差周波同期サンプリング法を用いた超高速テラヘル ツ波形計測

差周波同期サンプリング法を用いた超高速テラヘル ツ波形計測

著者 谷 正彦, 古屋 岳, 堀田 和希, 山本 晃司, 宮丸  文章, 西澤 誠治

雑誌名 遠赤外領域開発研究

巻 12

ページ 173‑174

発行年 2011‑06

URL http://hdl.handle.net/10098/3664

♫ᅋἲே 㟁Ꮚ᝟ሗ㏻ಙᏛ఍ ಙᏛᢏሗ

THE INSTITUTE OF ELECTRONICS, IEICE Technical Report INFORMATION AND COMMUNICATION ENGINEERS Vol.110, No.66, LQE2010-2

ᕪ࿘Ἴྠᮇࢧࣥࣉࣜࣥࢢἲࢆ⏝࠸ࡓ㉸㧗㏿ࢸࣛ࣊ࣝࢶἼᙧィ 

㇂ ṇᙪ

ྂᒇ ᓅ

ᇼ⏣࿴ᕼ

ᒣᮏ᫭ྖ

ᐑ୸ᩥ❶

す⃝ㄔ἞

⚟஭኱Ꮫ㐲㉥እ㡿ᇦ㛤Ⓨ◊✲ࢭࣥࢱ࣮ ࠛ

⚟஭┴⚟஭ᕷᩥி

2

ಙᕞ኱Ꮫ⌮Ꮫ㒊 ࠛ

㛗㔝┴ᯇᮏᕷ᪫

ᰴ

ඛ➃㉥እ ࠛ

ᮾி㒔ඵ⋤Ꮚᕷ༓ே⏫

E-mail: [email protected]

࠶ࡽࡲࡋ ᪂ࡓ࡞㠀ྠᮇගࢧࣥࣉࣜࣥࢢ࡛࠶ࡿࠕᕪ࿘Ἴྠᮇࢧࣥࣉࣜࣥࢢࠖἲࢆ⏝࠸ࡓ㉸㧗㏿ࢸࣛ࣊ࣝࢶ(THz) Ἴ ᐃࢆሗ࿌ࡍࡿࠋᕪ࿘Ἴྠᮇࢧࣥࣉࣜࣥࢢ࡛ࡣ㸪࿘ᮇ㛫㝸ࡀ୍ᐃ㔞ቑຍ㸦ࡲࡓࡣῶᑡ㸧ࡍࡿගࣃࣝࢫิ㸪࠾ࡼࡧ ࡑࡢ1࿘ᮇ㛫㝸㐜ࢀࡓගࣃࣝࢫิࢆ࣏ࣥࣉග࠾ࡼࡧࣉ࣮ࣟࣈග࡜ࡋ࡚⏝࠸ࡿࠋ ᐃ᫬㛫❆156psࡢTHzἼᙧࢆ3ms

࡛ ᐃࡍࡿࡇ࡜࡟ᡂຌࡋࡓࠋࡋ࠿ࡋ㸪࣮ࣞࢨ࣮ࡢࢱ࢖࣑ࣥࢢࢪࢵࢱ࣮(~10ps)ࡢࡓࡵTHzࢫ࣌ࢡࢺࣝࡢ ᐃᖏᇦࡀไ 㝈ࡉࢀ࡚࠸ࡿࠋ௒ᚋ㸪 ᐃᖏᇦࢆᣑࡆࡿࡓࡵ࡟ࡣ࣮ࣞࢨ࣮ග※ࡢࢱ࢖࣑ࣥࢢࢪࢵࢱ࣮ࢆపῶࡍࡿᚲせࡀ࠶ࡿࠋ

࣮࣮࢟࣡ࢻ ࢸࣛ࣊ࣝࢶἼ㸪ࢸࣛ࣊ࣝࢶ᫬㛫㡿ᇦศග㸪㠀ྠᮇගࢧࣥࣉࣜࣥࢢ

Ultrafast Terahertz Wave Measurement Based on a New Asynchronous Sampling Method

Masahiko TANI

Takashi FURUYA

Kazuki HORITA

Kohji YAMAMOTO

Fumiaki MIYAMARU

and Seizi NISHIZAWA

1 Research Center for Development of Far-Infrared Region, University of Fukui 3-9-1 Bunkyo, Fukui 910-8507, Japan 2 Fuculty of Science, ShinShu University 3-1-1 Asahi, Matsumoto 390-8621, Japan

3 Advanced Infrared Spectroscopy Co., Ltd. 3-17-16 Sen-nin-cho, Hachioji 193-0835, Japan E-mail: [email protected]

Abstract We report ultrafast terahertz-wave measurements based on a new asynchronous sampling method, “difference frequency sampling”, where an optical pulse train with its interval is incremented by a constant time period and its one-cycle delayed pulse train is used as the pump and probe pulse trains. We demonstrated a 3-msec single-scan measurement for THz wave with a 156-ps time window. The relatively large timing-jitter 㸦~10ps㸧of the laser limited the measurement spectral bandwidth and should be reduced to extend the measurement spectral bandwidth.

Keyword THz Wave, THz time-domain spectroscopy, Asynchronous optical sampling

1.

ࡣ ࡌ ࡵ ࡟

ග ఏ ᑟ ࢔ ࣥ ࢸ ࢼ ➼ ࢆ ⏝ ࠸ ࡓ ࢸ ࣛ ࣊ ࣝ ࢶ ᫬ 㛫 㡿 ᇦ ศ ග ἲ 㸦 Terahertz Time-Domain Spectroscopy, ௨ ୗ THz-TDS࡜ ␎ グ 㸧ࡣ ရ ㉁ ⟶ ⌮ ࡸ ༴ 㝤 ≀ ᥈ ▱ ࡞ ࡝ ࡬ ࡢ ᛂ

⏝ ࡀ ᮇ ᚅ ࡉ ࢀ ࡿ ࠋ ࡋ ࠿ ࡋ ࡞ ࡀ ࡽ 㸪 ྠ ᡭ ἲ ࡛ ࡣ ୍ ⯡ ⓗ ࡟ ᶵ Ე ᘧ 㐜 ᘏ ࢫ ࢸ ࣮ ࢪ ࢆ ౑ ⏝ ࡋ ࡓ ࣏ ࣥ ࣉ ࣭ ࣉ ࣟ ࣮ ࣈ ᪉ ᘧ ࡀ ⏝ ࠸ ࡽ ࢀ ࡿ ࡓ ࡵ 㸪1 Ἴ ᙧ ࡢ ྲྀ ᚓ ࡟ ㏻ ᖖ ᩘ ศ ⛬ ᗘ ࢆ せ ࡍ ࡿ ࠋࡇ ࡢ   ᐃ ᫬ 㛫 ࡀ ⏘ ᴗ ฼ ⏝ ࡬ ࡢ ጉ ࡆ ࡜ ࡞ ࡗ ࡚ ࠸ ࡿ ࠋ

㏆ ᖺ 㸪 㠀 ྠ ᮇ ග ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ 㸦Asynchronous Optical

Sampling, ௨ ୗAOS࡜ ␎ グ 㸧 ࡟ ࡼ ࡾ 㸪 ᶵ Ე ᘧ ᫬ 㛫 ᤲ ᘬ

࡟ ẚ ࡭ 㸪3 ᱆ ⛬ ᗘ ࡢ   ᐃ ᫬ 㛫 ࡢ ▷ ⦰ ࡀ ሗ ࿌ ࡉ ࢀ[1]㸪 THz-TDSࡢ ⏘ ᴗ ฼ ⏝ ࡬ ࡢ ᮇ ᚅ ࡀ 㧗 ࡲ ࡗ ࡚ ࠸ ࡿ ࠋAOSࡣ 㧗 ㏿ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ἲ ࡜ ࡋ ࡚ ඃ ࢀ ࡓ ᡭ ἲ ࡛ ࠶ ࡿ ࡀ 㸪 ௨ ୗ ࡢ ࡼ ࠺ ࡞ ၥ 㢟 Ⅼ ࡀ ࠶ ࡿ ࠋ

(i)   ᐃ ᫬ 㛫 ❆ 㸦 㐜 ᘏ ᫬ 㛫 ࡢ ᤲ ᘬ ᫬ 㛫 ᖜ 㸧 ࡣ ບ ㉳ ࣞ

࣮ ࢨ ࣮ ࡢ ⧞ ㏉ ࡋ ࿘ ᮇ ࡟ ᅛ ᐃ ࡉ ࢀ ࡿ ࠋ ࡋ ࡓ ࡀ ࡗ ࡚ 㸪

㏻ ᖖ ⏝ ࠸ ࡽ ࢀ ࡿ ࣔ ࣮ ࢻ ྠ ᮇ ᆺ ࡢ ࣇ ࢙ ࣒ ࢺ ⛊ ࣞ ࣮ ࢨ ࣮ ࡛ ࡣ 10ns๓ ᚋ ࡢ   ᐃ ᫬ 㛫 ❆㸦 ࡑ ࡢ ㏫ ᩘ ࡀ   ᐃ ࡢ ࿘ Ἴ ᩘ ศ ゎ ୖ 㝈 ࡟ ࡞ ࡿ 㸧࡜ ࡞ ࡿ ࡀ 㸪㧗 ࿘ Ἴ ᩘ ศ

172 173

研究報告１９

ゎ ࢆ せ ࡋ ࡞ ࠸ ᛂ ⏝ ࡛ ࡣ 㸪ࢹ ࣮ ࢱ ྲྀ ᚓ ࡢ ↓ 㥏 ᫬ 㛫 ࡀ ከ ࡃ ࡞ ࡿ ࠋ

(ii) 2 ྎ ࡢ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ ࡀ ࢃ ࡎ ࠿ ࡟ ␗ ࡞ ࡿ ࣞ ࣮ ࢨ ࣮ ࡀ ᚲ せ ࡛ 㸪ࡑ ࡢ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ ࢆ ⢭ ᐦ ࡟ ไ ᚚ 㸪Ᏻ ᐃ

໬ ࡍ ࡿ ᚲ せ ࡀ ࠶ ࡿ ࡓ ࡵ 㸪ᚲ ↛ ⓗ ࡟ ࢩ ࢫ ࢸ ࣒ ࡀ 㧗 ౯

࠿ ࡘ 」 㞧 ࡟ ࡞ ࡿ ࠋ

ᡃ ࠎ ࡣAOSࡢ ၥ 㢟 Ⅼ ࢆ ᨵ ၿ ࡋ 㸪 AOSࡼ ࡾ ࡶ   ᐃ ᫬ 㛫 ࢆ1᱆ ௨ ୖ ▷ ⦰ ࡍ ࡿ ࡇ ࡜ ࢆ ┠ ⓗ ࡜ ࡋ ࡚ 㸪 ᪂ ࡓ ࡞ ࢧ ࣥ

ࣉ ࣜ ࣥ ࢢ ᪉ ᘧ ࡛ ࠶ ࡿ ࠕ ᕪ ࿘ Ἴ ྠ ᮇ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ࠖ ࢆ ᥦ

᱌ ࡋ 㸪 ࡑ ࡢ ཎ ⌮ ᐇ ド ᐇ 㦂 ࢆ ⾜ ࡗ ࡓ ࡢ ࡛ 㸪 ࡑ ࡢ ⤖ ᯝ ࢆ ሗ

࿌ ࡍ ࡿ ࠋ

2. ᕪ ࿘ Ἴ ྠ ᮇ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ࡢ ཎ ⌮

ᕪ ࿘ Ἴ ྠ ᮇ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ࡛ ࡣ1ྎ ࡢ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ ྍ ኚ ࣞ ࣮ ࢨ ࣮ ࢆ ࣏ ࣥ ࣉ ཬ ࡧ ࣉ ࣟ ࣮ ࣈ ග ※ ࡜ ࡋ 㸪 ࣏ ࣥ ࣉ ග

ࡲ ࡓ ࡣ ࣉ ࣟ ࣮ ࣈ ග ࡢ ග ㊰ ࡟ ࣞ ࣮ ࢨ ࣮ ࡢ ᇶ ‽ ⧞ ㏉ ࡋ ࿘ Ἴ

ᩘ ࡢ 㸯 ࿘ ᮇ ศ ࡟ ┦ ᙜ ࡍ ࡿ ᫬ 㛫 㐜 ᘏ ࢆ ୚ ࠼ ࡿ ࠋ ࣞ ࣮ ࢨ ࣮ ࡢ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ ࢆ 㐃 ⥆ ⓗ ࡟ ኚ ໬ ࡉ ࡏ ࡿ ࡇ ࡜ ࡛ 㸪 ࣏ ࣥ ࣉ ග ࡲ ࡓ ࡣ ࣉ ࣟ ࣮ ࣈ ග ࡢ ᫬ 㛫 ᤲ ༳ ࡀ ྍ ⬟ ࡜ ࡞ ࡿ ࠋ ᕪ ࿘ Ἴ

ྠ ᮇ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ࡢ ࢱ ࢖ ࣑ ࣥ ࢢ ࢳ ࣕ ࣮ ࢺ ࢆ ᅗ1࡟ ♧ ࡍ ࠋ ᅗ 1࡛ ࡣ ࣞ ࣮ ࢨ ࣮ ࡢ ග ࣃ ࣝ ࢫ ิ ࡢ ࿘ ᮇ ࡣ 㸪 ึ ᮇ ࿘ ᮇ T

࠿ ࡽ'tࡎ ࡘ ቑ ຍ ࡍ ࡿ ࠋ1࿘ ᮇ 㐜 ࢀ ࡢ ࣃ ࣝ ࢫ ิ ࡜ ඖ ࡢ ࣃ

ࣝ ࢫ ิ ࢆ 㔜 ࡡ ࡿ ࡜ 㸦 ୍ ᪉ ࡀ ࣏ ࣥ ࣉ ග ࣃ ࣝ ࢫ 㸪 ࡶ ࠺ ୍ ᪉ ࡀ ࣉ ࣟ ࣮ ࣈ ග ࡜ ࡋ ࡚THzἼ ࡢ Ⓨ ⏕ ࡜ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ࡟ ⏝

࠸ ࡽ ࢀ ࡿ 㸧㸪㸰 ࡘ ࡢ ග ࣃ ࣝ ࢫ ࡢ ┦ ᑐ 㐜 ᘏ ᫬ 㛫 ࡣ ࣃ ࣝ ࢫ ࡈ

࡜ ࡟'tࡎ ࡘ ࡎ ࢀ ࡚ ࠸ ࡃ ࠋࡇ ࡢ ࡼ ࠺ ࡟ ࡋ ࡚ 㸪⧞ ㏉ ࡋ ࿘ ᮇ 㸦 ࠶ ࡿ ࠸ ࡣ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ 㸧ࡣ ኚ ໬ ࡍ ࡿ ࡀ 㸪AOS࡜ ྠ ᵝ

࡟ ᶵ Ე ⓗ ࡞ ㉮ ᰝ ࡞ ࡋ ࡟ 㸪 㐜 ᘏ ᫬ 㛫 ࢆ ⮬ ാ ᤲ ᘬ ࡛ ࡁ ࡿ ࠋ

ࡲ ࡓ ⧞ ㏉ ࡋ ࿘ ᮇ ࡢ ไ ᚚ ࡟ ࡼ ࡾ 㸪   ᐃ ᫬ 㛫 ❆ ࡣ ௵ ព ࡟ タ ᐃ ࡛ ࡁ ࡿ ࡢ ࡛ 㸪 ᚲ せ ࡞ ࿘ Ἴ ᩘ ศ ゎ ࡟ ྜ ࢃ ࡏ ࡚ タ ᐃ ࡛ ࡁ

ࡿ ࠋ ౛ ࠼ ࡤ 100MHz ࡢ ࣔ ࣮ ࢻ ྠ ᮇ ࣞ ࣮ ࢨ ࣮ ࢆ ⏝ ࠸ ࡓ AOS ࡛ ࡣ 㸪 ⧞ ㏉ ࡋ ࿘ ᮇ ࡣ 10ns ࡛ ࠶ ࡾ 㸪   ᐃ ᫬ 㛫 ❆ ࡶ 10ns ࡜ ࡞ ࡿ 㸦 ࿘ Ἴ ᩘ ศ ゎ ࡣ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ ࡜ ྠ ࡌ 100MHz㸧ࠋ ࡋ ࠿ ࡋ ᚲ せ ࡞   ᐃ ᫬ 㛫 ❆ ࡀ 㸪 Ἴ ᙧ ୰ ᚰ ௜ ㏆ ࡢ 100ps࡛ ࠶ ࡿ ࡞ ࡽ 㸪9.9nsࡣ ↓ 㥏 ࡞ ィ   ᫬ 㛫 ࡜ ࡞ ࡿ ࠋ

୍ ᪉ 㸪 ᕪ ࿘ Ἴ ྠ ᮇ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ࡛ ࡣ ࣞ ࣮ ࢨ ࣮ ࡢ ⧞ ㏉ ࡋ

࿘ Ἴ ᩘ ࢆ ไ ᚚ ࡋ ࡚ 㸪  ᐃ ᫬ 㛫 ❆ ࢆ100ps࡟ ࡛ ࡁ ࡿ ࡢ ࡛ 㸪

↓ 㥏 ᫬ 㛫 ࡀ ࡞ ࡃ 㸪ୖ ࡢ ౛ ࡛ ࡣAOS࡟ ẚ ࡭ ࡚   ᐃ ᫬ 㛫 ࢆ 1/100࡟ ▷ ⦰ ࡛ ࡁ ࡿ ࠋ ࡲ ࡓ ↓ 㥏 ᫬ 㛫 ࡀ ࡞ ࡃ ࡞ ࡗ ࡓ ศ 㸪

ᅗ1 ᕪ ࿘ Ἴ ྠ ᮇ ࢧ ࣥ ࣉ ࣜ ࣥ ࢢ ᴫ ᛕ ᅗ

ྠ ࡌ   ᐃ ᫬ 㛫 ࡛ ಙ ྕ ᑐ 㞧 㡢 ẚ(SNR)ࡶ ྥ ୖ ࡍ ࡿ 㸦 ୖ ࡢ

౛ ࡛ ࡣSNRࡣ10ಸ ᨵ ၿ ࡉ ࢀ ࡿ 㸧ࠋ 3. ᐇ 㦂

ບ ㉳ ග ※ ࡟ ࡣ ⧞ ࡾ ㏉ ࡋ ࿘ Ἴ ᩘ ྍ ኚ ࡢ ࣇ ࢓ ࢖ ࣂ ࣮ ࣞ

࣮ ࢨ ࣮ 㸦 Ἴ 㛗 780 nm,ᖹ ᆒ ฟ ຊ 30 mW, ࣃ ࣝ ࢫ ᖜ130 fs, ᇶ ‽ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ 40 MHz㸧 ࢆ ౑ ⏝ ࡋ ࡓ ࠋ ࣏ ࣥ ࣉ ග ࡢ ග ㊰ 㛗 ࢆ ࣉ ࣟ ࣮ ࣈ ග ࡟ ᑐ ࡋ7.5 m㛗 ࡃ ྲྀ ࡿ ࡇ ࡜ ࡟ ࡼ

ࡾ 㸪40 MHz ࡢ ⧞ ㏉ ࡋ ࿘ ᮇ ࡟ ┦ ᙜ ࡍ ࡿ ᫬ 㛫 㐜 ᘏ ࢆ ୚ ࠼ ࡓ ࠋ ᮏ ᐇ 㦂 ࡛ ࡣ ࣞ ࣮ ࢨ ࣮ ࡢ ⧞ ㏉ ࡋ ࿘ Ἴ ᩘ ࢆ 39.85MHz

࠿ ࡽ40.10 MHzࡲ ࡛   ᐃ ᫬ 㛫3 msec㸦 ⧞ ࡾ ㏉ ࡋ333Hz㸧

࡛ ኚ ໬ ࡉ ࡏ ࡓ ࠋ ࡇ ࡢ ࿘ Ἴ ᩘ ᤲ ᘬ ᖜ ࡣ   ᐃ ᫬ 㛫 ❆156 ps

࡟ ┦ ᙜ ࡋ 㸪3 msec ࡢ ᤲ ᘬ ᫬ 㛫 ࡣ ⣙13 ୓ Ⅼ ࡢ   ᐃ Ⅼ ᩘ

࡟ ┦ ᙜ ࡍ ࡿ ࠋ ࢚ ࣑ ࢵ ࢱ ࣮ ࡟ ࡣ ࣎ ࢘ ࢱ ࢖ ᆺ ග ఏ ᑟ ࢔ ࣥ ࢸ ࢼ ࢆ ౑ ⏝ ࡋ 㸪100 Vp-p㸪100 kHzࡢ ࣂ ࢖ ࢔ ࢫ ኚ ㄪ ࢆ ୚ ࠼ ࡓ ࠋࢫ ࣃ ࢖ ࣛ ࣝ ᆺ ග ఏ ᑟ ࢔ ࣥ ࢸ ࢼ ࡛THzἼ ࢆ ཷ ಙ ࡋ 㧗

㏿ ᛂ ⟅ ྍ ⬟ ࡞ 㟁 Ⲵ ࢔ ࣥ ࣉ ࡛ ቑ ᖜ ᚋ 㸪 㧗 ㏿ ࣟ ࢵ ࢡ ࢖ ࣥ ࢔

ࣥ ࣉ ࢆ ⏝ ࠸ ࡚ ࣟ ࢵ ࢡ ࢖ ࣥ ᳨ ฟ ࢆ ⾜ ࡞ ࡗ ࡓ ࠋ

-100 0 100

-1.0 -0.5 0.0 0.5

Signal(arb. unit)

Time (ps)

ᅗ 2 ᕪ ࿘ Ἴ ྠ ᮇ ࢔ ࣥ ࣉ ࣜ ࣥ ࢢ ࡟ ࡼ ࡾ ྲྀ ᚓ ࡋ ࡓ THz

᫬ 㛫 Ἴ ᙧ ࠋ   ᐃ ᫬ 㛫3ms㸪   ᐃ ᫬ 㛫 ❆156 psࠋ 4. ⤖ ᯝ ࡜ ⪃ ᐹ

ᚓ ࡽ ࢀ ࡓ ᫬ 㛫 Ἴ ᙧ ࢆ ᅗ2࡟ ♧ ࡍ ࠋ ཯ ᑕ ࡟ ࡼ ࡿ ࣋ ࣮ ࢫ

ࣛ ࢖ ࣥ ࡢ ṍ ࡳ ࡣ ࠶ ࡿ ࡶ ࡢ ࡢ0 ps௜ ㏆ ࡟THzἼ ᙧ ࣆ ࣮ ࢡ

ࢆ ᚓ ࡓ ࠋ ࣆ ࣮ ࢡ ఩ ⨨ ࡢ ࡎ ࢀ ࡣ 㐜 ᘏ ⤒ ㊰ ࡀ7.5 m࠿ ࡽ ഹ

࠿ ࡟ ࡎ ࢀ ࡚ ࠸ ࡓ ࡓ ࡵ ࡛ ࠶ ࡿ ࠋࡇ ࡢ ⤖ ᯝ ࠿ ࡽ 㸪3 msࡢ ᤲ

༳ ᫬ 㛫 ࡛ ᫬ 㛫 ❆156 psࡢTHzἼ ᙧ ࡀ   ᐃ ྍ ⬟ ࡛ ࠶ ࡿ ࡇ

࡜ ࢆ ☜ ㄆ ࡛ ࡁ ࡓ ࠋ ୍ ᪉ 㸪   ᐃ Ἴ ᙧ ࡣ ⮬ ື ࢫ ࢸ ࣮ ࢪ ࢆ ⏝

࠸ ࡓ 㐜 ᘏ ᫬ 㛫 ㉮ ᰝ ࡢ ሙ ྜ ࡼ ࡾ ࡶ ࠿ ࡞ ࡾ ᣑ ࡀ ࡗ ࡚ ࠸ ࡿ 㸦 ࡋ ࡓ ࡀ ࡗ ࡚ ࢫ ࣌ ࢡ ࢺ ࣝ ᖏ ᇦ ࡀ ⊃ ࠸ 㸧ࠋࡇ ࢀ ࡣ ⏝ ࠸ ࡓ ࣞ

࣮ ࢨ ࣮ ࡢ ࢱ ࢖ ࣑ ࣥ ࢢ ࢪ ࢵ ࢱ ࣮ ࡟ ㉳ ᅉ ࡍ ࡿ ࡜ ᛮ ࢃ ࢀ ࡿ ࠋ

┦ ஫ ┦ 㛵 ࡟ ࡼ ࡿ ࢱ ࢖ ࣑ ࣥ ࢢ ࢪ ࢵ ࢱ ࣮ ࡣ 10ps ᙅ ࡛ ࠶ ࡗ ࡓ ࠋ ௒ ᚋ 㸪 Ἴ ᙧ   ᐃ ࡢ ᫬ 㛫 ศ ゎ ࢆ ᨵ ၿ ࡍ ࡿ 㸪 ࡍ ࡞ ࢃ ࡕ   ᐃ ࡢ ࢫ ࣌ ࢡ ࢺ ࣝ ᖏ ᇦ ࢆ ᣑ ࡆ ࡿ ࡓ ࡵ ࡟ ࡣ 㸪 ࣞ ࣮ ࢨ ࣮ ග

※ ࡢ ࢱ ࢖ ࣑ ࣥ ࢢ ࢪ ࢵ ࢱ ࣮ ࢆ ప ῶ ࡍ ࡿ ᚲ せ ࡀ ࠶ ࡿ ࠋ ᮏ ◊ ✲ ࡣ JSTඛ ➃ ィ   ศ ᯒ ᢏ ⾡ ࣭ᶵ ჾ 㛤 Ⓨ ஦ ᴗ ࡟ ࡼ

ࡿ ຓ ᡂ ࢆ ཷ ࡅ ࡚ ⾜ ࢃ ࢀ ࡓ ࠋ

ᩥ ⊩

[1] T. Yasui, E. Saneyoshi, and T. Araki: Appl. Phys.

Lett. 87, 061101 (2005).

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