Multiphoton fluorescence microscopy is a powerful new technology that enables the acquisition of optical sections without the use of a pinhole aperture typically used for confocal microscopy. The technique is based upon the two-photon principle: A fluorescent molecule simultaneously absorbs two photons producing an electronic transition from the ground to excited state equal to two times the energy of each incident photon. - [Read Multiphoton Images from LSM 510 NLO System]
Diffraction-limited optical microscopy requires that the spatial resolution of an image is limited by the wavelength of the incident light & by the numerical apertures of the condenser & objective lens systems.The development of near-field scanning optical microscopy (scanning near-field optical microscopy) has allowed for a imaging technique that retains the various contrast mechanisms afforded by optical microscopy methods while attaining spatial resolution beyond the optical diffraction limit - [Read Near-Field Scanning Optical Microscopy]
Reflected light microscopy is often referred to as incident light, epi-illumination, or metallurgical microscopy, and is the method of choice for fluorescence and for imaging specimens that remain opaque even when ground to a thickness of 30 microns. - [Read Reflected Light Microscopy]