no. 3, page 030010. On page 030010-3, the caption for Figs. 5 (a)–(c) should read “2 μm silica” (not 3 μm polystyrene).The authors would like to apologize for an error in the paper Chinese Optics Letters vol. 15, no. 3, page 030010. On page 030010-3, the caption for Figs. 5 (a)–(c) should read “2 μm silica” (not 3 μm polystyrene)..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 093502 (2017)
Quantum optics
Effect of unbalanced and common losses in quantum photonic integrated circuits
Ming Li, Changling Zou, Guangcan Guo, and Xifeng Ren
Loss is inevitable for the optical system due to the absorption of materials, scattering caused by the defects, and surface roughness. In quantum optical circuits, the loss can not only reduce the intensity of the signal, but also affect the performance of quantum operations. In this work, we divide losses into unbalanced linear losses and shared common losses, and provide a detailed analysis on how loss affects the integrated linear optical quantum gates. It is found that the orthogonality of eigenmodes and the unitary phase relation of the coupled waveguide modes are destroyed by the loss. As a result, the fidelity of single- and two-qubit operations decreases significantly as the shared loss becomes comparable to the coupling strength. Our results are important for the investigation of large-scale photonic integrated quantum information processes.Loss is inevitable for the optical system due to the absorption of materials, scattering caused by the defects, and surface roughness. In quantum optical circuits, the loss can not only reduce the intensity of the signal, but also affect the performance of quantum operations. In this work, we divide losses into unbalanced linear losses and shared common losses, and provide a detailed analysis on how loss affects the integrated linear optical quantum gates. It is found that the orthogonality of eigenmodes and the unitary phase relation of the coupled waveguide modes are destroyed by the loss. As a result, the fidelity of single- and two-qubit operations decreases significantly as the shared loss becomes comparable to the coupling strength. Our results are important for the investigation of large-scale photonic integrated quantum information processes..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 092701 (2017)
Tunable interaction-free all-optical switching in a five-level atom-cavity system
Tiantian Liu, Gongwei Lin, Fengxue Zhou, Li Deng, Shangqing Gong, and Yueping Niu
A scheme is proposed for tunable all-optical switching based on the double-dark states in a five-level atom-cavity system. In the scheme, the output signal light of the reflection and the transmission channels can be switched on or off by manipulating the control field. When the control light is coupled to the atom-cavity system, the input signal light is reflected by the cavity. Thus, there is no direct coupling between the control light and the signal light. Furthermore, the position of the double-dark states can be changed by adjusting the coherent field, and, thus, the switching in our scheme is tunable. By presenting the numerical calculations of the switching efficiency, we show that this type of the interaction-free all-optical switching can be realized with high switching efficiency.A scheme is proposed for tunable all-optical switching based on the double-dark states in a five-level atom-cavity system. In the scheme, the output signal light of the reflection and the transmission channels can be switched on or off by manipulating the control field. When the control light is coupled to the atom-cavity system, the input signal light is reflected by the cavity. Thus, there is no direct coupling between the control light and the signal light. Furthermore, the position of the double-dark states can be changed by adjusting the coherent field, and, thus, the switching in our scheme is tunable. By presenting the numerical calculations of the switching efficiency, we show that this type of the interaction-free all-optical switching can be realized with high switching efficiency..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 092702 (2017)
Generation of temporal multimode squeezed states of femtosecond pulse light
Chihua Zhou, Changchun Zhang, Hongbo Liu, Kui Liu, Hengxin Sun, and Jiangrui Gao
Nonclassical optical frequency combs play essential roles in quantum computation in the continuous variable regime. In this work, we generate multimode nonclassical frequency comb states using a degenerate type-I synchronously pumped optical parametric oscillator and directly observe the squeezing of the leading five temporal modes of femtosecond pulsed light. The overlapping spectra of these modes mean that the temporal modes are suitable for use in real-world quantum information applications.Nonclassical optical frequency combs play essential roles in quantum computation in the continuous variable regime. In this work, we generate multimode nonclassical frequency comb states using a degenerate type-I synchronously pumped optical parametric oscillator and directly observe the squeezing of the leading five temporal modes of femtosecond pulsed light. The overlapping spectra of these modes mean that the temporal modes are suitable for use in real-world quantum information applications..
Chinese Optics Letters
- Publication Date: Sep. 10, 2017
- Vol. 15, Issue 9, 092703 (2017)
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