共查询到20条相似文献,搜索用时 15 毫秒
1.
A numerical investigation has been carried out on the influence of the antireflection (AR) coating of laser, the coupling efficiency of laser and fiber (), and the reflectivity of fiber grating (R
g) on the side-mode suppression ratio (SMSR) of the fiber grating external cavity laser (FGECL). The FGECL was fabricated by the assembly of the multimode Fabry–Perot (FP) laser chip and fiber grating. The results showed that the FGECL with a lower AR coating, higher and R
g exhibited a better SMSR. A comparison of the SMSR dependence on the and R
g showed that SMSR increased more rapidly with increasing than SMSR for R
g. These spectral characteristic studies of the SMSR dependence on the device parameters of the AR coating, , and R
g may provide useful device designs for the practical fabrication of a FGECL for use in dense wavelength division multiplexing (DWDM) applications. 相似文献
2.
V. G. Arakcheev V. N. Bagratashvili A. A. Valeev V. B. Morozov A. N. Olenin V. K. Popov D. V. Yakovlev 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(7):1062-1066
Coherent anti-Stokes Raman scattering spectra measured within the Q-branch of the vibrational transition ν1 are used to gain insights into the state of carbon dioxide molecules in nanopores of Vycor™ glass at room temperature (20.5°C)
and a subcritical temperature of 30.5°C and gas pressures up to the saturation point P
sat for each temperature. Along with the main spectral component, belonging to gaseous CO2 molecules, the spectra recorded at pressures close to P
sat feature a second (low-frequency) component. The second component is associated with the contribution from the CO2 molecules trapped inside pores. A spectral deconvolution with account for the interference of these two bands makes it possible
to estimate the spectral characteristics of the second (low-frequency) component at each temperature. At 20.5°C, the bandwidth
of the low-frequency component decreases with CO2 pressure, a behavior that can be explained by the transition of CO2 from the adsorbed to the condensed state in the pore. At the subcritical temperature of 30.5°C, the spectral width of the
second component is pressure-independent and close to the value measured in the bulk of the supercritical fluid, a result
likely associated with a low-temperature shift of the critical point of the substance trapped in nanopores. 相似文献
3.
H. Urbánková 《Czechoslovak Journal of Physics》1987,37(8):911-918
A quartz CO2 waveguide laser with external totally reflecting mirrors and a NaCl plate for the output power coupling is described. The output power was measured as a function of the distance of the mirrors from the waveguide aperture. Using a diffraction grating instead of one of the mirrors the output power at the 10 P(20) line was measured as a function of the mirror position. The results sustain the assumption of a multimode waveguide structure. 相似文献
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The spectral focusing characteristics of a grazing-incidence flat-field spectrometer with a spherical variable-line-spacing grating in the 5-40nm spectral range are presented. The spectrometer can be used for any object at a distance in the 50mm-infinity range from the grating apex with a diffracted spectrum sharply focused on an almost flat focal plane at a constant distance from the grating apex. 相似文献
7.
Planar multiplexers based on echelle gratings are very popular devices for optical communication applications. However, the available channel number is restricted by the concept of free spectral range (FSR) due to their high operating diffraction order. Now, we can break the restriction of the FSR concept, and most of wavelengths in the operating passband of echelle grating multiplexers can be used based on a variable diffraction order design. We present the design, fabrication, and characterization of the echelle grating multiplexer with a single diffraction passband based on silica platform. 相似文献
8.
Radiophysics and Quantum Electronics - 相似文献
9.
A novel long period fiber grating (LPFG) sensor structure is proposed in this paper. It is constituted by coating an over-layer partially on the fiber grating. Then the LPFG has a two-section multilayer transversely distributed refractive index structure. Using coupling mode theory and transfer matrix method, the influences of refractive index, thickness and length of the coating layer on the spectral characteristics of the new type LPFG were analyzed. The simulation results show that the resonant band is split due to the particularity of the LPFG structure, and the wavelength splitting is strongly dependent on the parameters of the coating layer. This LPFG designing may solve the cross sensitive problem and then realize synchronous measurement of temperature, strain and other physical quantities. 相似文献
10.
A. V. Savushkin E. A. Sokolova G. P. Startsev M. P. Tveritinov 《Journal of Applied Spectroscopy》1988,49(1):753-756
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 49, No. 1, pp. 112–116, July, 1988. 相似文献
11.
We have experimentally investigated a basic ring laser gyroscope (RLG) with carbon dioxide gain, and studied the prospects of developing a practical CO2 RLG. Rotation sensing was demonstrated on a number of transitions in the 9.4 m and 10.4 m vibration-rotation bands. Gyro response is discussed with regard to lock-in, bias, homogeneous broadening effects, and high power operation. We show that such a system may offer important advantages over standard helium-neon RLGs, including reduced quantum limit and backscattering. The prospects and possible approaches for developing a practical high power CO2 RLG are discussed, and a method of eliminating cross-saturation at high pressure is proposed and analyzed. 相似文献
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Dual-functional diffraction grating based on selective metal deposition of photochromic diarylethene
Dual-functional diffraction gratings, which show different diffractions in transmission and reflection, are proposed as an essential optical element. We utilize a flattening effect of photochromic diarylethene (DAE) in the low glass transition temperature state and selective metal deposition to prepare the gratings. The uncolored lines of the colored DAE layer on a grating substrate with grooves were formed by red-laser scanning, and Mg evaporation onto the substrate without a shadow mask enabled Mg-line formation at right angles to the grooves. After being stored at 27 °C for 500 min, the sample showed two-dimensional diffraction in reflection but one-dimensional diffraction in transmission, meaning that a dual-functional grating was achieved. This result shows great potential as a key element for various future optical devices and systems. 相似文献
15.
The use of a diffraction grating as a dispersive one-dimensional beam expander with variable expansion ratio is described. The idea is applied to intracavity beam expansion in a dye laser cavity containing two gratings in a tandem configuration. By varying the beam expansion ratio up to 60 the laser linewidth may be reduced continously down to 0.1 cm-1. Linewidth calculations based on single pass estimates are presented and found to agree with experimental results. 相似文献
16.
S. Mory H.J. Patzold A. Rosenfeld S. Polze G. Korn J. Tilch 《Optics Communications》1979,29(2):201-203
A resonator arrangement for a cw-dye laser with a holographic grating for spectral narrowing and spectral variation is described. The grating is used at the grazing incidence. With this simple design we have got linewidth smaller than 0.01 nm. 相似文献
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S. L. Prunty 《International Journal of Infrared and Millimeter Waves》1993,14(10):2097-2107
The coupling efficiency in typical CO2 waveguide lasers when the feedback element is a diffraction grating is investigated theoretically. A scalar diffraction integral approach is adopted, and the laser is assumed to operate on its lowest loss waveguide mode. 相似文献
19.
《Infrared physics》1981,21(1):41-44
The purpose of this paper is to describe the design and the construction of a continuous wave CO2 laser for single line operation. This laser operates in a single axial mode with a frequency stabilization, at the maximum of the power profile, of better than 100 KHz. The output power is in the 0.1–5 W range. A variable coupling experiment is also described. This was used to obtain the gain of the amplifying medium and the optimum coupling for the maximum output power. 相似文献