共查询到20条相似文献,搜索用时 31 毫秒
1.
V. S. Gorelik A. D. Kudryavtzeva V. A. Orlovich M. V. Tareeva N. V. Tcherniega A. I. Vodchits 《Journal of Russian Laser Research》2011,32(3):277-286
We investigate stimulated scattering of light in globular photonic crystals infiltrated by water. Excitation of stimulated
scattering of light is realized using powerful ultrashort (70 ps) laser pulses with an energy of 35 mJ and a frequency repetition
of 15 Hz. We use the second-harmonic generation (532 nm) of the master oscillator and amplifier with a wavelength of 1064 nm.
The photonic crystals under study are artificial opals filled by water or ethanol. We characterize the sample structures employing
an electronic microscope along with the fiber-optics reflectance-spectroscopy technique. Photonic crystals have a stop band
near the spectral positions of the exciting line (532 nm) and the first satellite of stimulated Raman scattering of light
in water (649 nm). We observe a substantial reduction of the threshold of stimulated Raman scattering of light in water-infiltrated
artificial-opal matrices in comparison with that of pure water. Such a reduction is explained as the result of a sharp increase
in the photonic density of states near the stop-band edges of investigated photonic crystals. The reduction in the threshold
of stimulated Raman scattering of light in water-infiltrated artificial-opal matrices opens up the opportunity to observe
stimulated Raman scattering in numerous water media, including water solutions, biological and medical samples, heavy waters,
and others. 相似文献
2.
V. S. Gorelik A. D. Kudryavtseva N. V. Tcherniega A. I. Vodchits 《Journal of Russian Laser Research》2007,28(6):567-575
The characteristics of stimulated globular scattering such as the frequency shift, threshold, and conversion efficiency are
studied in photonic crystals (synthetic opal matrices and opal nanocomposites) at different temperatures. The results are
compared with the study of stimulated Raman scattering in calcite single crystals. In both cases, a decrease in temperature
from +20° C to −196° C resulted in an increase in the energy of stimulated scattering energy and its redistribution into the
higher-order components. 相似文献
3.
We investigate for the first time, to our knowledge, the enhancement of the stimulated Raman scattering in slow-light silicon-on-insulator (SOI) photonic crystal line defect waveguides. By applying the Bloch-Floquet formalism to the guided modes in a planar photonic crystal, we develop a formalism that relates the intensity of the downshifted Stokes signal to the pump intensity and the modal group velocities. The formalism is then applied to two prospective schemes for enhanced stimulated Raman generation in slow-light photonic crystal waveguides. The results demonstrate a maximum factor of 104(66,000) enhancement with respect to SOI channel waveguides. 相似文献
4.
Compression of chirped free femtosecond pulses in hollow-core photonic bandgap fibers is investigated numerically. The results show that intrapulse stimulated Raman scattering can improve the quality of the compressed pulse. Positive third-order dispersion is the main limitation on the compression of the femtosecond pulse. However, the combined effect of the intrapulse stimulated Raman scattering and the negative third-order dispersion can form still shorter pulses than is possible with intrapulse stimulated Raman scattering alone. We also investigate the influence of width and peak power of input pulse on pulse compression. 相似文献
5.
为解决传统拉曼放大器增益系数低和增益不平坦的问题,采用级联光子晶体光纤的设计方法设计了一种增益平坦的拉曼光纤放大器.采用受激拉曼散射效应的稳态分析理论,分析了光子晶体光纤的拉曼增益谱,建立了拉曼放大器的理论模型.通过解耦合方程,推导了实现增益平坦的约束条件,发现光纤长度和泵浦功率是影响拉曼光纤放大器增益平坦度的两个参数.仿真结果表明,在1 508~1 544 nm的带宽范围内,实现了一个增益高达21 dB,增益平坦度仅为0.14 dB的光子晶体拉曼光纤放大器,可在光纤通信系统应用中发挥重要作用. 相似文献
6.
N. V. Tcherniega A. D. Kudryavtseva 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2009,3(4):513-518
The results of the experimental study of nonlinear-optical effects in photonic crystals, i.e., synthetic opal matrices and nanocomposites (matrices with voids filled with different nonlinear liquids) are presented. The following nonlinear-optical effects were observed under experimental conditions: the photonic flame effect (PFE), stimulated globular scattering (SGS), and stimulated Raman scattering (SRS). The dependence of these effects on the excitation conditions, nanocomposite refractive index contrast, and sample temperature was studied. PFE lines were detected in the Stokes spectral region. SGS spectra at the temperature of liquid nitrogen were studied. 相似文献
7.
We study the effect of stimulated Raman scattering on four-wave mixing sidebands generated by pumping in the normal dispersion regime of a photonic crystal fiber. Q-switch nanosecond pulses at 1064 nm are used to generate signal and idler wavelengths by degenerate four-wave mixing. These three waves generate their own Raman Stokes orders, leading to a broadband supercontinuum. 相似文献
8.
We present what is to our knowledge the first complete measurement of the dependence of Raman gain on chromatic dispersion, fully revealing the influence of parametric four-wave mixing on stimulated Raman scattering. In particular, a threefold increase of the Raman gain is observed under phase-matching conditions, in excellent agreement with theoretical predictions. Our experiments, which were performed in a photonic crystal fiber, demonstrate that these unique fibers can be exploited to boost the performances of fiber Raman amplifiers. 相似文献
9.
Vladimir S. Gorelik Anna D. Kudryavtseva Nikolay V. Tcherniega 《Journal of Russian Laser Research》2008,29(6):551-557
The results of experimental studies of stimulated Raman scattering of light (SRS) excited in three-dimensional photonic crystals
— synthetic opal matrices infiltrated with Raman active media are presented. It is shown that the SRS threshold in such structures
decreases with respect to the SRS threshold in Raman active bulk materials. The influence of the photonic-band structure of
the active materials used on the SRS properties is estimated. 相似文献
10.
11.
We report on the generation of pure rotational stimulated Raman scattering in a hydrogen gas hollow-core photonic crystal fiber. Using the special properties of this low-loss fiber, the normally dominant vibrational stimulated Raman scattering is suppressed, permitting pure conversion to the rotational Stokes frequency in a single-pass configuration pumped by a microchip laser. We report 92% quantum conversion efficiency (40 nJ pulses in 2.9 m fiber) and threshold energies (3 nJ in 35 m) more than 1 x 10(6) times lower than previously reported. The control of the output spectral components by varying only the pump polarization is also shown. The results point to a new generation of highly engineerable and compact laser sources. 相似文献
12.
V. S. Gorelik A. D. Kudryavtseva N. V. Tcherniega A. I. Vodchits V. A. Orlovich 《Journal of Russian Laser Research》2013,34(1):50-58
We study stimulated Raman scattering (SRS) in liquids (water and ethanol) embedded into photonic crystals (artificial opals) under excitation with 60 ps laser pulses at 532 nm. We observe a substantial decrease of the SRS threshold when the focused laser beam excites the crystals near their surface. The spatial distance between the beam center and the surface of the crystals is close to their nanoscale structure. The decrease in the SRS threshold is due to a substantial increase in the photonic-state density near the edges of the photonic crystal stop zones and the so-called Mie resonances in active media near the nanosized globules. This leads to a considerable increase in the local-electric-field intensity, causing the SRS threshold reduction. Such a method of reducing the SRS threshold opens up a way of creating new efficient laser sources based on photonic crystals and their use for different applications in nanotechnologies. 相似文献
13.
White-light supercontinuum generation with 60-ps pump pulses in a photonic crystal fiber 总被引:17,自引:0,他引:17
Coen S Chau AH Leonhardt R Harvey JD Knight JC Wadsworth WJ Russell PS 《Optics letters》2001,26(17):1356-1358
The generation of a spatially single-mode white-light supercontinuum has been observed in a photonic crystal fiber pumped with 60-ps pulses of subkilowatt peak power. The spectral broadening is identified as being due to the combined action of stimulated Raman scattering and parametric four-wave-mixing generation, with a negligible contribution from the self-phase modulation of the pump pulses. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate that ultrafast femtosecond pulses are not needed for efficient supercontinuum generation in photonic crystal fibers. 相似文献
14.
Spatial, temporal, and spectral characteristics of stimulated light scattering (SS) in water were investigated in both nano- and picosecond ranges under different experimental conditions and compared with the analogous characteristics of stimulated light scattering in other liquids. Stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) of light were studied. The results obtained provide useful information on the structure of water, its purity, and additions, which can result in its pollution. The excitation conditions of stimulated light scattering (SS) in one spatial mode and with maximum pulse energy conversion were determined. It is shown that stimulated light scattering can be successfully applied to control water quality (and it can be done very fast) as well as for information processing, i.e., the amplitude–phase structure of complex light fields can be registered in water as a dynamic hologram and reconstructed in real time. 相似文献
15.
Using ultrahigh-Q toroid microcavities on a chip, we demonstrate a monolithic microcavity Raman laser. Cavity photon lifetimes in excess of 100 ns combined with mode volumes typically of less than 1000 (microm)3 significantly reduce the threshold for stimulated Raman scattering. In conjunction with the high ideality of a tapered optical fiber coupling junction, stimulated Raman lasing is observed at an ultralow threshold (as low as 74 microW of fiber-launched power at 1550 nm) with high efficiency (up to 45% at the critical coupling point) in good agreement with theoretical modeling. Equally important, the wafer-scale nature of these devices should permit integration with other photonic, mechanical, or electrical functionality on a chip. 相似文献
16.
Stokes amplification regimes in quasi-cw pumped hydrogen-filled hollow-core photonic crystal fiber 总被引:1,自引:0,他引:1
Pure rotational stimulated Raman scattering spectra containing nine strong spectral components were generated from a approximately 11 m long hollow-core photonic crystal fiber filled with hydrogen and pumped with nanosecond pulses having energies around 100-300 nJ. Observation of both transient and steady-state scattering threshold behavior is reported. Passage from the transient to the steady state is observed with a pulse as long as 14 ns. Convenient analytical expressions for energy and power threshold are deduced for the present configuration. 相似文献
17.
V. S. Gorelik L. I. Zlobina P. P. Sverbil’ A. B. Fadyushin A. V. Chervyakov 《Journal of Russian Laser Research》2005,26(3):211-227
The optical properties of three-dimensional photonic crystals associated with the form of reflection spectra from their surface (appearance of a forbidden gap in the energy spectrum) and with the specific features of Raman scattering are analyzed. Idealized models of the energy band structure of photonic crystals are studied. Expressions for the group velocity of photons with energy close to the forbidden gap are derived. Experimental results on the Raman scattering in photonic crystals based on artificial opal as well as in fused silica are discussed. Bands due to quantum-size effects (presence of nanoclusters in fused silica and nanoglobules forming the lattice of globular photonic crystals) were manifested in the spectra of inelastic light scattering. It is proposed to use photonic crystals for the creation of sensitive sensors of organic and inorganic substances using modern Raman techniques. 相似文献
18.
The switching dynamics of ultrashort pulse under the effects of intrapulse stimulated Raman scattering (ISRS) and intermodal
dispersion in a nonlinear two-core photonic crystal fiber coupler is investigated theoretically. A general model is proposed
that includes all the significant linear and nonlinear effects. In particular, we demonstrate with numerical examples how
the interaction of ISRS and intermodal dispersion affects the pulse shape. 相似文献
19.