The Large Optical Test and Integration Site (LOTIS) at the Lockheed Martin Space Systems
Company in Sunnyvale, CA, has successfully reached Initial Operational Capability (IOC).
LOTIS is designed for the verification and testing of optical systems. The facility consists of a
large, temperature stabilized vacuum chamber that also functions as a class 10k cleanroom.
Within this chamber and atop an advanced vibration-isolation bench are the 6.5 meter diameter
LOTIS Collimator and Scene Generator, LOTIS alignment and support equipment. IOC included
completion of the entire facility as well as operation of the LOTIS collimator in air. Wavefront
properties of the collimator will be described as well as facility vibration isolation properties and
turbulence levels within the collimator test chamber. User-specific test capabilities will also be
addressed for two major areas of concern.
Lockheed Martin Space Systems Company has completed the Large Optical Test and Integration Site (LOTIS) at its
Sunnyvale, CA campus. Central to the LOTIS testing facility is a 6.5-meter diameter optical collimator housed in a
large, temperature controlled and vibration isolated high-vacuum chamber. A measurement has been made of the
atmospheric turbulence inside the LOTIS vacuum chamber testing environment at ambient pressure and temperature
near floor level where distorting turbulence may be most persistent. Turbulence is one of the many components that
define the overall LOTIS Collimator optical testing capabilities at ambient air pressure. Experimental measurements
have been made with a non-phase-shifting Fizeau interferometer along a 50-foot horizontal propagation path in double
pass. Results presented here represent root-mean-square (RMS) wavefront error over an 18-inch aperture and the
corresponding atmospheric coherence length, <i>r</i><sub>o</sub> (Fried's parameter). In addition, an analysis was performed to calculate
the optical line-of-sight jitter response of the LOTIS Collimator system and facility due to base-level vibration
disturbances. Vibration survey measurements were made using accelerometers mounted to the vacuum chamber
foundation to create a Power Spectral Density (PSD) plot of the measured seismic and vacuum chamber mechanically
induced vibration disturbances. The measured PSD was used as the base input to a system-level finite element model
that included the LOTIS Collimator, the Flat Mirror Positioning structure and a generic Unit Under Test all mounted on
the LOTIS Vibration Isolation Bench to assess the whole system jitter response. Results presented here represent the
RMS jitter in nanoradians through the optical path of the LOTIS Collimator due to base-level induced seismic and
chamber mechanical vibrations.
The Large Optical Test and Integration Site (LOTIS) at Lockheed Martin Space Systems Company (LMSSC) in
Sunnyvale, California was designed and constructed in order to allow advanced optical testing for systems up to a
maximum aperture of up to 6.5 meters in air or vacuum over a bandwidth of 0.4 to over 5 μm with a design field of view
of 1.5 milliradians. Previously reported information for the LOTIS 6.5 meter diameter Collimator was based on data
collected during initial testing of this device at the University of Arizona's Steward Observatory Mirror Laboratory. This
paper will report progress and new results for the LOTIS Collimator as it is re-assembled and tested during its final
integration into its facility at LMSSC. In addition, we will discuss Scene Projection Technology (SPT) capabilities that
can be added to provide user test capabilities meeting or exceeding many of the original specifications of the Collimator,
primarily in increased optical bandwidth and field-of-view. Finally, we will describe additional optical tools (e.g.,
interferometers and smaller collimators) that are integral to the LOTIS facility that can provide flexible optical testing
options for a wide array of users.
The Large Optical Test and Integration Site (LOTIS) at the Lockheed Martin Space Systems Company in Sunnyvale,
CA is designed for the verification and testing of optical systems. The facility consists of a large, temperature
stabilized vacuum chamber that also functions as a class 10k cleanroom. Within this chamber and atop an advanced
vibration-isolation bench are the 6.5 meter diameter LOTIS Collimator and Scene Generator, LOTIS alignment and
support equipment. The optical payloads are also placed on the vibration bench in the chamber for testing. The Scene
Generator is attached to the Collimator forming the Scene Projection System (SPS) and this system is designed to
operate in both air and vacuum, providing test imagery in an adaptable suite of visible/near infrared (VNIR) and
midwave infrared (MWIR) point sources, and combined bandwidth visible-through-MWIR point sources, for testing
of large aperture optical payloads. The heart of the SPS is the LOTIS Collimator, a 6.5m f/15 telescope, which projects
scenes with wavefront errors <85 nm rms out to a ±0.75 mrad field of view (FOV). Using field lenses, performance
can be extended to a maximum field of view of ±3.2 mrad. The LOTIS Collimator incorporates an extensive integrated
wavefront sensing and control system to verify the performance of the system, and to optimize its actively controlled
primary mirror surface and overall alignment. Using these optical test assets allows both integrated component and
system level optical testing of electro-optical (EO) devices by providing realistic scene content. LOTIS is scheduled to
achieve initial operational capability in 2008.
The emergence of commercially available diode pumped solid state lasers in the 3-10 watt power range has created alternative laser sources for many light industrial applications. Laser marking, micro-machining, resistor trimming, disk texturing, and rapid prototyping are some of the applications which can benefit from this technology. In this paper, we describe fiber-coupled diode bar pumped Nd:YAG and Nd:YVO<SUB>4</SUB> lasers with short pulse, high energy, and relatively high average power developed for these applications. Our design emphasizes system efficiency and simplicity to minimize the cost of ownership. The excellent beam spatial quality and pulse-to-pulse stability of these devices results in improved process yields for the end user.
Current results for diode pumped solid state lasers are driven by advances in diode laser technology. Diode arrays in the 10 - 20 watt range are now available in useful formats which allow coupling into side- and end-pumped laser configurations. Side-pumped designs have traditionally produced higher output power at the expense of mode quality. End-pumped devices, on the other hand, have shown high mode quality but have been limited in their output power or pulse energy. Results are given which demonstrate new end-pumped laser coupling and cavity configurations which allow both high mode quality and increased power output.