Jarzembski Amun, Shaskey Cedric, Murdick Ryan A, Park Keunhan
Appl Opt. 2019 Mar 10;58(8):1978-1983. doi: 10.1364/AO.58.001978.
Due to its superb imaging spatial resolution and spectroscopic viability, scattering-type scanning near-field optical microscopy (s-SNOM) has proven to be widely applicable for nanoscale surface imaging and characterization. However, limited works have investigated the sensitivity of the s-SNOM signal to sample temperature. This paper reports the sample temperature effect on the non-interferometric (self-homodyne) s-SNOM scheme at a visible wavelength (λ=638 nm). Our s-SNOM measurements for an arrayed vanadium/quartz sample demonstrate a monotonic decrease in signal intensity as sample temperature increases. As a result, s-SNOM imaging cannot distinguish quartz or vanadium when the sample is heated to ∼309 K: all signals are close to the root-mean-square noise of the detection scheme used for this study (i.e., 19 μV-rms). While further studies are required to better understand the underlying physics of such temperature dependence, the obtained results suggest that s-SNOM measurements should be carefully conducted to meet a constant sample temperature condition, particularly when a visible-spectrum laser is to be used as the light source.
由于其出色的成像空间分辨率和光谱可行性，散射型扫描近场光学显微镜（s-SNOM）已被证明广泛适用于纳米级表面成像和表征。然而，仅有有限的研究探讨了s-SNOM信号对样品温度的敏感性。本文报道了在可见波长（λ=638 nm）下样品温度对非干涉（自外差）s-SNOM方案的影响。我们对排列的钒/石英样品进行的s-SNOM测量表明，随着样品温度升高，信号强度呈单调下降。结果，当样品加热到约309 K时，s-SNOM成像无法区分石英或钒：所有信号都接近本研究中使用的检测方案的均方根噪声（即19 μV-rms）。虽然需要进一步研究以更好地理解这种温度依赖性的潜在物理机制，但所得结果表明，特别是当使用可见光谱激光作为光源时，应在恒定样品温度条件下仔细进行s-SNOM测量。
