Abstract: A method and apparatus are operative to control the desired level of population inversion in a gain medium having an amplified spontaneous emission (ASE) spectrum which is characterized by distinct short- and long-wavelength regions. The control is realized by the apparatus configured to determine a relationship between the regions of the ASE spectrum represented by respective frequencies which are filtered by respective frequency discriminators. The apparatus includes a controller operative to process the filtered frequencies by determining a relationship between amplitudes of the respective filtered frequencies which represents a measured level of population inversion. Upon mismatch between the measured level and desired level of the population inversion, a control signal is coupled into a pulse generator or pump or both. In response, the pulse generator may output a pulse, or/and the pump may be completely shut down to lower the level of the measured inversion.

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa<Qsat_gb, wherein Qsat_sa is a saturation energy of the SA, and Qsat_gb is a saturation energy of the gain blocks. The SA is further configured with a recovery time ?<1/f providing for the substantially closed state of the SA, wherein the f is a pulse repetition rate, and with the recovery time ? smaller than a round trip time Tround_trip=2*(L1+L2)*n/c, where L1, L2—lengths of the respective gains gain blocks, n—a refractive index of active media, c—a speed of light in vacuum.

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa<Qsat_gb, wherein Qsat_sa is a saturation energy of the SA, and Qsat_gb is a saturation energy of the gain blocks. The SA is further configured with a recovery time ?<1/f providing for the substantially closed state of the SA, wherein the f is a pulse repetition rate, and with the recovery time ? smaller than a round trip time Tround_trip=2*(L1+L2)*n/c, where L1, L2—lengths of the respective gains gain blocks, n—a refractive index of active media, c—a speed of light in vacuum.

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa<Qsat_gb, wherein Qsat_sa is a saturation energy of the SA, and Qsat_gb is a saturation energy of the gain blocks. The SA is further configured with a recovery time ?<1/f providing for the substantially closed state of the SA, wherein the f is a pulse repetition rate, and with the recovery time ? smaller than a round trip time Tround_trip=2*(L1+L2)*n/c, where L1, L2—lengths of the respective gains gain blocks, n—a refractive index of active media, c—a speed of light in vacuum.

Abstract: A high power pulsed laser system is configured with at least two gain blocks and with at least one saturable absorber (SA) coupled to the output and input of the respective gain blocks. The SA is configured so that Qsat_sa<Qsat_gb, wherein Qsat_sa is a saturation energy of the SA, and Qsat_gb is a saturation energy of the gain blocks. The SA is further configured with a recovery time ?<1/f providing for the substantially closed state of the SA, wherein the f is a pulse repetition rate, and with the recovery time ? smaller than a round trip time Tround_trip=2*(L1+L2)*n/c, where L1, L2—lengths of the respective gains gain blocks, n—a refractive index of active media, c—a speed of light in vacuum.