Internally-doubled, composite-cavity microlaser

Claim 2

The microlaser of claim 1, wherein said gain medium comprises a sub-millimeter thickness of a stoichiometric crystal having parallel faces which are polished to etalon tolerances.

Claim 3

The microlaser of claim 2, wherein said source has a pumping wavelength; and wherein said one face has high reflectivity at said fundamental wavelength and high transmission at said pumping wavelength of said source.

Claim 4

The microlaser of claim 1, wherein the said close face and said opposite face of said harmonic conversion means are substantially parallel to each other.

Claim 5

The microlaser of claim 1, further including coated spacer rail means, carried by at least one of said faces of said harmonic conversion means and said gain medium, for separating said harmonic conversion means from said gain medium.

Claim 6

The microlaser of claim 5, wherein said coated spacer rail means comprises at least one strip of e-beam evaporated A1₂O₃ for separating said harmonic conversion means from said gain medium.

Claim 7

The microlaser of claim 1, wherein said close face carries coating means for achieving in excess of ninety percent transmission at said fundamental wavelength.

Claim 8

The microlaser of claim 1, wherein said opposite face of said harmonic conversion means carries coating means for achieving substantially more reflection than transmission at said harmonic.

Claim 9

The microlaser of claim 1, wherein said harmonic conversion means comprises a sub-millimeter thickness of a nonlinear optical material.

Claim 10

The microlaser of claim 1, wherein said harmonic conversion means has two orthogonal axes of polarization; and wherein said gain medium has crystal axes which are aligned to said polarization axes of said harmonic conversion means.

Claim 11

The microlaser of claim 10, wherein said control means comprises a quarter-waveplate whose axes are at an acute angle relative to and in a plane generally parallel to said polarization axes.

Claim 12

A laser comprising: a. a sub-millimeter thickness of a lasant gain medium having two opposite and substantially parallel surfaces, said gain medium producing a lasant output in response to optical pumping and one of said surfaces being highly reflective of laser light from said gain medium; b. harmonic sub-resonator means for harmonically converting the lasant output of said gain medium, said harmonic sub-resonator means comprising a sub-millimeter thickness of a non-linear optical crystal having two opposite and substantially parallel faces which carry coating means for harmonic resonance and having one face located adjacent to one of said two surfaces of said gain medium; c. phase control means, located adjacent to the other of said two faces of said harmonic sub-resonator means, for maximizing harmonic conversion and for reflecting light towards said one surface of said gain medium; and d. preserving means, coated on at least one of said phase control means and said harmonic sub-resonator means, for preserving the parallelism of said one surface and said one face and for separating said one surface from said one face.

Claim 13

A frequency doubled microlaser which is adapted to be pumped by and close-coupled to laser diode means, comprising: a sub-millimeter thickness of a solid gain medium having two opposite coated surfaces of which one surface provides high reflectivity at a first predetermined wavelength and high transmission at a pumping wavelength and of which the opposite surface is anti-reflection coated for said first predetermined wavelength; a sub-millimeter thickness of non-linear optical crystal means having a close face which is located adjacent to said opposite surface of said gain medium and which is coated for high transmission at said first predetermined wavelength and high reflectivity at a second predetermined wavelength which is a harmonic of said first predetermined wavelength and having an opposite face which is coated for high transmission at said first predetermined wavelength and for substantially more reflection than transmission at said second predetermined wavelength, said close face and said opposite face of said non-linear optical crystal means being substantially parallel to one another; quarter-waveplate means having one surface which is located adjacent to said opposite face of said non-linear optical crystal means and which is anti-reflection coated at said first predetermined wavelength and said second predetermined wavelength and having an opposite surface which is coated for high reflectivity at said first predetermined wavelength and high transmission at said second predetermined wavelength; and means for preserving the parallelism of said coated surfaces and coated faces and for separating said coated surfaces and coated faces, said means for preserving the parallelism of said coated surfaces and coated faces and separating said coated surfaces and coated faces comprising a plurality of evaporated metal oxide strips which are carried by at least one of said adjacent coated surfaces and coated faces of said gain medium and said optical crystal means and carried by at least one of said adjacent coated surfaces and coated faces of said optical crystal means and said quarter-waveplate means.