Optimized Spatial Resolution, Sensitivity, Measurement Speed and Artifact Reduction in Photothermal AFM-IR

Photothermal AFM-IR enables chemical identification through nanoscale imaging & spectroscopy. Since the technique’s development by Alexandre Dazzi in 2005 [1], significant progresses have been made in the IR laser sources, system designs and operating modes to improve the detection sensitivity, lateral resolution, measurement speed and correction for mechanical artifacts [2,3,4]. In this work we examine the key factors governing performance in photothermal AFM-IR and introduce different approaches to optimize performance. Each approach is illustrated with examples that achieve high sensitivity of <1 nm, high lateral resolution of <2 nm and high scan rates for IR imaging. [1] Dazzi, A., Prazeres, R., Glotin, F., Ortega, J. M., Opt. Lett. 30, 2388-2390 (2005) [2] Lu, F., Jin, M., Belkin, M. A., Nat. Photon. 8, 307-312 (2014) [3] Mathurin, J. et al. Analyst. 143, 5940-5949 (2018) [4] Ramer, G., Reisenbauer, F., Steindl, B., Tomischko, W., Lendl, B. Appl. Spectrosc. 71, 2013-2020 (2017)