High-power ultraviolet 278 nm laser from fourth-harmonic generation of a Nd:YAG laser in CsB3O5

We demonstrate a high-power UV 278 nm laser by fourth-harmonic generation (FHG) of a 1112 nm Nd:YAG laser in a nonlinear optical (NLO) crystal CsB3O5 (CBO) for the first time, to our best knowledge. A 30 W level diode-pumped Q-switched Nd:YAG laser at 1112 nm with beam quality factor M2=1.2 was used as the fundamental light source at a pulse width of 500 ns. With an LiB3O5 crystal, the 1112 nm laser was first frequency-doubled to 556 nm with an average output power of 13.5 W. It was then frequency doubled again in a CBO crystal to obtain the FHG output at 278 nm. The maximum average output power of the 278 nm laser is up to 1.5 W. The results demonstrated that CBO crystal is a promising NLO material for UV high-power lasers below 300 nm.     

La2CaB10O19晶体高效紫外激光输出研究

La2CaB10O19(LCB)为可通过Nd∶YAG激光三倍频产生355 nm紫外激光的非线性光学晶体,其光学性能可与商用化的LiB 3O 5(LBO)晶体媲美,但抗潮解特性优势明显。本文对用LCB晶体实现355 nm紫外激光输出的三倍频产生过程进行了优化设计,利用走离补偿方法来提高激光输出转换效率。通过在光路中加入沿θ=45°方向切割、厚度为1.2 mm的方解石晶体走离补偿片,在脉冲宽度为60 ns、重复频率10 kHz的激光参数下实现355 nm输出功率由12 W提升至20 W;在脉冲宽度为25 ps、重复频率为10 Hz的激光参数下355 nm转换效率由28.3%提升至35.2%。     

High sensitive and ultrafast UV photodetector based on ZrO_2 single crystals

The fast-response ultraviolet (UV) photoelectric effect in ZrO2 single crystals with interdigitated electrodes has been investigated experimentally at room temperature. The photovoltage of ZrO2 single crystals exhibits a linear dependence on applied bias and light power density. The photocurrent responsivity to the UV light with a wavelength of 253.65 nm is 9.8 mA/W. For the photovoltaic pulse, a rise time of 501 ps and a full width at half maximum of 1.5 ns have been obtained, when the ZrO2 single crystal ...     

The third-order optical nonlinearity of the stainless steel doped SrTiO_3 thin film grown by L-MBE

Stainless steel-doped SrTiO3 thin films were fabricated by laser molecular beam epitaxy (L-MBE). Nonlinear optical property of the thin film was measured by the single beam Z-scan technique at the wavelength of 532 nm. Two two-phonon absorption coefficient and nonlinear refractive index were determined to be 9.37 x 10-7 m/W and 1.55 x 10-6 esu, respectively. The merit figure T was calculated to be 1.8, satisfying condition T < 1 for an optical switch. The thin film has a very promising prospect for the applications in optical device.     

不同晶向SrTiO3上外延GaAs薄膜的光谱研究

利用MBE生长技术,成功地在不同晶向SrTiO3(100)(111)(110)衬底上生长了GaAs薄膜,利用显微Raman和荧光光谱（PL）对此进行了研究。实验结果表明,在不同晶向SrTiO3上生长的GaAs薄膜有不同的晶向和应力状态。荧光光谱（PL）研究表明在SrTiO3(100)(111)晶面上生长的GaAs薄膜的PL峰发生明显的蓝移。研究表明在SrTiO3(110)面上生长的GaAs薄膜和体单晶基本上一致,有更好的光学质量。     

水热法制备表面修饰的钛酸锶纳米微粉

以工业原料和常用试剂ＴｉＣｌ４、Ｓｒ（）ＮＯ３）２和ＫＯＨ为基础原料，通过添加表面活性剂十二烷基苯磺酸（ＤＢＳ），并采用制备出表面包裹有ＤＢＳ的钛酸锶纳米微粉姘应用红外光谱，Ｘ射线衍射谱，透射电子显微镜，热分析等一系列手段对其微结构进行了表征。结果表明：样品为表面包裹ＤＢＳ的钛酸锶纳同粉，其形态较为规则，粒度分布较窄，单分散性较好，粒子的平均粒径为１２０ｍｍ，包裹膜的平均厚度为６ｎｍ左右，根据Ｘ光     

High-power ultraviolet 278-nm laser from fourth-harmonic generation of an Nd:YAG amplifier in CsB_3O_5 crystal

We report on the experimental investigation and theoretical analysis of a nanosecond pulse high power ultraviolet(UV) 278 nm laser by fourth-harmonic generation(FHG) of a 1112-nm Nd:YAG amplifier in LiB_3O_5(LBO) and CsB_3O_5(CBO) crystals. The UV laser delivers a maximum average power of 10.3 W at 278 nm with peak power of 36.8 k W under input pump power of 41 W at 556 nm. This is, to the best of our knowledge, the highest output power at the specific UV wavelength of 278 nm. We also performed the theoretical investigation on the FHG with a model in the Gaussian approximation of both spatial and temporal profiles, especially accounting for the two-photon absorption effect in CBO crystal for the first time. The average output power, pulse width, and beam spatial distribution of the UV laser were simulated. The theoretical calculations are in close agreement with the experimental results.     

Narrowband ultraviolet photodetector based on MgZnO and NPB heterojunction

An ultraviolet photodetector was fabricated based on Mg_0.07Zn_0.93O heterojunction. N, N'-bis (naphthalen-1-y1)-N, N'-bis(pheny) benzidine was selected as the hole transporting layer. I-V characteristic curves of the device were measured in the dark and under the illumination of 340?nm UV light with density of 1.33 mW/cm². The device showed a low dark current of about 3×10^-10 A and a high photo-dark current ratio of 1×10⁵ at -2 V bias. A narrowband photoresponse was observed from 300 to 400?nm and centered at 340?nm with a full width at half-maximum of only 30?nm. The maximum peak response is at 340?nm, which is 0.192 A/W at the bias of -1 V.     

LD泵浦全固态355nm紫外皮秒脉冲激光器

利用激光二极管（LD）端面抽运Nd∶YVO4激光晶体皮秒三倍频355nm全固态紫外激光器,采用半导体可饱和吸收镜（SESAM）锁模技术及皮秒再生放大技术,对1 064 nm基波采用Ⅰ类相位匹配Li3B3O5（LBO）晶体二倍频和Ⅱ类相位匹配LBO晶体三倍频,获得了稳定性好、倍频效率较高的355 nm紫外激光输出。当二极管泵浦功率为5 W时,获得了脉宽为17 ps、重复频率为1 Hz、单脉冲能量为129.6 J的稳定三倍频紫外激光输出,基频光到二倍频光和三倍频光的转换效率分别达到60.3%和16.6%,3 h输出单脉冲能量的抖动在0.58%以下。     

一种嘧啶铱（Ⅲ）配合物的结构及光电性质研究

合成了一种铱配合物（DFPPM=2-（2,4-二氟苯基）嘧啶,acac=乙酰丙酮）,利用 X 射线单晶衍射仪测定了该化合物的晶体结构。利用紫外-可见吸收光谱、发射光谱对其光物理性质进行研究。结果表明：（DFPPM）₂ Ir（acac）的单晶结构属于三斜晶系,P-1空间群,晶胞参数a=14.444 4（7）nm,b=18.047 9（10）nm,c=19.220 0（9）nm,α=113.115（5）°;,β=90.453（4）°;,γ=90.989（4）°;,V=4 607.0（4）nm³。（DFPPM）₂ Ir（acac）在二氯甲烷溶液中的发射峰为 496 nm。以（DFPPM）₂ Ir（acac）为客体材料,制备了结构为ITO/NPB（40 nm）/CBP：（DFPPM）₂Ir（acac）（质量分数10%,30 nm）/TPBi（15 nm）/Alq₃（50 nm）/Mg：Ag（150 nm,10：1）/Ag（10 nm）的器件,器件的发射峰位于494 nm,最大亮度达到21 400 cd/m²,最大电流效率为12.0 cd/A,最大功率效率为 5.4 lm/W。     

High-efficiency Simple Structure White Organic Light-emitting Devices Based on Rubrene Ultrathin Layer

White organic light-emitting devices (WOLEDs) were fabricated with an ultrathin layer of rubrene inserted between NPB and TPBI. With a simple three-layer structure of ITO/NPB(50 nm)/rubrene(0.1 nm)/TPBI(50 nm)/LiF/Al, a white light with CIE coordinates of (0.31, 0.30) were generated. The device gave a maximum luminance efficiency of 2.04 lm/W at 5 V. Furthermore, with a multilayer structure of ITO/m-MTDATA(30 nm)/NPB(20 nm)/rubrene(0.1 nm)/TPBI(40 nm)/Alq₃(10 nm)/LiF/Al, the device reached a maximum luminance efficiency of 4.29 lm/W at 4 V and the luminance could exceed 10 000 cd/m² at 10 V.     

Generation of femtosecond laser pulses at 396 nm in K_3B_6O_(10)Cl crystal

K_3B_6O_(10)Cl(KBOC), a new nonlinear optical crystal, shows potential advantages for the generation of deep ultraviolet(UV) light compared with other borate crystals. In this paper we study for the first time the second harmonic generation(SHG) of a femtosecond Ti:sapphire amplifier with this crystal. Laser power is obtained to be as high as 220 m W at the central wavelength of 396 nm with a 1-mm-long crystal, and the maximum SHG conversion efficiency reaches 39.3%. The typical pulse duration is 83 fs. The results show that second harmonic(SH) conversion efficiency has the room to be further improved and that the new nonlinear crystal is very suited to generate the high efficiency deep ultraviolet laser radiation below 266 nm.     

Cr3+在SrTiO3晶体中的晶场能级

由激发光谱及荧光光谱的测量,运用Tanabe-Sugano能量矩阵计算了Cr3+在SrTiO3晶体中的晶场能级.     

Fabrication of transparent p-n junction composed of heteroepitaxially grown p-Li<Subscript>0.15</Subscript>Ni<Subscript>0.85</Subscript>O and n-ZnO films for UV-detector applications

Thin films of high-quality p-type Li_0.15Ni_0.85O (LNO) and n-type ZnO were heteroepitaxially grown on MgO(111) substrate by pulsed laser deposition technique to form transparent wide bandgap heterojunctions. The epitaxial nature of this p-LNO/n-ZnO/MgO heterojunction was confirmed to be (111)LNO||(0001)ZnO||(111)MgO (out-of-plane) and (002)LNO||(1002)ZnO||(002)MgO (in-plane) by X-ray diffraction. Optical transmittance spectrum and I–V characteristics were obtained at room temperature. The heterojunction exhibits reasonable optical transmittance of 50–60% on average in the whole infrared and visible region, and highly asymmetric electrical rectification with a turn-on voltage of about 1.0 V and a small leakage current. The highest photoresponsivity for a wavelength of 350 nm is 3.4×10³ V/W when the junction is irradiated under 5 μW UV illumination. The spectral response peak is obtained in the UV region and a reasonable large responsivity is shown for this p-LNO/n-ZnO/MgO heterojunction, which suggests the possibility of an inexpensive transparent oxide UV detector in a wide variety of electronics applications. PACS 68.55.Jk; 81.05.Dz; 81.15.Fg     

Nd:YAG陶瓷与单晶4F3/2–4I13/2跃迁的弱谱线多波长激光性能对比

报道了基于半导体激光端面抽运Nd:YAG的⁴F_3/2–⁴I_13/2 跃迁的弱谱线多波长激光输出. 实验对比了透明陶瓷与单晶材料的激光输出特性, 表明透明陶瓷和单晶材料荧光谱强度的略微差异, 导致了多波长输出时相同两个波长之间的激光强度比在两种材料中的差异. 基于两种耦合输出镜片, 激光阈值都在2 W左右. 在13.5 W的抽运功率下, 基于Nd:YAG透明陶瓷获得了输出功率4.05 W、强度比1 :2的1338与1356 nm双波长激光和输出功率3.65 W、强度比13 : 1的1356与1414 nm 双波长激光, 斜率效率分别达33.9% 和31.9%.     

光折变晶体钛酸钡锶电荷传输参数的测量

报道用两波耦合技术测量光折变晶体钛酸钡锶(Ba_(1-x)Sr_xTiO-3,BST)的电荷传输参数φμτ在激光波长λ=515nm和光功率密度I—1W/cm~2下测得光折变响应时间为0.5sec.考虑到BST晶体吸收系数的光强相关性,修改了光栅形成率的函数变量,得到BST晶体的暗电导σ_a和电荷传输参数φμτ的拟合值分别为1.0×10~(-11)(Ωcm)~(-1)和2.8×10~(-10)cm~2/V.     

Performance of a polarizer using synthetic mica crystal in the 12-25 nm wavelength range

To develop polarizer functioning in the extreme ultraviolet (EUV) and soft X-ray region, the polar- ization performance of synthetic mica has been investigated theoretically with a simulation code using Fresnel equations and optical constants from the Henke database. The reflectance of synthetic mica crystal for s and p polarization was measured to investigate its polarization performance in a home-made synchrotron radiation soft X-ray polarimeter at beamline 3W1B, Beijing Synchrotron Radiation Facility (BSRF). The reflectivity of the synthetic mica crystal at an angle of grazing incidence of 48° was obtained from the experimental data, which is about 4.8x10<'-3> at 25 nm and 6.0×10<'-4> at 12 nm, and the linear polarizance of the X-ray reflected by the synthetic mica crystal that we measured using an analyzer-rotating method increases from 80% to 96.6% in this EUV region, while higher than 98.2% in the simulation. The result indicates that this synthetic mica crystal works as a practical polarizer in this EUV region of 12-25 nm, and also in an extensive wavelength region higher than 25 nm.     

Violet light generation by frequency doubling of GaAlAs diode laser using a metallo-organic complex crystal ZnCd(SCN)4

Violet 404-nm radiation is generated by type-I single-pass frequency doubling of the output of an GaAlAs diode laser in critically phase-matched ZnCd(SCN)₄ (ZCTC) crystal, a metallo-organic complex crystal. In this paper, its refractive index and second-harmonic generation phase-matching angles are reported. Using a 3-mm-long ZCTC crystal, a diode laser power of 473 mW generated 390 μW of second-harmonic radiation. More recently, 380-nm, 20 μW ultraviolet (UV) radiation is also realized by frequency doubling of the 100 mW output of a continuous-wave Ti:sapphire laser at 760 nm. ZCTC is a promising UV nonlinear optical candidate material for frequency doubling of diode lasers.     

基于复合腔的波长可调谐连续橙红色激光器

设计并研制了一种基于复合腔结构的波长可调谐、瓦级连续输出的橙红色激光器.该激光器是由半导体激光侧泵Nd∶GdVO_4晶体产生p-偏振1 062.9nm基频光的谐振腔和使用周期性极化晶体MgO∶PPLN(三个极化周期为29.0μm、29.8μm和30.8μm)的单共振光学参量振荡器组成.在两个谐振腔的重叠区域,利用Ⅱ类临界相位匹配KTP晶体对s-偏振信号光与p-偏振1 062.9nm基频光进行腔内和频.通过对MgO∶PPLN晶体进行三个不同极化周期的调谐和30℃~200℃范围内的温度调谐,在三个波段(613.4~619.2nm@29.0μm、620.2~628.9nm@29.8μm和634.4~649.1nm@30.8μm)获得了波长可调谐的橙红色激光连续输出,并在相应波段(3 980.0~3 758.5nm@29.0μm、3 714.2~3 438.3nm@29.8μm和3 278.0~2 940.2nm@30.8μm)获得了波长可调谐的中红外闲频光的连续输出.在30℃最低调谐温度,通过改变晶体的极化周期,在613.4nm、620.2nm和634.4nm处测得最大连续输出功率分别为1.52 W、2.21 W和3.03 W,对应的三束闲频光最大连续输出功率分别为2.36 W@3 980.0nm、3.17 W@3 714.2nm和4.13 W@3 278.0nm.     

三维超分子配合物[Zn（C_（12）H_8N_3）_2·H_2O]的水热合成、晶体结构及光致发光1

通过水热法合成了一种三维超分子配合物Zn（C12H8N3）2.H2O,经元素分析、紫外和红外光谱对其进行表征。用X射线单晶衍射测定了其晶体结构,该配合物晶体属单斜晶系,P21/c空间群,晶胞参数为：a=1.25239（10）nm,b=1.30233（11）nm,c=1.33167（11）nm,β=102.6950（10）°,Z=4,[Zn（C12H8N3）2.H2O],Mr=471.81,V=2.1189（3）nm^3,Dc=1.479g·cm^-3,μ=1.189mm^-1,F（000）=968,R1=0.0300,WR2=0.1017,GOF=1.005。该化合物由1个Zn（Ⅱ）离子、2个2-（2-吡啶基）苯并咪唑阴离子和1分子配位水组成。其中2-（2-吡啶基）苯并咪唑的1位氮原子、吡啶环上氮原子及水分子中氧原子与锌（Ⅱ）离子配位,形成五配位的畸变三角双锥结构,单胞分子之间通过氢键O（w）-H…N和π-π堆积作用相互构成三维网状超分子体系。固态荧光测试显示,该配合物具有强的蓝色荧光发射（λmax=456nm）。