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Complex impedance, FT-Raman, and photoluminescence spectroscopic studies of pure and L-phenylalanine doped ammonium dihydrogen phosphate single crystals: the correlation with hydrogen bonding defect
摘要： Ammonium dihydrogen phosphate (ADP) is an important nonlinear optical (NLO) material used for electro-optical applications. The aromatic side chain contained dopant like L-phenylalanine causes defect in ADP. The pure and L-phenylalanine doped ADP crystals are grown using slow solvent evaporation technique at room temperature. The Powder XRD spectra suggest tetragonal crystal system and slit shifting of peak. The FT-Raman shows strong absorption peak at 922 cm?1 due to v1 group symmetry of P - OH for all grown crystals without shifting indicating the single phase nature of all the crystals. The photoluminescence study suggests the presence of defects in doped crystals compared to the pure one due to increase of Stokes shift and vibrational energy relaxation phenomena. The dielectric constant and dielectric loss have shown the usual behavior with respect to frequency and temperature. The calculated electro-optic coefficient is found to be in accordance with dielectric constant. The protonic conduction is prevailing for electric transport, and from Jonscher’s plot, the correlation barrier hopping (CBH) is confirmed. The Nyquist plot and modulus spectra of pure ADP show the presence of grain and grain boundary while the same plots for L-phenylalanine doped ADP show the presence of grain only. The stretch exponent exhibits non-Debye-type relaxation.
关键词： Photoluminescence,Protonic conductivity,Impedance spectroscopy,Dihydrogen phosphate,Raman spectroscopy
更新于2025-11-14 15:26:12
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Effect of external stresses on the optical and electronic properties of potassium dihydrogen phosphate crystals
摘要： Potassium dihydrogen phosphate (KDP) has been extensively used in electro-optic switches and laser spectroscopy in modulating the frequency of laser radiation. When making refined optical KDP components for such applications, the external stresses in the manufacturing process can introduce changes in their optical and electronic properties. With the aid of the ab initio density functional theory analysis, this paper investigates the effect of stresses on the absorption coefficient, band gap, refractive index, dielectric function and Plasmon energy. It was found that the stress-induced variations in these properties are due to a change of KDP molecular structures. The microstructural changes induced by the uniaxial (along the <110> direction) or by the biaxial (<100> and <010> directions) or by the triaxial (<100>, <010> and <001> directions) tensile stresses bring about significant changes in the optical and electronic properties of KDP.
关键词： Density functional theory,Potassium dihydrogen phosphate,optical properties,stress
更新于2025-09-23 15:23:52
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A Report on Growth And Spectroscopic Studies on The L-Tartaric Acid Doped Potassium Dihydrogen Phosphate Non-Linear Optical Single Crystals
摘要： In recent years study of non-linear optical (NLO) materials is gaining rapid momentum due to their needs in several device applications. Potassium Dihydrogen Phosphate (KDP) is a well-known NLO material, whose non-linearity is enhanced by doping with amino acids. In this present study, single crystal of L-Tartaric acid doped potassium Dihydrogen phosphate (LTKDP) have been grown by slow evaporation method at room temperature. Good quality transparent crystals were obtained with 27-30 days. The crystallinity and cell parameters were characterized by X-ray diffraction analysis (XRD), the shifts in frequency assignments of various functional groups of KDP due to the addition of L-Tartaric acid was analysed by Fourier transform infrared (FTIR) and Fourier transform Raman spectroscopic studies. The dielectric constant and the dielectric loss of the single crystals were studied as a function of frequency. Kurtz- Perry power technique was employed to determine the Second Harmonic Generation (SHG) efficiency of LTKDP single crystal.
关键词： X-ray diffraction,SHG efficiency,L-Tartaric acid,slow evaporation method,FT-Raman,Potassium Dihydrogen Phosphate,FTIR,non-linear optical materials
更新于2025-09-23 15:19:57
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Investigation into the room temperature creep-deformation of potassium dihydrogen phosphate crystals using nanoindentation
摘要： It has been a tremendous challenge to manufacture damage-free and smooth surfaces of potassium dihydrogen phosphate (KDP) crystals to meet the requirements of high-energy laser systems. The intrinsic issue is whether a KDP crystal can be plastically deformed so that the material can be removed in a ductile mode during the machining of KDP. This study investigates the room temperature creep-deformation of KDP crystals with the aid of nanoindentation. A stress analysis was carried out to identify the creep mechanism. The results showed that KDP crystals could be plastically deformed at the nano-scale. Dislocation motion is responsible for creep-deformation. Both creep rate and creep depth decrease with decrease in peak force and loading rate. Dislocation nucleation and propagation bring about pop-ins in the load-displacement curves during nanoindentation.
关键词： Dislocation,Potassium dihydrogen phosphate (KDP) crystals,Creep-deformation,Stress
更新于2025-09-09 09:28:46
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Rapid Fabrication of Porous Anodic Alumina Films with Large Interpore Distances in an Ethylene Glycol and Ammonium Dihydrogen Phosphate-Based Electrolyte
摘要： Porous anodic alumina (PAA) ?lms have become popular nanotemplates due to the ordered hexagonal pore array structure. The fabrication of well-ordered PAA ?lms with larger interpore distances is still a challenge to date. Here, we develop a unique electrolyte system based on the reaction products of ethylene glycol (EG) with ammonium dihydrogen phosphate (ADP). In the novel electrolytes, stable high-voltage anodization with extremely high current densities (the peak value is close to 300 mA cm?2) can be realized at 400 V or even higher without breakdown. In 5 wt% EG-ADP-based electrolyte containing phosphoric acid, a well-ordered PAA ?lm with an interpore distance of ～610 nm can be fabricated at 250 V at a high growth rate of 1.3 μm · min?1.
关键词： Porous anodic alumina,high-voltage anodization,ethylene glycol,ammonium dihydrogen phosphate,interpore distance
更新于2025-09-09 09:28:46
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Using polarization control plate to suppress transverse stimulated Raman scattering in large-aperture KDP crystal
摘要： Transverse stimulated Raman scattering (TSRS) is strongly generated in the third-harmonic-generation crystal potassium dihydrogen phosphate (KDP) and can even damage the KDP crystal in inertial confinement fusion drivers. In this work, a method to suppress TSRS is proposed in which the polarization control plate (PCP) is moved to a new position in the existing optical path. The proposed method can suppress TSRS significantly and doubles the laser threshold intensity in KDP crystal when the order of the PCP is 16. This result is attributed to the reduction of the gain length for the Stokes radiation. The proposed method may also be used to suppress other nonlinear effects, including transverse stimulated Brillouin scattering in large-aperture optical components.
关键词： transverse stimulated Raman scattering,Polarization control plate,potassium dihydrogen phosphate (KDP)
更新于2025-09-04 15:30:14