經濟部中央標準局貝工消费合作社印製 Α7 Β7 五、發明説明（i ) 發明背景 快速且大範圍之掃描式光學延遲裝置有許多的用途， 諸如光學倍頻自相關器[Chi-Luen Wang and Ci-Ling Pan，Opt· Lett·, 20, 1292 (1995)]以及栗-探（pump probe)實驗[Feruz Ganikhanov， Gong-Ru Lin, Wen-Chungg Chen, C.-S. Chang, and Ci-Ling Pan, 67, 3465 (1995)]等。目前較常見的方式，是在自相關器中置入一個 抖動器[R· F. Fork and F. A. Beissoer，Appl. Opt. 3534 (1978)]或是旋 轉平行鏡組[Z. A. Yasa and N. M. Amer，Opt. Commun. 36, 406 (1981)] 的掃插式光學延遲元件，可將光脈衝之自相關訊號經由示 波器顯示出來。此外，利用光柵、透鏡以及振鏡的組合， 可以得到掃描速度高達百赫茲的光學延遲[Z. A. Yasa and N. M. Amer，Opt. Commun. 36, 406 (1981)]。然而上述的各種方式的 掃描範圍皆只有數皮秒，如果欲以此方式掃描寬度較寬的 光脈衝或是響應時間較長之泵探實驗，是無法達成的。此 外，利用光電式量測電晶體之S參數時[K.F.Kw〇ng，D. Yankelevich, K. C. Chu, Heritage, and A. Dienes, Opt. Lett. 18, 558 (1993)]，需要有較長時間之光學延遲，以便能精確得到元 件低頻的響應。利用凸輪與滑軌的組合，可以產生3 0 0皮 秒的掃描式光學延遲[D. C. Edelstein，R. B. Romney, and M. Scheuermann, Rev. Sci. Instrum. 62, 579 (1991)];而利用旋轉稜鏡的 組合，已可達成範圍高達1奈秒（nanosecond)之快速掃描自 相關器[G. Xinan，M. Lambsdorff，J. Kuhl，and E. Biachang, Rev. Sci. Instrum. 59, 2088 (1988)]。 -3- 本紙張尺度適用中國國家標準（CNS ) A4規格（21〇χ297公釐） ----------農-- {請先閱讀背面之注意事項再填寫本頁) -·* 經濟部中央標準局員工消費合作社印製 〇l^44〇 a7 ____B7____ 五、發明説明（2 ) 發明之詳細說明 本發明利用一個新設計的螺旋形反射面鏡，作爲快速 且較大範圍之掃描式光學延遲線，於本發明之一較佳具體 實施例中已可達成八十皮秒的掃描範圍，且已運用於二倍 頻非線性自相關器中，成功的掃描出皮秒級的光脈衝自相 關訊號。 圖（一）是依本發明之一較佳具實施例所完成的螺旋形 反射面鏡的結構示意圖。螺旋形反射面鏡的數學方程式可 以用柱座標描述如下： 2 π z — d φ = 0 ' (1) 其中2與0分別是沿著轉軸與轉動方向的座標軸之値，d 則是螺牙距。而垂直於其表面之正則化（normalized)法 線可表爲： η = -2Kp z--j -- - φ (2) 」4π「ρ2 + d2 ^4π2ρ2 +d2 只要入射光的方向平行於轉軸（即ζ軸），則鏡面旋轉 時入射光在鏡面反射之點的半徑P將保持固定，再由公式 (2)得知，反射點的法線的方向亦將保持不變，也就是反 射光的方向保持固定，只是有一個空間上微小的平移，如 果將反射光以透鏡聚焦，可以在焦平面將光束聚在同一點 上。 -4- 本紙張尺度適用中國國家橾準（CNS ) A4規格（210X297公釐） ------^----β —— ί請先閱讀背面之注意事項再填寫本頁) .1.Τ B7____ 五、發明説明（3 ) 爲證實此槪念，如圖（一）所示之螺旋形反射面鏡被製 作，其製作的方式是先以車床切削一個圓柱鋁塊，類似方 形螺紋的作法，做出粗略的形狀後，再以不同粗糙度的砂 紙，加以多層次的硏磨、拋光，直到表面達到反射面鏡的 要求。其直徑（D)是50mm，螺牙距（d)是12mm，深（T) 是15mm。該螺旋形反射面鏡的轉軸被連接上一個直流伺 服馬達（未示於圖中），做連續性的旋轉。當一入射光以平 行於該轉軸的方向射入後，經由鏡面反射會生一反射光， 該反射光的光程因該螺旋形反射面鏡的鏡面被旋轉，會不 斷的線性改變，其光程變化如圖（二）所示，其週期決定於 馬達的轉速，總光程差則決定於螺牙距，在本實施例中是 八十皮秒，相對於光束在12mm長度來回的時間。.如果欲 以此方式得到奈秒級之總光程差，則螺牙距的大小須高達 150mm，或是利用多個螺旋形反射面鏡進行來回多次反 射。 經濟部中央標準局貝工消費合作社印製 .(請先閱讀背面之注意事項再填寫本") 爲證明本發明此一實施例的光學延遲線（含屬（一）之 螺旋形反射面鏡及未示於圖（一）中的該直流伺服馬達）的 實用性，我們將其應用於二倍頻自相關器（second-harmonic generation autocorrelator)，其系統結構如圖（三）所示。待測光 進入自相關器後，以分光鏡10分爲兩束光，利用螺旋形 反射面鏡20反射其中一束光。螺旋形反射面鏡20的位置 必須精確調整，以使反射光得以保持在整個系統的光學平 面上’而反射點通常是選擇在接近螺旋形反射面鏡20的 邊緣’因爲越接近外側，反射光的變形越小。由於鏡面法 -5- 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） 經濟部中央標準局員工消費合作社印聚 A7 B7 五、發明説明（4 ) 線有一個0方向的分量，因此反射光與入射光之間有—個 夾角Θ，可表爲： (3) 將該兩束光以透鏡30聚焦，焦點上置入一個非線性 二倍頻晶體40，以產生待測光之二倍頻光訊號，再通過 —滴波器 50 爲一光電倍增管 60( photomultiplier tube, ΡΜΤ)所 接收。二倍頻光訊號在該光電倍增管6〇被轉換成電訊號 再送入示波器70中，以觀察掃描出的自相關訊號。 我們一個1.7皮秒的光脈衝送入圖（三）所示之二倍頻 自相關器（gecond-harmonic generation autocorrelator)作爲待測光 源，當螺旋形反射面鏡20被旋轉時，由示波器70得到圖 (四）的週期性掃描訊號，圖（五）則是將圖（四）所示的掃描 訊號的時間軸展開的結果。從圖（四）及圖（五）可以看出此 二倍頻自相關器的掃描頻率高達43.5Hz，且準確掃出脈 衝寬度。這個自相關訊號不太對稱，乃因爲我們在此實施 例所使用的馬達轉軸之穩定性較差，造成旋轉時有些搖晃 所致。此可以利用較穩定的馬達以解決目前這個問題。 這個線性掃描式之光學延遲方式的時間解析度可表 爲. -6 - 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） ------------------訂------缚 i .(請先閱讀背面之注意事項再填寫本頁) A7 B7 五、發明説明（，） 5 上述式（4)中W是光束寬度，C則是光在眞空中之光 速。目前這個實施例之解析度大約是在0.5皮秒，主要是 限制於光束的寬度（約1mm)及螺旋形反射面鏡螺距對反 射點的半徑之比値（d / p )，如果欲得到1 〇飛秒 (femtosecond)的解析度，必須將螺距降爲目前的二十 分之一，或是盡可能加大螺旋形反射面鏡的半徑，但利用 較小螺距之螺旋形反射面鏡會使總延遲時間（2 d / c )變 小。 經濟部中央標準局貝工消费合作社印製 (請先閱讀背面之注意事項再填寫本頁) 本發明之螺旋形反射面鏡除了圖（一）所示具有螺旋曲 面外，尙有其他不同的設計例如可將該螺旋曲面分成複數 個互相連接的平面反射鏡，如圖（六）所示，其中每一平面 反射鏡的表面正則化法線垂直於該轉軸半徑方向，且每一 平面反射鏡的表面正則化法線與該轉軸之軸心的夾角保持 固定，此夾角可以是任意角度。本發明之螺旋形反射面鏡 的螺旋曲面亦可被分成複數個互相連接的凹面鏡，如圖 (七）所示，或是複數個互相連接的凸面鏡（未示於圖中）， 其中每一個凹或凸面反射鏡的光學對稱軸垂直於該轉軸半 徑方向，且每一個凹或凸面反射鏡的光學對稱軸與該轉軸 之軸心的夾角保持固定，此夾角可以是任意角度。可被輕 易了解的我們亦可在同一個螺旋形反射面鏡上作出分別含 有螺旋曲面、複數個互相連接的平面反射鏡及凹（凸）面鏡 的不同區段。 -7- 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） 五、發明説明（6 ) 從以上說明可以看出，本發明揭示了一種含有螺旋形 反射面鏡之高速且較大範圍之掃描式光學延遲裝置。經過 實際的實驗證實，可運用於自相關器中成功的掃描出皮秒 級光脈衝的自相關曲線，而具有硏究上及商業上的利用價 値。 圖示說明 圖（一）爲依本發明之第一較佳具體實施例所完成的螺 旋形反射面鏡的立體示意圖。 圖（二）顯示了含有圖（一）之螺旋形反射面鏡的掃描式 光學延遲裝置之光程差對時間的變化。 圖（三）爲依本發明所完之二倍頻自相關器的示意圖。 圖（四〉爲圖（三）之二倍頻自相關器的示波器所顯示之 週期性掃描光脈衝自相關訊號。 圖（五）爲時間軸被展開之圖（四）之週期性掃描光脈衝 自相關訊號。 圖（六）依本發明之第二較佳具體實施例所完成的螺旋 形反射面鏡的立體示意圖。 經濟部中央標準局貝工消費合作社印製 ,(請先閱讀背面之注意事項再填寫本頁) 圖（七）依本發明之第三較佳具體實施例所完成的螺 旋形反射面鏡的立體示意圖。 -8- 本紙張尺度適用中國國家榇準（CNS ) A4規格（210X297公釐）Printed by the Beigong Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs Α7 Β7 V. Description of the invention (i) Background of the invention The fast and wide-ranging scanning optical delay device has many uses, such as an optical frequency doubler autocorrelator [Chi-Luen Wang and Ci-Ling Pan, Opt · Lett ·, 20, 1292 (1995)] and the pump probe experiment [Feruz Ganikhanov, Gong-Ru Lin, Wen-Chungg Chen, C.-S. Chang, and Ci- Ling Pan, 67, 3465 (1995)] etc. At present, the more common way is to place a ditherer in the autocorrelator [R · F. Fork and FA Beissoer, Appl. Opt. 3534 (1978)] or a rotating parallel mirror group [ZA Yasa and NM Amer, Opt . Commun. 36, 406 (1981)] 's sweeping optical delay element can display the auto-correlation signal of the optical pulse through the oscilloscope. In addition, using the combination of grating, lens and galvanometer, an optical delay with a scanning speed of up to 100 Hz can be obtained [Z. A. Yasa and N. M. Amer, Opt. Commun. 36, 406 (1981)]. However, the scanning range of the above-mentioned methods is only a few picoseconds. If you want to scan a light pulse with a wider width or a pumping experiment with a longer response time in this way, it cannot be achieved. In addition, when the S parameter of the transistor is measured by photoelectric method [KFKw〇ng, D. Yankelevich, KC Chu, Heritage, and A. Dienes, Opt. Lett. 18, 558 (1993)], it takes a long time Optical delay so that the low frequency response of the component can be accurately obtained. Using the combination of cam and slide rail, a scanning optical delay of 300 picoseconds can be generated [DC Edelstein, RB Romney, and M. Scheuermann, Rev. Sci. Instrum. 62, 579 (1991)]; and the use of rotating edges The combination of mirrors can achieve a fast scanning autocorrelator with a range of up to 1 nanosecond [G. Xinan, M. Lambsdorff, J. Kuhl, and E. Biachang, Rev. Sci. Instrum. 59, 2088 (1988 )]. -3- This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (21〇χ297mm) ---------- Agriculture-{Please read the precautions on the back before filling this page)-· * Printed by the Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy 〇l ^ 44〇a7 ____B7____ V. Description of the invention (2) Detailed description of the invention The present invention uses a newly designed spiral reflecting mirror as a fast and large-scale scan The optical delay line has achieved a scanning range of 80 picoseconds in a preferred embodiment of the present invention, and has been used in a double-frequency nonlinear autocorrelator to successfully scan picosecond light. Pulse autocorrelation signal. Figure (1) is a schematic view of the structure of a spiral reflecting mirror completed according to a preferred embodiment of the present invention. The mathematical equation of the spiral reflecting mirror can be described by the column coordinates as follows: 2 π z — d φ = 0 '(1) where 2 and 0 are the values of the coordinate axes along the axis of rotation and the direction of rotation, respectively, d is the pitch of the screw thread . The normalized normal normal to the surface can be expressed as: η = -2Kp z--j--φ (2) ”4π“ ρ2 + d2 ^ 4π2ρ2 + d2 as long as the direction of the incident light is parallel to the axis of rotation (Namely the ζ axis), the radius P of the point where the incident light reflects on the mirror surface will remain fixed when the mirror surface rotates, and then from formula (2), the direction of the normal of the reflection point will also remain unchanged, that is, the reflected light The direction is kept fixed, but there is a slight translation in space. If the reflected light is focused with a lens, the beam can be focused on the same point in the focal plane. -4- This paper scale is applicable to China National Standard (CNS) A4 specifications (210X297mm) ------ ^ ---- β —— Please read the precautions on the back and then fill out this page) .1.Τ B7____ 5. Description of the invention (3) To confirm this concept, As shown in Figure (1), a spiral reflective mirror is manufactured. The method is to cut a cylindrical aluminum block with a lathe, similar to a square thread, and make a rough shape, and then use different roughness sandpaper , Add multiple levels of grinding and polishing until the surface reaches the The diameter (D) is 50mm, the screw pitch (d) is 12mm, and the depth (T) is 15mm. The rotating shaft of the spiral reflecting mirror is connected to a DC servo motor (not shown in the figure), which is continuous When an incident light enters in a direction parallel to the axis of rotation, a reflected light is generated through the mirror reflection, and the optical path of the reflected light is rotated by the mirror surface of the spiral reflection mirror, and will be continuously linear. Change, its optical path changes as shown in Figure (2), its period depends on the speed of the motor, the total optical path difference depends on the pitch of the screw, in this embodiment is 80 picoseconds, relative to the beam at a length of 12mm Back and forth time. If you want to get the total optical path difference in the order of nanoseconds in this way, the pitch of the screw must be as high as 150mm, or multiple spiral reflection mirrors can be used to reflect back and forth multiple times. Central Standard of the Ministry of Economic Affairs Printed by Jubei Consumer Cooperative. (Please read the precautions on the back before filling in this ") In order to prove the optical delay line of this embodiment of the present invention (including the spiral reflecting mirror belonging to (1) and not shown in The DC servo motor in Figure (1)) Practicability, we applied it to the second-harmonic generation autocorrelator, and its system structure is shown in Fig. 3. After the light to be measured enters the autocorrelator, it is divided into two beams by the beam splitter 10. The spiral reflection mirror 20 is used to reflect one of the beams. The position of the spiral reflection mirror 20 must be precisely adjusted so that the reflected light can be maintained on the optical plane of the entire system. The reflection point is usually selected to be close to the spiral shape The edge of the reflective mirror 20 'is closer to the outside, the smaller the distortion of the reflected light. Since the mirror method -5- This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) Employee Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs India Poly A7 B7 5. Description of the invention (4) The line has a component in the 0 direction, so there is an angle Θ between the reflected light and the incident light, which can be expressed as: (3) Focus the two beams with the lens 30, A non-linear frequency-doubling crystal 40 is placed on the focal point to generate the frequency-doubling optical signal of the light to be measured, which is then connected to a photomultiplier tube 60 (PMT) through the dripper 50 Close. The double frequency optical signal is converted into an electrical signal at the photomultiplier tube 60 and then sent to the oscilloscope 70 to observe the scanned autocorrelation signal. Our 1.7 picosecond light pulse is sent to the second-frequency autocorrelator (gecond-harmonic generation autocorrelator) shown in Figure (3) as the light source to be measured. When the spiral reflective mirror 20 is rotated, it is obtained by the oscilloscope 70 Figure (4) shows the periodic scanning signal, and Figure (5) is the result of expanding the time axis of the scanning signal shown in Figure (4). It can be seen from Figure (4) and Figure (5) that the scanning frequency of this double-frequency autocorrelator is up to 43.5 Hz, and the pulse width is accurately scanned out. This autocorrelation signal is not very symmetrical, because the stability of the motor shaft used in this embodiment is poor, resulting in some shaking during rotation. This can use a more stable motor to solve the current problem. The time resolution of this linear scanning optical delay method can be expressed as: -6-This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297mm) -------------- ---- Subscribe ------ Binding i. (Please read the precautions on the back before filling this page) A7 B7 5. Description of the invention (,) 5 W in the above formula (4) is the beam width, C is It is the speed of light in the sky. At present, the resolution of this embodiment is about 0.5 picoseconds, which is mainly limited to the width of the beam (about 1mm) and the ratio of the pitch of the spiral reflecting mirror to the radius of the reflection point (d / p), if you want to get 1 〇 Femtosecond (femtosecond) resolution, the pitch must be reduced to the current twentieth, or the radius of the spiral reflective mirror as much as possible, but the use of a smaller spiral spiral reflective mirror will make The total delay time (2 d / c) becomes smaller. Printed by the Beigong Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the precautions on the back and then fill out this page). The spiral reflective mirror of the present invention has a different design than the spiral surface shown in figure (1). For example, the spiral curved surface can be divided into a plurality of interconnected plane mirrors, as shown in (VI), wherein the surface normalization normal of each plane mirror is perpendicular to the radius of the rotation axis, and each plane mirror ’s The angle between the surface normalization normal and the axis of the rotating shaft remains fixed, and this angle can be any angle. The spiral curved surface of the spiral reflecting mirror of the present invention can also be divided into a plurality of interconnected concave mirrors, as shown in Figure (7), or a plurality of interconnected convex mirrors (not shown in the figure), each of which is concave Or the optical symmetry axis of the convex mirror is perpendicular to the radius direction of the rotation axis, and the angle between the optical symmetry axis of each concave or convex mirror and the axis of the rotation axis remains fixed, and this angle can be any angle. It is easy to understand that we can also make different sections with spiral curved surface, a plurality of interconnected flat mirrors and concave (convex) mirrors on the same spiral reflecting mirror. -7- This paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297mm) 5. Description of the invention (6) From the above description, it can be seen that the present invention discloses a high-speed and large Range of scanning optical delay devices. It has been proved by practical experiments that it can be used in autocorrelator to successfully scan the autocorrelation curve of picosecond light pulse, and it has the value of research and commercial utilization. Description of the figures Figure (1) is a perspective schematic view of a spiral reflecting mirror completed according to the first preferred embodiment of the present invention. Figure (2) shows the change of the optical path difference with time of the scanning optical delay device containing the spiral reflective mirror of Figure (1). Figure (3) is a schematic diagram of the double frequency autocorrelator completed in accordance with the present invention. Picture (4) is the auto-correlation signal of the periodic scanning light pulse displayed by the oscilloscope of the frequency-doubling autocorrelator of picture (3). Picture (5) is the periodic scanning light pulse of the expanded view (4) of the time axis Self-relevant signal. Figure (6) A three-dimensional schematic diagram of a spiral reflecting mirror completed according to the second preferred embodiment of the present invention. Printed by the Beigong Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs, (please read the notes on the back first Please fill in this page for details) Figure (7) A three-dimensional schematic view of a spiral reflecting mirror completed in accordance with the third preferred embodiment of the present invention. 210X297mm)