BBO晶体的五倍频

本文报道了用BBO晶体对Nd:YAG激光器输出的1064nm光的五倍频,获得了213nm的紫外输出,266nm转换至213nm的转换效率达48%.并用数值积分的方法从理论上分析了1064nm与266nm的混频过程,得出的结论与实验结果相符.     

利用椭圆高斯光束产生266nm紫外连续激光

本文采用商用532 nm激光器作为基频光源,利用偏硼酸钡(β-BBO)晶体进行外腔倍频,实现了266 nm连续激光的高效输出.文中详细模拟了BBO晶体中的束腰形状对倍频效率的影响,仿真和实验结果均表明椭圆高斯光束可以有效改善走离效应,提高倍频转换效率.通过优化蝶形倍频腔,可以使椭圆高斯光束在腔内共振,当1 W基频光输入时可输出约180 mW的266 nm紫外连续激光,倍频转换效率达到18%.     

Harmonic and sum-frequency generation of pulsed laser radiation in BBO,LBO, and KD*P

The optical properties of the nonlinear crystals lithium borate (LBO), barium borate (BBO) and deuterated potassium phosphate (KD*P) are compared for second and third harmonic generation of Nd:YAG laser radiation. In an experimental investigation the conversion efficiency has been measured as a function of the energy density of 8 ns long laser pulses, generated by a commercial Nd:YAG oscillator-amplifier system. In LBO and BBO the second harmonic generation saturates at an energy density of about 1.5 J cm^–2 at efficiencies of 55–60%. In KD*P comparable efficiencies (40–55%) require energy densities of 2–2.6 J cm^–2. Similar results are obtained for frequency tripling. In LBO and BBO saturated efficiencies of 20–25% are measured at an energy density of about 1.5 J cm^–2. In KD*P efficiencies of 20% are obtained at energy densities exceeding 2 J cm^–2. Besides for doubling and tripling of Nd:YAG laser radiation the phase-matching is calculated for frequency conversion of tunable laser light. The results demonstrate that in LBO and BBO phase-matched sum-frequency mixing of UV and infrared laser light generates tunable radiation at wavelengths as short as the transmission cut-off at 160 nm and 190 nm, respectively.     

飞秒脉冲激光的倍频实验研究

用互类匹配ＢＢＯ晶体对近红外波段钛宝石飞秒脉冲激光做倍频实验，取得近３０％的转换效率，对飞秒脉冲激光倍频的有关问题进行了分析讨论．     

Two-order Interference of Single Photon

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｎｑｕａｎｔｕｍｃｏｍｍｕｎｉｃａｔｉｏｎａｎｄｑｕａｎｔｕｍｃｏｍｐｕｔｉｏｎ ,ｔｗｏ ｓｔａｔｅｓｙｓｔｅｍｓｈａｖｅｂｅｅｎｕｓｅｄｔｏｅｎｃｏｄｅａｑｕａｎｔｕｍｂｉｔｉｎｆｏｒｍａｔｉｏｎａｎｄｗｅｔｒａｄｉｔｉｏｎａｌｌｙｒｅｐｒｅｓｅｎｔｔｈｅｔｗｏｑｕａｎｔｕｍｓｔａｔｅｓｂｙ 0〉ａｎｄ 1〉 ,ｒｅｓｐｅｃｔｉｖｅｌｙ .Ａ ｑｕａｎｔｕｍｂｉｔｃａｎｂｅｒｅｐｒｅｓｅｎｔｅｄｂｙａｓｉｎｇｌｅ ｐａｒｔｉｃｌｅｓｙｓｔｅｍ ,ａｎｄｔｗｏｑｕａｎｔｕｍｂ…     

BBO晶体中飞秒脉冲的二次和三次谐波振荡产生

同时考察了群速色散失配、最低阶群速色散和二阶群速色散。研究了在ＢＢＯ晶体中飞秒激光脉冲的谐产生，计算了ＢＢＯ晶体的作为波长函数的晶体的最低阶和二谐群速色散，借助求解改进的耦合波方程的数值计算，得到了飞秒脉冲的二次及三次谐波辐射，分析了最低工阶及二阶ＧＶＤ对于基波脉冲和谐波脉的影响，最后考虑了三次谐波产生中群速失配的补偿。     

BBO晶体四倍频全固态小功率紫外激光器

 利用KTP晶体和BBO晶体,进行了激光二极管泵浦的Nd:YVO₄声光调Q激光脉冲四倍频实验。在不同绿光功率入射时,获得光束的束腰半径和紫外转换效率的依赖关系:当绿光功率为1.10 W,束腰半径为12.4 μm时,得到了210 mW的准连续266 nm紫外脉冲输出,四倍频转换效率为19.1%。实验还对紫外远场光斑分别在o光振动面和e光振动面内进行分析,指出了BBO晶体在该两平面内不同的倍频接受角是造成椭圆形紫外光斑和主光斑附近明暗条纹的主要原因。     

Theoretical treatment and simulation of new UV crystal CsLiB6O10 in third-harmonic generation

We calculated theoretically the properties of the nonlinear crystal CsLiB₆O₁₀ (CLBO) in third-harmonic generation (THG). These are the phase matching angle, the effective nonlinear coefficient, the walk-off angle, the permitted angle, and the permitted wavelength, and we found that CLBO has a small walk-off angle and large permitted parameters, as compared with BBO. The numerical simulation curves of the conversion efficiency were obtained for the case where CLBO was used in THG of a Q-switched Nd:YAG laser with a wavelength of 1064 nm and different pump powers and the optimized efficiency was as high as 22%. All this suggests that the CLBO crystal is more suitable for generating intense higher order harmonic radiation.     

A comparative study of laser second harmonic generation in some crystals

Comparison of the conversion efficiency for efficient second-harmonic generation of Nd: YAG laser radiation is reported for KDP, LAP, KTP, BBO and LBO crystals. Conversion efficiencies as high as 50% and 46% were obtained for our laboratory-grown KDP and LAP crystals respectively, for power densities well below their damage thresholds.     

Efficient generation of tunable VUV laser radiation below 205 nm by SFM in BBO

Design and performance characteristics of a tunable dye laser system for sum frequency mixing (SFM) in a BBO crystal are presented. The system is composed of two tunable pulsed dye lasers pumped synchronously by the second harmonic of a commercial Nd:YAG laser. The radiation produced by the first dye laser is frequency doubled by second-harmonic generation (SHG) in KDP and subsequently mixed by SFM in BBO with the light of the second dye laser. The interest was focussed on generation of tunable laser radiation below 205 nm with high output power and long-time wavelength stability. High conversion efficiencies enable output energies of 100 J (20 kW) at 196 nm using only moderate Nd:YAG pump energies of 67 mJ. Altogether, a laser system with very good specifications for analytical application in the near VUV spectral region is reported.     

激光二极管侧面泵浦高功率266 nm紫外激光器

 报道了一种半导体激光列阵侧面泵浦Nd：YAG四倍频266 nm全固态紫外激光器,采用Z型腔结构,Ⅰ类临界相位匹配LBO和BBO晶体分别作为二倍频晶体和四倍频晶体。在调制频率为5 kHz时,最终获得了2.1 W的266 nm紫外激光输出,单脉冲能量420 μJ, 绿光到紫外激光的转换率为13.13%,在相同的泵浦功率下利用V型腔结构仅获得305 mW的266 nm紫外激光输出。     

Design of the Seed Source for High Power KrF Excimer Laser System

１ＩｎｔｒｏｄｕｃｔｉｏｎＥｘｃｉｍｅｒｌａｓｅｒｓａｒｅｔｈｅｐｕｌｓｅｄｇａｓｌａｓｅｒｗｈｉｃｈｏｐｅｒａｔｅａｔａｎｕｍｂｅｒｏｆｆｉｘｅｄｗａｖｅｌｅｎｇｔｈｓｉｎｔｈｅｒｅｇｉｏｎｏｆｕｌｔｒａｖｉｏｌｅｔ．Ｈｏｗｅｖｅｒ,ｉｔｓｐｕｌｓ...     

Harmonic generation in bismuth triborate (BiB3O6)

We report a study of second- and third-harmonic generation in BiB₃O₆ (BiBO). The effective nonlinearity, phase-matching angle, acceptance bandwidth, and walk-off are calculated and analyzed within the principal planes of the optical indicatrix. In the experiment, the phase-matched harmonic generation is investigated within the xz and yz planes. Also, the temperature dependence of the noncritical phase matching for laser radiation propagating along the z axis is measured for second-harmonic generation (SHG) at crystal temperatures of 25–265^∘C. The corresponding wavelengths of the laser radiation are in the range of 1.16 to 1.34μm. In addition, SHG of 1342-nm radiation of a q-switched Nd:YVO₄ laser system is investigated for noncritical and critical phase matching. The achieved conversion efficiencies are 59% and 20%, respectively. Besides SHG, third-harmonic generation (THG) of 1064-nm, ns laser pulses is investigated. The measured conversion efficiency is as high as 34%. For THG the properties of BiBO are compared with those of BBO and LBO.     

相位失配法实现倍频稳定输出的模拟分析

 对BBO晶体Ⅰ类相位匹配倍频过程和KTP晶体XY平面内的Ⅱ类相位匹配倍频过程进行数值模拟,结果表明：Ⅰ类和Ⅱ类相位匹配倍频过程,都可通过引入适量的相位失配量实现稳定倍频输出;随着相位失配量的增大,实现稳定倍频输出所需的晶体长度都变小,倍频稳定输出起伏变小,倍频转换效率有不同程度的下降;相对于XY平面内的Ⅱ类相位匹配倍频过程,BBO晶体的Ⅰ类相位匹配倍频过程对相位匹配偏离角更敏感,且稳定输出时倍频转换效率更低。     

Generation of UV radiation at 335.5 nm based on frequency-quadrupling of a diode-pumped Nd:YVO4 laser

The generation of ultraviolet （UV） light at 335.5 nm based on frequency quadrupling of a diode-end- pumped Q-switched Nd：YVO4 laser at 1342 nm was demonstrated. KTP crystal was used for generation of wavelength of 671 nm by intracavity doubling and LBO （BBO） crystal was exploited for the subsequent external fourth harmonic generation （FHG）. With 6.3-W absorbed pump power and 10-kHz frequency repetition rate, the UV output power of 35 and 63 mW were obtained by using LBO and BBO as frequency quadrupling nonlinear crystals, respectively. The experimental results show that the conversion efficiency （red-UV） of 6.4% for BBO crystal is higher than that of 3.5% for LBO crystal, but the UV beam quality obtained by LBO crystal is better than by BBO crystal.     

在BBO中产生217.3-2 21.4nm高功率和频输出

用Q-YAG激光的三次谐波(355nm)与调谐的Rh·6G染料激光在β-BaB2O4(BBO)晶体中和频,获得217.3～221.4nm连续调谐输出,和频输出的最大能量为250μJ,转换效率为11%.我们还讨论了获取最大和频输出能量的一些实验条件.     

Picosecond Self-modelocked Wavelength Tunable Ti:Al_2O_3 Laser

1.IntroductionTi:Alzoscrystalasabroadtunablesolid--statelasermaterialbasedonvibronicallybroadenedtransitionsinmetalions,hasseenaresurgenceofresearchanddevelopmentrecently.TheadvantagesofTi:A12O3crystalincludebroadabsorptionandemissionspectrumbandwidth,highbeamqualityandcapabilityofallsolid--stateoperation.KerrlensmodelockedTi:sapphirelaserspumpedbyCWargon--ionlasersarewidelyusedasasourceoffemtosecondopticalpulsesll~'j.KerrlensmodelockingutlizestheorstiealKerreffecttoproduceafastpulse--shor…     

BBO晶体在CPM非稳腔Nd：YAG激光器中的腔内倍频效应

本文报道用BBO晶体作为腔内倍频元件,在带抗共振环的对撞脉冲锁模非稳腔Nd:YAG激光器中实现腔内倍频激光输出,获得倍频能量转换效率为50.4%.理论和实验均证明了该激光器的BBO腔内倍频转换效率高于腔外倍频转换效率.     

Increased spectral bandwidths in nonlinear conversion processes by use of multicrystal designs

The fourth-harmonic generation of broadband 243-nm radiation is reported. The broadband radiation is achieved by implementation of a multicrystal design to overcome spectral bandwidth limitations, and a plane-wave analysis is developed that shows increased spectral bandwidths for these designs. The fourth harmonic of a Cr:LiSAF laser operating at 972 nm is generated in beta-barium borate (BBO). The results demonstrate a spectral bandwidth at 243 nm more than five times broader than that which is expected from a single BBO crystal of equivalent length.     

高峰值266nm紫外激光器

报道了一种激光二极管(LD)端面泵浦的Nd:YAG声光Q开关高峰值功率266nm紫外激光器。该激光器采用紧凑的平平腔结构,LBO和BBO分别作为其二倍频和四倍频晶体。分别利用高偏振比LD阵列(40∶1)、低偏振比LD阵列(5∶1)及低偏振LD阵列腔内放置布氏片结构进行了实验。当注入功率为25W、调制频率为10kHz时,以上结构分别得到功率0.85,0.61和0.72W的266nm紫外光输出。其中,采用高偏振比LD阵列的输出功率最高,单脉冲能量为85μJ,脉宽为5ns,峰值功率高达17kW,泵浦光到紫外光的光-光转换率达3.4%。