紫外光预电离ArF和KrF准分子激光器

本文报导紫外光预电离ArF和KrF准分子激光器的实验研究.输出激光能量ArF105毫焦耳、KrF185毫焦耳.文中讨论了各种参数对激光性能的影响.     

光刻用准分子激光器

用KrF准分子激光器作光源的64M bit-DRAM的光刻生产线已正式引进到半导体工厂。准分子激光器的生产也逐渐走向正规。并且,ArF准分子激光器光刻的研究开发是以1G bit DRAM为主,不仅要提高准分子激光器的性能.还要达到高可靠性、易维修、操作简单。本文将介绍准分子激光器在高性能、高可靠性方面的研究课题及现状。其次介绍生产用KrF准分子激光器以及研究用ArF准分子激光器的最新开发动向及其外围课题。     

氟化氪(KrF)准分子激光器

自从1975年Velazco和Setser提出稀有气体卤化物准分子激光器方案以来,在短短两年的时间里,准分子激光器获得了极为迅速的发展,XeBr、XeF、KrF、ArFXeCl、KrCl、ArCl等稀有气体卤化物准分子激光器先后研制成功,而其中被公认为最有希望获得高能量、高功率、高效率的体系是KrF.与XeF相比,KrF有更高的饱和能量密度,因为它的感应辐射截面比 XeF/小一个     

KrF激光器的新记录：平均功率为200瓦

通用电话电子希尔伐尼亚公司创造了氟化氪激光器平均输出功率的新记录——249毫微米处气体输运KrF系统产生的功率达210瓦。对KrF激光器来说，1千赫之重复率也是从未达到过的最高值。     

高效率放电抽运KrF准分子激光器

248 nm放电抽运KrF准分子激光器在微电子学和医学等领域有重要的应用价值。在大多数应用中,激光器的最大输出效率和能量都是十分重要的参数。为了提高激光器输出效率和能量,实现KrF准分子激光器的稳定放电,采用新型开关电源和结构紧凑的张氏电极,并通过优化储能/放电电容比例和工作气体配比等方法,研制出了一台小型高效率放电抽运KrF准分子激光器。研究了开关电源对充放电特性的影响,以及气体配比对激光输出效率和能量的影响。该激光器的各项参数相比以往的产品有了较大改善,可重复频率为1~80 Hz,输出效率最高达2.5%,最大单脉冲输出能量380 mJ;当工作电压高于25 kV时,激光输出能量不稳定度约为1.8%。     

XeF(C-Α)准分子激光器—— 一种可见波段高效可调谐激光

到目前为止，具有较高功率和高效率的激光器仅存在于红外和紫外波段。CO2激光器(λ=248 nm)的效率达到30%，KrF激光器(λ=248 nm)的效率为15%。在可见光波段 (400~700 nm)仅有染料激光器，其效率在1%以下，它用于工业的可能性实际上无从提起。幸好这一欠缺可由XeF(C—A)激光器来弥补。像KrF激光器一样，它属于准分子激光器。     

CLEO′85会议上的气体激光器、半导体激光器和若干新应用

从这次会议发表的文章内容看,可以认为CLEO充分显示了它的高水平。据日本电信电话株式会社茨城电气通信研究所内田帧二参加这次会议所见,8fs超短脉冲发生、光孤立子波传播、半导体激光器的15GHz直接调制等专题都具有极高的技术水平。下面就日本等国有关人员参加这次会议的见闻摘录如下。在气体激光器方面,最近的中心话题是准分子激光装置及其有关的应用,谈及的内容很宽,从核聚变用电子束泵浦KrF激光器到微电子学加工。美国Los Alamos国家实验室R.J.Jensen以“Los Alamos KrF激光器计划”为题做了特邀报告。在该计划中,现在研     

符合亚微型平版印刷术要求的紫外准分子激光器

鉴于1988年3月在加利福尼亚州圣克拉拉举办的SPIE微型平版印刷术专题讨论会,Lambda Physik公司将推出一种OEM平版印刷术激光器.据马萨诸塞州阿克顿办事处的Lindsay Austin说,KrF激光器在248.4nm波长上发射功率2W.     

专利与文献

一、激光器件4001 大功率固体激光器固体し-ザ-の高出力化,し-ザ-研究,金辺忠他,1987,Vol.15,NO.6.pp.332-340.本文介绍连续或高重复脉冲固体激光器,脉冲输出之大功率激光系统,并介绍了提高输出功率的要素和有关的系统技术。[珂]4002 大功率气体激光器氖体し-ザ-の高出力化,し-ザ-研究,植田宪一,1987,Vol.15,NO.6,pp.342-346.本文首先概括了大功率气体激光器的现状,然后重点叙述了电子束激励KrF激光器的现状和发展前景。[珂]4003 大功率半导体激光器     

宽带高光束质量KrF激光器的实验研究

利用SBS作为相位共轭镜,对宽带KrF自由振荡激光器的光束质量进行了改善。在KrF激光能量为36mJ,脉宽为13.7ns,束散角为9.5倍衍射限的条件下,获得输出能量为20.8mJ,脉宽为4.3ns,束散角为6.4倍衍射限的高光束质量宽带KrF激光。     

双向四电子束泵浦KrF主放大器能量沉积

用三维电子输运Ｍｏｎｔｅ－Ｃａｒｌｏ（ＭＣ）方法研究了双向四电子束泵浦ＫｒＦ准分子激光器ＭＯＰＡ系统中主放大器（Ｈ１Ｍ）的能量沉积空间分布。计入了Ｈｉｂａｃｈｉ结构和主膜的影响。对０．５ＭｅＶ的电子，泵浦方向能量沉积基本均匀，而在轴向，因为两窗口间的１４ｃｍ“死区”使得能量沉积呈“马鞍形”，峰谷比为２～３。给出了能量沉积的总量及能量沉积效率与电子束能的关系曲线，为Ｍａｒｘ发生器的二极管电压进行优化设计提供了依据。     

确定KrF激光光束品质的光楔法

运用光楔对发散角较大、光束品质不够好的ＫｒＦ激光光束进行了分光测量，测量了ＫｒＦ激光光束的一维能量分布和远场发散角；具体计算了ＫｒＦ激光光束剖面的能量密度分布的均匀性。     

Tunable multiline distributed feedback dye laser based on the phenomenon of excitation energy transfer

Tunable multiline distributed feedback (DFB) lasing has been observed in the mixture of dyes rhodamine 6G (R6G) and cresyl violet (CV). The dye-pair is pumped by the two pairs of the pump beams derived from a common source at two different angles. A variation in DFB geometry up to seven orders suggests that the third order Bragg diffraction is suitable for such studies. A detailed study at high dye concentrations has been done by steady-state and ps time-resolved spectroscopy. The energy transfer phenomenon and the self-absorption mechanism both, are found to be responsible for the observed tunability and multiline lasing. The threshold energies required for the DFB lasing are also given here.     

Analysis of quenching conditions of Fabry-Perot mode lasing in semiconductor stripe-contact lasers

Radiative characteristics of semiconductor stripe-contact lasers operating under quenching conditions of Fabry-Perot-mode lasing are studied. It is found that reversible turning off of Fabry-Perot-mode lasing is caused by switching to closed-mode lasing. Radiative characteristics of the closed mode are controlled by the mode structure with the close-to-zero loss for radiation output, which covers the entire crystal. The main threshold conditions of closed-mode lasing are a decrease in interband absorption in the passive region and an increase in the modal gain of the closed-mode lasing line. It is shown that a decrease in interband absorption in the passive region can be provided by both spontaneous emission from the injection region and lasing-mode photons. An increase in the modal gain of the closed-mode lasing line is provided by shifting the energy minima of the conduction band and maxima of the valence band of the injection region with respect to the energy bands of the passive region.     

Efficient E-beam excitation of XeCl

Efficient laser output at 308 nm has been obtained from XeCl in an Ne/Xe/HCl mixture at a pressure of 4 atm bye-beam excitation and bye-beam controlled discharge pumping. Maximum energy extraction is 7 J/1 fore-beam excitation and 9 J/1 for thee-beam controlled discharge. Efficiencies based on total energy deposited in the gas are approximately 4 percent. Similar results were obtained with KrF in the same device, indicating that undere-beam ore-beam controlled discharge excitation, XeCl may be as efficient as KrF.     

KrF激光和脉冲CO2激光损伤K9玻璃的实验对比与分析

对KrF准分子激光辐照K9玻璃进行了损伤实验,并与脉冲CO2激光损伤K9玻璃进行了对比分析,研究了紫外和远红外两种激光系统对同种光学材料的损伤特性。实验结果结果表明,KrF准分子激光和脉冲CO2激光对K9玻璃的损伤形貌基本相同,损伤主要是热力耦合损伤机制,但是两者在损伤阈值和损伤时间等方面仍有很大差别。与脉冲CO2激光相比,K9玻璃的KrF准分子激光损伤阈值更低,并且损伤持续时间更短。通过两类激光在波长和光子能量上的巨大差异可以很好地解释这一现象。该研究结果对准分子激光在空间工程应用上有着非常重要的参考价值。     

SPPs激射中Airy表面等离子的特性分析

为了研究表面等离子体(SPPs)传播产生的Airy等离子的特性,分析和仿真了Airy等离子的独特性质。利用SPPs的激射原理,对Airy等离子的本征态进行了理论分析,研究了光栅耦合SPPs的激射结构中Airy等离子的性质。结果表明:无衍射的Airy表面等离子不仅具有在近场能量放大和快速传播的特性,而且还能利用其特性控制光束的传播;Airy表面等离子只有在一定宽度下与光激发的相互作用才能抑制能量损耗,在基质宽度小于600 nm左右时无法出现显著的Airy表面等离子;不同宽度的基质条件下激射能量与产生Airy离子的趋势一致;Airy表面等离子在激发能量较小时就能实现快速传播,在2.3 eV作用时能量的增加对Airy的等离子的作用不再明显。这一研究对于SPPs的强局域化应用实现、表面光学处理和线性控制无衍射SP光学产生了积极的作用。     

Room-Temperature Exceptional-Point-Driven Polariton Lasing from Perovskite Metasurface

Excitons in lead bromide perovskites exhibit high binding energy and high oscillator strength, allowing for a strong light-matter coupling regime in the perovskite-based cavities localizing photons at the nanoscale. This opens up the way for the realization of exciton-polariton Bose–Einstein condensation and polariton lasing at room temperature – the inversion-free low-threshold stimulated emission. However, polariton lasing in perovskite planar photon cavities without Bragg mirrors has not yet been observed and proved experimentally. In this study, perovskite metasurface is employed, fabricated with nanoimprint lithography, supporting so-called exceptional points to demonstrate the room-temperature polariton lasing. The exceptional points in exciton-polariton dispersion of the metasurface appear upon optically pumping in the nonlinear regime in the spectral vicinity of a symmetry-protected bound state in the continuum providing high mode confinement with the enhanced local density of states beneficial for polariton condensation. The observed lasing emission possesses high directivity with a divergence angle of 1° over one axis. The employed nanoimprinting approach for solution-processable large-scale polariton lasers is compatible with various planar photonic platforms suitable for on-chip integration.