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Other areas of optics|4 Article(s)
Generation of Full Band Millimeter-Wave White Noise Using Two Incoherent Optical Frequency Comb Mixing Base on Vernier Effect
Yimin Huang, Wenjie Liu, Ya Guo, Junbin Liu, Youwen Zhang, Yuehui Sun, Lianglun Cheng, and Yuncai Wang
A method that can generate ultra-wide and flat noise in the whole millimeter-wave band is proposed. Based the vernier effect, the frequency intervals and incoherent light widths of the main ruler and the subordinate ruler are designed by using two incoherent optical frequency combs with different frequency intervals. Simulation results show that the proposed method can generate ultra-wide band and flat full-band millimeter-wave white noise with a frequency range of 30-300 GHz. Experimentally, the amplified spontaneous emission noise is filtered out of two comb-shaped lights with a vernier frequency interval through a programmable filter, and two millimeter-wave white noises are achieved based on uni-traveling-carrier photodetector with two different band widths. The frequency ranges of the two white noises are 130-170 GHz and 280-380 GHz, and the corresponding flatness are ±2.25 dB and ±3.10 dB, which verifies the correctness of the proposed theory. A method that can generate ultra-wide and flat noise in the whole millimeter-wave band is proposed. Based the vernier effect, the frequency intervals and incoherent light widths of the main ruler and the subordinate ruler are designed by using two incoherent optical frequency combs with different frequency intervals. Simulation results show that the proposed method can generate ultra-wide band and flat full-band millimeter-wave white noise with a frequency range of 30-300 GHz. Experimentally, the amplified spontaneous emission noise is filtered out of two comb-shaped lights with a vernier frequency interval through a programmable filter, and two millimeter-wave white noises are achieved based on uni-traveling-carrier photodetector with two different band widths. The frequency ranges of the two white noises are 130-170 GHz and 280-380 GHz, and the corresponding flatness are ±2.25 dB and ±3.10 dB, which verifies the correctness of the proposed theory.
Acta Optica Sinica
- Publication Date: Jul. 10, 2022
- Vol. 42, Issue 13, 1335001 (2022)
Three-Dimensional Optical Tweezers Based on Fibonacci Zone Plate
Xinyu Zhang, Shubo Cheng, and Shaohua Tao
Fibonacci zone plate (FiZP), with properties of bi-foci in focal plane and self-reconstruction, can simultaneously trap particles positioned in two different planes and move particles freely in the focal plane. The structure and axial strength of FiZP are analyzed. The experimental platform is established by combination of liquid crystal spatial light modulator, inverted optical microscope and optical elements, and used to capture particles in three dimensions. Experiments show that the FiZP beam has three-dimensional optical acquisition characteristics, and can be used to build three-dimensional optical tweezers and achieve complex capture function. Fibonacci zone plate (FiZP), with properties of bi-foci in focal plane and self-reconstruction, can simultaneously trap particles positioned in two different planes and move particles freely in the focal plane. The structure and axial strength of FiZP are analyzed. The experimental platform is established by combination of liquid crystal spatial light modulator, inverted optical microscope and optical elements, and used to capture particles in three dimensions. Experiments show that the FiZP beam has three-dimensional optical acquisition characteristics, and can be used to build three-dimensional optical tweezers and achieve complex capture function.
Acta Optica Sinica
- Publication Date: Oct. 14, 2017
- Vol. 37, Issue 10, 1035001 (2017)
Study on Laser Trapping Rayleigh Particles Based on the Nanolens
Liu Zilong, and Zhang Bo
An idea that Rayleigh particles can be captured by replacing the geometry optical lens in the traditional optical tweezers with nano-lens is proposed. We calculate the diffraction field of a plane wave passed through the nano-lens by using the finite difference time domain (FDTD) method and the radiation force acted on the Rayleigh particles in the field based on the point dipole approximation method. The results show that, comparing to best results (focal spot close to the diffraction limit) of conventional optical tweezers, the trapping efficiency, stable trapping zone length and quality factor of the proposed tweezers can be greatly improved. Especially for the two capture zones on the both sides of nano-lens, the trapping efficiency and quality factor can be improved by 2 to 3 orders of magnitude, and also the force of trapped particles has a strong polarization dependence (unlike conventional optical tweezers), which can be used to achieve rotation operation of particles. An idea that Rayleigh particles can be captured by replacing the geometry optical lens in the traditional optical tweezers with nano-lens is proposed. We calculate the diffraction field of a plane wave passed through the nano-lens by using the finite difference time domain (FDTD) method and the radiation force acted on the Rayleigh particles in the field based on the point dipole approximation method. The results show that, comparing to best results (focal spot close to the diffraction limit) of conventional optical tweezers, the trapping efficiency, stable trapping zone length and quality factor of the proposed tweezers can be greatly improved. Especially for the two capture zones on the both sides of nano-lens, the trapping efficiency and quality factor can be improved by 2 to 3 orders of magnitude, and also the force of trapped particles has a strong polarization dependence (unlike conventional optical tweezers), which can be used to achieve rotation operation of particles.
Acta Optica Sinica
- Publication Date: Jan. 01, 2013
- Vol. 33, Issue 9, 935001 (2013)
Optic Fiber Oxygen Sensor based on Fluorescence Quenching
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By using Ru(phen) 3Br 2 as the indicator, a fiber optic oxygen sensor based on fluorescence quenching has been developed. The weak fluorescence signal has been detected by the lock in technology and the detection of the concentration of oxygen has been achieved by detecting the hysteresis of phase shift. The sensor has the detecting limit of 5×10 -6 and the detecting accuracy of 5×10 -7 , and its response time is less than 10 seconds. It also has good reproducibility, stability and strong ability of immunity from disturbance. By using Ru(phen) 3Br 2 as the indicator, a fiber optic oxygen sensor based on fluorescence quenching has been developed. The weak fluorescence signal has been detected by the lock in technology and the detection of the concentration of oxygen has been achieved by detecting the hysteresis of phase shift. The sensor has the detecting limit of 5×10 -6 and the detecting accuracy of 5×10 -7 , and its response time is less than 10 seconds. It also has good reproducibility, stability and strong ability of immunity from disturbance.
Acta Optica Sinica
- Publication Date: Jan. 01, 2003
- Vol. 23, Issue 3, 381 (2003)
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