System and method for sensing atmospheric contaminants using transmitter with dual optical parametric oscillators and receiver for the same

A transmitter comprising:

• first means for providing a collimated beam of electromagnetic energy at a first frequency;
• second means for shifting the frequency of said beam from said first frequency to a second frequency and outputting said beam at said second frequency;
• means for switching a polarization state of said second beam and providing third and fourth beams therefrom, said third beam having a first polarization and said fourth beam having a second polarization, said second polarization being orthogonal relative to said first polarization;
• and
• third means for shifting said third beam from said second frequency to a third frequency;
• fourth means for shifting said fourth beam from said second frequency to a third frequency;
• and
• means for combining said frequency shifted third and fourth beams.

A system for transmitting electromagnetic energy in the 8-12 micro range comprising:

• first means for providing a collimated beam of electromagnetic energy at a first frequency;
• a Q switch in optical alignment with said beam;
• second means for shifting the frequency of said beam from said first frequency to a second frequency and outputting said beam at said second frequency;
• means for switching a polarization state of said second beam and providing third and fourth beams therefrom, said third beam having a first polarization and said fourth beam having a second polarization, said second polarization being orthogonal relative to said first polarization;
• and
• third means for shifting said third beam from said second frequency to a third frequency, said third frequency being in the 8-12 micro range;
• fourth means for shifting said fourth beam from said second frequency to said third frequency;
• and
• means for combining said frequency shifted third and fourth beams.

A system for sensing chemicals comprising:

• a transmitter comprising:
• first means for providing a collimated beam of electromagnetic energy at a first frequency;
• a passive Q switch in optical alignment with said beam;
• second means for shifting the frequency of said beam from said first frequency to a second frequency;
• means for switching a polarization state of said second beam and providing third and fourth beams therefrom, said third beam having a first polarization and said fourth beam having a second polarization, said second polarization being orthogonal relative to said first polarization;
• and
• third means for shifting said third beam from said second frequency to a third frequency;
• fourth means for shifting said fourth beam from said second frequency to a third frequency;
• and
• means for combining said frequency shifted third and fourth beams and a receiver adapted to receive a return signal from said transmitter.

A method for transmitting a signal in the 8-12 micron range including the steps of:

• providing a collimated beam of electromagnetic energy at a first frequency with a neodymium-YAG laser;
• Q switching said beam;
• shifting the frequency of said switched beam from said first frequency to a second frequency using a first optical parametric oscillator;
• shifting said beam from said second frequency to a frequency in the 8-12 micron range using second and third optical parametric oscillators, said second and third optical parametric oscillators being cadmium selenide and
• outputting said beam with a frequency in the 8-12 micron range.

A method for sensing chemicals including the steps of:

• providing a collimated beam of electromagnetic energy at a first frequency;
• passively Q switching said beam;
• shifting the frequency of said beam from said first frequency to a second frequency;
• switching a polarization state of said second beam and providing third and fourth beams therefrom, said third beam having a first polarization and said fourth beam having a second polarization, said second polarization being orthogonal relative to said first polarization;
• and
• shifting said third beam from said second frequency to a third frequency;
• shifting said fourth beam from said second frequency to a third frequency;
• combining said frequency shifted third and fourth beams into a fifth beam;
• transmitting said fifth beam and
• receiving a return signal from said fifth beam.