Passively Q-switched picosecond microlaser

Claim 2

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a duration of less than about 1 nanosecond are generated.

Claim 3

The laser of claim 1 wherein said second mirror is an output coupler having reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant.

Claim 4

The laser of claim 1 wherein said gain medium and said saturable absorber are two separate materials comprised of dopants in a common host and wherein said gain medium and said saturable absorber are joined by diffusion bonding.

Claim 5

The laser of claim 3 wherein said gain medium is doped with Nd 3+ and said saturable absorber is doped with Cr 3+ .

Claim 6

The laser of claim 3 wherein said host material comprises YAG.

Claim 7

The laser of claim 1 wherein said gain medium and said saturable absorber are the same crystal.

Claim 8

The laser of claim 1 wherein said gain medium is epitaxially grown on said saturable absorber.

Claim 9

The laser of claim 1 wherein said saturable absorber is epitaxially grown on said gain medium.

Claim 10

The laser of claim 1 wherein said pump source comprises an optical fiber for transmitting pump light energy; said optical fiber being optically coupled to said first mirror for pumping said gain medium with said light energy.

Claim 11

The laser of claim 9 wherein said optical coupling between said optical fiber and said first mirror is without intermediate focussing optics.

Claim 12

The laser of claim 1 further comprising nonlinear optical crystals disposed in proximity with said second mirror for frequency conversion of said pulses emitted by said laser.

Claim 13

The laser of claim 11 wherein said nonlinear optical crystals comprise a single frequency-doubling crystal.

Claim 14

The laser of claim 1 wherein said resonant cavity is less than 2 mm in length.

Claim 15

The laser of claim 1 wherein said gain medium comprises a solid-state material.

Claim 16

The laser of claim 14 wherein said gain medium is selected from the group consisting of Nd 3+ :YAG and Nd 3+ :YVO 4 .

Claim 17

The laser of claim 1 wherein said saturable absorber comprises a solid-state material.

Claim 18

The laser of claim 16 wherein said saturable absorber is selected from the group consisting of Cr 4+ :YAG, LiF:F 2 - , a semiconductor material, and a semiconductor-doped-glass material.

Claim 19

The laser of claim 1 wherein said mirrors are flat.

Claim 20

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a laser-diode pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a peak power greater than about 10 kilowatts are generated.

Claim 21

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a laser-diode pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a peak power greater than about 10 kilowatts are generated.

Claim 22

The laser of claim 19 wherein said second mirror is of reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant.

Claim 23

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; e) a laser-diode pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a peak power greater than about 10,000 times said laser-diode pump power are generated.

Claim 24

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; e) a laser-diode pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a peak power greater than about 10,000 times said laser-diode pump power are generated.

Claim 25

The laser of claim 21 wherein said second mirror is of reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant.

Claim 26

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; said second mirror having a reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber preventing the onset of said pulses until the average inversion density within said resonant cavity reaches a value of: ##EQU5## where N 0 is the average inversion density, σ is the emission cross section at the oscillating frequency, l rt is the round-trip path length of light within the cavity, γ sat ,rt is the round-trip intracavity saturable loss constant, γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant, and γ op is the output-coupling loss constant.

Claim 27

A passively Q-switched laser comprising: a) a resonant cavity formed between a first mirror and a second mirror; said second mirror having a reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber preventing the onset of said pulses until the average inversion density within said resonant cavity reaches a value of: ##EQU5## where N 0 is the average inversion density, σ is the emission cross section at the oscillating frequency, l rt is the round-trip path length of light within the cavity, γ sat ,rt is the round-trip intracavity saturable loss constant, γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant, and γ op is the output-coupling loss constant.

Claim 28

A passively Q-switched laser for producing high-peak-power pulses of light comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a duration of less than about 1 nanosecond are generated; said gain medium and said saturable absorber being two separate materials comprised of dopants in a common host; said gain medium and said saturable absorber being bonded by diffusion bonding.

Claim 29

A passively Q-switched laser for producing high-peak-power pulses of light comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a duration of less than about 1 nanosecond are generated; said gain medium and said saturable absorber being two separate materials comprised of dopants in a common host; said gain medium and said saturable absorber being bonded by diffusion bonding.

Claim 30

A passively Q-switched laser for producing high-peak-power pulses of light comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a laser-diode pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a peak power of greater than about 10,000 times said laser-diode pump power are generated; said gain medium and said saturable absorber being two separate materials comprised of dopants in a common host; said gain medium and said saturable absorber being bonded by diffusion bonding.

Claim 31

A passively Q-switched laser for producing high-peak-power pulses of light comprising: a) a resonant cavity formed between a first mirror and a second mirror; b) a gain medium disposed within said resonant cavity for producing laser gain; c) a laser-diode pump source for energizing said gain medium; and d) a saturable absorber disposed within said resonant cavity; said saturable absorber, said second mirror, and said laser gain being selected so that output pulses having a peak power of greater than about 10,000 times said laser-diode pump power are generated; said gain medium and said saturable absorber being two separate materials comprised of dopants in a common host; said gain medium and said saturable absorber being bonded by diffusion bonding.

Claim 32

A passively Q-switched laser for producing high-peak-power pulses of light, comprising: a) a gain medium having opposed first and second faces for producing laser gain from light emitted by a pump source; said first face being highly transmissive to light emitted from said pump and being highly reflective to light at the lasing wavelength; and b) a saturable absorber having opposed first and second faces; said first face of said saturable absorber being disposed adjacent said second face of said gain medium at an interface; said interface being highly transmissive of light at said lasing wavelength; said second face of said saturable absorber having a reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip saturable loss constant, and γ par ,rt is the round-trip unsaturable parasitic loss constant.

Claim 33

A passively Q-switched laser for producing high-peak-power pulses of light, comprising: a) a gain medium having opposed first and second faces for producing laser gain from light emitted by a pump source; said first face being highly transmissive to light emitted from said pump and being highly reflective to light at the lasing wavelength; and b) a saturable absorber having opposed first and second faces; said first face of said saturable absorber being disposed adjacent said second face of said gain medium at an interface; said interface being highly transmissive of light at said lasing wavelength; said second face of said saturable absorber having a reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip saturable loss constant, and γ par ,rt is the round-trip unsaturable parasitic loss constant.

Claim 34

The laser of claim 26 wherein said interface between said gain medium and said saturable absorber is highly reflective to light emitted from said pump.

Claim 35

The laser of claim 26 wherein said first face of said gain medium and said second face of said saturable absorber are made highly reflective by the deposition of a dielectric coating.

Claim 38

The method of claim 29 wherein said second mirror is an output coupler having reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant.

Claim 39

The method of claim 29 further comprising the step of diffusion bonding said gain medium and said saturable absorber wherein said gain medium and said saturable absorber are two separate materials comprised of dopants in a common host.

Claim 40

The method of claim 29 wherein said gain medium and said saturable absorber are the same crystal.

Claim 41

The method of claim 29 wherein said gain medium is epitaxially grown on said saturable absorber.

Claim 42

The method of claim 29 wherein said saturable absorber is epitaxially grown on said gain medium.

Claim 43

The method of claim 29 wherein said pump source comprises an optical fiber for transmitting pump light energy; said optical fiber being optically coupled to said first mirror for pumping said gain medium with said light energy.

Claim 44

The method of claim 29 further comprising the step of disposing nonlinear optical crystals in proximity with said second mirror for frequency conversion of said pulses emitted by said laser.

Claim 47

The method of claim 37 wherein said second mirror comprises an output coupler having reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant.

Claim 50

The method of claim 39 wherein said second mirror comprises an output coupler having reflectivity R, where R=exp(γ.sub.par,rt -κγ.sub.sat,rt), κ is in the range from 0.0 to 1.5, γ sat ,rt is the round-trip intracavity saturable loss constant, and γ par ,rt is the round-trip intracavity unsaturable parasitic loss constant.

Claim 53

The method of claim 41 wherein said interface between said gain medium and said saturable absorber is highly reflective to light emitted from said pump.

Claim 54

The method of claim 41 wherein said first face of said gain medium and said second face of said saturable absorber are made highly reflective by the deposition of a dielectric coating.