Cascaded noncritical optical parametric oscillator

A method for providing laser light that is tunable over a relatively wide wavelength range, the method comprising:

• providing a laser pump beam having a selected pump wavelength;
• receiving the pump beam at a first selected noncritically phase matched nonlinear crystal positioned within a first optical cavity, and providing a first cavity output laser beam having at least a first selected wavelength in a first wavelength range;
• receiving the first cavity beam at a second selected noncritically phase matched nonlinear crystal positioned within a second optical cavity, converting the first cavity beam and issuing a second cavity laser output beam having a second selected wavelength in a second wavelength range whose lower limit and upper limit are above a lower limit and above an upper limit, respectively, for the first range,
• providing the first nonlinear crystal with an effective length of propagation L1(x) of the pump beam through the first crystal that varies discretely, among at least first, second and third distinct values, with a distance x, measured from a selected axis having a first direction that is substantially parallel to the path of propagation, in a second direction substantially perpendicular to the first direction, where the distance x is varied by translating the first crystal in the second direction;
• and
• providing at least first, second and third paths of pump beam propagation, corresponding to the respective first, second and third distinct values of the effective length of propagation L1(x) of the pump beam through the first crystal,
• whereby a shift in the selected wavelength in the first range is accompanied by a shift to a larger wavelength in the second wavelength in the second range and the selected wavelength in the first range is discretely tunable.

A method for providing laser light that is tunable over a relatively wide wavelength range, the method comprising:

• providing a laser pump beam having a selected pump wavelength;
• receiving the pump beam at a first selected noncritically phase matched nonlinear crystal positioned within a first optical cavity, and providing a first cavity output laser beam having at least a first selected wavelength in a first wavelength range;
• receiving the first cavity beam at a second selected noncritically phase matched nonlinear crystal positioned within a second optical cavity, converting the first cavity beam and issuing a second cavity laser output beam having a second selected wavelength in a second wavelength range whose lower limit and upper limit are above a lower limit and an upper limit, respectively, for the first range,
• providing the second nonlinear crystal with an effective length of propagation L2(x) of the first cavity beam through the second crystal that varies continuously with a distance x, measured from a selected axis having a first direction that is substantially parallel to the path of propagation, in a second direction substantially perpendicular to the first direction, where the distance x is varied by translating the second crystal in the second direction;
• and
• providing at least first and second paths of pump beam propagation, corresponding to respective first and second distinct values of the effective length of propagation L2(x) of the first cavity beam through the second crystal,
• whereby a shift in the selected wavelength in the first range is accompanied by a shift to a larger wavelength in the second wavelength in the second range and the selected wavelength in the second range is continuously tunable.

A method for providing laser light that is tunable over a relatively wide wavelength range, the method comprising:

• providing a laser pump beam having a selected pump wavelength;
• receiving the pump beam at a first selected noncritically phase matched nonlinear crystal positioned within a first optical cavity, and providing a first cavity output laser beam having at least a first selected wavelength in a first wavelength range;
• receiving the first cavity beam at a second selected noncritically phase matched nonlinear crystal positioned within a second optical cavity, converting the first cavity beam and issuing a second cavity laser output beam having a second selected wavelength in a second wavelength range whose lower limit and upper limit are above a lower limit and an upper limit, respectively, for the first range,
• providing the second nonlinear crystal with an effective length of propagation L2(x) of the first cavity beam through the second crystal that varies discretely among at least first, second and third distinct values with a distance x, measured from a selected axis having a first direction that is substantially parallel to the path of propagation, in a second direction substantially perpendicular to the first direction, where the distance x is varied by translating the second crystal in the second direction;
• and
• providing at least first, second and third paths of pump beam propagation, corresponding to the respective first, second and third distinct values of the effective length of propagation L2(x) of the first cavity beam through the second crystal,
• whereby a shift in the selected wavelength in the first range is accompanied by a shift to a larger length in the second wavelength in the second range and the selected wavelength in the second range is discretely tunable.