The invention relates to a method for determining at least one beam propagation parameter (M.sup.2, w.sub.0, θ, z.sub.0) of a laser beam, comprising: directing the laser beam through a lens arrangement towards a spatially resolving detector, imaging the laser beam at a plurality of different focus positions (F1, . . . ) relative to the spatially resolving detector by adjusting a focal length (f.sub.1, . . . ) of the lens arrangement, and determining the at least one beam propagation parameter (M.sup.2, w.sub.0, θ, z.sub.0) by evaluating an intensity distribution (l(x,y)) of the laser beam on the spatially resolving detector at the plurality of different focus positions (F1, . . . ). The method comprises adjusting the focal length (f.sub.1, . . . ) of the lens arrangement by arranging lens elements (A1, . . . ; B1, . . . ) having different focal lengths (f.sub.A1, . . . ; f.sub.B1, . . . ) in a beam path of the laser beam.

A method for adaptively splitting a coherent primary light beam, comprising producing a desired far-field distribution by phase modulating the primary light beam with a Spatial Light Modulator (SLM), the primary coherent light beam being directed to reflect on a display element of the spatial light modulator, thereby avoiding any moving elements to shape the primary coherent light beam, extracting from the primary light beam, after it has passed the spatial light modulator, a monitoring beam and a main beam, measuring the monitoring beam with a camera, directing the desired far-field distribution in the monitoring beam on a sensor surface of the camera. In a first option, the method comprises guiding the primary beam through a first focusing element (L1) that is configured to focus the far-field distribution onto a focusing plane of the first focusing element as a real output distribution, and focusing the far-field distribution in the monitoring beam onto the sensor surface of the camera by means of the first focusing element. In a second option, the method comprises guiding the monitoring beam through a second focusing element (L2) that is configured to focus the far-field distribution on the sensor surface of the camera. For either the first or the second option, the method further comprises adjusting a dynamic range of the camera using a variable intensity regulator to control the intensity of the incoming monitoring beam as a function of the far-field distribution, and configuring a closed loop to enable a phase calculation for the display element of the spatial light modulator, whereby an output signal from the camera is input into the closed loop for a plurality of iterations of a phase-calculation algorithm performed by a controller, wherein in the first option, the first focusing element is used, excluding the second focusing element, and in the second option, the second focusing element is used, excluding the first focusing element.

Apparatus and associated methods relate to creating corrected images of a scene for a terminal-imaging seeker using an electrically-controllable coded-aperture mask pattern embodied in a programmable spatial light modulator. The coded-aperture mask pattern includes a plurality of pinhole-like apertures, each of which is configured to perform pinhole-like lensing of the scene. The plurality of pinhole-like apertures form a multiplex of overlapping images on a focal plane array aligned with the optical axis. An image processor reconstructs, based on a configuration of the plurality of pinhole-like apertures and the multiplex of overlapping images, a single image of the scene.

The invention relates to a method for determining at least one beam propagation parameter (M.sup.2, w.sub.0, , Z.sub.0) of a laser beam, comprising: directing the laser beam through a lens arrangement towards a spatially resolving detector, imaging the laser beam at a plurality of different focus positions (F1, . . . ) relative to the spatially resolving detector by adjusting a focal length (f.sub.1, . . . ) of the lens arrangement, and determining the at least one beam propagation parameter (M.sup.2, w.sub.0, , Z.sub.0) by evaluating an intensity distribution (l(x,y)) of the laser beam on the spatially resolving detector at the plurality of different focus positions (F1, . . . ). The method comprises adjusting the focal length (f.sub.1, . . . ) of the lens arrangement by arranging lens elements (A1, . . . ; B1, . . . ) having different focal lengths (f.sub.A1, . . . ; f.sub.B1, . . . ) in a beam path of the laser beam.

Apparatus and associated methods relate to creating corrected images of a scene for a terminal-imaging seeker using an electrically-controllable coded-aperture mask pattern embodied in a programmable spatial light modulator. The coded-aperture mask pattern includes a plurality of pinhole-like apertures, each of which is configured to perform pinhole-like lensing of the scene. The plurality of pinhole-like apertures form a multiplex of overlapping images on a focal plane array aligned with the optical axis. An image processor reconstructs, based on a configuration of the plurality of pinhole-like apertures and the multiplex of overlapping images, a single image of the scene.

A device for calibrating an in-line sensor is disclosed, including a housing having a first aperture and a second aperture arranged along an optical path extending through the housing, a first filter and a second filter disposed within the housing such that the filters are moveable from an operating position to a calibration position. In the calibration position the filters are arranged in the optical path and the housing includes a connection adjacent each of the first aperture and the second aperture, the connection structured to enable the housing to be reversibly attached to a flow cell, a detector and a light source of an in-line sensor.

A device for calibrating an in-line sensor is disclosed, including a housing having a first aperture and a second aperture arranged along an optical path extending through the housing, a first filter and a second filter disposed within the housing such that the filters are moveable from an operating position to a calibration position. In the calibration position the filters are arranged in the optical path and the housing includes a connection adjacent each of the first aperture and the second aperture, the connection structured to enable the housing to be reversibly attached to a flow cell, a detector and a light source of an in-line sensor.

A spot shape detection apparatus for detecting the spot shape of a laser beam oscillated from a laser oscillator includes: a focusing leans for focusing the laser beam oscillated by the oscillator; a rotary body (mirror holder) in which a plurality of mirrors for reflecting the laser beam having passed through the focusing lens are disposed on concentric circles; a drive source (motor) for rotating the rotary body at a predetermined period; a beam splitter for branching return beams of the laser beam reflected by the plurality of mirrors of the rotary body; an imaging unit which is disposed in a direction in which the return beams are branched by the beam splitter and which images spot shapes of the return beams; and a display unit for displaying images obtained by imaging by the imaging unit, in relation with the plurality of mirrors.

A spot shape detection apparatus for detecting the spot shape of a laser beam oscillated from a laser oscillator includes: a focusing leans for focusing the laser beam oscillated by the oscillator; a rotary body (mirror holder) in which a plurality of mirrors for reflecting the laser beam having passed through the focusing lens are disposed on concentric circles; a drive source (motor) for rotating the rotary body at a predetermined period; a beam splitter for branching return beams of the laser beam reflected by the plurality of mirrors of the rotary body; an imaging unit which is disposed in a direction in which the return beams are branched by the beam splitter and which images spot shapes of the return beams; and a display unit for displaying images obtained by imaging by the imaging unit, in relation with the plurality of mirrors.

Various embodiments include systems and methods to provide selectable variable gain to signals in measurements using incident radiation. The selectable variable gain may be used to normalize signals modulated in measurements using incident radiation. The selectable variable gain may be attained using a number of different techniques or various combinations of these techniques. These techniques may include modulating a modulator having modulating elements in which at least one modulating element acts on incident radiation differently from another modulating element of the modulator, modulating the use of electronic components in electronic circuitry of a detector, modulating a source of radiation or combinations thereof. Additional apparatus, systems, and methods are disclosed.