Abstract: The invention relates to a system and to a corresponding method for optical coherence tomography having an interferometer (10) for emitting light with which a specimen (1) is irradiated, the interferometer (10) comprising a beam splitter (13) and at least one reflector (12) the optical distance (I) of which from the beam splitter (13) can be changed by an optical path (L), and a detector (30) with a first number of detector elements arranged in a first area for collecting light which is reflected by the specimen (1). In order to be able to record images of a specimen, in particular in real time, more simply and quickly, the system is operated in a first mode in which light reflected by the specimen (1) is only collected by a second number of detector elements of the detector (30) and converted into corresponding detector signals, the second number of detector elements being smaller than the first number of detector elements.

Abstract: Improved ease of mode matching to a passive optical cavity is provided by selecting a cavity design that has a predetermined deviation from a reference cavity design having high transverse mode degeneracy. This predetermined deviation tends to be small, so that the first overlap of high-order transverse modes with the lowest order transverse mode in frequency occurs at relatively high transverse mode numbers. Coupling to high-order transverse modes is thereby reduced, since high-order transverse modes having relatively high transverse mode numbers tend to be more difficult to couple to, and tend to have high loss. During assembly of such a cavity, it can be useful to apply a perturbation to the cavity to further optimize mode matching. For example, the length of an enclosed cavity can be adjusted by altering the number and/or length of spacers in the cavity housing.

Abstract: Disclosed herein are methods and apparatus for testing interferometric modulators. The interferometric modulators may be tested by applying a time-varying voltage stimulus and measuring the resulting reflectivity from the modulators.