Selection of Laser

1. 532nm and 633nm lasers were selected first for inorganic samples.

2. 633nm and 785nm lasers were first selected for organic samples.

3. Select 785nm laser for samples with fluorescence interference.

Testing tips: Objective selection for samples

1. Solid samples: flatter surface (50x, 100x), rough surface (50xL).

2. For opaque samples, use a high magnification objective (high numerical aperture, N.A.), while for transparent samples, a low magnification objective will give a better signal, such as a 20x short-focus objective.

3. Powder sample: The powder sample should be flattened with a slide before testing to obtain a flat surface; it is recommended to use a 50xL telephoto lens, and special attention should be paid to protect the lens surface from staining when using a short-focus lens.

4. Liquid samples: Use 50xL or 20x lenses.

Explain: Lindong Ma, 2022 doctoral students

Photograph: Yuqing Liu, 2022 master-Mingmin Li's team

Montage: Xuejie Jiang, 2022 master-Peng Zhang's team