title: Apertureless near-field/far-field CW two-photon microscope for biological and material imaging and spectroscopic applications.
abstract: We present the development of a versatile spectroscopic imaging tool to allow for imaging with single-molecule sensitivity and high spatial resolution. The microscope allows for near-field and subdiffraction-limited far-field imaging by integrating a shear-force microscope on top of a custom inverted microscope design. The instrument has the ability to image in ambient conditions with optical resolutions on the order of tens of nanometers in the near field. A single low-cost computer controls the microscope with a field programmable gate array data acquisition card. High spatial resolution imaging is achieved with an inexpensive CW multiphoton excitation source, using an apertureless probe and simplified optical pathways. The high-resolution, combined with high collection efficiency and single-molecule sensitive optical capabilities of the microscope, are demonstrated with a low-cost CW laser source as well as a mode-locked laser source.
authors.affiliation: Department of Physics, Portland State University, P.O. Box 751, Portland, Oregon 97207, USA.
authors.forename: Derek B
authors.initials: DB
authors.lastname: Nowak
authors.forename: A J
authors.initials: AJ
authors.lastname: Lawrence
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Sánchez
mesh_terms: D000818:Animals; D002417:Cattle; D004730:Endothelium, Vascular / Q000648:ultrastructure; D007834:Lasers; D007909:Lenses; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation*; D011651:Pulmonary Artery / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*