in apparatus for superresolution microscopy or microlithography , wherein a spot in the specimen to be examined or in the microlithographic medium is raised to an excited state by a first pulse of light , and a second pulse of light reduces the excitation in the peripheral parts of the spot to increase the resolution of the instrument , a method whereby the wavelength of the second pulse in the specimen or medium is the same as the wavelength of the first pulse , thereby allowing the cost and complexity of the apparatus to be lowered .