Microscopic methods for examining objects, in particular samples or tissue samples, sometimes require illumination devices, in particular, laser devices, which are capable of producing laser light of different wavelengths. Some microscopy methods require the illumination device to provide laser light of different wavelengths simultaneously. Supercontinuum lasers, also referred to as white-light lasers or broadband laser light sources, are suitable for this purpose. These lasers produce laser light over a broad spectrum, in particular continuously over a plurality of colors, especially ones that are visible and distinguishable by the eye, so that the broadband laser light produced appears to the eye as white light.
The white laser light can be produced in various ways. For example, the light of a conventional laser which produces laser light in a very small wavelength range, especially laser light of a single wavelength, may be coupled into an optical element which broadens the spectrum of the laser beam in the desired way. Suitable for this purpose is an optical element which is specifically designed to broaden the spectrum of the laser light beam as opposed to conventional optical elements, such as lenses, where the broadening of the spectrum is an undesired side effect. In particular, it is known to design light-conducting fibers in such a way that when light is passed therethrough, strong non-linear optical effects are produced which broaden the monochromatic laser light spectrally, converting it into white laser light. During the spectral broadening, it is normal for dispersion effects to occur, affecting the white laser light produced.
German Patent Application DE 101 15 486 A1 describes an entangled-photon microscope having a light source and an objective. The entangled-photon microscope has a microstructured optical element disposed between the light source and the objective and capable of producing entangled photons therein, the entangled photons propagating in a beam inside and outside the microstructured optical element. The microstructured optical element is constructed from a plurality of micro-optical structure elements which have at least two different optical densities. The micro-optical structure elements are, for example, cannulas, webs, honeycombs, tubes or cavities. Alternatively, or in addition, the microstructured optical element may have alternating regions of homogeneous and inhomogeneous structure. Alternatively or additionally, the microstructured optical element is formed of adjacent glass or plastic materials and cavities, and is configured as a light-conducting fiber. The fibers can be produced by extending glass tubes or glass blocks arranged in a pattern.
German Patent Application DE 101 15 509 A1 describes a confocal microscope which uses an optical device for spectral broadening of a laser pulse generated by a pulsed laser. The pulsed laser generates a pulsed laser beam which is passed through the optical device. The optical device includes a photonic-band-gap material which converts the narrow-band pulsed laser beam into illuminating light of broad spectral bandwidth.