A method of microscopy is disclosed. The method comprises directing a pulse of a pump optical beam to form an optical spot on a substance and measuring changes in a temperature-dependent or photo-excited property of the substance. The method further comprises analyzing the measured changes to distinguish between information pertaining to the property at a portion of the spot, and information pertaining to the property at other portions of the spot. A largest diameter of the portion of the spot is optionally and preferably less than a central wavelength of the pump optical beam.