A single pass actuator (70, 200), such as a deformable mirror (70), quickly changes, preferably in less than 1 ms, the focus and hence the spot size of ultraviolet or visible wavelength laser pulses to change the fluence of the laser output (66) at the workpiece surface between at least two different fluence levels to facilitate processing top metallic layers (264) at higher fluences and underlying dielectric layers (266) at lower fluences to protect bottom metallic layers (268). The focus change is accomplished without requiring Z-axis movement of the laser positioning system (62). In addition, the spot size can be changed advantageously during trepanning operations to decrease via taper, reduce lip formation, increase throughput, and/or minimize damage.

Laser system and method for single press micromachining of multilayer workpieces

A light detection and ranging (LIDAR) system uses dual detectors to provide three-dimensional imaging of underwater objects (or other objects hidden by a partially transmissive medium). One of the detectors is a low resolution, high bandwidth detector. The other is a high resolution, narrow bandwidth detector. An initial laser pulse is transmitted to known x-y coordinates of a target area. The photo signals returned from the target area from this initial pulse are directed to the low resolution, high bandwidth detector, where a preliminary determination as to the location (depth, or z coordinate) of an object in the target area is made based on the time-of-receipt of the return photo signal. A second laser pulse is then transmitted to the target area and the return photo signals from such second laser pulse are directed to the high resolution, narrow bandwidth detector. This high resolution detector is gated on at a time so that only photo signals returned from a narrow "slice" of the target area (corresponding to the previously detected depth of the object) are received. An image of the detected object is then reconstructed from the signals generated by the high resolution detector. In a preferred embodiment, the two detectors are housed in a single digicon tube, with magnetic deflection being used to steer the beam to the appropriate detector.

Dual detector lidar system and method

An apparatus and method for characterizing an energy beam (such as a laser) with a two-dimensional wavefront sensor, such as a Shack-Hartmann lenslet array. The sensor measures wavefront slope and irradiance of the beam at a single point on the beam and calculates a space-beamwidth product. A detector array such as a charge coupled device camera is preferably employed.

Beam characterization by wavefront sensor

A rigid mount and method of mounting for a wavefront sensor A wavefront dissector, such as a lenslet array, is rigidly mounted at a fixed distance relative to an imager, such as a CCD camera, without need for a relay imaging lens therebetween

Fixed mount wavefront sensor

Actuator arrays for use in adaptive-optical elements and optical systems containing at least one such element are disclosed. The actuator arrays provide more precise control of the shape of the adaptive-optical surface while utilizing fewer actuators than conventional systems. An adaptive-optical system of an embodiment includes an array of force devices coupled to a deformable optical surface. The force devices of the array are arranged in braking groups and force-altering groups such that each force device belongs to a respective combination of braking group and force-altering group. A respective force controller is coupled to the force devices of each force-altering group, and a respective braking controller is coupled to the force devices of each braking group. The force-altering group adjusts as required the respective forces exerted on the optical surface by the force devices of the respective force-altering group, whereas the braking controller when actuated prevents changes in respective forces exerted by the force devices of the respective braking group.

Adaptive-optics actuator arrays and methods for using such arrays

An extendable large aperture phased array mirror system includes a plurality of mirror segments cooperatively configured to receive an incoming electromagnetic beam In response to signals from a sensor indicative of wavefront distortion in the beam, a control apparatus displaces a plurality of segment actuators to configure the mirror segments to generate an outgoing conjugate phase electromagnetic beam

Extendable large aperture phased array mirror system

An adaptive optics wavefront control system is presented wherein phase errors are reduced to a minimum using a coarse/fine gradient sensor.

Wavefront control system using optical coarse/fine gradient sensor

The new Phased Array Mirror, Extendible Large Aperture (PAMELA) technology can be applied to innovative designs for large astronomical telescopes and laser beam directors. Filled primary apertures with diameters exceeding 15 m will be capable of diffraction-limited imaging of objects at visible wavelengths. The same aperture can function as a nearly perfect conventional telescope primary mirror when objects or reference stars are too faint for adaptive compensation of atmospheric turbulence. This performance will be accomplished by means of a dual-mode control system which utilizes either local figure sensing to yield a nearly perfect wide-field, highly segmented mirror or a fully adaptive wavefront compensation system to drive the mirror segments to the phase conjugate positions to correct for atmospheric turbulence within the isoplanatic angle restriction. The active optics sensing for local figure control can be accomplished either by using differential height and tilt sensors on each segment or by using an optical interferometer at the center of curvature of the primary mirror. This paper presents a design concept for a 10-m telescope with a spherical primary mirror composed of about 10,000 10-cm diameter hexagonal segments. Principles of operation are described, and estimates of performance are given.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Innovative approach to next-generation telescope design

This paper provides the first public disclosure of an optical technology which makes possible important new opportunities for the construction of very large telescopes. This technology, developed by Kaman Corporation in an Independent Research and Development program extending over the past several years, is generically known as PAMELAN, an acronym for Phased Array Mirror, Extendable Large Aperture. Kaman's patented PAMELA, approach leads directly to the ability to build rugged, diffraction-limited optical telescopes or beam expanders for ground-based or orbital deployment that have unprecedentedly low weight. In addition, the entire optical system will be fault-tolerant, leading to large expected savings in overall system cost and complexity. These attributes make PAMELATM a prime candidate technology to benefit both civilian and military optical systems in such areas as laser applications, imaging, remote sensing, and communications. PAMELATM will also have broad applicability to the needs of astronomy.

John D. G. Rather

Papers

Extendable large aperture phased array mirror system

Wavefront control system using optical coarse/fine gradient sensor

Innovative approach to next-generation telescope design

PAMELA: High Density Segmentation For Large, Ultra-Light, High Performance Mirrors.