Figure 1. Comparison of point-scan vs line-scanning configuration of Brillouin microscopy.

(a) The traditional configuration couples a confocal microscope with a spectrometer. A spatial point of the sample is selected by the microscope and its spectrum is measured by the spectrometer. Thus, the images are formed by scanning the sample point-by-point. (b) In the new configuration, by arranging the illumination path and detection path at an angle (90 degree), many points along the line beam can be measured simultaneously and the images can be formed by scanning the line beam. (c) Schematic of the line-scanning Brillouin spectroscopy. M: mirror; O1,O2,O3: objective lens. Sc: spherical lens for beam collimation; Cy1, Cy2, Cx: cylindrical lenses; Si: spherical lens for imaging purpose.