Расчет эффективности удвоения частоты излучения субтерагерцового гиротрона за счет решеточной нелинейности в монокристаллической пластине InP

In this work, we calculated the efficiency of second harmonic generation for sub-THz gyrotron radiation in a single-crystal InP plate embedded in a conical metal waveguide. For the values of the losses at the doubled frequency (depending on the degree of purity of the InP crystal), the dimensions of the wafer are revealed that provide the optimal effective frequency conversion. Thus, the conversion factor f –>2f can reach 5 W/kW^2 when pumped at a frequency of 263 GHz and a loss of alpha_2f = 0.1 cm^-1. The possibility of a noticeable increase in the efficiency of frequency doubling with fine tuning of the phase matching due to the selection of the size of the submicron gap between the InP plate and the plates of the metal waveguide is shown. The results obtained can be used to solve applied problems in the field of dynamic nuclear polarization spectroscopy and nuclear magnetic resonance studies.

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Frequency Doubling and Polarization Coupling Using Birefringence-Phase-Matching and Quasi-Phase-Matching Simultaneously in Single Optical Superlattice

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.529.81 ◽

2012 ◽

Vol 529 ◽

pp. 81-86 ◽

Cited By ~ 1

Author(s):

Dong Huang ◽

Yu Qing Wang ◽

Jian Yi Luo

Keyword(s):

Electric Field ◽

Harmonic Generation ◽

Frequency Conversion ◽

Second Harmonic ◽

Frequency Doubling ◽

Phase Matching ◽

Fundamental Wave ◽

Optical Superlattice ◽

Quasi Phase Matching ◽

Dc Electric Field

We proposed a method to simultaneously implement birefringence-phase-matching (BPM) and quasi-phase-matching (QPM) second harmonic generation (SHG) and polarization coupling including six mismatches of wave vectors, in general case, in an optical superlattice (OSL). And the numerical simulations of SHG and polarization coupling in the OSL are carried out. The results indicate that unlike those of SHG processes with only one second harmonic (SH) reported, when one e-polarized fundamental pump is injected into the OSL, another o-polarized fundamental wave, an o-polarized and an e-polarized SHs can be simultaneously generated. The magnitudes of the o-polarized fundamental wave and SHs can be manipulated by an external dc electric field, which is useful when frequency conversion and signal tuning are required simultaneously.

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Growth and properties of KBe2BO3F2 crystal

Journal of Materials Research ◽

10.1557/jmr.2003.0345 ◽

2003 ◽

Vol 18 (10) ◽

pp. 2478-2485 ◽

Cited By ~ 13

Author(s):

Jiyang Wang ◽

Chenqian Zhang ◽

Yaogang Liu ◽

Jianxiu Zhang ◽

Xiaobo Hu ◽

...

Keyword(s):

Harmonic Generation ◽

Conversion Efficiency ◽

Second Harmonic ◽

Frequency Doubling ◽

Molar Ratio ◽

Phase Matching ◽

Spontaneous Nucleation ◽

Force Microscopy ◽

Atomic Force ◽

The Ideal

Single crystals of KBeBO3F (KBBF) up to 2 mm in thickness were grown by using a spontaneous nucleation method. The flux was composed of KF and B2O3, and the optimal ratio for growing KBBF single crystal thicker than 1 mm is suggested to be (1.0–1.5):(5.0):(0.7–1.2) (KBBF:KF:B2O3) in molar ratio. The ideal morphology of.KBBF is two sets of tabular facets and a set of rhombic facets. Surface morphology.was characterized both by optical microscopy and atomic force microscopy. Transmission spectra showed that high transmission was maintained up to 170 nm. Based on refractive index measurements, phase matching curves for types I and II were determined. Using a prism coupling method, the effective fourth harmonic generation for an Nd:YAB laser was realized in an 0.6-mm-thick KBBF sample. The output energy of the 266-nm beam was 0.282 mJ, and the conversion efficiency was 11.8%. A 183.6-nm laser over 1 mW was obtained from a Ti:sapphire second harmonic generation beam in an 0.8-mm KBBF sample. The conversion efficiency reached 2.3%. A 179.4-nm laser was also observed from a 358.7-nm laser by directly frequency doubling. This is the shortest wavelength obtained through nonlinear optical processes in a solid-state laser.

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Widely Tunable Angular Non-Critical Phase-Matching Wavelengths from 0.72 to 1.42 μm Based on RE1xRE21−xCOB Mixed Crystals

Crystals ◽

10.3390/cryst10090744 ◽

2020 ◽

Vol 10 (9) ◽

pp. 744

Author(s):

Ranran Li ◽

Hongwei Qi ◽

Yanqing Liu ◽

Fapeng Yu ◽

Pingzhang Yu ◽

...

Keyword(s):

Rare Earth ◽

Frequency Conversion ◽

Second Harmonic ◽

Theoretical Calculations ◽

Mixed Crystals ◽

Phase Matching ◽

Rare Earth Ion ◽

Ti:Sapphire Lasers ◽

High Efficient ◽

Critical Phase

The angular non-critical phase-matching (A-NCPM) second-harmonic-generation (SHG) properties of RE1xRE21−xCOB (RE1, RE2 = Y, Gd, La, Tm, Sm, and Nd) type mixed crystals including NCPM wavelength and conversion efficiency were detailedly investigated. Theoretical calculations manifest that the A-NCPM SHG scope of these crystals is 0.72~1.42 µm, and in experiments, the A-NCPM SHG waveband of 0.72~1.25 µm has been realized, by changing the ratio of the rare-earth elements RE1 and RE2 in RE1xRE21−xCOB crystals. Comparing to the temperature-dependent A-NCPM SHG of 0.95~1.34 µm in LiB3O5 (LBO) crystal, the composition-dependent A-NCPM SHG of 0.72~0.95 µm in RE1xRE21−xCOB type crystals is unique and has special significance for the frequency conversion of Ti:Sapphire lasers. Relationships between the birefringence and radius of rare-earth ion RE3+ in RE1xRE21−xCOB mixed crystals were discussed. Aiming for the A-NCPM SHG of 0.72~1.42 µm, we supply a clear, completed, and optimized solution on how to select the compositions of RE1xRE21−xCOB mixed crystals. Under focusing light beam conditions, high efficient A-NCPM SHG for both OPO and Ti:sapphire lasers were realized experimentally by using long Y- and Z-cut RE1xRE21−xCOB crystal samples.

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Beam Control in an Intracavity Frequency-Doubling Semiconductor Disk Laser

Applied Sciences ◽

10.3390/app9081584 ◽

2019 ◽

Vol 9 (8) ◽

pp. 1584 ◽

Cited By ~ 1

Author(s):

Guanyu Hou ◽

Lijie Wang ◽

Jian Feng ◽

Andreas Popp ◽

Berthold Schmidt ◽

...

Keyword(s):

Second Harmonic ◽

Beam Quality ◽

Frequency Doubling ◽

Green Laser ◽

Beam Profile ◽

Fine Tuning ◽

Intracavity Frequency Doubling ◽

Disk Laser ◽

Intracavity Frequency ◽

Semiconductor Disk Laser

In this paper, we have demonstrated a 1.3 W green laser using a V-shaped intracavity frequency doubling 1036 nm semiconductor disk laser. The beam quality of the fundamental and second harmonic generation (SHG) laser is investigated. It has been found that the output lasers at the fundamental and SHG wavelength both suffer from reduced beam quality along with power scaling. The measured beam profile is elliptical under high power operation. In order to improve the SHG laser beam, an intracavity aperture is employed to control the mode characteristics of fundamental frequency light. By fine-tuning the aperture, a nearly circular beam profile with improving beam quality and brightness is realized.

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Second Harmonic Generation Properties of RbTiOPO4 Crystal

Materials Science Forum ◽

10.4028/www.scientific.net/msf.663-665.373 ◽

2010 ◽

Vol 663-665 ◽

pp. 373-376

Author(s):

Yong Guang Zhao ◽

Zheng Ping Wang ◽

Xun Sun ◽

Hao Hai Yu ◽

Lei Guo ◽

...

Keyword(s):

Second Harmonic Generation ◽

Harmonic Generation ◽

Nonlinear Optical ◽

Second Harmonic ◽

Frequency Doubling ◽

Damage Threshold ◽

Laser Damage Threshold ◽

Phase Matching ◽

Angular Acceptance ◽

Nonlinear Optical Coefficient

For RbTiOPO4 (RTP) crystal, the second harmonic generation (SHG) properties of 1064nm are discussed, including phase matching (PM) direction, effective nonlinear optical coefficient (deff), walk-off angle, and angular acceptance. For the frequency doubling of nano-second and pico-second Nd:YAG laser, the conversion efficiency of RTP crystal can reach 51 % and 57 %, respectively. The laser damage threshold of RTP crystal is measured.

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Phase-matched nonlinear second-harmonic generation in plasmonic metasurfaces

Nanophotonics ◽

10.1515/nanoph-2018-0181 ◽

2019 ◽

Vol 8 (4) ◽

pp. 607-612 ◽

Cited By ~ 3

Author(s):

S. Hamed Shams Mousavi ◽

Robert Lemasters ◽

Feng Wang ◽

Ali Eshaghian Dorche ◽

Hossein Taheri ◽

...

Keyword(s):

Second Harmonic Generation ◽

Harmonic Generation ◽

Frequency Conversion ◽

Second Harmonic ◽

Matching Condition ◽

Phase Matching ◽

Nonlinear Frequency ◽

Nonlinear Frequency Conversion ◽

Phase Matching Condition ◽

Plasmon Modes

AbstractThe phase matching between the propagating fundamental and nonlinearly generated waves plays an important role in the efficiency of the nonlinear frequency conversion in macroscopic crystals. However, in nanoscale samples, such as nanoplasmonic structures, the phase-matching condition is often ignored due to the sub-wavelength nature of the materials. Here, we first show that the phase matching of the lattice plasmon modes at the fundamental and second-harmonic frequencies in a plasmonic nanoantenna array can effectively enhance the surface-enhanced second-harmonic generation. Additionally, a significant enhancement of the second-harmonic generation is demonstrated using stationary band-edge lattice plasmon modes with zero phase.

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Answer to Comment on Noiseless amplification in cavitybased optical systems with an internal two-photon process. II. Self-frequency-doubling laser and second-harmonic generation, self-down-converting laser`

Journal of Modern Optics ◽

10.1080/095003497154012 ◽

1997 ◽

Vol 44 (3) ◽

pp. 653-654

Author(s):

A. Pregnolato ◽

L. Spinelli ◽

L. A. Lugiato ◽

I. E. Protsenko

Keyword(s):

Second Harmonic Generation ◽

Harmonic Generation ◽

Second Harmonic ◽

Frequency Doubling ◽

Optical Systems ◽

Two Photon ◽

Photon Process

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Study on the "Phase Hopping" AC-AC Frequency Conversion Method with Approximately Continuous Frequencies

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096513999200611161226 ◽

2020 ◽

Vol 13 (8) ◽

pp. 1217-1226

Author(s):

Zhengwang Xu ◽

Guozhuang Jiang ◽

Ke Kun ◽

Yuchun Yi

Keyword(s):

Output Voltage ◽

Frequency Conversion ◽

Frequency Control ◽

Actual Application ◽

Power Frequency ◽

Voltage Frequency ◽

The Law ◽

Large Cycle ◽

Selection Of ◽

Conversion Technology

Background: The output voltage frequency for the previously proposed "phase hopping" AC-AC frequency conversion technology is determined by the law that the number of output voltage cycles is reduced by one relative to the power frequency in a large cycle containing six jumps. According to the law, only a limited number of output frequencies, such as 37.5 Hz, 42.86 Hz and 45 Hz are found. Due to the large spacing between the output frequencies, the "phase hopping" frequency conversion technology is difficult to put into practical use. Methods: In this paper, the law of the output frequency control is generalized so that the number of output cycles in a large cycle is reduced by n relative to the power frequency. The analysis shows that the appropriate selection of large cycles, including the number of power frequency cycles and the value of n, can find more frequencies to be used. Reducing the interval between the output frequencies within 1Hz. Results: The analysis results were verified in simulation by MATLAB, and the harmonics and the feasibility of the actual application were analyzed. Conclusion: Finally, an experimental platform was built and an experimental analysis was carried out. The experimental results show that the theoretical and simulation analyses are correct.

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Evaluation of Optimal Vibrotactile Feedback for Force-Controlled Upper Limb Myoelectric Prostheses

Sensors ◽

10.3390/s19235209 ◽

2019 ◽

Vol 19 (23) ◽

pp. 5209 ◽

Cited By ~ 1

Author(s):

Andrea Gonzalez-Rodriguez ◽

Jose L. Ramon ◽

Vicente Morell ◽

Gabriel J. Garcia ◽

Jorge Pomares ◽

...

Keyword(s):

Real Time ◽

Upper Limb ◽

Closed Loop ◽

Fine Tuning ◽

Vibrotactile Feedback ◽

Loop Control ◽

Myoelectric Prostheses ◽

Amplitude Level ◽

Real Time Application ◽

Selection Of

The main goal of this study is to evaluate how to optimally select the best vibrotactile pattern to be used in a closed loop control of upper limb myoelectric prostheses as a feedback of the exerted force. To that end, we assessed both the selection of actuation patterns and the effects of the selection of frequency and amplitude parameters to discriminate between different feedback levels. A single vibrotactile actuator has been used to deliver the vibrations to subjects participating in the experiments. The results show no difference between pattern shapes in terms of feedback perception. Similarly, changes in amplitude level do not reflect significant improvement compared to changes in frequency. However, decreasing the number of feedback levels increases the accuracy of feedback perception and subject-specific variations are high for particular participants, showing that a fine-tuning of the parameters is necessary in a real-time application to upper limb prosthetics. In future works, the effects of training, location, and number of actuators will be assessed. This optimized selection will be tested in a real-time proportional myocontrol of a prosthetic hand.

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