高效率糾纏光子對的產生及量測

Demonstration of a high-efficiency biphoton source

林駿(LIN, CHUN)

指導教授 ： 褚志崧

國立清華大學/理學院/物理學系/碩士(2015年)

摘要

單光子和糾纏光子在量子物理學上佔有十分重要的一席之地，其扮演著實現量子電腦與量子密碼學中最重要的基石。所以，產生優秀的糾纏光子源儼然成為了量子光學研究中的核心。過去雖然也有人達成高效率的糾纏光子對，但往往是在Cavity、脈衝雷射等方法下達成。在不使用上述方法時，糾纏光子對的detection rate約為900（1/s/mW）[4-1]。我們利用一台中心波長為532nm的連續式雷射，將其打入一塊非線性光學晶體（KTP晶體），找到了一組高效率的糾纏光子對，其detection rate高達26675（1/s/mW）。這對糾纏光子對為Type II SPDC，兩光子之波長分別為1038nm與1091.2nm。進一步的，在實驗上我們藉由改變不同的實驗架構去觀察這對糾纏光子的不同性質，包含biphoton rate、anticorrelation parameter、spectrum和Franson Interference。

關鍵字

糾纏光子

並列摘要

Single and entangled photons, in particular, have now played an important role in quantum physics. They are the most important cornerstone to realize quantum computers and quantum cryptography. It is therefore necessary to develop high-efficiency entangled photon source for studying quantum optics. Although high efficiency entangled photon pairs have been demonstrated, they are often achieved with cavity and pulsed lasers. When not using the above method, the highest reported detection rate of entangled photon pairs is about 900 (1/s/mW). We use continuous wave laser which wavelength is 532nm, focused into a nonlinear optical crystal (KTP crystal). We observed a highly efficient entangled photon pairs with a detection rate up to 26675 (1/s/mW). These entangled photon pairs are of Type II Spontaneous parametric down-conversion, with wavelengths of 1038nm and 1091.2nm. In addition, we use various methods to measure their intensity correlation and to explore their properties, including biphoton rate, anticorrelation parameter, spectrum and Franson Interference.

並列關鍵字

biphoton

參考文獻

1-1. A. Kuhn, M. Hennrich, and G. Rempe, Deterministic Single-Photon Source for Distributed Quantum Networking, Phys. Rev. Lett. 89, 067901(2002).

1-2. V. Balic´, D. A. Braje, P. Kolchin, G. Y. Yin, and S. E. Harris, Generation of Paired Photons with Controllable Waveforms, Phys. Rev. Lett. 94, 183601 (2005).

1-3. M. Scholz, L. Koch, R. Ullmann, and O. Benson, Single-mode operation of a high-brightness narrow-band single-photon source, Appl. Phys. Lett. 94 , 201105 (2009).

2-1. Robert W. Boyd - Nonlinear Optics Third Edition.

2-2. Chih-Sung Chuu - ABCD Formulism for Spontaneous Parametric Down Conversion