High power laser with tuning and line narrowing capability

Claim 2

A high power, Q-switched, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium comprising neodymium-doped glass disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; an electro-optical phase-shifting cell disposed within the cavity in the path of the emitted optical energy; and a birefringent filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium, said birefringent filter having refractive indices along mutually perpendicular α, β and γ directions and being cut with its β axis normal to said one face and being rotatable about said β axis.

Claim 3

The apparatus of claim 1 wherein said birefringent filter is comprised of a LiNbO 3 uniaxial crystal.

Claim 4

The apparatus of claim 2 including means coupling a voltage across opposite end faces of said filter.

Claim 5

The apparatus of claim 1 wherein said birefringent filter is comprised of a KD*P uniaxial crystal.

Claim 6

The apparatus of claim 4 including means coupling a voltage across opposite end faces of said filter.

Claim 7

A high power, Q-switched, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium comprising neodymium-doped glass disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; an electro-optical phase-shifting cell disposed within the cavity in the path of the emitted optical energy; a birefringent filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium, said birefringent filter having refractive indices along mutually perpendicular α, β and γ directions and being cut with its β axis normal to its face and being rotatable about said β axis; and a non-linear crystal situated in the path of optical energy emitted from said cavity, the angular position of said filter being selected such that two discrete line wavelengths are emitted from said cavity and optically mixed in said nonlinear crystal to produce a beat frequency wavelength.

Claim 8

A high power, Q-switched, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium comprising neodymium-doped glass disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; an electro-optical phase-shifting cell disposed within the cavity in the path of the emitted optical energy; a birefringent filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium, said birefringent filter having refractive indices along mutually perpendicular α, β and γ directions and being cut with its β axis normal to its face and being rotatable about said β axis; and a non-linear crystal situated in the path of optical energy emitted from said cavity, the angular position of said filter being selected such that two discrete line wavelengths are emitted from said cavity and optically mixed in said nonlinear crystal to produce a beat frequency wavelength.

Claim 9

The apparatus of claim 6 wherein said birefringent filter is comprised of LiNbO 3 uniaxial crystal.

Claim 10

The apparatus of claim 7 including means coupling a voltage across opposite end faces of said filter.

Claim 11

The apparatus of claim 6 wherein said birefringent filter is comprised of a KD*P uniaxial crystal.

Claim 12

The apparatus of claim 9 including means coupling a voltage across opposite end faces of said filter.

Claim 13

A high power, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; a birefringent electro-optic filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium, said birefringent filter having refractive indices along mutually perpendicular α, β and γ directions and being cut with its β axis normal to said one face; and means coupling a controllable DC voltage across opposite end faces of said filter.

Claim 14

A high power, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; a birefringent electro-optic filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium, said birefringent filter having refractive indices along mutually perpendicular α, β and γ directions and being cut with its β axis normal to said one face; and means coupling a controllable DC voltage across opposite end faces of said filter.

Claim 15

The apparatus of claim 11 wherein said birefringent filter is comprised of a LiNbO 3 uniaxial crystal.

Claim 16

The apparatus of claim 11 wherein said birefringent filter is comprised of a KD*P uniaxial crystal.

Claim 17

A high power, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; a birefringent electro-optic filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium; means coupling a controllable D.C. voltage across oppisite end faces of said filter; and a nonlinear crystal situated in the path of optical energy emitted from said cavity, the angular position of said filter being selected such that two discrete line wavelengths are emitted from said cavity and optically mixed in said nonlinear crystal to produce a beat frequency wavelength.

Claim 18

A high power, tunable laser comprising: an optically-resonant cavity having reflector means at either end thereof; an active medium disposed within said cavity so as to emit optical energy in a direction normal to the reflecting surface of each of said reflector means; a birefringent electro-optic filter situated within the cavity and having at least one face substantially at the Brewster angle with respect to the path of optical energy emitted from the active medium; means coupling a controllable D.C. voltage across oppisite end faces of said filter; and a nonlinear crystal situated in the path of optical energy emitted from said cavity, the angular position of said filter being selected such that two discrete line wavelengths are emitted from said cavity and optically mixed in said nonlinear crystal to produce a beat frequency wavelength.

Claim 19

The apparatus of claim 14 wherein said birefringent filter is comprised of a LiNbO 3 uniaxial crystal.

Claim 20

The apparatus of claim 14 wherein said birefringent filter is comprised of a KD*P uniaxial crystal.

Claim 23

The method of claim 17 wherein said two discrete wavelength lines are mixed to produce a single beat frequency output coherent optical wavelength.

Claim 24

The method of claim 18 wherein said laser exhibits a variable free spectral range, said method further including the step of varying the degree of phase retardation of said optical oscillations so as to vary said free spectral range and thereby vary said beat frequency output wavelength.

Claim 25

The method of claim 19 wherein the step of varying the degree of phase retardation of said optical oscillations comprises rotating a birefringent filter situated within said cavity in the path of optical energy traversing said cavity.

Claim 26

The method of claim 19 wherein said step of varying the degree of phase retardation of said optical oscillations comprises varying an electrical voltage across opposite end faces of a birefringent filter situated within said cavity in the path of optical energy traversing said cavity.