Table of Content

15 January 2001, Volume 30 Issue 1

Previous Issue    Next Issue

Synthetic Crystals toward New Era

JIANG Min-Hua

2001, 30(1):  1-9. 

Asbtract ( 26 )   PDF (248KB) ( 38 )  

Related Articles | Metrics

Synthetic crystals are the basic electronic and photonic materials.This paper reviews the development of synthetic crystals in the fields of electronic,opto-electronic and photonic materials with respect to the progress of IT.In new century(Tera-Era)the central role of single crystals is and will almost certainly continue to be in global IT.

Dielectric Superlattices

2001, 30(1):  10-27. 

Asbtract ( 43 )   PDF (579KB) ( 36 )  

Related Articles | Metrics

This paper reviews the main achievements in dielectric superlattice field.Much has been focused on the work done in our Lab.Since 1980,we have extended the concept of superlattice from semiconductor to dielectrics,fabricated the periodic and guasi-periodic dielectric superlattice,realized the second hamonic generation (SHG),multiple wavelength SHG,third hamonic generation,optic bistability and ultrasonic generation with high freguency.

Progress in E-O Research for KTP Crystals

SHEN De-zhong

2001, 30(1):  28-35. 

Asbtract ( 37 )   PDF (259KB) ( 44 )  

Related Articles | Metrics

The electro-optical(E-O)properties of KTP crystal were mentioned briefly and compared with that of KD*P and LN crystals in this paper.Main progress in E-O applications for KTP crystals was summarized.Merits and demerits in E-O applications for KTP crystals grown by the hydrothermal technique and by the flux method respectively were analyzed.Finally,the situation on E-O applications for KTP crystal with low conductivity grown by flux method was presented.

Overview of Violet and Deep-UV Nonlinear Optical Crystals in the Last Decade

CHEN Chuang-tian

2001, 30(1):  36-42. 

Asbtract ( 59 )   PDF (243KB) ( 61 )  

Related Articles | Metrics

The investigations on violet and deep-UV nonlinear optical crystals over the last decade,including successes and failures,are discussed in this paper.Successes include the discovery of KBBF crystal which produces the shortest second harmonic output (184.7nm),and KABO crystal which has been successfully grown to centimeter size and is a promising candidate for the fourth and fifth harmonic generation of Nd∶YAG laser light.However,we were surprised that the SBBO crystal which has good linear and nonlinear properties lacks structural completeness.As a result,the crystal cannot be used yet.Although we have spent about ten years on this field,the search for deep-UV nonlinear optical crystals is still not satisfactory.In the near future we will make greater efforts to improve the quality of the crystals we have discovered and will continue to search for the new ones that can overcome the problems of existing crystals.

Development of Nonlinear Optical Borates Containing B3O7 Groups

WU Yi-cheng

2001, 30(1):  43-48. 

Asbtract ( 42 )   PDF (230KB) ( 25 )  

Related Articles | Metrics

Nonlinear optical borates LiB3O5,CsB3O5 and CsLiB6O10 contain B3O7 anionic groups as basic structural units.They have similar linear and nonlinear optical features,such as a short ultraviolet cutoff,a relatively large nonlinear optical coefficient and a high optical damage threshold,which make them suitable for frequency conversion in the ultraviolet region.This paper presents a description of the recent development of these crystals.

Surface Structures Dominated by the Growth Units of Anionic Coordination Polyhedra(Ⅱ)

ZHONG Wei-zhuo;XU Gui-sheng;LUO Hao-su;WU Yong-jun;HE Tian-hou;HUA Su-kun

2001, 30(1):  49-52. 

Asbtract ( 28 )   PDF (153KB) ( 32 )  

Related Articles | Metrics

The relationship between the surface structure patterns and corresponding orientation of anionic coordination polyhedra in some allomeric crystals is discussed.It is suggested that the surface structure patterns on crystal faces correspond to the appearance of anionic coordination polyhedra on these faces.Allomeric crystals growth exhibit the same configuration,combination fashion and orientation of anionic coordination polyhedra.As a result,they have identical surface structure patterns and similar morphologies.

Morphology of Yb∶YAl3(BO3)4 Crystals Related to the Growth Rate

2001, 30(1):  53-58. 

Asbtract ( 30 )   PDF (203KB) ( 29 )  

Related Articles | Metrics

The morphologies of Yb∶YAl3(BO3)4 crystals related to the growth rates(corresponding to the rates of decreasing temperature)are observed.These small crystals were obtained from spontaneous nucleation based on different rates of decreasing temperature.The crystals with the size larger than 2mm have simple morphology composed by ｛1120｝ and ｛1011｝only,which is independent from the rate of decreasing temperature.But the crystals with the size smaller than 2mm have complicated morphologies composed by some rare crystal forms when the rate of decreasing temperature is high.It is reflected that some faces with high surface energy developed in the early growth stage when growth rate is high,but these faces disappeared soon during further growth.That means the crystals grow mainly on the low energy faces:｛1120｝ and ｛1011｝.The surface roughness of the crystals is different,which is corresponding to different growth rates.At high growth rate,the morphologies of ｛1120｝ and ｛1011｝ are changed from smooth to rough,and that of ｛0001｝ keeps rough.From the crystal structure,we qualitatively discussed the Jackson Factor α and the growth mechanisms of these three kinds of faces.

A New UV-nonlinear Optical Material Ba2Be2B2O7

2001, 30(1):  59-62. 

Asbtract ( 23 )   PDF (129KB) ( 22 )  

Related Articles | Metrics

A new nonlinear optical material Ba2Be2B2O7 (Abbr.TBO) was synthesized by high temperature solid state reaction.TBO and SBBO (Sr2Be2B2O7)crystals had the same basic structure unit［BO3］.The powder second harmonic generation (SHG) of TBO was twice as large as that of KDP.TBO crystal had good chemical and physical stability,anti-deliquescence and moderate hardness.It was easy to process and polish.

Study on Crystal Growth and Integrality of AgGaS2

ZHU Xing-hua;ZHAO Bei-Jun;ZHU Shi-fu;YU Feng-liang;SHAO Shuang-yun;SONG Fang;GAO De-you;CAI Li

2001, 30(1):  63-66. 

Asbtract ( 24 )   PDF (131KB) ( 26 )  

Related Articles | Metrics

High-pure AgGaS2 polycrystal of single-phase and high-density has been synthesized by two-zone vapor-transporting and temperature-oscillating method.The lattice constant and the location of S atom were calculated to be a＝5.753nm,c＝10.3008nm and x＝0.279,with little discrepancy comparing to PDF value,which showed the high-quality of our synthesized polycrystal.Single crystal with 15mm in diameter and 30mm in length has also been grown by modified Bridgman method.By observation on appearance,X-ray diffractin on cleavage faces,it showed that the crystal is crystallized with good integrality.

Optical and Mechanical Properties of Transparent Polycrystalline Spinel

HUANG Cun-xin;LEI Mu-yun;PENG Zai-xue;DU Hong-bing

2001, 30(1):  67-71. 

Asbtract ( 35 )   PDF (148KB) ( 25 )  

Related Articles | Metrics

Transparent polycrystalline spinel fabricated by hot pressing high pure ultrafine spinel powder in vacuum,then hot isostatic pressing the sintered body was reported in this paper.The optical and mechanical properties was measured.It has excellent mechanical,thermal and optical properties,high abrasion and erosion resistance as well.It also can resist the radiation of UV and sunlight.It has the similar properties as the sapphire and is cheaper than the later.The large size spinel is availible now.

Raw Material Synthesis of YVO4 Birefringent Crystal and Investigation on the Optimun Conditions

ZHU Yue-mei;LIN Bo;XIONG Jian-hua;TENG Shuo

2001, 30(1):  72-74. 

Asbtract ( 35 )   PDF (100KB) ( 29 )  

Related Articles | Metrics

The raw material synthesis of YVO4 by liquid phase reaction has been described in this paper.The effects of preparation conditions were discussed and the optimum was obtained.It is important that synthesis process must be standardized to achieve purity,uniformity and reproducibility of the raw materials for industrial productions.As a result,the fine large YVO4 single crystal ( 42×42mm) has been successfully produced with this raw material and the melt remained would still be suitable for crystal growth after as many as 10 runs.

Effect of Iron Impurity on Refractivity of LiNbO3 Crystals

LIU Guo-qing;LIU Jin-wei;TAO Shi-quan

2001, 30(1):  75-78. 

Asbtract ( 26 )   PDF (121KB) ( 22 )  

Related Articles | Metrics

The refractive indexes and lattic constants of LiNbO3 and two kinds of Fe∶LiNbO3 crystals have been measured and compared.The refractive index and lattic constants of Fe∶LiNbO3 had little changed.The cause of changing have been discussed and analyzed.

Study on the Thermoluminescence Properties of CaF2∶Dy

CHEN Wei;YANG Bai-rui;JIA Shuan-wen

2001, 30(1):  79-84. 

Asbtract ( 32 )   PDF (187KB) ( 25 )  

Related Articles | Metrics

The 25-290K and 300-670K thermoluminescence(TL) spectra in the X-ray irradiated CaF2∶Dy were measured and analyzed.Thermal peaks were detected at 76、84、137、170、349、363、388、414、437 and 465K with the narrow emission bands centered at 480、575、675 and 775nm.Additional broad emission bands were observed on the shorter wavelength side as well as those narrow bands in the X-ray induced radioluminescence(RL)spectra.With the reference of the mechanical parameters obtiained from the analysis of the glow curves,it is suggested that the narrow band emissions were produced by the nearby hole-Dy2+ recombination though the potential barrier and the broad bands were from the exciton or self-trapped exciton emissions.The thermal emissions below 380K are not thermally stable at room temperature and the visible light can bleach all those TL peaks.

Measurement of Principal Refractive Indices and the Thermal Refractive Index Coefficients of Yttrium Vanadate

SHI Hong-sheng;ZHANG Ge;SHEN Hong-yuan

2001, 30(1):  85-88. 

Asbtract ( 45 )   PDF (139KB) ( 67 )  

Related Articles | Metrics

The measurement of principal refractive indices and the thermal refractive index coefficients of yttrium vanadate(YVO4)are reported in this paper.The principal refractive indices of the crystal have been measured by selfcollimating method for the wavelenths of 488nm,632.8nm,1079.5nm and 1341.4nm in the temperature range of 20-140℃.The thermal refactive index coefficients have been obtained at these wavelenths and the constants of modified Sellmeier’s equation are also obtained in the measured temperature range.The value of birefringence (Δn) of 1064nm is calculated by Sellmeier’s equation.The calculated value agrees fairly well with the value published in the paper.

Catalytic Function of Mg3N2 in the Formation of hBN

XU Xiao-wei;LIU Zhi-fu;ZHAO Hong-mei;LI Yu-ping

2001, 30(1):  89-92. 

Asbtract ( 25 )   PDF (108KB) ( 22 )  

Related Articles | Metrics

The function of Mg3N2 in the reaction between B4C and NH4Cl has been investigated under normal pressure and high temperature.Results of FTIR and XRD analysis indicated that under 950℃and N2 condition,no hBN was obtained from Mg3N2-B4C reaction and only small amount of hBN was found in the product of B4C-NH4Cl system，while large amount of hBN was achieved from the product of B4C-NH4Cl-Mg3N2 system.The catalytic function of Mg3N2 is proposed from these reactions.

Study on Czochralski Growth of TeO2 Single Crystal and Defects

JI Xiao-hong;SANG Wen-bin;LIU Dong-hua;LI Dong-mei;QIAN Yong-biao;SHI Wei-min;MIN Jia-hua

2001, 30(1):  93-98. 

Asbtract ( 32 )   PDF (220KB) ( 48 )  

Related Articles | Metrics

The formation mechanism of main defects in TeO2 single crystals grown by Czochralski technique and the effects of growth parameters on defects have been studied in this paper.The results showed that the cracking in TeO2 single crystal is mainly related to the temperature gradient.To avoid the crystal being cracked and to decrease the dislocation density,the crystal can be grown under temperature gradient of 20-25℃/cm.And the incorporation of gas inclusions into the crystal is due to the pulling rate and the seed rotation rate.The crystal without bubbles can be obtained when a rotation rate of 15-18r/min and a pulling rate of 0.55mm/h are employed,which can lead a concave solid-liquid interface.The reason for growth steps in crystal can be explained by the instability of temperature and growth speed during growth process.

Optical Transmittance Properties of VO2 Thermochromatic Thin Films Affected by Electron Irradiation

LU Yong;LIN Li-bin;ZOU Pin;HE Jie;LU Tie-cheng

2001, 30(1):  99-104. 

Asbtract ( 31 )   PDF (161KB) ( 21 )  

Related Articles | Metrics

VO2 thermochromatic thin films have been irradiated by electron beam with energy of 1.7MeV and flux from 1013/cm2 to 1015/cm2 .Un-irradiated and irradiated samples have been characterized by XPS and UV-VIS analysis.At the same time,the hysteresis characteristics of light changing with temperature at 900nm have been studied.The results show that a part of V4+ions change into V5+ after irradiated by electron beam and the transmittance properties have obvious variation before and after irradiation.The maximum change of transmittance during phase transition process is the sample irradiated by 1014/cm2 electron beam.The change of optical transmittance properties have been discussed .

Crystal Defects in Synthetic Diamond Prepared by Static Catalyst Method

YIN Long-wei;LI Mu-sen;CHEN Zhi;SUN Dong-sheng;DONG Xiu-mei;ZHENG Pei-zhi

2001, 30(1):  105-108. 

Asbtract ( 28 )   PDF (128KB) ( 23 )  

Related Articles | Metrics

Transmisson electron microscopy (TEM) has been used to investigate the microstructures and analyze the defects in synthetic diamond prepared under high temperature-high pressure in the presence of FeNi alloy catalyst.It was found that there exist prismatic dislocations,stacking faults,array of dislocations and dislocation network.The formation mechanism of these defects was studied.Results show that defects in the diamond were closely related to high temperature-high pressure synthesis process and originated mainly from excess amount of saturated vacancies and internal stress generated by micro-inclusions.