螢光奈米鑽石發光中心之量子自旋同調操控

Coherent Control on the Spins of Nitrogen-Vacancy Centers in Diamond Nanoparticles

劉修源(Hsiou-Yuan Liu)

指導教授 ： 易富國

共同指導教授 ： 張銘顯(Ming-Shien Chang)

國立臺灣大學/理學院/物理研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.02673

摘要

鑽石除了可用於裝飾上，還有其他在科學研究上具有突破性的應用。帶有氮聯袂空缺有色缺陷的奈米鑽石有著穩定的化性及無毒性，是為能發出強烈螢光的生物標記。此外，其電子基態可細分為三個子能階(三聯triplet)，其中兩者為簡併的m = ±1 另一者為m = 0。他們之間的分隔為2.87 GHz。這個分隔可以被外加的磁場所影響，進而一來可成為一靈敏的磁場計，二來如應用到生物體內，更可能達到奈米解析度的MRI 量測。而這個三聯基態的2.87 GHz 分隔所展現的長時同調性，亦使奈米鑽石螢光缺陷於量子資訊處理領域成為一個具吸引力的頻率量子位元。

在本論文中，我們展現了奈米鑽石螢光缺陷的三聯基態之同調控制。我們透過2.87 GHz 微波的使用及其後的光學偵測，觀測到了缺陷中心的m = ±1 及m = 0 之間的Rabi 振蕩。為了要確保同調性在量子調控時，持續足夠久的時間，我們進行了徑向方向平衡回復的實驗。為了確認實驗中的缺陷中心為單一中心，我們使用光子的反成群(antibunching) 性質來進行測量。此實驗的結果為後續實驗之濫觴，讓往後的生物體量測實驗及量子資訊處理可以從一定的基礎上延續。

關鍵字

螢光奈米鑽石 ； 氮聯袂空缺有色中心 ； 電子自旋共振 ； 磁場計 ； 奈米MRI ； 實溫量子位元

並列摘要

A nanodiamond containing nitrogen-vacancy color center defects presents a chemically stable and nontoxic strong fluorescent marker for bio-imaging applications. In addition, the m = ±1 and m = 0 sublevels of the ground triplet electronic state in a fluorescent diamond nitrogen-vacancy center (NV) are split and separated by 2.87 GHz. This separation can be altered by an external magnetic field. Thus an NV can be utilized as a sensitive magnetometer, and it provides an opportunity to realize MRI with nanometer resolution when introduced in bio samples. The simple electronic structure and 2.87 GHz splitting in the ground triplet electronic spin with relatively long coherence time also make an NV center an attractive candidate for room-temperature frequency quantum bit (frequency qubit) for quantum information processing.

In this thesis we present coherent manipulation on the ground triplet electronic spin states in an NV center in diamond nanocrystal. The Rabi oscillation between the m=±1 and m = 0 sublevels of an NV center was achieved by applying a resonant microwave at 2.87 GHz, following an optical detection. The make sure the coherence is long enough for the quantum amplitude manipulation, a longitudinal relaxation experiment is performed. To verify single NV center in an nanocrystal, a photon antibunching test was utilized. Our investigation here provides a good starting point for further bio-sensing and quantum information applications.

並列關鍵字

fluorescent nanodiamond ； nitrogen-vacancy color center ； electron spin resonance ； magnetometer ； nano-MRI ； room-temperature qubit

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