We propose and demonstrate a high efficiency broadband near infrared single-photon upconversion and detection with a broadband pump laser based on sum frequency conversion in the PPLN crystal. By using a pump laser centered at 1040 nm with a spectral bandwidth of 10 nm, the signal single-photons centered at 1562 nm with a broadband bandwidth up to 7.2 nm are frequency-converted from the near infrared to the visible regime. A maximum conversion efficiency of 18.8% is achieved, while the background noise is measured to be only 1.2 × 10 −3 counts/pulse. The corresponding spectral linewidth of the upconverted photons is 0.2 nm. This scheme of broadband infrared single-photon upconversion and detection provides potential solutions in infrared laser ranging, broadband infrared imaging and quantum key distribution.

中文翻译：

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高效宽带近红外单光子频率上变频和检测*

我们提出并演示了一种高效的宽带近红外单光子上变频和基于PPLN晶体中和频转换的宽带泵浦激光器进行检测。通过使用以1040 nm为中心，光谱带宽为10 nm的泵浦激光器，将以1562 nm为中心，带宽高达7.2 nm的信号单光子从近红外频率转换为可见光状态。最高转换效率为18.8％，而背景噪声仅为1.2×10 -3个计数/脉冲。上转换光子的相应光谱线宽为0.2 nm。这种宽带红外单光子上转换和检测方案为红外激光测距，宽带红外成像和量子密钥分配提供了潜在的解决方案。