Microcrystal laser for generating laser pulses
A microcrystal laser for generating laser pulses has a laser resonator which has a laser medium arranged between two mirrors; and an arrangement for stabilizing the optical path length is provided. The laser resonator has a saturable absorber medium for pulse generation.
1. A microcrystal laser for generating laser pulses comprising:
a laser resonator defined by first and second spaced apart mirrors, the first minor being a saturable absorber;
a laser medium located between the first and second minors, and wherein an air gap is provided located within the laser resonator at a position between the first mirror and the laser medium and wherein second minor functions as the output coupler for the laser resonator and wherein the gain medium is excited by directing pump light through the first minor and wherein a coating is provided on one of (1) the side of the laser medium facing the saturable absorber or (2) the side of the saturable absorber facing the gain medium, said coating for reflecting pump light back into the gain medium;
a support for carrying the first mirror and including a spacer coupled to said laser medium, said spacer spanning the air gap in a direction of an optical path length of the laser resonator, said spacer having a coefficient of thermal expansion selected so that when the microcrystal laser is heated, the spacer will expand at a rate that causes the width of the air gap to vary in a manner to adjust the optical path length of the laser resonator; and
a control device for monitoring the output of the microcrystal laser and in response thereto varying the temperature of the microcrystal laser in order to vary the optical path length of the laser resonator.
2. The laser recited in claim 1 wherein the coefficient of thermal expansion of the spacer is higher than the coefficient of thermal expansion of the saturable absorber.
3. The laser recited in claim 1 further including a control device for controlling the optical path length of the laser resonator as a function of the output power of one of the microcrystal laser, the pulse repetition rate, and the wavelength of the laser mode.
4. The laser recited in claim 1 , wherein the geometrical path length of the laser resonator is less than 500 μm.
5. The laser recited in claim 1 , wherein the laser medium includes a side facing the saturable absorber medium; and wherein said coating for reflecting pump light back into the laser medium is provided on the side facing the saturable absorber medium.