University of Rochester

Samuel A Letzring

Terrance J Kessler

Stanley Skupsky

Theodore Sizer, Ii

Mark D Skeldon

John Michael Soures

Irl N Duling, Iii

Carl H Petras

Robert W Short

Stephen Craxton

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

Pulse shaping system

A temporally shaped or modified optical output pulse is generated from a bandwidth-encoded optical input pulse in a system in which the input pulse is in the form of a beam which is spectrally spread into components contained within the bandwidth, followed by deflection of the spectrally spread beam (SBD) thereby spatially mapping the components in correspondence with the temporal input pulse profile in the focal plane of a lens, and by spatially selective attenuation of selected components in that focal plane. The shaped or modified optical output pulse is then reconstructed from the attenuated spectral components. The pulse-shaping system is particularly useful for generating optical pulses of selected temporal shape over a wide range of pulse duration, such pulses finding application in the fields of optical communication, optical recording and data storage, atomic and molecular spectroscopy and laser fusion. An optical streak camera is also provided which uses SBD to display the beam intensity in the focal plane as a function of time during the input pulse.

System for generating shaped optical pulses and measuring optical pulses

In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies ('colors') cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers.

System for obtaining smooth laser beams where intensity variations are

A Pockels cell driver useful to operate the Pockels cell as an optical shutter to select one or more laser pulses out of a train of laser pulses when the Pockels cell is placed between crossed polarizers. The Pockels cell is connected through a storage capacitor, of higher capacitance than the capacitance of the Pockels cell, directly to a high voltage source and is charged to high voltage. The cell is charged and the storage capacitor is discharged through a microwave triode which is triggered by an avalanche transistor switch circuit. By directly charging the Pockels cell, lower currents are used than with conventional Pockels cell drivers using transmission lines to connect to the Pockels cell and gas filled tubes to switch a pulse-forming line. The Pockels cell shutter can be operated to provide transmission intervals for the laser pulses of the order of a nanosecond at high repetition rates, up to 10 KHz, without jitter in the timing of the transmission interval and for long periods of time without frequent need for replacement of the microwave triode.

Growing community of inventors

Honeoye Falls, NY, United States of America

Samuel A Letzring