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1.
AlxGa1−xAs LPE growth was studied within the temperature range of 930–900°C with Al concentrations in solutions from 0.04 to 2.4 at.%. AlAs concentration in layers has been shown to grow with the cooling rate increase of solution. Interface and volume nucleation parameter dependence of Ki and Kv and formation time tf on Al concentration in Ga solution have been found. Addition of Al to Ga solution increases critical values of As supersaturation (supercooling) and, as a result, increase in thickness of AlxGa1−xAs layers compared with GaAs layers have been determined in spite of As concentration lowering in Ga solution. 相似文献
2.
Three basic cases of LPE growth with and without nucleation were examined. The expressions for layer thickness and growth efficiency calculations were developed. Criteria for LPE growth classification were obtained. It was shown the nucleation takes place at critical values of supersaturation of the solution. The values of critical supersaturation may be calculated from growth efficiency experimental data for LPE growth. 相似文献
3.
Chen QF Troshyn A Ernsting I Kayser S Vasilyev S Nevsky A Schiller S 《Physical review letters》2011,107(22):223202
Using an ultrastable continuous-wave laser at 580 nm we performed spectral hole burning of Eu(3+):Y(2)SiO(5) at a very high spectral resolution. The essential parameters determining the usefulness as a macroscopic frequency reference, linewidth, temperature sensitivity, and long-term stability, were characterized using a H-maser stabilized frequency comb. Spectral holes with a linewidth as low as 6 kHz were observed and the upper limit of the drift of the hole frequency was determined to be 5±3 mHz/s. We discuss the necessary requirements for achieving ultrahigh stability in laser frequency stabilization to these spectral holes. 相似文献
4.
Vasilyev S Schiller S Nevsky A Grisard A Faye D Lallier E Zhang Z Boyland AJ Sahu JK Ibsen M Clarkson WA 《Optics letters》2008,33(13):1413-1415
A narrow-linewidth mid-IR source based on difference-frequency generation of an amplified 1.5 microm diode laser and a cw Tm-doped fiber laser in orientation-patterned (OP) GaAs has been developed and evaluated for spectroscopic applications. The source can be tuned to any frequency in the 7.6-8.2 microm range with an output power of 0.5 mW. The measured characteristics of the OP-GaAs sample demonstrate a high quality of the material. 相似文献
5.
A. N. Goncharov A. Y. Nevsky M. N. Skvortsov 《Applied physics. B, Lasers and optics》1995,60(1):43-45
The second-order Stark shift of the components of the hyperfine structure of the transition1
g
+
( = 0,j = 13, 15) 3
ou
+
( = 43,j = 12, 16) (of molecular iodine have been studied by means of saturated absorption spectroscopy in an external cell with the I2 vapour located in an electric field. The anisotropic polarizabilities of the upper and lower levels together with the difference between the isotropic polarizabilities of the levels of the transition have been obtained. 相似文献
6.
S. Vasilyev H.-E. Gollnick A. Nevsky A. Grisard E. Lallier B. Gérard J. Jimenez S. Schiller 《Applied physics. B, Lasers and optics》2010,100(4):737-747
The effects of coupling between clockwise and counterclockwise modes in ring resonators due to back reflections from QPM gratings
in nonlinear crystals are investigated. We demonstrate, using simulations, that the non-phase-matched back reflection due
to typical imperfections of the QPM grating has a relevant magnitude and can give rise to the coupling. We developed an analytical
model and evaluated parameters of a singly resonant OPO in the presence of this coupling, which indicates that the threshold
pump power is doubled in the limit of strong coupling. We also evaluated the effect of the coupling with respect to resonant
power enhancement for cavity-enhanced nonlinear frequency mixing applications, finding that the enhancement is reduced by
up to a factor four. Experimental observations based on PPLN and orientation-patterned GaAs crystals and model predictions
are in good agreement. We propose and demonstrate a method for active stabilization of ring resonators with mode coupling
that relies on the dissimilarity of the coupled forward and backward modes. 相似文献
7.
S. Vogt C. Lisdat T. Legero U. Sterr I. Ernsting A. Nevsky S. Schiller 《Applied physics. B, Lasers and optics》2011,104(4):741-745
We present the setup and test of a transportable clock laser at 698 nm for a strontium lattice clock. A master-slave diode
laser system is stabilized to a rigidly mounted optical reference cavity. The setup was transported by truck over 400 km from
Braunschweig to Düsseldorf, where the cavity-stabilized laser was compared to a stationary clock laser for the interrogation
of ytterbium (578 nm). Only minor realignments were necessary after the transport. The lasers were compared using a Ti:Sapphire
frequency comb as a transfer oscillator. The generated virtual beat showed a combined linewidth below 1 Hz (at 1156 nm). The
transport back to Braunschweig did not degrade the laser performance, as was shown by interrogating the strontium clock transition. 相似文献
8.
S.?VasilyevEmail author A.?Nevsky I.?Ernsting M.?Hansen J.?Shen S.?Schiller 《Applied physics. B, Lasers and optics》2011,103(1):27-33
A compact setup for generation, frequency stabilization, and precision tuning of UV laser radiation at 313 nm was developed.
The source is based on frequency quintupling of a C-band telecom laser at 1565 nm, amplified in a fiber amplifier. The maximum
output power of the source at 313 nm is 100 mW. An additional feature of the source is the high-power output at the fundamental
and the intermediate second- and third-harmonic wavelengths. The source was tested by demonstration of laser cooling of Be+ ions in an ion-trap apparatus. The output of the source at the third-harmonic wavelength (522 nm) was used for stabilization
of the laser frequency to molecular iodine transitions. Sub-Doppler spectroscopy and frequency measurements of hyperfine transitions
in molecular iodine were carried out in the range relevant for the Be+ laser cooling application. 相似文献
9.
A. Yu. Nevsky U. Bressel I. Ernsting Ch. Eisele M. Okhapkin S. Schiller A. Gubenko D. Livshits S. Mikhrin I. Krestnikov A. Kovsh 《Applied physics. B, Lasers and optics》2008,92(4):501-507
We demonstrate a diode laser system which is suitable for high-resolution spectroscopy in the 1.2 μm and yellow spectral ranges.
It is based on a two-facet quantum dot chip in a Littrow-type external cavity configuration. The laser is tunable in the range
1125–1280 nm, with an output power of more than 200 mW, and exhibits a free-running line width of 200 kHz. Amplitude and frequency
noise were characterized, including the dependence of the frequency noise on the cavity length. Frequency stabilization to
a high-finesse reference cavity is demonstrated, whereby the line width was reduced to approx. 30 kHz. Using a femtosecond
frequency comb, the residual frequency instability was determined and found to be below 300 Hz on the time scales 1–300 s.
Yellow light (>3 mW) at 578 nm was generated by frequency doubling in an enhancement cavity containing a PPLN crystal. The
source has potential application for precision spectroscopy of ultra-cold Yb atoms and cold molecular hydrogen ions. 相似文献
10.
Rednikov AY; Zhao Hong; Sadhal SS; Trinh EH 《The Quarterly Journal of Mechanics and Applied Mathematics》2006,59(3):377-397
The steady (acoustic) streaming associated with a sphericaldrop displaced from the velocity antinode of a standing waveis studied. The ratio of the particle size to the acoustic wavelengthis treated as small but non-zero, and the solution is developedin the form of a two-term expansion in terms of the correspondingsmallness parameter. The drop viscosity is assumed to be muchhigher than that of the surrounding fluid, which is the casefor a drop in a gas medium. There are essentially three distinctregions where the steady streaming flow is analysed: insidethe drop (internal circulation), in the Stokes shear-wave layerat the surface on the gas side, and the gas outside the Stokeslayer (the outer streaming region). Solutions for the internalcirculation and the outer streaming are obtained in the limitof small Reynolds number. Despite the gas-to-liquid viscosity ratio being small, the outerstreaming may be dramatically affected by the fact that thesphere is liquid as opposed to solid. The parameter that measuresthe effect of liquidity is essentially the viscosity ratio dividedby the relative (to the particle size) thickness of the Stokeslayer. The case of a solid sphere is recovered by letting thisparameter go to zero. 相似文献