Apparatus and method for super-resolution brillouin microscopy

An apparatus for super-resolution Brillouin microscopy comprising

• a probe laser that emits a first laser beam;
• a polarizer through which the first laser beam passes;
• a first quarter-wave plate through which the first laser beam passes after the polarizer;
• a first objective lens that focuses the first laser beam onto a sample, wherein the first laser beam has a beam spot with a diffraction-limited Gaussian intensity profile;
• a pump laser that emits a second laser beam;
• a second quarter-wave plate that receives the second laser beam;
• a depletion laser that emits a third laser beam;
• a phase plate through which the third laser beam passes to modify its wavefront phase such that the third laser beam has a donut shape;
• a second objective lens that focuses the second laser beam and the third laser beam onto the sample, wherein a beam spot from the third laser beam is overlaid with Gaussian-shape beam spots of the first laser beam and the second laser beam;
• and
• a detector configured to detect a stimulated Brillouin gain (SBG) signal and a stimulated Brillouin loss (SBL) signal, wherein the apparatus is configured to adjust frequencies of the probe laser, the pump laser, and the depletion laser to establish stimulated emission depletion such that a Brillouin signal created from a subtracted region of the Gaussian-shape beam spots and donut beam is collected by the second objective lens and redirected into the detector.