اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدRemarkable enhancement in crystalline perfection, Second Harmonic Generation Efficiency, Optical Transparency and laser damage threshold in KDP crystals by L-threonine doping
60
0
0.0
(
0
)
تأليف
S. K. Kushwaha
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Effect of L-threonine (LT) doping on crystalline perfection, second harmonic generation (SHG) efficiency, optical transparency and laser damage threshold (LDT) in potassium dihydrogen phosphate (KDP) crystals grown by slow evaporation solution technique (SEST) has been investigated. The influence of doping on growth rate and morphology of the grown crystals has also been studied. Powder X-ray diffraction data confirms the crystal structure of KDP and shows a systematic variation in intensity of diffraction peaks in correlation with morphology due to varying LT concentration. No extra phase formation was observed which is further confirmed by Fourier Transform (FT) Raman studies. High-resolution X-ray diffraction curves indicate that crystalline perfection has been improved to a great extent at low concentrations with a maximum perfection at 1 mol% doping. At higher concentrations (5 to 10 mol%), it is slightly reduced due to excess incorporation of dopants at the interstitial sites of the crystalline matrix. LDT has been increased considerably with increase in doping concentration, whereas SHG efficiency was found to be maximum at 1 mol% in correlation with crystalline. The optical transparency for doped crystals has been increased as compared to that of pure KDP with a maximum value at 1 mol% doping.
قيم البحث
اقرأ أيضاً
Enhancement of second harmonic generation (SHG) efficiency and the correlation between crystalline perfection and SHG with urea doping on tristhioureazinc(II) sulphate (ZTS) single crystals have been investigated. ZTS is a potential semiorganic nonli
near optical (NLO) material. Pure and urea doped single crystals of ZTS have been successfully grown by slow evaporation solution technique (SEST). Presence of dopants has been confirmed and analyzed by Fourier transform infrared (FTIR) spectrometer. The influence of urea doping at different concentrations on the crystalline perfection has been thoroughly assessed by high resolution X-ray diffractometry (HRXRD). HRXRD studies revealed that the crystals could accomodate urea in ZTS up to some critical concentration without any deterioration in the crystalline perfection. Above this concentration, very low angle structural grain boundaries were developed and it seems, the excess urea above the critical concentration was segregated along the grain boundaries. At very high doping concentrations, the crystals were found to contain mosaic blocks. The SHG effeiciency has been studied by using Kurtz powder technique. The relative SHG efficiency of the crystals was found to be increased substantially with the increase of urea concentration. The correlation found between the crystalline perfection and SHG efficiency was discussed.
Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principles calculation of the linear and no
nlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potential linear augmented plane wave (FP-LAPW) method. Our calculations show a large anisotropy of the linear and nonlinear optical susceptibilities. The observed dependences of the second order susceptibilities for the static frequency limit and for the frequency may be a consequence of different contribution of electron-phonon interactions. The imaginary parts of the second order SHG susceptibility chi_{123}^{(2)}(omega), chi_{112}^{(2)}(omega), chi_{222}^{(2)}(omega), and chi_{213}^{(2)}(omega) are evaluated. We find that the 2(omega) inter-band and intra-band contributions to the real and imaginary parts of chi_{ijk}^{(2)}l(omega) show opposite signs. The calculated second order susceptibilities are in reasonably good agreement with the experimental measurements.
A systematic {it ab initio} study of the second-order nonlinear optical properties of BN nanotubes within density functional theory in the local density approximation has been performed. Highly accurate full-potential projector augmented-wave method
was used. Specifically, the second-harmonic generation ($chi_{abc}^{(2)}$) and linear electro-optical ($r_{abc}$) coefficients of a large number of the single-walled zigzag, armchair and chiral BN nanotubes (BN-NT) as well as the double-walled zigzag (12,0)@(20,0) BN nanotube and the single-walled zigzag (12,0) BN-NT bundle have been calculated. Importantly, unlike carbon nanotubes, both the zigzag and chiral BN-NTs are found to exhibit large second-order nonlinear optical behavior with the $chi_{abc}^{(2)}$ and $r_{abc}$ coefficients being up to thirty times larger than that of bulk BN in both zinc-blende and wurtzite structures, indicating that BN-NTs are promising materials for nonlinear optical and opto-electric applications. Though the interwall interaction in the double-walled BN-NTs is found to reduce the second-order nonlinear optical coefficients significantly, the interwall interaction in the single-walled BN-NT bundle has essentially no effect on the nonlinear optical properties. The prominant features in the spectra of $chi_{abc}^{(2)}(-2omega,omega,omega)$ of the BN-NTs are suscessfully correlated with the features in the linear optical dielectric function $epsilon (omega)$ in terms of single-photon and two-photon resonances.
Based on an accurate first principles description of the energetics in H-bonded KDP, we conduct a first study of nuclear quantum effects and of the changes brought about by deuteration. Cluster tunneling involving also heavy ions is allowed, the main
effect of deuteration being a depletion of the proton probability density at the O-H-O bridge center, which in turn weakens its proton-mediated covalent bonding. The ensuing lattice expansion couples selfconsistently with the proton off-centering, thus explaining both the giant isotope effect, and its close connection with geometrical effects.
Nonreciprocal devices that allow the light propagation in only one direction are indispensable in photonic circuits and emerging quantum technologies. Contemporary optical isolators and circulators, however, require large size or strong magnetic fiel
ds because of the general weakness of magnetic light-matter interactions, which hinders their integration into photonic circuits. Aiming at stronger magneto-optical couplings, a promising approach is to utilize nonlinear optical processes. Here, we demonstrate nonreciprocal magnetoelectric second harmonic generation (SHG) in CuB2O4. SHG transmission changes by almost 100% in a magnetic-field reversal of just 10 mT. The observed nonreciprocity results from an interference between the magnetic-dipole- and electric-dipole-type SHG. Even though the former is usually notoriously smaller than the latter, it is found that a resonantly enhanced magnetic-dipole-transition has a comparable amplitude as non-resonant electric-dipole-transition, leading to the near-perfect nonreciprocity. This mechanism could form one of the fundamental bases of nonreciprocity in multiferroics, which is transferable to a plethora of magnetoelectric systems to realize future nonreciprocal and nonlinear-optical devices.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
