High-energy, multi-spectral laser for surf-zone mine countermeasures

Coherent Technologies, Inc. proposes to develop a transmitter for a surf-zone mine countermeasures (SZMC) system. The sensor will search for mines and surface targets in shallow water, beach and low vegetation areas. The SZMC sensor will use a multi-band,dual-polarization illuminator and produce range-resolved, multi-spectral images suitable for advanced-target-recognition (ATR) algorithm processing. The system will employ a diode-pumped, laser transmitter utilizing patent-pending transmitter technology.Diode-pumping is necessary to ensure ruggedness, energy efficiency, and low maintenance. The proposed transmitter technology enables compactness and minimizes laser cooling requirements. The transmitter is configured in a master oscillator/ power amplifier(MOPA) architecture to enable short (1-3ns) pulse generation in a flat-top beam at all design wavelengths. The MOPA architecture is inherently scalable: each stage is compact and readily ruggedizable, and can provide very efficient heat extraction.The Phase I effort has (i) developed a detailed design for a multi-band transmitter that simultaneously provides an output of 3 45mJ per channel at up to seven lines, with a growth path to higher energy per channel; and (ii) outlined a sensor developmentpath via LADAR and imaging modeling to ensure that the Navy has a useful device at the end of Phase II. The Phase II effort will carry-out the following work:(i) build a MOPA to generate 1.3 micron light under the baseline program(ii) integrate the transmitter with Navy supplied components (such as receive optics and camera) so that a fieldable sensor is available at the end of Phase II.(iii) provide Options to:(1) add the frequency converters to generate the laser lines at 656, 745, and 1489nm, and integrate these with the fieldable sensor(2) build and integrate a second MOPA to generate 1.05-micron light with frequency conversion to 523 nm.(3) build and integrate a third harmonic generator to frequency convert the 1.3-micron light to 438nm.The Navy will then have a functioning sensor for field testing. CTI's proven ability to engineer rugged, electro-optic systems for high shock, vibration and temperature range environments provides leverage for a successful overall development program. Highelectrical efficiency, visible and short-wave infrared, pulsed laser sources are needed for a variety of applications including: detection and imaging, altimetry and ranging, terrain mapping, designation, search and rescue beacons, surgery, photodynamictherapy and cosmetic skin repair.