AI 中文总结
该研究提出一种基于啁啾飞秒激光的宽带外差干涉架构，利用光谱复用与数值相关技术提升信噪比，可实现J+H波段高分辨率光谱成像，为天文干涉测量提供了新方案。
AI 中文摘要
红外外差干涉测量为长基线望远镜阵列提供了可扩展的直接干涉测量替代方案。然而，在近红外波长下，其灵敏度受限于电子探测带宽和光参考的散粒噪声。长期以来，通过光谱复用的并行探测被认为是提高外差干涉仪信噪比（SNR）的潜在手段。我们提出一种新的外差探测架构，基于锁模激光器产生的高度色散宽带脉冲、快速光电探测器及数值相关技术。该架构可利用商用组件实现简便的光谱复用以提高SNR，同时将瞬时波长覆盖范围扩展至J和H波段同时运行，还支持高分辨率光谱成像（分辨率R≈10³-10⁴）。我们推导了基于平衡光电探测的双臂外差干涉仪的SNR模型，并将该模型应用于所提出的架构，采用工作在1.56微米、带宽8纳米的全光纤单光谱通道干涉仪的测量数据。实验中，我们在光谱通量密度为188皮瓦/纳米、积分时间0.4毫秒的条件下，实现了超过2的SNR。对积分时间和光谱通道数量进行缩放后，结果表明，在典型大气相干时间内，使用1平方米望远镜即可实现最亮H波段恒星的条纹可见度。这些成果是向宽带、可扩展外差干涉仪迈出的重要一步，证明了超快激光和电信技术在J+H波段天文干涉测量中的潜力。此外，该架构通过结合宽带光谱复用与数值相关技术，还为无需额外光谱仪的直接光谱成像开辟了路径。
英文摘要
Infrared heterodyne interferometry offers a scalable alternative to direct interferometry for long-baseline telescope arrays. However, at near-infrared wavelengths, its sensitivity is limited by the electronic detection bandwidth and shot noise from the optical reference. Parallel detection via spectral multiplexing has long been identified as a potential means to increase the signal-to-noise ratio of heterodyne interferometers. We propose a new heterodyne detection architecture based on highly dispersed broadband pulses from a mode-locked laser, fast photoreceivers, and numerical correlation. This enables straightforward spectral multiplexing with commercial components to increase the SNR, while extending instantaneous wavelength coverage to simultaneous J- and H-band operation. The scheme also supports high-resolution spectroscopic imaging ($R \simeq 10^{3}-10^{4}$). We derive the SNR of a two-arm heterodyne interferometer based on balanced photodetection and apply the model to the proposed scheme, using measurements from a single-spectral-channel, all-fiber interferometer operating at 1.56 micrometer over an 8 nanometer bandwidth. We experimentally demonstrate an SNR exceeding 2 for a spectral flux density of 188 pW/nm, with an integration time of 0.4 ms. Scaling the integration time and number of spectral channels suggests that fringe visibility of the brightest H-band stars could be achieved with 1 m$^2$ telescopes within the typical atmospheric coherence time. These results represent a significant step toward broadband, scalable heterodyne interferometers, demonstrating the potential of ultrafast laser and telecommunications technologies for astronomical interferometry in the J+H bands. By combining broadband spectral multiplexing with numerical correlation, the architecture also opens a route to direct spectro-imaging without an additional spectrometer.
Comments7 pages, 7 figures
