Abstract: An apparatus and method for determining the extinction of laser light through a fluid is disclosed. The fluid is passed in a conduit having a light transmissive window. A laser beam having intensity I.sub.1 is passed through the window into the fluid. A prong shaped probe having first and second probe sections is disposed in the fluid flow. The first probe section includes a beamsplitter at a distance d.sub.1 from the window for redirecting a portion of the beam onto a first photodiode array, to determine the beam intensity I.sub.2. The remaining portion of the beam tranverses a distance d.sub.2 and is directed through a prism onto a second photodiode array to determine its intensity I.sub.3. Based on the intensities I.sub.1, I.sub.2 and I.sub.3 and given d.sub.1 and d.sub.2, the extinction values E.sub.1 and E.sub.2 may be calculated. Fluid optical density may then be determined as a function of the extinction.

Abstract: The present invention provides an improved fiber optic magnetometer having particular application for use in environments having large magnetic field ranges and gradients, such as space based applications. The magnetometer includes a laser which generates a coherent beam of light which is split by a beam splitter into first and second beams. The first beam is passed through a single mode fiber optic having a short metallic conductor attached to it. This fiber is referred to as the "sensor arm" of the magnetometer. The second beam is passed through another single mode fiber which is wrapped around a modulator that is coupled to a feedback circuit. This adjusts the magnetometer such that ambient system noise is filtered and the device is maintained at maximum sensitivity. The output of the two fibers is combined forming a Mach-Zehnder interferometer. A current I is passed through the conductor in the sensor arm.

Abstract: An improved folded cavity laser having particular application to holographic imaging is disclosed. The laser includes a lasing medium, such as for example a ruby rod, which is optically or electronically "pumped" in order to provide laser light. The medium includes first and second optical surfaces disposed at opposite ends of the lasing medium. A retro-reflecting roof mirror is disposed in optical alignment with the second optical surface of the lasing medium. A transverse mode selector is provided in optical alignment with the first surface of the lasing medium in order to surpress all transverse modes except those of a desired character. In the present embodiment, the transverse mode selector includes two apertures of approximately two millimeters diameter in order to obtain a laser output with a TEM.sub.00 mode.

Abstract: An apparatus and method for determining the size and velocity of particles, droplets and the like is disclosed. Laser beams of the same wavelength having different diameters are caused to cross and form an interference pattern. The scattered light caused by particles, droplets or the like passing through the interference pattern is sensed by a collection means. The scattered signal is passed through a high pass filtering means to isolate Doppler (AC) components, and a low pass filtering means to isolate a DC pedestal signal. The AC signal is processed to provide the velocity, and the DC signal is processed to provide the size of the particle, droplet or the like. The position of the AC Doppler components in the scattered signal indicates the position of the particle in the cross-section of the larger diameter beam.

Abstract: An apparatus for combining optical images which is particularly suited for use in integrated circuit lead wire gang bonding systems is disclosed. The apparatus includes an objective lens to gather and focus light rays reflected from an object, such as a microelectronic device. A beamsplitter provides first and second images of the object which are inverted with respect to one another. The images are directed onto mirrowed prism surfaces, such that only selected portions of the first and second images actually strike each prism face. That portion of each image which does strike the respective prism face is reflected upward and combined to form one resulting image. Viewing means are provided to view the resultant image.

Abstract: An apparatus for sizing particles, droplets or the like, particularly suited for determining the size of droplets in high number density sprays, is described. The apparatus employs the interferometer principle and off-axis collection to limit probe volume and to limit the light scatter detection to refraction and reflection. The central portion of the interference pattern is distinguished in an alternate embodiment by using a second laser beam as a pointer beam.