MTI is a comprehensive research and development project that includes up-front modeling and analysis, satellite system design, fabrication, assembly and testing, on-orbit operations, and experimentation and data analysis. The satellite is designed to collect radiometrically calibrated, medium resolution imagery in 15 spectral bands ranging from 0.45 to 10.70 micrometer. The payload portion of the satellite includes the imaging system components, associated electronics boxes, and payload support structure. The imaging system includes a three-mirror anastigmatic off-axis telescope, a single cryogenically cooled focal plane assembly, a mechanical cooler, and an onboard calibration system. Payload electronic subsystems include image digitizers, real-time image compressors, a solid state recorder, calibration source drivers, and cooler temperature and vibration controllers. The payload support structure mechanically integrates all payload components and provides a simple four point interface to the spacecraft bus. All payload components have been fabricated and tested, and integrated.

Los Alamos National Laboratories has completed the design, manufacture and calibration of a vacuum-compatible, tungsten lamp, integrating sphere. The light source has been calibrated at the National Institute of Standards and Technology and is intended for use as a calibration standard for remote sensing instrumentation. Calibration 2(sigma) uncertainty varied with wavelength from 1.21% at 400 nm and 0.73% at 900 nm, to 3.95% at 2400 nm. The inner radius of the Spectralon-coated sphere is 21.2 cm with a 7.4 cm square exit aperture. A small satellite sphere is attached to the main sphere and its output coupled through a stepper motor driven aperture. The variable aperture allows a constant radiance without effecting the color temperature output from the main sphere. The sphere's output is transmitted into a vacuum test environment through a fused silica window that is an integral part of the outer housing of the vacuum shell assembly. The atmosphere within this outer housing is composed of 240 degree(s)K nitrogen gas, provided by a custom LN2 vaporizer unit. Use of the nitrogen gas maintains the internal temperature of the sphere at a nominal 300 degree(s)K +/- 10 degree(s). The calibrated spectral range of the source is 0.4 micrometers through 2.4 micrometers . Three, color temperature matched, 20 W bulbs together with a 10 W bulb are within the main integrating sphere. Two 20 W bulbs, also color temperature matched, reside in the satellite integrating sphere. A silicon and a germanium broadband detector are situated within the inner surface of the main sphere. Their purpose is for the measurement of the internal broadband irradiance. A fiber-optic-coupled spectrometer measures the internal color temperature that is maintained by current control on the lamps. Each lamp is independently operated allowing for radiances with common color temperatures ranging from near 0.026 W/cm2/sr to about 0.1 W/cm2/sr at a wavelength of 0.9 micrometers (the location of the peak spectral radiance).

A radiometric calibration station (RCS) is being assembled at the Los Alamos National Laboratory (LANL) which will allow for calibration of sensors with detector arrays having spectral capability from about 0.4-15 micrometers. The configuration of the LANL RCS is shown. Two blackbody sources have been designed to cover the spectral range from about 3-15 micrometers, operating at temperatures ranging from about 180-350 K within a vacuum environment. The sources are designed to present a uniform spectral radiance over a large area to the sensor unit under test. THe thermal uniformity requirement of the blackbody cavities has been one of the key factors of the design, requiring less than 50 mK variation over the entire blackbody surface to attain effective emissivity values of about 0.999. Once the two units are built and verified to the level of about 100 mK at LANL, they will be sent to the National Institute of Standards and Technology (NIST), where at least a factor of two improvements will be calibrated into the blackbody control system. The physical size of these assemblies will require modifications of the existing NIST Low Background Infrared (LBIR) Facility. LANL has constructed a bolt-on addition to the LBIR facility that will allow calibration of our large aperture sources. Methodology for attaining the two blackbody sources at calibration levels of performance equivalent to present state of the art will be explained in the paper.

We report on the design details of the first ultraviolet (UV) free-electron laser (FEL) oscillator driven by low-energy electrons from a radio-frequency linear accelerator. In our experiment we used a high-current, high brightness electron beam in combination with a wiggler of novel design to produce an FEL that lased at wavelengths from 369 to 380 nm using 45.9–45.2 MeV electrons. In addition we performed a proof-of-principle experiment that demonstrated the first ever photolithography on a photoresist-coated silicon wafer using an FEL light source.

Los Alamos National Laboratories has begun construction of a visible/infrared radiometric calibration station that will allow for absolute calibration of optical and IR remote sensing instruments with clear apertures less than 16 inches in diameter in a vacuum environment. The calibration station broadband sources will be calibrated at the National Institute of Standards and Technology (NIST) and allow for traceable absolute radiometric calibration to within +/- 3% in the visible and near IR (0.4-2.5 micrometers ), and less than +/- 1% in the infrared, up to 12 micrometers . Capabilities for placing diffraction limited images of for sensor full-field flooding will exist. The facility will also include the calibration of polarization and spectra effects, spatial resolution, field of view performance, and wavefront characterization. The configuration of the vacuum calibration station consists of an off-axis 21 inch, f/3.2, parabolic collimator with a scanning fold flat in collimated space. The sources are placed, via mechanisms to be described, at the focal plane of the off-axis parabola. Vacuum system pressure will be in the 10-6 Torr range. The broadband white-light source is a custom design by LANL with guidance from Labsphere Inc. The continuous operating radiance of the integrating sphere will be from 0.0-0.006 W/cm2/Sr/micrometers (upper level quoted for approximately 500 nm wavelength). The blackbody source is also custom designed at LANL with guidance from NIST. The blackbody temperature will be controllable between 250-350 degree(s)K. Both of the above sources have 4.1 inch apertures with estimated radiometric instability at less than 1%. The designs of each of these units will be described. The monochromator and interferometer light sources are outside the vacuum, but all optical relay and beam shaping optics are enclosed within the vacuum calibration station. These sources are to be described, as well as the methodology for alignment and characterization.

Two versions of the ``Phase-Step Mirror`` (PSM), a novel optical component that prevents the formation of sidebands in a Free-Electron Laser (FEL) were tested on the Los Alamos National Laboratory (LANL) APEX FEL. Sideband suppression and frequency control with high extraction efficiency and single line, transform limited operation were demonstrated. The results of our LANL experiments and computer simulations showed that for very high gain applications, the first-order sideband is completely suppressed, but the laser gain is so strong that on about pass 300 the sideband at the second-order or next free spectral range of the PSM appears. This second-order sideband may be suppressed by designing a PSM with grooves having two alternating depths, one chosen to suppress the first-order sideband, and the other, the second-order sideband.

The major factors impacting the design of a high power 10 kW FEL oscillator are mirror thermal distortion and electron and optical beam loss in the wiggler. Thermal absorption directly impacts the determination of the optimum wiggler gap. Choice of the proper wiggler bore must be made by balancing requirements for electron beam clearance with those for obtaining adequate wiggler magnetic field strength. This balance is further complicated by optical vignetting and achieving an intracavity optical intensity sufficient to taper the wiggler without thermally damaging the resonator mirrors. The final design must also limit the bandwidth of the optical radiation so that the maximum wiggler taper efficiency can be realized. The overall design methodology and final design choices required to meet these various constraints are discussed.

Several optomechanical tasks for the Los Alamos National Laboratory's (LANL) Free- Electron Laser (FEL) were set by the envisioned project goals as early as 1988. Unfortunately, the FEL project has been set aside due to funding constraints. The tasks reported on here required extensive modeling for final adaptability into the FEL environment. The systems to be described are best identified as (1) a Brewster attenuation device, (2) an optical mode relay lens system, (3) a spectral harmonics band-filtering system, (4) a 25-nm micropulse spectrometer system, (5) a 12.5-nm micropulse spectrometer system, (6) a 0.6-nm micropulse spectrometer system, and (7) a reflective mode profile rotator. The Brewster attenuation device was successfully used inside the FEL resonator. The optical mode relay lens system, spectral harmonics band filtering system, and reflective mode profile rotator were completed but never used. The 25-nm micropulse spectrometer was optically and mechanically completed, but the detector electronics were never finished. The 12.5- and 0.6-nm micropulse spectrometers were never assembled, due to hardware that was common to the 25-nm system.

We report on experimental studies of an ultraviolet (UV) free-electron laser (FEL) oscillator driven by low-energy electrons from a radio-frequency linear accelerator. Previous UV FELs have been driven by 350-800-MeV electrons from storage rings. We verify the concept of driving an UV FEL with a low-energy, but high-current, low-emittance electron beam. This and other innovations allowed the FEL to lase at wavelengths from 369 to 380 nm using 45.9-45.2-MeV electrons, and to achieve a peak optical output power of 270 kW. The experimental results are in good agreement with simulations.

The Boeing HAP (High Average Power) experiment had been reconfigured throughout 1989–1990 to incorporate a grazing incidence, 133-m round-trip ring resonator. Initial spectral, mode stability, coherence length, and interferometric wave-front quality measurements have been taken. This paper reports on the optical measurement techniques and data used to characterize the resonator optical output as 2.0 to 2.5 λ OPD. Raw data-reduction methodology and analysis supporting the subtraction of effects caused by the 7× beam reducer, fold mirrors, and the radial shear interferometer itself are included. Noteworthy observations, such as the ability to overlay interferometric fringe data over the length of a macropulse (≈180 micropulses) without destroying the fringe visibility and the occurrence of centrally localized (≈30% of the diameter) disturbances of the fringe pattern are also discussed. Coherence length measurements, made by using the interferometer, showed the spectral bandwidth to be between 64 and 120 μm. Attempts to measure the micropulse-to-micropulse mode stability were made and are discussed as well.

We report initial results on the APEX (APLE prototype experiment) photoinjector-driven infrared free-electron laser (FEL). The APEX FEL is operating in support of a Boeing Aerospace and Electronics/Los Alamos National Laboratory collaboration to build the average power laser experiment (APLE). Our system uses a high quantum efficiency (3–7%) multi-alkali photocathode, illuminated with a frequency-doubled Nd:YLF mode locked laser at 21.7 MHz. The photocathode is located in this first cell of a six-cell 1.3 GHz, 6 MeV photoinjector that feeds a linac with a final energy up to 40 MeV. Because the illuminating laser pulse on our photocathode is short (10 ps), no pulse compression is required in the linac. Emittance measurements made after the second linac tank at 15 MeV have shown that a normalized emittance (for 90% of the particles) of less than 50π mm mrad can be achieved at a peak micropulse current of 300 A. Our initial lasing has been at a wavelength of 3.6 μm over a 30 μs macropulse with an electron beam energy of 35 MeV and a 2.7 cm period permanent magnet wiggler. We are continuing to characterize and optimize our system, with particular emphasis on understanding and minimizing electron beam emittance-growth mechanisms, and subsequently improving the quality of the beam delivered to the wiggler.