Light-Induced Order-of-Magnitude Decrease in the Electric Field for Domain Nucleation in MgO-Doped Lithium Niobate Crystals
نویسندگان
چکیده
周期分極反転素子は,いまや波長変換において欠かせないデバイス であり,その作製技術には高い関心が集まっている.光アシストによ る分極反転法は,従来の櫛型構造電極を用いた分極反転法と比べ,よ り細かい周期の分極反転構造を作製できる方法として注目されてい る.本論文では,下図に示すような光学配置により,ニオブ酸リチウ ム結晶における光照射の分極反転への影響を調べた.著者らは可視光 照射により分極反転ドメインの核形成電場が大幅に減少することを発 見し,その減少率はノンドープ結晶で30%,マグネシウムドープ結 晶で約90%に達するという結果を得ている.また,このような効果 は光照射をしているときのみ起こり,入射する面の方向 (+C面, -C面)には依存しないとも報告している.(図3,表1,文献18) 光アシストによる分極反転のメカニズムは,いまだ解明されていな い部分が多い.本論文のような研究が進み,今後,より短周期で高品 質な周期分極反転素子が作製できるようになることを期待したい. (藤村 隆史) 光アシスト分極反転法の実験配置
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