Method of and apparatus for generating intracavity double raman shifted laser pulses

An output laser pulse generator apparatus, said output laser pulse having any wavelength within a range of 2 to 5 microns, said apparatus comprising:

• a pump laser cavity comprising an oscillator rod to generate a pump beam along a pump beam axis extending in a first plane and having a portion out of said first plane in a second plane parallel to said first plane;
• a Raman device in said pump laser cavity and in said second plane along said portion of said pump beam axis in said second plane;
• and
• an optics system in said pump beam axis in said first and second planes, said system designed to detect said pump beam along said portion of said pump beam axis in said second plane, said system comprising a first prism in said first plane and a second prism in said second plane.

In an output laser beam generator apparatus, said apparatus comprising a tunable laser cavity comprising an oscillator rod made of tunable laser material which operates to generate an initial laser beam, said laser cavity further comprising a Raman device coupled to said rod to double Raman shift the wavelength of said initial laser beam and generate a first beam and said output laser beam at respective first and second Stokes wavelengths, said output laser beam being in a range of from 2 to 5 microns;

• the improvement comprising:
• said Raman device being located inside said tunable laser cavity;
• a first Stokes cavity comprising said Raman device and a first optical system, said first optical system returning said first beam at said first Stokes wavelength to said Raman device along a first path;
• a second Stokes cavity comprising said Raman device and said optical system, said first optical system returning said second beam at said second Stokes wavelength to said Raman device along a second path;
• and
• a pumping system coupled to said oscillator rod to pump said tunable laser material, said system comprising either one or more diode lasers or one or more flashlamps;
• said double Raman shifting being performed by said Raman device in response to pumping by either of said one or more diode lasers or said one or more flashlamps.

A method of generating an output laser beam using a tunable pump laser cavity that generates an initial laser beam, and a Raman device;

• said Raman device being responsive to said initial laser beam and double Raman shifting the wavelength of said initial laser beam to generate first and second beams at respective first and second Stokes wavelengths, said second beam being said output laser beam, said method comprising the steps of:
• locating said Raman device inside said tunable pump laser cavity to generate said first beam and said second beam;
• returning said first beam to said Raman device along a first path in a first Stokes cavity comprising said Raman device and a first optical system effective at said first Stokes wavelength;
• and
• returning said second beam to said Raman device along a second path in a second Stokes cavity comprising said Raman device and said optical system effective at said second Stokes wavelength.

A method of generating an output laser pulse having any wavelength within a range of 2 to 5 microns, said method comprising the steps of:

• defining a pump laser cavity having a pump beam axis extending in a first plane and having a portion out of said plane in a second plane parallel to said first plane;
• providing an oscillator rod to generate a pump beam along said pump beam axis in said first plane;
• providing a Raman device in said pump laser cavity and in said second plane along said portion of said pump beam axis in said second plane;
• and
• deflecting said pump beam from said first plane to coincide with said portion of said pump beam axis in said second plane.

In an output laser pulse generator apparatus, said apparatus comprising an oscillator laser cavity comprising an oscillator rod made of tunable laser material that generates an initial laser beam, said cavity further comprising a Raman device coupled to said rod to double Raman shift the wavelength of said initial laser beam into a range of from two to five microns to form said output laser pulse, said Raman device being responsive to said initial laser beam to generate first and second beams at respective first and second Stokes wavelengths, said output laser beam being at said second Stokes wavelength, the improvement comprising:

• a first Stokes cavity comprising said Raman device and a first optical system effective at said first Stokes wavelength to return said first beam to said Raman device along a first path;
• a second Stokes cavity comprising said Raman device and said first optical system effective at said second Stokes wavelength to return said first beam to said Raman device along a second path;
• and
• said oscillator laser cavity further comprising a lens system effective to focus said initial beam and form an initial beam waist at a given location within said Raman device.

In an output laser pulse generator apparatus, said output laser pulse having any wavelength within a range of 2 to 5 microns, said apparatus comprising a pump cavity providing a pump beam to a Raman device;

• the improvement in said apparatus comprising:
• said Raman device being located in a first plane spaced from a second plane that is parallel to said first plane in an orthogonal axis system having x,y, and z axes, said Raman device having a first x axis within said first plane, said first plane containing a first y axis perpendicular to said x axis, said second plane having a second x axis parallel to said first x axis and a second y axis parallel to said first y axis;
• an oscillator rod of said pump cavity being positioned in said second plane to generate said pump beam along said second x axis;
• a pair of prisms, a first one of said prisms being mounted in said first plane to reposition said pump beam from said first y axis to said first x axis and from said first x axis to said first y axis, a second one of said prisms being mounted in said second plane to reposition said pump beam from said second y axis to said second x axis and from said second x axis to said second y axis;
• a first mirror positioned to direct said beam propagating in said first y axis along a z axis toward said second plane;
• and
• a second mirror positioned to direct said beam propagating in said z axis along said second y axis toward said second prism.