Generation and application of efficient solid-state laser pulse trains

• US 6,998,567 B2
• Filed: 01/31/2003
• Issued: 02/14/2006
• Est. Priority Date: 01/31/2003
• Status: Active Grant

• Current Assignee: Trimedyne Incorporated (InnovaQuartz, LLC)
• Original Assignee: Trimedyne Incorporated (InnovaQuartz, LLC)
• Inventors: Yeik, Glenn
• Primary Examiner(s): Heinrich, Samuel M.
• Application Number:
  US10/355,952
• Publication Number:
  US 20040151217A1
• Time in Patent Office: 1,110 Days
• Field of Search: 219/121.6, 219/121.61, 219/121.62, 21912167-12169, 219/121.78, 219/121.83, 372/25, 372/35, 372/69, 606 4- 6, 606 10- 12, 351/209, 351/211
• US Class Current: 219/121.61
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/034 Observing the temperature of the workpiece
• CPC Class Codes: B23K 26/0622 by shaping pulses
• CPC Class Codes: B23K 26/702 Auxiliary equipment

Abstract

A method and devices for generating laser pulse trains for delivery to a target including the use of a single laser generator which produces a plurality of pulse groupings of two or more individual laser pulses within each laser pulse train, generated at selected time intervals. The time intervals between the individual pulses within each of the pulse groupings along with the intervals between pulse groupings themselves are selected and controlled by a controller in reference to several variables including the emission and energy storage lifetimes of the lasing medium, the thermal diffusion time constant of the target, the time required to cool the target after the application of laser pulses to its ambient temperature, and the dissipation time of acoustic waves generated by the pulses.

Claims

1. A device for generating laser pulse trains for delivery to a target comprising;

a single laser generator for generating and delivering a plurality of laser pulse groupings as a laser pulse train to a target at selected time intervals wherein each of the laser pulse groupings comprises two or more individual successive pulses generated at selected time intervals; and

a controller operably associated with the generator for selecting and controlling the time intervals between each of the pulse groupings and each of the individual pulses;

wherein the laser generator has a lasing medium selected from the group consisting of Er;

YAG, Tm;

YAG, Ho;

YAG, Er;

YLF, Tm;

YLF, Ho;

YLF, Er;

YSGG, Tm;

YSGG, TmHo;

YAG, CrTmHo;

YAG and ruby, and wherein the laser pulse train has a pulse width of 100 to 800 microseconds and a pulse repetition rate of 1 to 100 Hertz.

2. The device of claim 1 wherein the controller additionally selects and controls the amplitude, duration and shape of each of the individual pulses in each of the laser pulse trains.

3. The device of claim 2 wherein the controller is a central processing unit.

4. The device of claim 1 further comprising a sampling monitor operably associated with the controller for sampling and monitoring the characteristics of the individual pulses generated by the generator.

5. The device of claim 1 wherein the generator is a resonator.

6. The device of claim 1 wherein the generator is an oscillator consisting of a pump chamber housing a solid-state lasing medium having relatively long emission and energy storage lifetime and a flash lamp.

7. The device of claim 1 further comprising a feedback monitor operably associated with the controller for monitoring and controlling the characteristics of the pulses delivered to the target.

8. The device of claim 1 wherein the generator is a continuous-wave pump for pumping a solid-state medium by a semiconductor laser diode source and a Q-switch.

9. The device of claim 1 further including an aiming beam generator.

10. The device of claim 1 wherein the pulse width is 300 microseconds, the pulse repetition rate is 15 Hertz, and pulse spacing within a laser pulse grouping is 0.1 to 10 milliseconds.

11. The device of claim 1 wherein the lasing medium has a host crystal selected from the group consisting of Y₃Al₅O₁₂ (YAG), Y₃Sc₂Ga₃O₁₂ (YSGG), LiYF₄ (YLF), Gd₃Sc₂Ga₃O₁₂ (GSGG), Y₃Ga₅O₁₂ (YGG), Y₃AlO₃ (YAP), LaF₃, BaY₂F₈, and KCaF₃.