Three-Photon Absorption in Napthalene Crystals by Laser Excitation
Three-Photon Absorption in Napthalene Crystals by Laser Excitation
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DOI：
10.1103/physrevlett.12.612
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发表时间：
1964-06
影响因子：
8.6
通讯作者：
S. Singh;L. Bradley
中科院分区：
文献类型：
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作者：
S. Singh;L. Bradley
来自脉冲红宝石激光器的强烈单色辐射已成功地用于证明固体中的双光子过程。我们通过观察在25 000到31 000厘米之间的紫外荧光的产生，在红宝石激光的14400厘米线激发下发现了萘单晶的三光子吸收。结晶萘是一种适合观察三光子过程的材料，因为它在激光频率或两倍激光频率（28800 cm'）处都没有吸收带系统。最低的三重态激发态和单重态激发态的0-0跃迁分别位于21 300和31 700 cm'处。但存在较强的吸收体系~（f= 0）。132)在40000到45000厘米之间，激光的三光子吸收可以发生。用熔体和正己烷溶液中的区域精炼材料生长出萘单晶。大脉冲(0。由24000转/分旋转棱镜开关的红宝石激光Q正入射于萘晶体的ah面。激光腔的发射端由康宁2-58红通滤光片组成，以消除氙气闪光灯发出的杂散紫外线到达同一位置的可能性
The intense monochromatic radiation from pulsed ruby lasers has been successfully used for demonstrating two-photon processes''in solids.% e have detected three-photon absorp-tion in single crystals of naphthalene excited by the 14400 cm'line of a ruby laser by observing the generationof uv fluorescent light between 25 000 and 31 000 cm'. Crystalline naphthalene is a suitable mat, erial for observing a three-pho-ton process because it has no absorption band system at either the laser frequency or twice the laser frequency (28800 cm'). The 0-0 tran-sitions of the lowest triplet and singlet excited states are situated at 21 300 and 31 700 cm', respectively. However, there is a relatively strong absorption system~(f= 0. 132) between 40000 and 45000 cm' to which three-photon ab-sorption from the laser can take place. Single crystals of naphthalene were grown from zone-refined material fromthe melt as mell as from solution in normal hexane. The unfocused red beam from a giant-pulse (0. 07-joule output) ruby laser Q switched by a 24000-rpm rotating prism was incident normal to the ah plane of the naphthalene crystal. The emitting end of the laser cavity mas formed by a Corning 2-58 redpass filter to eliminate the possibility of stray uv light from the xenon flash lamp reaching the sam-