Back to results
US 5,394,413 AGranted
Passively Q-switched picosecond microlaser
AssigneeMassachusetts Institute of Technology
InventorJohn J. Zayhowski
Life of this patent
Estimating the term…
Abstract
An apparatus and method for a passively Q-switched microlaser for producing high-peak-power pulses of light of extremely short duration are disclosed. The apparatus comprises a gain medium and saturable absorber disposed within a laser cavity. When the cavity is pumped, the saturable absorber prevents the onset of lasing until the inversion density within the cavity reaches a critical value. The length of the cavity, the material parameters, and the reflectivities of the mirrors are selected such that pulses of duration less than about 1 ns and of peak power in excess of about 10 kW are obtained. The invention has application in high-precision optical radar, nonlinear optics, micromachining, microsurgery, robotic vision, and other technologies requiring high-peak-power laser pulses of extremely short duration.
Claims43
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.
3 more elements
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.
3 more elements
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.
3 more elements
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(.gamma..sub.par,rt -.kappa..gamma..sub.sat,rt),
- .kappa. is in the range from 0.0 to 1.5, .gamma..sub.sat,rt is the round-trip intracavity saturable loss constant, and .gamma..sub.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.sub.0 is the average inversion density, .sigma. is the emission cross section at the oscillating frequency, l.sub.rt is the round-trip path length of light within the cavity, .gamma..sub.sat,rt is the round-trip intracavity saturable loss constant, .gamma..sub.par,rt is the round-trip intracavity unsaturable parasitic loss constant, and .gamma..sub.op is the output-coupling loss constant.
7 more elements
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.
5 more elements
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.
5 more elements
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(.gamma..sub.par,rt -.kappa..gamma..sub.sat,rt),
- .kappa. is in the range from 0.0 to 1.5, .gamma..sub.sat,rt is the round-trip saturable loss constant, and .gamma..sub.par,rt is the round-trip unsaturable parasitic loss constant.
6 more elements
A method of forming a passively Q-switched laser comprising the steps of:
- a) forming a resonant cavity between a first mirror and a second mirror;
- b) disposing a gain medium within said resonant cavity for producing laser gain;
- c) energizing said gain medium with a pump source;
- and
- d) disposing a saturable absorber within said resonant cavity;
- selecting said saturable absorber, said second mirror, and said laser gain so that output pulses having a duration of less than about 1 nanosecond are generated.
3 more elements
A method for forming a passively Q-switched laser comprising the steps of:
- a) forming a resonant cavity between a first mirror and a second mirror;
- b) disposing a gain medium within said resonant cavity for producing laser gain;
- c) energizing said gain medium with a laser-diode pump source;
- and
- d) disposing a saturable absorber within said resonant cavity;
- selecting said saturable absorber, said second mirror, and said laser gain so that output pulses having a peak power greater than about 10 kilowatts are generated.
3 more elements
A method for forming a passively Q-switched laser comprising the steps of:
- a) forming a resonant cavity between a first mirror and a second mirror;
- b) disposing a gain medium within said resonant cavity for producing laser gain;
- c) energizing said gain medium with a laser-diode pump source;
- and
- d) disposing a saturable absorber within said resonant cavity;
- selecting said saturable absorber, said second mirror, and said laser gain so that output pulses having a peak power greater than about 10,000 times said laser-diode pump power are generated.
3 more elements
A method for forming a passively Q-switched laser for producing high-peak-power pulses of light having extremely short duration comprising the steps of:
- a) forming 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) disposing a saturable absorber having opposed first and second faces adjacent to said gain medium;
- said first face of said saturable absorber being disposed adjacent to 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(.gamma..sub.par,rt -.kappa..gamma..sub.sat,rt),
- .kappa. is in the range from 0.0 to 1.5, .gamma..sub.sat,rt is the round-trip saturable loss constant, and .gamma..sub.par,rt is the round-trip unsaturable parasitic loss constant.
6 more elements
Dependencies are inferred from the claim text.