Laser scanning microscope for low temperature single molecule and microscale spectroscopy based on gradient index optics

A scanning optical microscope for low temperature imaging and spectroscopy with a gradient index rod-shaped microlens as an objective lens is presente d. The solid immersion effect enhances the resolution to 310 nm of the full -width at half-maximum at the wavelength of 545 nm. Laser scanning mechanis m located outside an optical cryostat enables to achieve large scanning ran ges independent of temperature. The performance is demonstrated at 1.6 K on single molecules of terrylene in a dodecane crystal and on molecular J agg regates in thin polymer films. (C) 1999 American Institute of Physics. [S00 34-6748(99)04104-0].