共查询到20条相似文献,搜索用时 62 毫秒
1.
V. A. Lisinetskii D. N. Bus’ko R. V. Chulkov A. S. Grabchikov P. A. Apanasevich V. A. Orlovich 《Journal of Applied Spectroscopy》2008,75(2):300-307
We have studied the conditions resulting in maximum lowering of the excitation threshold for pulsed stimulated Raman (SRS)
lasers. It has been shown theoretically that in order to achieve the lowest possible values of laser radiation pulse energy
needed to excite lasing in SRS lasers, we need high reflection of the cavity mirrors and low losses at the wavelength of the
1st Stokes component, high reflection of the output mirror at the wavelength of the pump radiation, and also matching of the
confocal parameters for the exciting laser radiation and the cavity with each other and with the length of the Raman-active
medium. The experimentally achieved excitation threshold for an SRS laser based on a barium nitrate crystal was 6 μJ, which
quantitatively corresponds well to the calculation results. Lasing of up to five Stokes components simultaneously occurred.
The efficiency for conversion of the laser radiation to one component was as high as 39%.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 284–290, March–April, 2008. 相似文献
2.
Christophe Hecquet Franck Delmotte Marie-Fran?oise Ravet-Krill Sébastien de Rossi Arnaud Jérome Fran?oise Bridou Fran?oise Varnière Evgueni Meltchakov Frédéric Auchère Angelo Giglia Nicola Mahne Stefano Nanaronne 《Applied Physics A: Materials Science & Processing》2009,95(2):401-408
In this paper, we present a study on two-channel multilayer mirrors which can operate at two wavelengths in Extreme Ultraviolet
(EUV) spectral range. We propose a new method to design two-channel EUV multilayer mirrors with enhanced spectral selectivity.
The mirror structure is a stack of two periodic multilayers separated by a buffer layer. We have defined the main parameters
which allow adjustment of the distance between different order Bragg’s peak and of wavelength positions of reflectivity minima.
Two mirrors have been designed and deposited for solar EUV telescope applications by using this method. The first mirror reflects
Fe IX–X line (17.1 nm) and Fe XVI (33.5 nm) lines with attenuation of the He II line (30.4 nm). The second mirror reflects
Fe IX–X and He II lines with attenuation of Fe XV (28.4 nm) and Fe XVI lines. Measurements with synchrotron radiation source
confirm that, in both cases, for these mirrors, we are able to adjust reflectivity maxima (Bragg peak position) and minima.
Such multilayers offer new possibilities for compact design of multi-wavelength EUV telescopes and/or for high spectral selectivity. 相似文献
3.
N. S. Ginzburg V. Yu. Zaslavskii I. V. Zotova A. M. Malkin N. Yu. Peskov A. S. Sergeev 《Technical Physics》2011,56(2):155-163
Combination of various modifications of Bragg structures makes it possible to control electromagnetic fluxes in the interaction
space, thus ensuring spatial coherence of radiation for high superdimensionality in two transverse coordinates required, which
is for the operation of free electron lasers with distributed feedback in the submillimeter range. We propose that coupling
between traveling and quasi-critical waves in the input Bragg mirror be used for mode selection in the “narrow” transverse
coordinate directed along the normal to the conductors forming a planar waveguide. A traditional Bragg structure coupling
copropagating and counterpropagating wave flows can be used as the output mirror. 相似文献
4.
P. P. Pashinin S. F. Rastopov A. T. Sukhodol'sky 《Optical and Quantum Electronics》1990,22(5):443-452
Relaxation oscillations of intensity in lumped-distributed feedback dye lasers are observed. These are caused by a competition between distributed feedback (DFB) and a feedback caused by an external mirror cavity. The effect is interpreted in terms of rate equations which include the time delay of radiation reflected from external mirrors relative to radiation due to periodic structure. 相似文献
5.
The influence of phase correlations of components on the energy and polarization parameters of output radiation have been
calculated within the framework of the formalism of polarization components. It is shown that these correlations have a marked
effect only on the energy characteristics. At the same time, an analysis of the polarization characteristics of a probe wave
provides rich information for the analysis of the phase-polarization structure of radiation. An analysis of experimental data
allows the inference that the correlation of components is relatively weak even for lasers with a high-Q resonator and at
a high excess of threshold values.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 5, pp. 591–597, September–October, 2005. 相似文献
6.
Experimental Investigation of High Power Erbium-Ytterbium Co-doped Double Clad Fibre Laser 下载免费PDF全文
All-fibre high power erbium-ytterbium co-doped double clad fibre lasers are proposed and demonstrated. By using different back-cavity mirrors, the different double clad fibre lasers are constructed. It is experimentally found that the output behaviour of laser can be controlled by a back-cavity mirror. The lower the reflectivity of the back-cavity mirror, the higher the output power and the high the slop efficiency. The maximum output power is about 1.6 W and the slop efficiency is 27.6%. 相似文献
7.
S. S. Andreev M. M. Barysheva N. I. Chkhalo S. A. Gusev A. E. Pestov V. N. Polkovnikov D. N. Rogachev N. N. Salashchenko Yu. A. Vainer S. Yu. Zuev 《Technical Physics》2010,55(8):1168-1174
Multilayer X-ray mirrors that are based on La/B4C and La/B9C and intended for the reflection of X-ray radiation in the spectral region near λ = 6.7 nm are prepared and studied. Reflection
coefficients at a level of 40–60% are achieved for mirrors with various periods. The difference in the interlayer roughnesses
reconstructed from the data measured in the hard and soft X-ray spectral regions is explained using a structural model with
an asymmetric permittivity profile in a mirror period. A proximate technique is developed to estimate the permittivity profile
in a multilayer-structure period using reflectometry data. The effect of antidiffusion Sn, Cr, and Mo barriers on the reflection
coefficient of multilayer La/B4C structures is studied experimentally 相似文献
8.
Adel Bousseksou Sophie Bouchoule Moustafa El Kurdi Martin Strassner Isabelle Sagnes Paul Crozat Joel Jacquet 《Optical and Quantum Electronics》2006,38(15):1269-1278
We report on the design, fabrication, and characterization of InP-based 1.55 μm wavelength large diameter (50 μm) electrically pumped vertical external cavity surface emitting lasers (EP-VECSELs). The hybrid device consists of a half
vertical cavity surface emitting laser (1/2-VCSEL) structure assembled with a concave dielectric external mirror. The 1/2-VCSEL
is monolithically grown on InP substrate and includes a semiconductor Bragg mirror and a tunnel junction for electrical injection.
Buried (BTJ) and ion implanted (ITJ) tunnel junction electrical confinement schemes are compared in terms of their thermal
and electrical characteristics. Lower thermal resistance values are measured for BJT, but reduced current crowding effects
and uniform current injection are evidenced for ITJ. Using the ITJ technique, we demonstrate Room-Temperature (RT) continuous-wave
(CW) single transverse mode laser operation from 50-μm diameter EP-VECSEL devices. We show that the experimental laser optical output versus injected current (L–I) curves are well-reproduced by a simple analytical thermal model, consistent with the thermal resistance measurements performed
on the 1/2-VCSEL structure. Our results indicate that thermal heating is the main mechanism limiting the maximum CW output
power of 50-μm diameter VECSELs, rather than current injection inhomogeneity. 相似文献
9.
In the present work, a multiwavelength Raman fiber laser based in a Sagnac configuration is presented. The Sagnac configuration
is composed of a Hi–Bi photonic crystal fiber in the middle of two dispersion compensation fibers. The pump power induces
two random mirrors to work in opposite directions in the Sagnac, leading to the amplified signal and the multiple scattering
signals from the random mirror traveling through the Hi–Bi photonic crystal fiber in a counter-propagating way interfering
in the output port. 相似文献
10.
The influence of the tuning of the radiation frequency of quantum-well heterolasers within the limits of their amplification
band on the output laser radiation parameters at different frequencies of pump-current modulation has been numerically simulated
using two optical models of an active medium under the assumption that the excess of the invariable component of the pump
current over its threshold value at any point of the amplification band is constant. It has been established that the amplitude-detuning
characteristics of the lasers studied are linear at high current-modulation frequencies and nonlinear at medium ones. The
behavior of the nonlinear spectral response of a laser diode is explained by its multiresonance structure and is mainly determined
by the ratio between the pump-current modulation frequency and the maximum resonance frequency of the laser.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 473–478, July–August, 2005. 相似文献
11.
V. Vaicikauskas R. Antanavicius R. Januskevicius 《International Journal of Infrared and Millimeter Waves》1997,18(2):383-389
ATR prism was used firstly as the FIR laser output coupler. Such output mirror possesses good separation of the pump (λ≈10μm)
and FIR radiation without losses. Transmittance of this mirror can be simply controlled by adjustment of gap between two output
prisms. The dependence of mirror output characteristics on pump radiation polarization, prism refractive index, gap between
prisms are under consideration. 相似文献
12.
2 ) nonlinear crystal is reported. The device uses a standing-wave dual-resonator scheme to enhance both near-infrared lasers.
For 7 mW of 778.2-nm and 275 mW of 842.5-nm input powers, 40 nW of 10.2-μm radiation is generated by a preliminary setup.
A μW-level range output power is expected after optimization of the device optical components. This compact tunable source
will allow Fabry–Pérot high-resolution Doppler-free spectroscopy of spherical molecules, such as OsO4 or SF6, in the 9–11 μm range as an alternative source to frequency-stabilized CO2 lasers.
Received: 17 March 1998 相似文献
13.
I. V. Kozhevnikov 《Journal of Russian Laser Research》1995,16(5):387-413
The theory of turning soft x-ray SXR radiation beams by means of concave surfaces through multiple reflections (the “whispering-gallery”
effect) is developed. It is demonstrated that concave mirrors are capable of turning an SXR beam by an arbitrary angle determined
by their aperture angle. The reflectivities are of the same order of magnitude as those of multilayer mirrors (20–80% at a
turn by 90°). The turning mirrors feature a wide spectral transmission band (Δλ ∼ λ). The potentialities of concave mirrors
and hollow cylindrical waveguides with respect to concentration and collimation of SXR radiation are considered. The requirements
imposed on the smoothness of the reflecting surfaces are obtained and the optimal (as to their optical properties) materials
are chosen for their fabrication. The theoretical results are compared to experimental data.
Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva (Proceedings of the Lebedev Physical Institute, Russian Academy
of Sciences, Moscow), Vol. 196, pp. 143–167, 1989. 相似文献
14.
V. I. Borisov A. M. Kroll V. P. Minkovich N. P. Minkovich 《Journal of Applied Spectroscopy》1999,66(2):278-281
The lasingin an Nd:YAG laser with a fiber-optic reflector in the form of a loop was experimentally investigated. Two designs
of the laser with a fiber-optic loop reflector were considered. In the laser of the first type the reflector was formed by
a fragment of a fiber guide the ends of which were placed in the focal plane of a microscope objective. In the laser of the
second type the role of the output mirror was played by a loop-shaped fiber-optic reflector made on the basis of a V-shaped
fused three-fiber splitter. It is shown that when such lasers operate in the regime of free-running lasing, in them there
takes place the effect of nonlinear conversion of the generated radiation frequency in the Stokes and anti-Stokes regions
of the spectrum.
Institute of Applied Optics, National Academy of Sciences of Belarus, 11, Belynitskii-Birulya Str., Mogilev, 212793, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 259–262, March–April, 1999. 相似文献
15.
F. Bridou M. Cuniot-Ponsard J.-M. Desvignes A. Gottwald U. Kroth M. Richter 《Applied Physics A: Materials Science & Processing》2011,102(3):641-649
Efficient polarizing as well as non-polarizing mirrors for a wavelength of λ=121.6 nm (hydrogen Lyman-α radiation) are necessary to achieve an experimental determination of the magnetic field in the solar corona through the Hanle
effect. We have designed, realized and characterized such mirrors. These consist of glass coated with a thin-film stack. The
coatings use the most reflective (Al) and most transparent (fluorides) materials at this wavelength. Different coatings were
explored which involve an increasing number of films in the coating stack. At the incident angle of maximum polarization where
the p-polarized reflectivity R
p is minimized, an s-polarized reflectivity R
s as high as 69% is experimentally obtained with a coating made of a Fabry–Pérot resonator. To our knowledge, this value is
the highest ever reported for a polarizing mirror at this wavelength. Additionally, efficient non-polarizing mirrors have
been designed and realized by using a two-layer coating (MgF2/Al/glass). By optimizing the fluoride layer thickness, a mirror with non-polarizing properties in the whole range of incident
angles was realized. 相似文献
16.
J. P. Allain M. Nieto-Perez M. R. Hendricks P. Zink C. Metzmacher K. Bergmann 《Applied Physics A: Materials Science & Processing》2010,100(1):231-237
Sn+ irradiations of Ru single-layer mirrors (SLM) simulate conditions of fast-Sn ion exposure in high-intensity 13.5 nm lithography
lamps. Ultra-shallow implantation of Sn is measured down to 1–1.5 nm depth for energies between 1–1.3 keV at near-normal incident
angles on Ru mirror surfaces. The Sn surface concentration reaches an equilibrium of 55–58% Sn/Ru for near-normal incidence
and 36–38% for grazing incidence at approximately 63 degrees with respect to the mirror surface normal. The relative reflectivity
at 13.5 nm at 15-degree incidence was measured in-situ during Sn+ irradiation. For near-normal Sn+ exposures the reflectivity is measured to decrease between 4–7% for a total Sn fluence of 1016 cm−2. Theoretical Fresnel reflectivity modeling shows for the same fluence assuming all Sn atoms form a layer on the Ru mirror
surface, that the reflectivity loss should be between 15–18% for this dose. Ex-situ absolute 13.5 nm reflectivity data corroborate
these results, indicating that implanted energetic Sn atoms mixed with Ru reflect 13.5-nm light differently than theoretically
predicted by Fresnel reflectivity models. 相似文献
17.
N. Rehfeld U. Gerhardt E. Dietz 《Applied Physics A: Materials Science & Processing》1973,1(4):229-232
We use a 0.5 m Seya-Namioka monochromator and two gold plated cylindrical mirrors to set up an optical system which produces
a collimated beam of plane polarized, monochromatic radiation in the vacuum ultraviolet region. The two mirrors compensate
for the astigmatism of the Seya-Namioka monochromator, thereby increasing the spectral resolution drastically. The degree
of linear polarization is about 0.97–1.00 in the spectral region of 6–11.5 eV. 相似文献
18.
An analysis of the power-current and tuning characteristics of asymmetric multiple-layer inhomogeneously pumped quantum-well
lasers with mode selection in the external resonator was performed. It is shown that the choice of the parameters of the barrier
and active layers of the laser heterostructure and optimization of the dispersion characteristics of the selective element
of the external resonator make it possible to realize continuous tuning of the lasing wavelength in a wide spectral range
at a practically constant output radiation power.
Reported at the Second International Scientific and Technical Conference on Quantum Electronics, Minsk, November 23–25, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 687–692, September–October, 1999. 相似文献
19.
研究了不同腔镜结构不同失调情况对空间谐振式激光陀螺中光束空间位置的影响.利用Collins积分与Collins程函理论以及MATLAB软件工具,对腔镜失调前后激光陀螺中光束传输进行了仿真计算.结果表明,相同失调量的不同反射镜所产生的拍频频差是不同的,且分别从M1和M4镜探测到的拍信号频不相同|对于小增益激光器,使用球面镜的腔镜结构较平面镜的腔镜结构更易形成稳定光束空间位置分布|由所计算的空间坐标xn可以看出,双向行波光束的光斑中心发生了偏移,在一定的失调量下将会影响到激光陀螺的拍频输出.研究结果对激光陀螺的工程检测和腔镜调整有指导作用,有助于激光陀螺测量准确度的提高. 相似文献
20.
N. S. Kazak V. K. Pavlenko E. G. Katranzhi A. A. Ryzhevich 《Journal of Applied Spectroscopy》2000,67(2):226-229
An effective method for suppressing free background generation is proposed. It is based on polarization separation of the
narrow-band output radiation of a controlled laser with a nonlinear mirror in the cavity. An increase in the integral ratio
between the energy of the narrow generation line and the integral value of the energy of the background over the entire gain
band of a wide-band laser from 0.17 to 55.00 has been attained.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 169–171, March–April, 2000. 相似文献