There is significant industry activity on delivery of 3D video to the home. It is expected that 3D capable
devices will be able to provide consumers with the ability to adjust the depth perceived for stereo content. This
paper provides an overview of related techniques and evaluates the effectiveness of several approaches. Practical
considerations are also discussed.
The DepthCube 3D Volumetric Display is a solid state, rear projection, volumetric display that consists of two main components: a high-speed video projector, and a multiplanar optical element composed of a air-spaced stack of liquid crystal scattering shutters. The high-speed video projector projects a sequence of slices of the 3D image into the multiplanar optical element where each slice is halted at the proper depth. Proprietary multiplanar anti-aliasing algorithms smooth the appearance of the resultant stack of image slices to produce a continuous appearing truly three-dimensional image. The resultant 3D image is of exceptional quality and provides all the 3D vision cues found in viewing real object.
We have developed a spectral phase measurement technique that provides a direct, sensitive, fast, and discontinuous phase measurement. We demonstrated this technique by measuring the quadratic, cubic, and 0-(pi) phase distortions.
We report on the development of a Chirped Pulse Amplification system in which the final amplifier is a large Ti:Sapphire disk pumped by a frequency doubled Nd:Glass laser. Using this amplifier we have produced near diffraction limited 120 fs pulses with energies in excess of 1 J. Focusing of these pulses results in peak irradiances exceeding 5 X 1019 W/cm2. The scalability of this amplifier to the 10 - 20 J level is also discussed.
We have used the direct optical spectral phase measurement (DOSPM) technique to characterize the cubic phase tuning ability of our pulse stretcher. We have compared the measured phase to the phase determined from cross-correlation measurements.
In analogy to Young's double slit interference, the phase of the temporal beat between two oscillators with different frequencies is precisely the spectral phase difference between those oscillators. We present a technique that directly measures the spectral phase of femtosecond optical pulses using this double slit interference principle. A pair of narrow slits in a thin opaque sheet select two spectral frequencies from the femtosecond pulse spectrum in a zero dispersion pulse stretcher. Measurement of the temporal phase of a family of beat frequencies obtained over a range of slit spacings yields the desired spectral phase directly. We demonstrate this technique by accurately measuring the quadratic phase added to 80 femtosecond optical pulses by a 6.5 cm block of BK-7 glass.
A multi-terawatt laser was used to generate and characterize plasmas appropriate for recombination pumped x-ray lasers. Thomson scattering was used to determine the electron and ion temperatures of a laser-produced, high-density helium plasma on a subpicosecond time-scale. A recombination pumped x-ray laser on the Lyman-alpha transition of hydrogen- like lithium was also studied.
Laser pulses with high intensity (up to 1018 W/cm2) and short duration (100 fs) were focused on gases and solids. The result was ionized material, and emission of short pulse x-rays and unicycle electromagnetic pulses with subpicosecond duration.
Progress on developing a multiterrawatt source of pulses with duration <100 fsec is described. The laser system is based
on chirped-pulse amplification in titanium-doped sapphire. Experimental results include the development of a stable oscillator
running at 812 nm, using hybrid mode-locking and compressed pulse pumping to produce <60 fsec pulses. Two methods of
active stabilization are used to produce reliable output. In addition, high-gain preamplification in Ti:sapphire has been
demonstrated, using a high-quality pump beam to produce gains of 130 per pass, and -10,000 in a simple double-pass gain
configuration, while avoiding crystal damage problems. Finally, grating pulse stretching and recompression from 60 fsec to
..3øø p and back down to 140 fsec has been demonstrated at low power.