Laser oscillator

A dye laser apparatus comprising:

• a dye cell forming part of an optical cavity;
• means for exciting or pumping the dye cell with a laser source of suitable wavelength and pulse repetition frequency, the dye cell being capable of producing unpolarized amplified spontaneous emission and narrow linewidth laser emission;
• multiple-prism grating means within the optical cavity for feeding back narrow linewidth polarized laser emission back to and through the dye cell;
• and
• output polarizer and reflecting coupler means for receiving a narrow linewidth polarized laser beam from the dye cell and for reflecting back to the dye cell a portion of the polarized laser beam and for transmitting as an output beam substantially without loss the remainder of the polarized laser beam, the output coupler means highly discriminating against the reflection back to the dye cell of unpolarized amplified simultaneous emission from the dye cell such that the intensity of amplified spontaneous emission is substantially reduced, the length of the optical cavity is short, and lasing within the cavity at more than one mode of lasing is inhibited.

A laser apparatus comprising:

• a dye cell forming a central part of an optical cavity having an effective length L, the dye cell being capable of emitting laser emission and amplified spontaneous emission (ASE) when excited;
• means for exciting or pumping the dye cell with light energy;
• reflecting and polarizing means at one end of the optical cavity for receiving emissions from the dye cell and for feeding back and through the dye cell polarized narrow linewidth laser emission;
• and
• multi-prism reflecting and polarizing output coupler means at the other end of the optical cavity for receiving polarized narrow linewidth laser emission and amplified spontaneous emission (ASE) from the dye cell, the multi-prism output coupler means reflecting a small portion of the polarized narrow linewidth laser emission back to the dye cell and for transmitting to outside of the optical cavity a desired narrow linewidth output laser beam, the output coupler means highly discriminating against the amplified spontaneous emission (ASE) from the dye cell such that the intensity of ASE in the output laser beam is very low relative to the intensity of the narrow linewidth laser emission, and the effective length L of the optical cavity is short.