ADP Crystals Research Articles

Improving fourth harmonic generation performance by elevating the operation temperature of ADP crystal.

In current inertial confinement fusion (ICF) facilities, potassium dihydrogen phosphate (KH2PO4, KDP) type crystals are the only nonlinear optical (NLO) materials that can satisfy the aperture requirement of the ICF laser driver. Ammonium dihydrogen phosphate (NH4H2PO4, ADP) crystal is a typical isomer of KDP crystal, with a large nonlinear optical coefficient, high ultraviolet transmittance, and large growth sizes, which is an important deep ultraviolet (UV) NLO material. In this paper, we investigated the effect of ADP temperature on its fourth-harmonic-generation (FHG) performance. When the temperature of the ADP crystal was elevated to 48.9 °C, the 90° phase-matched FHG of the 1064 nm laser was realized. Compared with the 79° phase-matched FHG at room temperature (23.0 °C), the output energy at 266 nm, conversion efficiency, angular acceptance, and laser-induced damage threshold (LIDT) increased 113%, 71%, 623%, 19.6%, respectively. It shows that elevating ADP temperature is an efficient method to improve its deep UV frequency conversion properties, which may also be available to other NLO crystals. This discovery provides a very valuable technology for the future development of UV, deep UV lasers in ICF facilities.

Growth and Temperature Properties of the Phase-Matching Angle of 23% Deuterated ADP Crystal.

Theoretical analysis indicated that partially deuterated ammonium dihydrogen phosphate (DADP) crystal with a deuterium content of 23% could realize spectral noncritical phase-matching (S-NCPM) for type-I frequency doubling of an Nd:glass laser. To explore the temperature dependence of the phase matching (PM) angle of the second harmonic generation (SHG) process and the output SHG bandwidth of DADP crystal at 1.053 μm, we used the point-seed rapid-growth method to grow targeted DADP crystal with 23% deuterium content. Experimental results indicated that the grown DADP crystal had high quality and large dimensions (7 × 6 × 6 cm3). Using a femtosecond OPO laser as a tunable light source, the temperature dependence of the PM angle of the SHG process in DADP crystal at 1.053 μm was investigated. The PM angle changed linearly with temperature, as predicted by the theoretical calculation. In addition, under the condition of higher temperature, broad bandwidths of the second harmonic of DADP crystal were still observed. These results provide excellent guidance and reference value for the application of wavelength insensitive phase-matched second harmonic generation in partially deuterated DADP.

Numerical simulation of thermal stress during the steady rotation in the growth of ADP crystals by solution circulating method

Transient numerical simulations were carried out to describe the temperature and thermal stress in ADP crystals during the steady rotation by solution circulating method (SCM). In a related paper (J. Crystal Growth 574 (2021) 126343), the effects of flow and heat transfer on the distribution of the supersaturation on the crystal face was discussed. This paper presents the corresponding results concerning the heat transfer occurring in the crystal. Emphasis is placed on studying the temperature and thermal stress distribution, since it is critically involved in the processes of crystal cracking. The evolution of the temperature and thermal stress in the crystal are studied as a function of crystal rotation rate, inlet velocity, and inlet temperature and crystal size. The numerical results seem to indicate that, as the rotation rate increases, the value of the σmax in crystal decreases and then increases, while the values of the σmax on crystal surface is increased. The increases of the inlet velocity and the inlet temperature lead to the increase of the σmax. Finally, As the crystal size gets large, the possibility of cracking arising in pyramidal zone is increased obviously.

220 nm deep-UV coherent source based on fifth-harmonic generation in ADP and DKDP crystals

Based on the 1.1 μm laser radiation obtained by parametrically amplifying Yb:YAG laser using frequency doubling of Nd:YAG laser, a 220 nm deep-UV coherent source was systematically presented via the efficient fifth-harmonic generation (FiHG) in NH4H2PO4 (ADP) and KD2PO4 (DKDP) crystals. In ADP crystals, noncritical phase-matching (NCPM) fourth-harmonic generation (FHG) and FiHG were realized at 109.4 and 31.6 °C, respectively. For DKDP crystals, we demonstrated the critical phase-matching FHG at 57.5 °C and verified that NCPM FiHG can be achieved at 38.7 °C, which was the first demonstration of the FiHG using the DKDP crystal to our knowledge. The energy-dependent conversion efficiencies, angular acceptances, and temperature acceptances of these nonlinear processes were systematically measured. The highest total conversion efficiencies from 1.1 μm to the fifth harmonic in ADP and DKDP crystals were 17.5% and 23.6%, respectively. Owing to the large-aperture availability of KDP-family crystals, this work paves the way for the generation and application of high-energy and high-peak-power deep-UV laser radiation.

Theoretical calculation and experimental research for structural stability and electronic properties induced by certain cluster defects in ADP crystal

Ammonium dihydrogen phosphate (NH4H2PO4, ADP) is an excellent nonlinear optical crystal and has had wide application. It was the same type of potassium dihydrogen phosphate (KH2PO4, KDP) with a similar crystal structure. The difference in structure and properties of ADP crystal in the presence of defects, especially cluster defects, was one of the important issues of concern in the research. In this work, first-principles calculation, coupled with HSE06 functional and the van der Waals-Wannier function method, was applied to investigate the structural stability and electronic properties induced by oxygen vacancy cluster defects and FeP2-+VO2+ cluster defects. And some spectra experiments, such as Raman spectroscopy, the Fourier transform infrared spectroscopy and the ultraviolet absorption spectroscopy, were also applied to investigate the detailed influence for ADP crystal doped with different Fe3+ concentration, which was grown with the “point-seed” rapid growth method. Combined with the theoretical results and the spectra tests, it confirmed that the structural changes in ADP crystal caused by oxygen vacancy cluster defect and FeP2-+VO2+ cluster defect were smaller than that in KDP crystal, mainly due to the restriction of hydrogen bonds and NH4+ group. With the increase of defect concentration, the microstructure stress could also damage the crystal structure due to the microscopic stress induced by Fe3+. The defect states moved towards right from 1.1 eV to 6.6 eV with the concentration of oxygen vacancy increasing. Similarly, the defect state composed of Fe 3d and O 2p states induced by FeP2- defect also moved to the conduction band minimum. The absorption peaks around 220-350 nm induced by FeP2- defect and FeP2-+VO2+ cluster defect were along the xy plane. It provided a good suggestion based on the calculation that it was very important to minimize defects or control cluster defect concentration during crystal growth.

Noncritical phase-matching fourth- and fifth-harmonic generation of 1077 nm laser using KDP-family crystals.

We systematically demonstrated the angular and temperature acceptances of noncritical phase-matching (NCPM) fourth- and fifth-harmonic generation (FHG and FiHG) of a 1077 nm laser in NH4H2PO4 (ADP), KH2PO4 (KDP), and KD2PO4 (DKDP) crystals. In this work, a new, to the best of our knowledge, laser frequency with a wavelength of 1077 nm was generated by optical parametric amplification, in which the pump light (526.3 nm) was generated by the frequency doubling of a Nd:YLF laser (1052.7 nm), and the signal light was a Yb:YAG laser (1029.5 nm). Subsequently, the 1077 nm laser was used as the fundamental wave for FHG and FiHG to obtain a deep-ultraviolet laser source. For ADP and DKDP crystals, NCPM FHG of a 1077 nm laser was realized at 74.0∘C and 132.5∘C, respectively, and large angular acceptances of 59.8 and 61.6 mrad were measured. For the FiHG, NCPM was realized in a KDP crystal at 48.5∘C with an angular acceptance of 56.4 mrad. The results pave the way for high-energy and high-power deep-ultraviolet laser generation using KDP-family crystals under noncryogenic conditions.

Electrical And Thermo Electrical Properties Of Adp And Kdp Crystals

ADP and KDP single crystals were prepared under growth from aqueous solution method. Large crystals of KDP, ADP were grown using Holden crystallizer. The structure of ADP and KDP were found using XRD study with morphology. The electrical conductivity is measured for ADP and KDP crystals, which shows that conductivity is minimum at 303K for ADP in the range from 303 – 463K, similarly for KDP conductivity is minimum at 330K in the range from 303K to 463K. The activation energies were found along ‘a’ and ‘c’ axes which are found to be from 0.2 to 1.87 eV. Seebeck Coefficient is found to be negative in the Temperature ranges between 335 -345K

Effect of Erioglaucine dye dopant on the structural, optical, mechanical, electrical and nonlinear properties of ammonium dihydrogen phosphate single crystal

Abstract The structural, optical, mechanical, electrical and nonlinear properties of standard Ammonium Dihydrogen Phosphate (NH4H2PO4, ADP) single crystals incorporating organic Erioglaucine dye dopant are presented. The effect of Erioglaucine dye dopant at varied concentration on these properties has been investigated through measurement of powder X-Ray Diffraction (XRD), UV–Vis and photoluminescence spectroscopy, Vickers microhardness, light dependent I–V measurements and Second Harmonic Generation studies. These measurements reveal that doping with increasing dye concentration of Erioglaucine leads to change in properties of the ADP single crystals, making them suitable for optoelectronic applications. The Erioglaucine doped ADP single crystals were grown using solvent evaporation technique at room temperature. Optical properties like absorbance and emission of these crystals are determined using UV–vis and photoluminescence spectroscopy, respectively. Optical bandgap and photoluminescence of the crystals are found to increase with dye doping, indicating their suitability in photonic applications. The mechanical properties of the crystals are determined using Vickers microhardness measurement technique. Light dependent I–V measurements exhibit negative photoconductivity behavior of the ADP crystals. However, the current through the crystals is observed to increase with increase in doping concentration of the Erioglaucine dye. Second Harmonic Generation studies show enhancement in nonlinearity for doped crystals. Our experiments indicate gradual variance in the crystallinity, emission, hardness, conductivity and nonlinearity of the sample with change in dye concentration.

Tailoring the low dielectric constant in glutamic acid doped ammonium dihydrogen phosphate single crystal by virtue of MPa shock waves for microelectronic applications: the complex impedance and modulus formulation studies

Ammonium Dihydrogen Phosphate, ADP, (NH4H2PO4) crystal has a wide range of applications in integrated and nonlinear optics. The amino acid-like l-glutamic acid (C5H9O4N) causes the defect in the framework of ADP crystal. The 0.6wt% l-glutamic acid doped ADP crystal is grown using the slow evaporation technique. The grown crystal is subjected under the shockwave of Mach number 1.7 and shock number 2, 4 and 6. The Powder XRD study shows the lattice strain introduced in the structure of grown crystals due to impose of the shockwave. The Photoluminescence confirmed the presence of D-defect and Self Trapped Excitons. The influence of shockwave on dielectric, impedance and modulus properties of glutamic acid doped ADP crystal is well studied in the frequency range of 100 Hz to 10 MHz and the temperature range of 323 K to 373 K. The shockwave is reduced the dielectric constant, A.C. Conductivity, strength of polarizibility and the grain capacitance. The Correlation Barrier Hopping (CBH) conduction mechanism is well studied for pristine and shocked glutamic acid doped ADP crystals over the temperature range considered. The presence of grain over the frequency range considered is identified and confirmed using the complex impedance and the complex modulus spectroscopy. The pristine and shocked glutamic acid doped ADP crystals have possessed the temperature-independent, Non-Debye type relaxation process. The results are discussed here.

Optical and SHG Measurements of Aminoacids doped ADP NLO crystals

L-Arginine and L-Alanine aminoacids doped ADP crystals were grown from aqueous solution by slow evaporation technique at constant temperature. The crystalline nature of the grown crystals was confirmed using powder X-ray diffraction technique. The vibrational frequencies of the grown crystals were identified using FTIR spectral analysis. Optical absorption study was carried out and a good transparency in the entire visible region was observed with the lower cutoff wavelength of 308 nm and 318 nm for the L-Alanine & L-Arginine doped crystals respectively. The transmission data has been used to evaluate the optical band gap of L-Alanine and L-Arginine doped ADP crystals and is found tobe 5.023 eV. Second harmonic generation (SHG) studies were performed by the classical Kurtz powder technique using a Nd: YAG laser operating at 1064 nm. The SHG efficiency of doped ADP is found to be higher compared to Pure ADP crystals.

Study on defect-induced damage behaviors of ADP crystals by 355 nm pulsed laser.

High-quality ammonium dihydrogen phosphate (NH4H2PO4, ADP) crystals were grown in Z direction and in defined crystallographic direction (θ=90°, φ=45°) by the rapid growth method, respectively. Defect-induced damage behavior in 355 nm of three types of ADP samples cutting in type-II matching and third harmonic generation direction from the as-grown crystals were investigated, including the initial laser induced damage (LID) characteristics and the physical and chemical properties of defects which serve as the damage precursors. The evaluations of damage behaviors include the "sampling" laser induced damage threshold (LIDT) by 1-on-1 and R-on-1 methods, bulk damage growth and bulk damage morphology. UV-visible transmittance spectrum, ultraviolet absorption spectrum, fluorescence spectrum, positron annihilation spectrum and the online light scattering measurements were carried out to investigate the defect-induced damage behavior in ADP crystals. The study will provide a reference for the investigations on laser induced damage properties of ADP crystals in short wavelength.

An analysis of flow and mass transfer of solution growth of NH4H2PO4 crystals by the modified seed mounting geometries

A modified seed mounting geometry is proposed, aiming to improve the distribution homogeneity of the supersaturation on the crystal face during the growth of ammonium dihydrogen phosphate (NH4H2PO4, ADP) crystals. To evaluate the modification, three dimension transient numerical simulation of flow and solute transfer involved in the growth of ADP crystals have been performed. The effects of flow on the surface supersaturation distribution is analyzed in detail. Compared with the ordinary seed mounting geometry, the modified geometry is able to suppress the formation of flow stagnation regions near the prismatic surface and improve the magnitude and the distribution homogeneity of the supersaturation. Particularly even at a lower rotation rate (ω = 30 rpm), the distribution of the surface supersaturation still possesses a better uniformity under the modified geometry. Meanwhile, with the increase of rotation rate, there is an improvement in the magnitude and the distribution of the supersaturation on the crystal surfaces. The effects of natural convection adjacent to prismatic faces can be ignored when rotation rate is equal to or greater than 50 rpm. Moreover, as the crystal size increases, the magnitude of the supersaturation on the prismatic surface declines a little, and its uniformity deteriorates gradually. Consequently, as the crystal growing, it should increase the rotation rate appropriately. Finally, etching studies reveal that the ADP crystals with higher quality can be obtained by modifying the seed mounting geometry simply.

Exploring remarkable impact of thiourea in enhancing the performance of NH4H2PO4 single crystal for photonic device applications

The present investigation is primarily aimed to investigate the impact of thiourea on characteristic properties of ammonium dihydrogen phosphate (NH4H2PO4, ADP) crystal to emphasize its utmost liability for designing nonlinear optical device applications. The most commercial slow solvent evaporation method has been opted to grow the undoped and thiourea doped ADP single crystals. The single crystal X-ray diffraction study has been employed to determine the structural parameters of undoped and thiourea doped ADP crystal. The elemental analysis has been performed to confirm the presence of thiourea in ADP crystal. The UV–visible studies have been carried out within 200–1100 nm to examine the constructive impact of thiourea on optical transparency and vital linear optical parameters (extinction coefficient, refractive index and reflectance) of ADP crystal. The Kurtz-Perry test has been employed to ascertain the enhancement in SHG efficiency of ADP crystal due to presence of thiourea. The third order nonlinear optical nature and properties such as nonlinear absorption (β), refraction (n2) and susceptibility (χ3) of T-ADP crystal has been examined at 632.8 nm by imposing the Z-scan studies. The color centered photoluminescence emission behavior of pure and thiourea doped ADP crystal has been investigated within 320–650 nm. Vickers microhardness study has been imposed to evaluate the role of thiourea in uplifting the hardness parameters of ADP crystal. The dielectric parameters (dielectric constant and dielectric loss) of undoped and thiourea doped ADP crystal has been comparatively investigated within the temperature range of 25–100 °C. The surface growth habitat of thiourea doped ADP crystal has been investigated by means of chemical etching technique.

Numerical simulation of the flow and mass transport during the growth of ADP crystals by additional stirrer

Abstract A stirrer is added to the traditional rotating crystal growth system of ammonium dihydrogen phosphate (NH4H2PO4, ADP), aiming at effectively utilizing the convection to improve the mass transfer and the distribution homogeneity of the supersaturation on the crystal face. 3D numerical simulation on flow and surface supersaturation distribution under different conditions is performed employing the finite-volume method, and the effect of flow on the surface supersaturation distribution is analyzed in detail. Compared with the traditional rotating-crystal system, the introduction of a stirrer can produce stronger axial flow and accordingly improve the magnitude and distribution homogeneity of the surface supersaturation, which is favorable to grow high quality crystals. As the stirrer rotation rate increases, the magnitude of the axial flow velocity increases, resulting in a reduction of the thickness of the solute boundary layer and an increase of the supersaturation on the crystal faces. Meanwhile, the homogeneity of the surface supersaturation is also improved. The crystal rotation rate strongly influences the magnitude and distribution of the prismatic surface supersaturation. As the crystal size increases from 25 cm to 35 cm, the distribution homogeneity of the prismatic surface supersaturation improves significantly, which is beneficial to crystal growth. Additionally, the importance of natural and forced convections in mass transport are discussed. Results show that the effects of natural convection adjacent to crystal faces can be ignored when stirrer rotation rate is greater than 400 rpm.

Structural stress and extra optical absorption induced by the intrinsic cation defects in KDP and ADP crystals: a theoretical study

VP5− defects are regarded as one of the main sources for the initial structural breakdown in KDP compared with ADP.

Homogeneity of large rapidly grown ADP crystals

DKDP crystal is a type of well-known excellent nonlinear optical material that can be used as 2ω, 3ω, and even 4ω harmonic converters. Compared to DKDP crystal, ADP has a larger nonlinear optical coefficient and higher laser damage threshold, so a larger energy and higher conversion efficiency can be expected from ADP crystals. In this paper, a high-quality ADP crystal (118 × 137 × 160 mm) was grown through point-seed rapid growth method within one month. The corresponding optical properties and homogeneity for noncritical phase-matching fourth harmonic generation were investigated. For the ADP sample with cross-section of 110 × 110 mm, the obtained homogeneity noncritical phase-matching temperature is 0.13 °C, which is superior to a DKDP crystal with the same growth parameters. Moreover, UV transmittance property of various thicknesses for ADP crystals was also explored. The transmittance at 263 nm is 88% and decreased 0.36% per millimeter. This result is much lower than the 0.63% for the DKDP crystal in the same thickness range. These results indicate ADP crystals are very promising candidates for noncritical phase-matching fourth harmonic generation.

Studies on Dielectric Properties of ADP Crystals

AbstractAmmonium dihydrogen phosphate (NH4HPO4, ADP) is an excellent inorganic nonlinear optical material with different device applications. The present work is based on the pure ADP crystals that is successfully grown from aqueous solution by slow evaporation technique at room temperature. The grown crystals are subjected to various characterizations like XRD, and dielectric studies. The crystalline nature and tetragonal structure of the grown crystals having lattice parameters are observed by powder X‐ray diffraction analysis. The dielectric properties such as dielectric constant and dielectric loss for the crystals at different areas are studied as a function of frequency in the range 50 kHz to 5 MHz at room temperature. It is found that the dielectric permittivity decreased exponentially at lower frequency region up to 1 kHz and then the dielectric permittivity remains constant at higher frequency region as the frequency increased. It is observed that as area of ADP crystal increases the dielectric constant increases and for area of 42 mm2 the dielectric constant value is high among all the different areas of ADP crystals.

True zero-order ADP crystal waveplate with millimeter thickness

For the first time, a series of true zero-order waveplates with millimeter thicknesses are designed and fabricated from ADP crystal. The basic principle is that the birefringence of crystal varies continuously with respect to the propagating direction of light wave. The characteristic parameters including angle, wavelength, temperature sensitivities are measured by the polarization interference method, at the same time the related theoretical analysis is given. The linear polarization rotation and add-voltage electro-optic Q-switching are realized with ADP half-waveplate (HWP) and quarter-waveplate (QWP), respectively. As a new-type polarization element with low-cost, large size and high optical damage threshold, true zero-order ADP waveplate is possible to find important applications in large-aperture and high-power laser systems.

Nonlinear optical characteristics of DADP crystals with different deuterium

DADP crystals with different deuterium as 0%, 30%, 50%, and 70% were grown via traditional temperature reduction method and the samples were gained from the as-grown crystals in the directions of Ι-type (θ = 90°,φ = 45°). The transmittance spectrum, UV absorption spectrum, and Raman spectrum were implemented to describe the properties of DADP crystals, and the deuteration of ADP crystals makes a difference on the absorption peaks in these spectrums. Particularly, the optical band gap Eg decreases with the accretion of deuterium content. The third-order nonlinear optical characteristics were systematically represented and tested by means of Z-scan measurements with Pico-second pulse laser irradiation at λ = 355 nm, with the results listing the reverse saturable absorption and self-focusing effect. The investigations may contribute to replenish and elucidate the application and laser-induced damage of DADP crystals.

Growth of NH4H2PO4 crystal in urea environment to optimize linear-nonlinear optical traits for photonic device applications

Linear and nonlinear optical properties of ammonium dihydrogen phosphate (ADP, NH4H2PO4) crystal are tailored by employing environmental growth in presence of urea and explore its applicability for photonic device applications. The structural parameters of pure and urea influenced ADP crystal has been determined by single crystal X-ray diffraction technique. The energy dispersive spectroscopic analysis has been employed to examine the constituent elements of grown crystal. The consequence of urea surrounding on optical transparency of ADP crystal has been examined within 200–1100 nm by means of UV–vis spectral analysis. The enhancing effect of urea on second harmonic generation (SHG) efficiency of ADP crystal has been determined using the Kurtz-Perry test. He-Ne laser assisted Z-scan technique has been employed to assess the third order nonlinear optical (TONLO) properties of urea affected ADP crystal at 632.8 nm. The magnitude of TONLO parameters (nonlinear refraction (n2), nonlinear absorption (β) and cubic susceptibility (χ3)) has been evaluated using the Z-scan transmittance data. The thermal stability of urea influenced ADP crystal has been experimentally evaluated by means of simultaneous thermogravimetric and differential thermal analysis.