Abstract: An apparatus and a method including exposing a first fluid to a pre-filter, observing the first fluid, introducing a second fluid to the first fluid, exposing the first and second fluids to a filter, and observing the first and second fluids wherein the observing the first fluid and observing the first and second fluids comprise optical measurements and the first fluid comprises material from a subterranean formation. Some embodiments may compare the optical measurements of the first fluid and the first and second fluids and/or estimate the first fluid's likelihood of forming precipitants with other fluids and/or the first fluid's asphaltene content.

Abstract: A new class of photonic devices called active optical antennas, which consist of metallic structures directly integrated on to the facet of a semiconductor lasers, and of instruments based on such antennas are disclosed. The structures consist of metallic elements which function as antennas at optical wavelengths by spatially concentrating laser radiation of wavelength in the range from the UV to the mid-infrared into spots (with sizes in the range 10-100 nm) in the so called near field zone, that is at subwavelength distances from the facet. Various antenna designs are considered depending on the laser under consideration and applications. This invention has wide ranging applications such as new microscopes for high-resolution spatially resolved imaging and spectroscopy, new probes for biology, laser assisted processing and repair of devices, circuits and masks, as well new optical tweezers and phased array devices. Microscopes and other systems based on this invention are discussed.