Picosecond optical radiation systems and methods of use

• US 10,285,757 B2
• Filed: 03/17/2014
• Issued: 05/14/2019
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Cynosure, LLC (Hologic Incorporated)
• Original Assignee: Cynosure, LLC (Hologic Incorporated)
• Inventors: Robertson, John, Hohm, Daniel, Hoffman, Christian
• Primary Examiner(s): Niu, Xinning (Tom)
• Application Number:
  US14/216,353
• Publication Number:
  US 20140321484A1
• Time in Patent Office: 1,884 Days
• CPC Class Codes: A61B 18/203 applying laser energy to the outside of the body
• CPC Class Codes: A61B 2018/0047 Upper parts of the skin, e.g. skin peeling or treatment of wrinkles
• CPC Class Codes: A61N 5/0616 Skin treatment other than tanning
• CPC Class Codes: A61N 5/067 using laser light
• CPC Class Codes: H01S 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H01S 3/0627 the resonator being monolithic, e.g. microlaser
• CPC Class Codes: H01S 3/08018 Mode suppression
• CPC Class Codes: H01S 3/08054 Passive cavity elements acting on the polarization, e.g. a polarizer for branching or walk-off compensation quarter-wave plates in a Q-switch laser H01S3/1124, H01S3/115
• CPC Class Codes: H01S 3/093 focusing or directing the excitation energy into the active medium
• CPC Class Codes: H01S 3/094038 End pumping
• CPC Class Codes: H01S 3/094076 Pulsed or modulated pumping H01S3/1024 takes precedence
• CPC Class Codes: H01S 3/094084 with pump light recycling, i.e. with reinjection of the unused pump light, e.g. by reflectors or circulators
• CPC Class Codes: H01S 3/1024 for pulse generation
• CPC Class Codes: H01S 3/107 using electro-optic devices, e.g. exhibiting Pockels or Kerr effect H01S3/1061, H01S3/1063, H01S3/1065 take precedence
• CPC Class Codes: H01S 3/1106 Mode locking
• CPC Class Codes: H01S 3/1109 Active mode locking
• CPC Class Codes: H01S 3/1121 Harmonically mode locking lasers, e.g. modulation frequency equals multiple integers or a fraction of the resonator roundtrip time
• CPC Class Codes: H01S 3/1611 neodymium
• CPC Class Codes: H01S 3/1623 chromium, e.g. Alexandrite
• CPC Class Codes: H01S 3/1633 BeAl2O4, i.e. Chrysoberyl
• CPC Class Codes: H01S 3/1643 : YAG
• CPC Class Codes: H01S 3/1673 : YVO4 [YVO]

Abstract

Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

Claims

1. A multi-mode laser comprising:

a first light source;

a resonator comprising a diffusing material, the diffusing material defining a resonant cavity, the resonator comprising a mode lock element, a multi-mode output, and a lasing medium; and

a diffusing element disposed in the resonant cavity and disposed between the first light source and the lasing medium, the diffusing element impinged upon by light from the first light source and scattering such light to the diffusing material;

the lasing medium disposed in the resonant cavity and impinged upon by light scattered from the diffusing material; and

the diffusing element directing light from the first light source to the diffusing material thereby enabling a substantially uniform gain across the lasing medium.

2. The laser of claim 1, further comprising a second light source, wherein the first light source and the second light source are pumped radiation sources.

3. The laser of claim 1, wherein the lasing medium is a crystal rod, wherein the crystal rod has a substantially uniform fluorescence profile in response to incident light from the first light source.

4. The laser of claim 1, wherein the diffusing element is an alumina rod.

5. The laser of claim 4, wherein the alumina rod has a diameter of about 0.063 inches.

6. The laser of claim 1, wherein the diffusing element is equidistant from the first light source and the lasing media, wherein the first light source is a flash lamp.

7. The laser of claim 1, wherein the diffusing element is at least one of a diffuser, a deflector, a scattering element, a refractor, a reflector, and a baffle.

8. The laser of claim 1, wherein the diffusing element is disposed on the lasing medium, is disposed on first the light source, or is disposed on both the lasing medium and the first light source.

9. The laser of claim 1 wherein the substantially uniform gain across the laser medium defines a gain region, wherein the gain region has a circular symmetry.

10. The laser of claim 1 further comprising a treatment beam delivery system configured to apply a treatment beam to tissue, wherein the treatment beam comprises picosecond pulses.

11. The laser of claim 1 wherein the resonator is a wavelength shifting resonator.